Commit Graph

2743 Commits

Author SHA1 Message Date
Russell Currey
1f9ad21c3b powerpc/mm: Implement set_memory() routines
The set_memory_{ro/rw/nx/x}() functions are required for
STRICT_MODULE_RWX, and are generally useful primitives to have.  This
implementation is designed to be generic across powerpc's many MMUs.
It's possible that this could be optimised to be faster for specific
MMUs.

This implementation does not handle cases where the caller is attempting
to change the mapping of the page it is executing from, or if another
CPU is concurrently using the page being altered.  These cases likely
shouldn't happen, but a more complex implementation with MMU-specific code
could safely handle them.

On hash, the linear mapping is not kept in the linux pagetable, so this
will not change the protection if used on that range. Currently these
functions are not used on the linear map so just WARN for now.

apply_to_existing_page_range() does not work on huge pages so for now
disallow changing the protection of huge pages.

[jpn: - Allow set memory functions to be used without Strict RWX
      - Hash: Disallow certain regions
      - Have change_page_attr() take function pointers to manipulate ptes
      - Radix: Add ptesync after set_pte_at()]

Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210609013431.9805-2-jniethe5@gmail.com
2021-06-21 21:13:20 +10:00
Michael Ellerman
3c53642324 Merge branch 'topic/ppc-kvm' into next
Merge some powerpc KVM patches from our topic branch.

In particular this brings in Nick's big series rewriting parts of the
guest entry/exit path in C.

Conflicts:
	arch/powerpc/kernel/security.c
	arch/powerpc/kvm/book3s_hv_rmhandlers.S
2021-06-17 16:51:38 +10:00
Aneesh Kumar K.V
07d8ad6fd8 powerpc/mm/book3s64: Fix possible build error
Update _tlbiel_pid() such that we can avoid build errors like below when
using this function in other places.

arch/powerpc/mm/book3s64/radix_tlb.c: In function ‘__radix__flush_tlb_range_psize’:
arch/powerpc/mm/book3s64/radix_tlb.c:114:2: warning: ‘asm’ operand 3 probably does not match constraints
  114 |  asm volatile(PPC_TLBIEL(%0, %4, %3, %2, %1)
      |  ^~~
arch/powerpc/mm/book3s64/radix_tlb.c:114:2: error: impossible constraint in ‘asm’
make[4]: *** [scripts/Makefile.build:271: arch/powerpc/mm/book3s64/radix_tlb.o] Error 1
m

With this fix, we can also drop the __always_inline in __radix_flush_tlb_range_psize
which was added by commit e12d6d7d46 ("powerpc/mm/radix: mark __radix__flush_tlb_range_psize() as __always_inline")

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210610083639.387365-1-aneesh.kumar@linux.ibm.com
2021-06-17 16:25:50 +10:00
Christophe Leroy
baf24d23be powerpc/32: Display modules range in virtual memory layout
book3s/32 and 8xx don't use vmalloc for modules.

Print the modules area at startup as part of the virtual memory layout:

[    0.000000] Kernel virtual memory layout:
[    0.000000]   * 0xffafc000..0xffffc000  : fixmap
[    0.000000]   * 0xc9000000..0xffafc000  : vmalloc & ioremap
[    0.000000]   * 0xb0000000..0xc0000000  : modules
[    0.000000] Memory: 118480K/131072K available (7152K kernel code, 2320K rwdata, 1328K rodata, 368K init, 854K bss, 12592K reserved, 0K cma-reserved)

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/98394503e92d6fd6d8f657e0b263b32f21cf2790.1623438478.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:11 +10:00
Christophe Leroy
91e9ee7e94 powerpc/32s: Rename PTE_SIZE to PTE_T_SIZE
PTE_SIZE means PTE page table size in most placed, whereas
in hash_low.S in means size of one entry in the table.

Rename it PTE_T_SIZE, and define it directly in hash_low.S
instead of going through asm-offsets.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/83a008a9fd6cc3f2bbcb470f592555d260ed7a3d.1623063174.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:10 +10:00
Christophe Leroy
e72421a085 powerpc: Define swapper_pg_dir[] in C
Don't duplicate swapper_pg_dir[] in each platform's head.S

Define it in mm/pgtable.c

Define MAX_PTRS_PER_PGD because on book3s/64 PTRS_PER_PGD is
not a constant.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/5e3f1b8a4695c33ccc80aa3870e016bef32b85e1.1623063174.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:10 +10:00
Christophe Leroy
45b30fafe5 powerpc: Define empty_zero_page[] in C
At the time being, empty_zero_page[] is defined in each
platform head.S.

Define it in mm/mem.c instead, and put it in BSS section instead
of the DATA section. Commit 5227cfa71f ("arm64: mm: place
empty_zero_page in bss") explains why it is interesting to have
it in BSS.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/5838caffa269e0957c5a50cc85477876220298b0.1623063174.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:10 +10:00
Christophe Leroy
e2c043163d powerpc/nohash: Remove DEBUG_HARDER
DEBUG_HARDER is not user selectable.

Remove it together with related messages.

Also remove two pr_devel() messages that should
likely have been pr_hard().

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0f25109b0e12fdd1e6541dedbb2212cc53526a57.1622712515.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:10 +10:00
Christophe Leroy
a36c0faf3d powerpc/nohash: Remove DEBUG_CLAMP_LAST_CONTEXT
DEBUG_CLAMP_LAST_CONTEXT was there in the old days to reduce
number of contexts in order to ease debugging implementation
of context switching, but that's been quite stable during
years now.

As it is not user selectable, remove it.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/da81837b452e8b9f1657b529b9c3050dc10b9770.1622712515.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:09 +10:00
Christophe Leroy
dac3db1edf powerpc/nohash: Remove DEBUG_MAP_CONSISTENCY
mmu_context handling has been there for years, so we
would know if there was problems with maps.

DEBUG_MAP_CONSISTENCY is not user selectable, remove it.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/6fe2b88956db53f8d6ee221525b2c5dc6aec82c6.1622712515.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:09 +10:00
Christophe Leroy
c13066e53a powerpc/nohash: Remove CONFIG_SMP #ifdefery in mmu_context.h
Everything can be done even when CONFIG_SMP is not selected.

Just use IS_ENABLED() where relevant and rely on GCC to
opt out unneeded code and variables when CONFIG_SMP is not set.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/cc13b87b0f750a538621876ecc24c22a07e7c8be.1622712515.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:09 +10:00
Christophe Leroy
a56ab7c729 powerpc/nohash: Convert set_context() to C
ppc8xx already has set_context() in C.

Other ones have it in assembly. The only thing it does is to
write the context id into SPRN_PID.

Do it in C.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a5d0759064f3831c6b88af49ef5d3b05ba1c4dad.1622712515.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:09 +10:00
Christophe Leroy
25910260ff powerpc/nohash: Refactor update of BDI2000 pointers in switch_mmu_context()
Instead of duplicating the update of BDI2000 pointers in
set_context(), do it directly from switch_mmu_context().

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/4c54997edd3548fa54717915e7c6ebaf60f208c0.1622712515.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:09 +10:00
Christophe Leroy
16132529ce powerpc/32s: Rework Kernel Userspace Access Protection
On book3s/32, KUAP is provided by toggling Ks bit in segment registers.
One segment register addresses 256M of virtual memory.

At the time being, KUAP implements a complex logic to apply the
unlock/lock on the exact number of segments covering the user range
to access, with saving the boundaries of the range of segments in
a member of thread struct.

But most if not all user accesses are within a single segment.

Rework KUAP with a different approach:
- Open only one segment, the one corresponding to the starting
address of the range to be accessed.
- If a second segment is involved, it will generate a page fault. The
segment will then be open by the page fault handler.

The kuap member of thread struct will now contain:
- The start address of the current on going user access, that will be
used to know which segment to lock at the end of the user access.
- ~0 when no user access is open
- ~1 when additionnal segments are opened by a page fault.

Then, at lock time
- When only one segment is open, close it.
- When several segments are open, close all user segments.

Almost 100% of the time, only one segment will be involved.

In interrupts, inline the function that unlock/lock all segments,
because not inlining them implies a lot of register save/restore.

With the patch, writing value 128 in userspace in perf_copy_attr() is
done with 16 instructions:

    3890:	93 82 04 dc 	stw     r28,1244(r2)
    3894:	7d 20 e5 26 	mfsrin  r9,r28
    3898:	55 29 00 80 	rlwinm  r9,r9,0,2,0
    389c:	7d 20 e1 e4 	mtsrin  r9,r28
    38a0:	4c 00 01 2c 	isync

    38a4:	39 20 00 80 	li      r9,128
    38a8:	91 3c 00 00 	stw     r9,0(r28)

    38ac:	81 42 04 dc 	lwz     r10,1244(r2)
    38b0:	39 00 ff ff 	li      r8,-1
    38b4:	91 02 04 dc 	stw     r8,1244(r2)
    38b8:	2c 0a ff fe 	cmpwi   r10,-2
    38bc:	41 82 00 88 	beq     3944 <perf_copy_attr+0x36c>
    38c0:	7d 20 55 26 	mfsrin  r9,r10
    38c4:	65 29 40 00 	oris    r9,r9,16384
    38c8:	7d 20 51 e4 	mtsrin  r9,r10
    38cc:	4c 00 01 2c 	isync
...
    3944:	48 00 00 01 	bl      3944 <perf_copy_attr+0x36c>
			3944: R_PPC_REL24	kuap_lock_all_ool

Before the patch it was 118 instructions. In reality only 42 are
executed in most cases, but GCC is not able to see that a properly
aligned user access cannot involve more than one segment.

    5060:	39 1d 00 04 	addi    r8,r29,4
    5064:	3d 20 b0 00 	lis     r9,-20480
    5068:	7c 08 48 40 	cmplw   r8,r9
    506c:	40 81 00 08 	ble     5074 <perf_copy_attr+0x2cc>
    5070:	3d 00 b0 00 	lis     r8,-20480
    5074:	39 28 ff ff 	addi    r9,r8,-1
    5078:	57 aa 00 06 	rlwinm  r10,r29,0,0,3
    507c:	55 29 27 3e 	rlwinm  r9,r9,4,28,31
    5080:	39 29 00 01 	addi    r9,r9,1
    5084:	7d 29 53 78 	or      r9,r9,r10
    5088:	91 22 04 dc 	stw     r9,1244(r2)
    508c:	7d 20 ed 26 	mfsrin  r9,r29
    5090:	55 29 00 80 	rlwinm  r9,r9,0,2,0
    5094:	7c 08 50 40 	cmplw   r8,r10
    5098:	40 81 00 c0 	ble     5158 <perf_copy_attr+0x3b0>
    509c:	7d 46 50 f8 	not     r6,r10
    50a0:	7c c6 42 14 	add     r6,r6,r8
    50a4:	54 c6 27 be 	rlwinm  r6,r6,4,30,31
    50a8:	7d 20 51 e4 	mtsrin  r9,r10
    50ac:	3c ea 10 00 	addis   r7,r10,4096
    50b0:	39 29 01 11 	addi    r9,r9,273
    50b4:	7f 88 38 40 	cmplw   cr7,r8,r7
    50b8:	55 29 02 06 	rlwinm  r9,r9,0,8,3
    50bc:	40 9d 00 9c 	ble     cr7,5158 <perf_copy_attr+0x3b0>

    50c0:	2f 86 00 00 	cmpwi   cr7,r6,0
    50c4:	41 9e 00 4c 	beq     cr7,5110 <perf_copy_attr+0x368>
    50c8:	2f 86 00 01 	cmpwi   cr7,r6,1
    50cc:	41 9e 00 2c 	beq     cr7,50f8 <perf_copy_attr+0x350>
    50d0:	2f 86 00 02 	cmpwi   cr7,r6,2
    50d4:	41 9e 00 14 	beq     cr7,50e8 <perf_copy_attr+0x340>
    50d8:	7d 20 39 e4 	mtsrin  r9,r7
    50dc:	39 29 01 11 	addi    r9,r9,273
    50e0:	3c e7 10 00 	addis   r7,r7,4096
    50e4:	55 29 02 06 	rlwinm  r9,r9,0,8,3
    50e8:	7d 20 39 e4 	mtsrin  r9,r7
    50ec:	39 29 01 11 	addi    r9,r9,273
    50f0:	3c e7 10 00 	addis   r7,r7,4096
    50f4:	55 29 02 06 	rlwinm  r9,r9,0,8,3
    50f8:	7d 20 39 e4 	mtsrin  r9,r7
    50fc:	3c e7 10 00 	addis   r7,r7,4096
    5100:	39 29 01 11 	addi    r9,r9,273
    5104:	7f 88 38 40 	cmplw   cr7,r8,r7
    5108:	55 29 02 06 	rlwinm  r9,r9,0,8,3
    510c:	40 9d 00 4c 	ble     cr7,5158 <perf_copy_attr+0x3b0>
    5110:	7d 20 39 e4 	mtsrin  r9,r7
    5114:	39 29 01 11 	addi    r9,r9,273
    5118:	3c c7 10 00 	addis   r6,r7,4096
    511c:	55 29 02 06 	rlwinm  r9,r9,0,8,3
    5120:	7d 20 31 e4 	mtsrin  r9,r6
    5124:	39 29 01 11 	addi    r9,r9,273
    5128:	3c c6 10 00 	addis   r6,r6,4096
    512c:	55 29 02 06 	rlwinm  r9,r9,0,8,3
    5130:	7d 20 31 e4 	mtsrin  r9,r6
    5134:	39 29 01 11 	addi    r9,r9,273
    5138:	3c c7 30 00 	addis   r6,r7,12288
    513c:	55 29 02 06 	rlwinm  r9,r9,0,8,3
    5140:	7d 20 31 e4 	mtsrin  r9,r6
    5144:	3c e7 40 00 	addis   r7,r7,16384
    5148:	39 29 01 11 	addi    r9,r9,273
    514c:	7f 88 38 40 	cmplw   cr7,r8,r7
    5150:	55 29 02 06 	rlwinm  r9,r9,0,8,3
    5154:	41 9d ff bc 	bgt     cr7,5110 <perf_copy_attr+0x368>

    5158:	4c 00 01 2c 	isync
    515c:	39 20 00 80 	li      r9,128
    5160:	91 3d 00 00 	stw     r9,0(r29)

    5164:	38 e0 00 00 	li      r7,0
    5168:	90 e2 04 dc 	stw     r7,1244(r2)
    516c:	7d 20 ed 26 	mfsrin  r9,r29
    5170:	65 29 40 00 	oris    r9,r9,16384
    5174:	40 81 00 c0 	ble     5234 <perf_copy_attr+0x48c>
    5178:	7d 47 50 f8 	not     r7,r10
    517c:	7c e7 42 14 	add     r7,r7,r8
    5180:	54 e7 27 be 	rlwinm  r7,r7,4,30,31
    5184:	7d 20 51 e4 	mtsrin  r9,r10
    5188:	3d 4a 10 00 	addis   r10,r10,4096
    518c:	39 29 01 11 	addi    r9,r9,273
    5190:	7c 08 50 40 	cmplw   r8,r10
    5194:	55 29 02 06 	rlwinm  r9,r9,0,8,3
    5198:	40 81 00 9c 	ble     5234 <perf_copy_attr+0x48c>

    519c:	2c 07 00 00 	cmpwi   r7,0
    51a0:	41 82 00 4c 	beq     51ec <perf_copy_attr+0x444>
    51a4:	2c 07 00 01 	cmpwi   r7,1
    51a8:	41 82 00 2c 	beq     51d4 <perf_copy_attr+0x42c>
    51ac:	2c 07 00 02 	cmpwi   r7,2
    51b0:	41 82 00 14 	beq     51c4 <perf_copy_attr+0x41c>
    51b4:	7d 20 51 e4 	mtsrin  r9,r10
    51b8:	39 29 01 11 	addi    r9,r9,273
    51bc:	3d 4a 10 00 	addis   r10,r10,4096
    51c0:	55 29 02 06 	rlwinm  r9,r9,0,8,3
    51c4:	7d 20 51 e4 	mtsrin  r9,r10
    51c8:	39 29 01 11 	addi    r9,r9,273
    51cc:	3d 4a 10 00 	addis   r10,r10,4096
    51d0:	55 29 02 06 	rlwinm  r9,r9,0,8,3
    51d4:	7d 20 51 e4 	mtsrin  r9,r10
    51d8:	3d 4a 10 00 	addis   r10,r10,4096
    51dc:	39 29 01 11 	addi    r9,r9,273
    51e0:	7c 08 50 40 	cmplw   r8,r10
    51e4:	55 29 02 06 	rlwinm  r9,r9,0,8,3
    51e8:	40 81 00 4c 	ble     5234 <perf_copy_attr+0x48c>
    51ec:	7d 20 51 e4 	mtsrin  r9,r10
    51f0:	39 29 01 11 	addi    r9,r9,273
    51f4:	3c ea 10 00 	addis   r7,r10,4096
    51f8:	55 29 02 06 	rlwinm  r9,r9,0,8,3
    51fc:	7d 20 39 e4 	mtsrin  r9,r7
    5200:	39 29 01 11 	addi    r9,r9,273
    5204:	3c e7 10 00 	addis   r7,r7,4096
    5208:	55 29 02 06 	rlwinm  r9,r9,0,8,3
    520c:	7d 20 39 e4 	mtsrin  r9,r7
    5210:	39 29 01 11 	addi    r9,r9,273
    5214:	3c ea 30 00 	addis   r7,r10,12288
    5218:	55 29 02 06 	rlwinm  r9,r9,0,8,3
    521c:	7d 20 39 e4 	mtsrin  r9,r7
    5220:	3d 4a 40 00 	addis   r10,r10,16384
    5224:	39 29 01 11 	addi    r9,r9,273
    5228:	7c 08 50 40 	cmplw   r8,r10
    522c:	55 29 02 06 	rlwinm  r9,r9,0,8,3
    5230:	41 81 ff bc 	bgt     51ec <perf_copy_attr+0x444>

    5234:	4c 00 01 2c 	isync

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Export the ool handlers to fix build errors]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/d9121f96a7c4302946839a0771f5d1daeeb6968c.1622708530.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:08 +10:00
Christophe Leroy
6b4d630068 powerpc/32s: Allow disabling KUAP at boot time
PPC64 uses MMU features to enable/disable KUAP at boot time.
But feature fixups are applied way too early on PPC32.

Now that all KUAP related actions are in C following the
conversion of KUAP initial setup and context switch in C,
static branches can be used to enable/disable KUAP.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Export disable_kuap_key to fix build errors]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/cd79e8008455fba5395d099f9bb1305c039b931c.1622708530.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:08 +10:00
Christophe Leroy
50d2f104cd powerpc/32s: Allow disabling KUEP at boot time
PPC64 uses MMU features to enable/disable KUEP at boot time.
But feature fixups are applied way too early on PPC32.

Now that all KUEP related actions are in C following the
conversion of KUEP initial setup and context switch in C,
static branches can be used to enable/disable KUEP.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7745a2c3a08ec46302920a3f48d1cb9b5469dbbb.1622708530.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:08 +10:00
Christophe Leroy
86f46f3432 powerpc/32s: Initialise KUAP and KUEP in C
In order to selectively activate KUAP and KUEP in a following patch,
perform KUAP and KUEP initialisation in C.

Unlike PPC64, PPC32 doesn't have an early_setup_secondary(),
so do it in start_secondary().

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/87be72023448dd4e476744ed279b8c04b8d08a1c.1622708530.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:08 +10:00
Christophe Leroy
863771a28e powerpc/32s: Convert switch_mmu_context() to C
switch_mmu_context() does things that can easily be done in C.

For updating user segments, we have update_user_segments().

As mentionned in commit b5efec00b6 ("powerpc/32s: Move KUEP
locking/unlocking in C"), update_user_segments() has the loop
unrolled which is a significant performance gain.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/05c0875ad8220c03452c3a334946e207c6ca04d6.1622708530.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:08 +10:00
Christophe Leroy
7235bb3593 powerpc/32s: move CTX_TO_VSID() into mmu-hash.h
In order to reuse it in switch_mmu_context(), this
patch moves CTX_TO_VSID() macro into asm/book3s/32/mmu-hash.h

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/26b36ef2939234a04b37baf6ffe50cba81f5d1b7.1622708530.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:08 +10:00
Christophe Leroy
91bb30822a powerpc/32s: Refactor update of user segment registers
KUEP implements the update of user segment registers.

Move it into mmu-hash.h in order to use it from other places.

And inline kuep_lock() and kuep_unlock(). Inlining kuep_lock() is
important for system_call_exception(), otherwise system_call_exception()
has to save into stack the system call parameters that are used just
after, and doing that takes more instructions than kuep_lock() itself.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/24591ca480d14a62ef910e38a5273d551262c4a2.1622708530.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:07 +10:00
Christophe Leroy
91ec66719d powerpc/32s: Move setup_{kuep/kuap}() into {kuep/kuap}.c
Avoids the #ifdef in mmu.c

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0b7a13d414837e58264edc336b89c2fe9f35f9bc.1622708530.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:07 +10:00
Christophe Leroy
f6025a140b powerpc/8xx: Allow disabling KUAP at boot time
PPC64 uses MMU features to enable/disable KUAP at boot time.
But feature fixups are applied way too early on PPC32.

But since commit c16728835e ("powerpc/32: Manage KUAP in C"),
all KUAP is in C so it is now possible to use static branches.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3dca510ce555335261a47c4799167da698f569c0.1622782111.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:07 +10:00
Christophe Leroy
10248dcba1 powerpc/44x: Implement Kernel Userspace Exec Protection (KUEP)
Powerpc 44x has two bits for exec protection in TLBs: one
for user (UX) and one for superviser (SX).

Clear SX on user pages in TLB miss handlers to provide KUEP.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/169310e08152aa1d96c979770291d165ec6896ae.1622616032.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:07 +10:00
Christophe Leroy
69d4d6e5fd powerpc: Don't use 'struct ppc_inst' to reference instruction location
'struct ppc_inst' is an internal representation of an instruction, but
in-memory instructions are and will remain a table of 'u32' forever.

Replace all 'struct ppc_inst *' used for locating an instruction in
memory by 'u32 *'. This removes a lot of undue casts to 'struct
ppc_inst *'.

It also helps locating ab-use of 'struct ppc_inst' dereference.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Fix ppc_inst_next(), use u32 instead of unsigned int]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7062722b087228e42cbd896e39bfdf526d6a340a.1621516826.git.christophe.leroy@csgroup.eu
2021-06-17 00:09:00 +10:00
Nicholas Piggin
2e1ae9cd56 KVM: PPC: Book3S HV: Implement radix prefetch workaround by disabling MMU
Rather than partition the guest PID space + flush a rogue guest PID to
work around this problem, instead fix it by always disabling the MMU when
switching in or out of guest MMU context in HV mode.

This may be a bit less efficient, but it is a lot less complicated and
allows the P9 path to trivally implement the workaround too. Newer CPUs
are not subject to this issue.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210528090752.3542186-22-npiggin@gmail.com
2021-06-10 22:12:14 +10:00
Marc Zyngier
13a9a5d17d powerpc: Add missing linux/{of.h,irqdomain.h} include directives
A bunch of PPC files are missing the inclusion of linux/of.h and
linux/irqdomain.h, relying on transitive inclusion from another
file.

As we are about to break this dependency, make sure these dependencies
are explicit.

Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-06-10 13:09:16 +01:00
Christophe Leroy
8e11d62e2e powerpc/mem: Add back missing header to fix 'no previous prototype' error
Commit b26e8f2725 ("powerpc/mem: Move cache flushing functions into
mm/cacheflush.c") removed asm/sparsemem.h which is required when
CONFIG_MEMORY_HOTPLUG is selected to get the declaration of
create_section_mapping().

Add it back.

Fixes: b26e8f2725 ("powerpc/mem: Move cache flushing functions into mm/cacheflush.c")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3e5b63bb3daab54a1eb9c20221c2e9528c4db9b3.1622883330.git.christophe.leroy@csgroup.eu
2021-06-06 21:43:11 +10:00
Linus Torvalds
8404c9fbc8 Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton:
 "The remainder of the main mm/ queue.

  143 patches.

  Subsystems affected by this patch series (all mm): pagecache, hugetlb,
  userfaultfd, vmscan, compaction, migration, cma, ksm, vmstat, mmap,
  kconfig, util, memory-hotplug, zswap, zsmalloc, highmem, cleanups, and
  kfence"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (143 commits)
  kfence: use power-efficient work queue to run delayed work
  kfence: maximize allocation wait timeout duration
  kfence: await for allocation using wait_event
  kfence: zero guard page after out-of-bounds access
  mm/process_vm_access.c: remove duplicate include
  mm/mempool: minor coding style tweaks
  mm/highmem.c: fix coding style issue
  btrfs: use memzero_page() instead of open coded kmap pattern
  iov_iter: lift memzero_page() to highmem.h
  mm/zsmalloc: use BUG_ON instead of if condition followed by BUG.
  mm/zswap.c: switch from strlcpy to strscpy
  arm64/Kconfig: introduce ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
  x86/Kconfig: introduce ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
  mm,memory_hotplug: add kernel boot option to enable memmap_on_memory
  acpi,memhotplug: enable MHP_MEMMAP_ON_MEMORY when supported
  mm,memory_hotplug: allocate memmap from the added memory range
  mm,memory_hotplug: factor out adjusting present pages into adjust_present_page_count()
  mm,memory_hotplug: relax fully spanned sections check
  drivers/base/memory: introduce memory_block_{online,offline}
  mm/memory_hotplug: remove broken locking of zone PCP structures during hot remove
  ...
2021-05-05 13:50:15 -07:00
Peter Xu
aec44e0f02 hugetlb: pass vma into huge_pte_alloc() and huge_pmd_share()
Patch series "hugetlb: Disable huge pmd unshare for uffd-wp", v4.

This series tries to disable huge pmd unshare of hugetlbfs backed memory
for uffd-wp.  Although uffd-wp of hugetlbfs is still during rfc stage,
the idea of this series may be needed for multiple tasks (Axel's uffd
minor fault series, and Mike's soft dirty series), so I picked it out
from the larger series.

This patch (of 4):

It is a preparation work to be able to behave differently in the per
architecture huge_pte_alloc() according to different VMA attributes.

Pass it deeper into huge_pmd_share() so that we can avoid the find_vma() call.

[peterx@redhat.com: build fix]
  Link: https://lkml.kernel.org/r/20210304164653.GB397383@xz-x1Link: https://lkml.kernel.org/r/20210218230633.15028-1-peterx@redhat.com

Link: https://lkml.kernel.org/r/20210218230633.15028-2-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Suggested-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Adam Ruprecht <ruprecht@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Cannon Matthews <cannonmatthews@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chinwen Chang <chinwen.chang@mediatek.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Michal Koutn" <mkoutny@suse.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oliver Upton <oupton@google.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Shawn Anastasio <shawn@anastas.io>
Cc: Steven Price <steven.price@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-05 11:27:20 -07:00
Linus Torvalds
d42f323a7d Merge branch 'akpm' (patches from Andrew)
Merge misc updates from Andrew Morton:
 "A few misc subsystems and some of MM.

  175 patches.

  Subsystems affected by this patch series: ia64, kbuild, scripts, sh,
  ocfs2, kfifo, vfs, kernel/watchdog, and mm (slab-generic, slub,
  kmemleak, debug, pagecache, msync, gup, memremap, memcg, pagemap,
  mremap, dma, sparsemem, vmalloc, documentation, kasan, initialization,
  pagealloc, and memory-failure)"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (175 commits)
  mm/memory-failure: unnecessary amount of unmapping
  mm/mmzone.h: fix existing kernel-doc comments and link them to core-api
  mm: page_alloc: ignore init_on_free=1 for debug_pagealloc=1
  net: page_pool: use alloc_pages_bulk in refill code path
  net: page_pool: refactor dma_map into own function page_pool_dma_map
  SUNRPC: refresh rq_pages using a bulk page allocator
  SUNRPC: set rq_page_end differently
  mm/page_alloc: inline __rmqueue_pcplist
  mm/page_alloc: optimize code layout for __alloc_pages_bulk
  mm/page_alloc: add an array-based interface to the bulk page allocator
  mm/page_alloc: add a bulk page allocator
  mm/page_alloc: rename alloced to allocated
  mm/page_alloc: duplicate include linux/vmalloc.h
  mm, page_alloc: avoid page_to_pfn() in move_freepages()
  mm/Kconfig: remove default DISCONTIGMEM_MANUAL
  mm: page_alloc: dump migrate-failed pages
  mm/mempolicy: fix mpol_misplaced kernel-doc
  mm/mempolicy: rewrite alloc_pages_vma documentation
  mm/mempolicy: rewrite alloc_pages documentation
  mm/mempolicy: rename alloc_pages_current to alloc_pages
  ...
2021-04-30 14:38:01 -07:00
Kefeng Wang
1f9d03c5e9 mm: move mem_init_print_info() into mm_init()
mem_init_print_info() is called in mem_init() on each architecture, and
pass NULL argument, so using void argument and move it into mm_init().

Link: https://lkml.kernel.org/r/20210317015210.33641-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>	[x86]
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>	[powerpc]
Acked-by: David Hildenbrand <david@redhat.com>
Tested-by: Anatoly Pugachev <matorola@gmail.com>	[sparc64]
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>	[arm]
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Guo Ren <guoren@kernel.org>
Cc: Yoshinori Sato <ysato@users.osdn.me>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "Peter Zijlstra" <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-30 11:20:42 -07:00
Nicholas Piggin
4ad0ae8c64 mm/vmalloc: remove unmap_kernel_range
This is a shim around vunmap_range, get rid of it.

Move the main API comment from the _noflush variant to the normal
variant, and make _noflush internal to mm/.

[npiggin@gmail.com: fix nommu builds and a comment bug per sfr]
  Link: https://lkml.kernel.org/r/1617292598.m6g0knx24s.astroid@bobo.none
[akpm@linux-foundation.org: move vunmap_range_noflush() stub inside !CONFIG_MMU, not !CONFIG_NUMA]
[npiggin@gmail.com: fix nommu builds]
  Link: https://lkml.kernel.org/r/1617292497.o1uhq5ipxp.astroid@bobo.none

Link: https://lkml.kernel.org/r/20210322021806.892164-5-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Cédric Le Goater <clg@kaod.org>
Cc: Uladzislau Rezki <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-30 11:20:40 -07:00
Nicholas Piggin
8309c9d717 powerpc: inline huge vmap supported functions
This allows unsupported levels to be constant folded away, and so
p4d_free_pud_page can be removed because it's no longer linked to.

Link: https://lkml.kernel.org/r/20210317062402.533919-8-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ding Tianhong <dingtianhong@huawei.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-30 11:20:40 -07:00
Nicholas Piggin
bbc180a5ad mm: HUGE_VMAP arch support cleanup
This changes the awkward approach where architectures provide init
functions to determine which levels they can provide large mappings for,
to one where the arch is queried for each call.

This removes code and indirection, and allows constant-folding of dead
code for unsupported levels.

This also adds a prot argument to the arch query.  This is unused
currently but could help with some architectures (e.g., some powerpc
processors can't map uncacheable memory with large pages).

Link: https://lkml.kernel.org/r/20210317062402.533919-7-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Ding Tianhong <dingtianhong@huawei.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64]
Cc: Will Deacon <will@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-30 11:20:40 -07:00
Nicholas Piggin
0f197ddce4 powerpc/64s: Fix mm_cpumask memory ordering comment
The memory ordering comment no longer applies, because mm_ctx_id is
no longer used anywhere. At best always been difficult to follow.

It's better to consider the load on which the slbmte depends on, which
the MMU depends on before it can start loading TLBs, rather than a
store which may or may not have a subsequent dependency chain to the
slbmte.

So update the comment and we use the load of the mm's user context ID.
This is much more analogous the radix ordering too, which is good.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210421151733.212858-1-npiggin@gmail.com
2021-04-23 01:38:03 +10:00
Christophe Leroy
39352430aa powerpc: Move copy_inst_from_kernel_nofault()
When probe_kernel_read_inst() was created, there was no good place to
put it, so a file called lib/inst.c was dedicated for it.

Since then, probe_kernel_read_inst() has been renamed
copy_inst_from_kernel_nofault(). And mm/maccess.h didn't exist at that
time. Today, mm/maccess.h is related to copy_from_kernel_nofault().

Move copy_inst_from_kernel_nofault() into mm/maccess.c

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/9655d8957313906b77b8db5700a0e33ce06f45e5.1618405715.git.christophe.leroy@csgroup.eu
2021-04-21 22:52:34 +10:00
Xiongwei Song
7153d4bf0b powerpc/traps: Enhance readability for trap types
Define macros to list ppc interrupt types in interttupt.h, replace the
reference of the trap hex values with these macros.

Referred the hex numbers in arch/powerpc/kernel/exceptions-64e.S,
arch/powerpc/kernel/exceptions-64s.S, arch/powerpc/kernel/head_*.S,
arch/powerpc/kernel/head_booke.h and arch/powerpc/include/asm/kvm_asm.h.

Signed-off-by: Xiongwei Song <sxwjean@gmail.com>
[mpe: Resolve conflicts in nmi_disables_ftrace(), fix 40x build]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1618398033-13025-1-git-send-email-sxwjean@me.com
2021-04-17 22:20:19 +10:00
Michael Ellerman
7098f8f0cf powerpc/mm/radix: Make radix__change_memory_range() static
The lkp bot pointed out that with W=1 we get:

  arch/powerpc/mm/book3s64/radix_pgtable.c:183:6: error: no previous
  prototype for 'radix__change_memory_range'

Which is really saying that it could be static, make it so.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2021-04-14 23:04:45 +10:00
Nicholas Piggin
c45ba4f44f powerpc: clean up do_page_fault
search_exception_tables + __bad_page_fault can be substituted with
bad_page_fault, do_page_fault no longer needs to return a value
to asm for any sub-architecture, and __bad_page_fault can be static.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210316104206.407354-10-npiggin@gmail.com
2021-04-14 23:04:44 +10:00
Nicholas Piggin
d738ee8d56 powerpc/64e/interrupt: handle bad_page_fault in C
With non-volatile registers saved on interrupt, bad_page_fault
can now be called by do_page_fault.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210316104206.407354-9-npiggin@gmail.com
2021-04-14 23:04:43 +10:00
Christophe Leroy
7e9ab144c1 powerpc/mem: Use kmap_local_page() in flushing functions
Flushing functions don't rely on preemption being disabled, so
use kmap_local_page() instead of kmap_atomic().

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b6a880ea0ec7886b51edbb4979c188be549231c0.1617895813.git.christophe.leroy@csgroup.eu
2021-04-14 23:04:19 +10:00
Christophe Leroy
6c96020882 powerpc/mem: Inline flush_dcache_page()
flush_dcache_page() is only a few lines, it is worth
inlining.

ia64, csky, mips, openrisc and riscv have a similar
flush_dcache_page() and inline it.

On pmac32_defconfig, we get a small size reduction.
On ppc64_defconfig, we get a very small size increase.

In both case that's in the noise (less than 0.1%).

text		data	bss	dec		hex	filename
18991155	5934744	1497624	26423523	19330e3	vmlinux64.before
18994829	5936732	1497624	26429185	1934701	vmlinux64.after
9150963		2467502	 184548	11803013	 b41985	vmlinux32.before
9149689		2467302	 184548	11801539	 b413c3	vmlinux32.after

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/21c417488b70b7629dae316539fb7bb8bdef4fdd.1617895813.git.christophe.leroy@csgroup.eu
2021-04-14 23:04:19 +10:00
Christophe Leroy
67b8e6af19 powerpc/mem: Help GCC realise __flush_dcache_icache() flushes single pages
'And' the given page address with PAGE_MASK to help GCC.

With the patch:

	00000024 <__flush_dcache_icache>:
	  24:	54 63 00 26 	rlwinm  r3,r3,0,0,19
	  28:	39 40 00 40 	li      r10,64
	  2c:	7c 69 1b 78 	mr      r9,r3
	  30:	7d 49 03 a6 	mtctr   r10
	  34:	7c 00 48 6c 	dcbst   0,r9
	  38:	39 29 00 20 	addi    r9,r9,32
	  3c:	7c 00 48 6c 	dcbst   0,r9
	  40:	39 29 00 20 	addi    r9,r9,32
	  44:	42 00 ff f0 	bdnz    34 <__flush_dcache_icache+0x10>
	  48:	7c 00 04 ac 	hwsync
	  4c:	39 20 00 40 	li      r9,64
	  50:	7d 29 03 a6 	mtctr   r9
	  54:	7c 00 1f ac 	icbi    0,r3
	  58:	38 63 00 20 	addi    r3,r3,32
	  5c:	7c 00 1f ac 	icbi    0,r3
	  60:	38 63 00 20 	addi    r3,r3,32
	  64:	42 00 ff f0 	bdnz    54 <__flush_dcache_icache+0x30>
	  68:	7c 00 04 ac 	hwsync
	  6c:	4c 00 01 2c 	isync
	  70:	4e 80 00 20 	blr

Without the patch:

	00000024 <__flush_dcache_icache>:
	  24:	54 6a 00 34 	rlwinm  r10,r3,0,0,26
	  28:	39 23 10 1f 	addi    r9,r3,4127
	  2c:	7d 2a 48 50 	subf    r9,r10,r9
	  30:	55 29 d9 7f 	rlwinm. r9,r9,27,5,31
	  34:	41 82 00 94 	beq     c8 <__flush_dcache_icache+0xa4>
	  38:	71 28 00 01 	andi.   r8,r9,1
	  3c:	38 c9 ff ff 	addi    r6,r9,-1
	  40:	7d 48 53 78 	mr      r8,r10
	  44:	7d 27 4b 78 	mr      r7,r9
	  48:	40 82 00 6c 	bne     b4 <__flush_dcache_icache+0x90>
	  4c:	54 e7 f8 7e 	rlwinm  r7,r7,31,1,31
	  50:	7c e9 03 a6 	mtctr   r7
	  54:	7c 00 40 6c 	dcbst   0,r8
	  58:	39 08 00 20 	addi    r8,r8,32
	  5c:	7c 00 40 6c 	dcbst   0,r8
	  60:	39 08 00 20 	addi    r8,r8,32
	  64:	42 00 ff f0 	bdnz    54 <__flush_dcache_icache+0x30>
	  68:	7c 00 04 ac 	hwsync
	  6c:	71 28 00 01 	andi.   r8,r9,1
	  70:	39 09 ff ff 	addi    r8,r9,-1
	  74:	40 82 00 2c 	bne     a0 <__flush_dcache_icache+0x7c>
	  78:	55 29 f8 7e 	rlwinm  r9,r9,31,1,31
	  7c:	7d 29 03 a6 	mtctr   r9
	  80:	7c 00 57 ac 	icbi    0,r10
	  84:	39 4a 00 20 	addi    r10,r10,32
	  88:	7c 00 57 ac 	icbi    0,r10
	  8c:	39 4a 00 20 	addi    r10,r10,32
	  90:	42 00 ff f0 	bdnz    80 <__flush_dcache_icache+0x5c>
	  94:	7c 00 04 ac 	hwsync
	  98:	4c 00 01 2c 	isync
	  9c:	4e 80 00 20 	blr
	  a0:	7c 00 57 ac 	icbi    0,r10
	  a4:	2c 08 00 00 	cmpwi   r8,0
	  a8:	39 4a 00 20 	addi    r10,r10,32
	  ac:	40 82 ff cc 	bne     78 <__flush_dcache_icache+0x54>
	  b0:	4b ff ff e4 	b       94 <__flush_dcache_icache+0x70>
	  b4:	7c 00 50 6c 	dcbst   0,r10
	  b8:	2c 06 00 00 	cmpwi   r6,0
	  bc:	39 0a 00 20 	addi    r8,r10,32
	  c0:	40 82 ff 8c 	bne     4c <__flush_dcache_icache+0x28>
	  c4:	4b ff ff a4 	b       68 <__flush_dcache_icache+0x44>
	  c8:	7c 00 04 ac 	hwsync
	  cc:	7c 00 04 ac 	hwsync
	  d0:	4c 00 01 2c 	isync
	  d4:	4e 80 00 20 	blr

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/23030822ea5cd0a122948b10226abe56602dc027.1617895813.git.christophe.leroy@csgroup.eu
2021-04-14 23:04:18 +10:00
Christophe Leroy
52d490437f powerpc/mem: flush_dcache_icache_phys() is for HIGHMEM pages only
__flush_dcache_icache() is usable for non HIGHMEM pages on
every platform.

It is only for HIGHMEM pages that BOOKE needs kmap() and
BOOK3S needs flush_dcache_icache_phys().

So make flush_dcache_icache_phys() dependent on CONFIG_HIGHMEM and
call it only when it is a HIGHMEM page.

We could make flush_dcache_icache_phys() available at all time,
but as it is declared NOKPROBE_SYMBOL(), GCC doesn't optimise
it out when it is not used.

So define a stub for !CONFIG_HIGHMEM in order to remove the #ifdef in
flush_dcache_icache_page() and use IS_ENABLED() instead.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/79ed5d7914f497cd5fcd681ca2f4d50a91719455.1617895813.git.christophe.leroy@csgroup.eu
2021-04-14 23:04:18 +10:00
Christophe Leroy
cd97d9e8b5 powerpc/mem: Optimise flush_dcache_icache_hugepage()
flush_dcache_icache_hugepage() is a static function, with
only one caller. That caller calls it when PageCompound() is true,
so bugging on !PageCompound() is useless if we can trust the
compiler a little. Remove the BUG_ON(!PageCompound()).

The number of elements of a page won't change over time, but
GCC doesn't know about it, so it gets the value at every iteration.

To avoid that, call compound_nr() outside the loop and save it in
a local variable.

Whether the page is a HIGHMEM page or not doesn't change over time.

But GCC doesn't know it so it does the test on every iteration.

Do the test outside the loop.

When the page is not a HIGHMEM page, page_address() will fallback on
lowmem_page_address(), so call lowmem_page_address() directly and
don't suffer the call to page_address() on every iteration.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/ab03712b70105fccfceef095aa03007de9295a40.1617895813.git.christophe.leroy@csgroup.eu
2021-04-14 23:04:18 +10:00
Christophe Leroy
e618c7aea1 powerpc/mem: Call flush_coherent_icache() at higher level
flush_coherent_icache() doesn't need the address anymore,
so it can be called immediately when entering the public
functions and doesn't need to be disseminated among
lower level functions.

And use page_to_phys() instead of open coding the calculation
of phys address to call flush_dcache_icache_phys().

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/5f063986e325d2efdd404b8f8c5f4bcbd4eb11a6.1617895813.git.christophe.leroy@csgroup.eu
2021-04-14 23:04:18 +10:00
Christophe Leroy
131637a17d powerpc/mem: Remove address argument to flush_coherent_icache()
flush_coherent_icache() can use any valid address as mentionned
by the comment.

Use PAGE_OFFSET as base address. This allows removing the
user access stuff.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/742b6360ae4f344a1c6ecfadcf3b6645f443fa7a.1617895813.git.christophe.leroy@csgroup.eu
2021-04-14 23:04:18 +10:00
Christophe Leroy
bf26e0bbd2 powerpc/mem: Declare __flush_dcache_icache() static
__flush_dcache_icache() is only used in mem.c.

Move it before the functions that use it and declare it static.

And also fix the name of the parameter in the comment.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3fa903eb5a10b2bc7d99a8c559ffdaa05452d8e0.1617895813.git.christophe.leroy@csgroup.eu
2021-04-14 23:04:18 +10:00
Christophe Leroy
b26e8f2725 powerpc/mem: Move cache flushing functions into mm/cacheflush.c
Cache flushing functions are in the middle of completely
unrelated stuff in mm/mem.c

Create a dedicated mm/cacheflush.c for those functions.

Also cleanup the list of included headers.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7bf6f1600acad146e541a4e220940062f2e5b03d.1617895813.git.christophe.leroy@csgroup.eu
2021-04-14 23:04:17 +10:00
Christophe Leroy
80edc68e04 powerpc/32s: Define a MODULE area below kernel text all the time
On book3s/32, the segment below kernel text is used for module
allocation when CONFIG_STRICT_KERNEL_RWX is defined.

In order to benefit from the powerpc specific module_alloc()
function which allocate modules with 32 Mbytes from
end of kernel text, use that segment below PAGE_OFFSET at all time.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a46dcdd39a9e80b012d86c294c4e5cd8d31665f3.1617283827.git.christophe.leroy@csgroup.eu
2021-04-14 23:04:13 +10:00
Vaibhav Jain
a5d6a3e73a powerpc/mm: Add cond_resched() while removing hpte mappings
While removing large number of mappings from hash page tables for
large memory systems as soft-lockup is reported because of the time
spent inside htap_remove_mapping() like one below:

 watchdog: BUG: soft lockup - CPU#8 stuck for 23s!
 <snip>
 NIP plpar_hcall+0x38/0x58
 LR  pSeries_lpar_hpte_invalidate+0x68/0xb0
 Call Trace:
  0x1fffffffffff000 (unreliable)
  pSeries_lpar_hpte_removebolted+0x9c/0x230
  hash__remove_section_mapping+0xec/0x1c0
  remove_section_mapping+0x28/0x3c
  arch_remove_memory+0xfc/0x150
  devm_memremap_pages_release+0x180/0x2f0
  devm_action_release+0x30/0x50
  release_nodes+0x28c/0x300
  device_release_driver_internal+0x16c/0x280
  unbind_store+0x124/0x170
  drv_attr_store+0x44/0x60
  sysfs_kf_write+0x64/0x90
  kernfs_fop_write+0x1b0/0x290
  __vfs_write+0x3c/0x70
  vfs_write+0xd4/0x270
  ksys_write+0xdc/0x130
  system_call+0x5c/0x70

Fix this by adding a cond_resched() to the loop in
htap_remove_mapping() that issues hcall to remove hpte mapping. The
call to cond_resched() is issued every HZ jiffies which should prevent
the soft-lockup from being reported.

Suggested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210404163148.321346-1-vaibhav@linux.ibm.com
2021-04-14 23:04:12 +10:00
Michael Ellerman
87e65ad7bd powerpc/mm/64s/hash: Add real-mode change_memory_range() for hash LPAR
When we enabled STRICT_KERNEL_RWX we received some reports of boot
failures when using the Hash MMU and running under phyp. The crashes
are intermittent, and often exhibit as a completely unresponsive
system, or possibly an oops.

One example, which was caught in xmon:

  [   14.068327][    T1] devtmpfs: mounted
  [   14.069302][    T1] Freeing unused kernel memory: 5568K
  [   14.142060][  T347] BUG: Unable to handle kernel instruction fetch
  [   14.142063][    T1] Run /sbin/init as init process
  [   14.142074][  T347] Faulting instruction address: 0xc000000000004400
  cpu 0x2: Vector: 400 (Instruction Access) at [c00000000c7475e0]
      pc: c000000000004400: exc_virt_0x4400_instruction_access+0x0/0x80
      lr: c0000000001862d4: update_rq_clock+0x44/0x110
      sp: c00000000c747880
     msr: 8000000040001031
    current = 0xc00000000c60d380
    paca    = 0xc00000001ec9de80   irqmask: 0x03   irq_happened: 0x01
      pid   = 347, comm = kworker/2:1
  ...
  enter ? for help
  [c00000000c747880] c0000000001862d4 update_rq_clock+0x44/0x110 (unreliable)
  [c00000000c7478f0] c000000000198794 update_blocked_averages+0xb4/0x6d0
  [c00000000c7479f0] c000000000198e40 update_nohz_stats+0x90/0xd0
  [c00000000c747a20] c0000000001a13b4 _nohz_idle_balance+0x164/0x390
  [c00000000c747b10] c0000000001a1af8 newidle_balance+0x478/0x610
  [c00000000c747be0] c0000000001a1d48 pick_next_task_fair+0x58/0x480
  [c00000000c747c40] c000000000eaab5c __schedule+0x12c/0x950
  [c00000000c747cd0] c000000000eab3e8 schedule+0x68/0x120
  [c00000000c747d00] c00000000016b730 worker_thread+0x130/0x640
  [c00000000c747da0] c000000000174d50 kthread+0x1a0/0x1b0
  [c00000000c747e10] c00000000000e0f0 ret_from_kernel_thread+0x5c/0x6c

This shows that CPU 2, which was idle, woke up and then appears to
randomly take an instruction fault on a completely valid area of
kernel text.

The cause turns out to be the call to hash__mark_rodata_ro(), late in
boot. Due to the way we layout text and rodata, that function actually
changes the permissions for all of text and rodata to read-only plus
execute.

To do the permission change we use a hypervisor call, H_PROTECT. On
phyp that appears to be implemented by briefly removing the mapping of
the kernel text, before putting it back with the updated permissions.
If any other CPU is executing during that window, it will see spurious
faults on the kernel text and/or data, leading to crashes.

To fix it we use stop machine to collect all other CPUs, and then have
them drop into real mode (MMU off), while we change the mapping. That
way they are unaffected by the mapping temporarily disappearing.

We don't see this bug on KVM because KVM always use VPM=1, where
faults are directed to the hypervisor, and the fault will be
serialised vs the h_protect() by HPTE_V_HVLOCK.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210331003845.216246-5-mpe@ellerman.id.au
2021-04-08 21:17:43 +10:00
Michael Ellerman
6f223ebe9c powerpc/mm/64s/hash: Factor out change_memory_range()
Pull the loop calling hpte_updateboltedpp() out of
hash__change_memory_range() into a helper function. We need it to be a
separate function for the next patch.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210331003845.216246-4-mpe@ellerman.id.au
2021-04-08 21:17:43 +10:00
Michael Ellerman
2c02e656a2 powerpc/64s: Use htab_convert_pte_flags() in hash__mark_rodata_ro()
In hash__mark_rodata_ro() we pass the raw PP_RXXX value to
hash__change_memory_range(). That has the effect of setting the key to
zero, because PP_RXXX contains no key value.

Fix it by using htab_convert_pte_flags(), which knows how to convert a
pgprot into a pp value, including the key.

Fixes: d94b827e89 ("powerpc/book3s64/kuap: Use Key 3 for kernel mapping with hash translation")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Link: https://lore.kernel.org/r/20210331003845.216246-3-mpe@ellerman.id.au
2021-04-08 21:17:43 +10:00
Jordan Niethe
b8b2f37cf6 powerpc/64s: Fix pte update for kernel memory on radix
When adding a PTE a ptesync is needed to order the update of the PTE
with subsequent accesses otherwise a spurious fault may be raised.

radix__set_pte_at() does not do this for performance gains. For
non-kernel memory this is not an issue as any faults of this kind are
corrected by the page fault handler. For kernel memory these faults
are not handled. The current solution is that there is a ptesync in
flush_cache_vmap() which should be called when mapping from the
vmalloc region.

However, map_kernel_page() does not call flush_cache_vmap(). This is
troublesome in particular for code patching with Strict RWX on radix.
In do_patch_instruction() the page frame that contains the instruction
to be patched is mapped and then immediately patched. With no ordering
or synchronization between setting up the PTE and writing to the page
it is possible for faults.

As the code patching is done using __put_user_asm_goto() the resulting
fault is obscured - but using a normal store instead it can be seen:

  BUG: Unable to handle kernel data access on write at 0xc008000008f24a3c
  Faulting instruction address: 0xc00000000008bd74
  Oops: Kernel access of bad area, sig: 11 [#1]
  LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA PowerNV
  Modules linked in: nop_module(PO+) [last unloaded: nop_module]
  CPU: 4 PID: 757 Comm: sh Tainted: P           O      5.10.0-rc5-01361-ge3c1b78c8440-dirty #43
  NIP:  c00000000008bd74 LR: c00000000008bd50 CTR: c000000000025810
  REGS: c000000016f634a0 TRAP: 0300   Tainted: P           O       (5.10.0-rc5-01361-ge3c1b78c8440-dirty)
  MSR:  9000000000009033 <SF,HV,EE,ME,IR,DR,RI,LE>  CR: 44002884  XER: 00000000
  CFAR: c00000000007c68c DAR: c008000008f24a3c DSISR: 42000000 IRQMASK: 1

This results in the kind of issue reported here:
  https://lore.kernel.org/linuxppc-dev/15AC5B0E-A221-4B8C-9039-FA96B8EF7C88@lca.pw/

Chris Riedl suggested a reliable way to reproduce the issue:
  $ mount -t debugfs none /sys/kernel/debug
  $ (while true; do echo function > /sys/kernel/debug/tracing/current_tracer ; echo nop > /sys/kernel/debug/tracing/current_tracer ; done) &

Turning ftrace on and off does a large amount of code patching which
in usually less then 5min will crash giving a trace like:

   ftrace-powerpc: (____ptrval____): replaced (4b473b11) != old (60000000)
   ------------[ ftrace bug ]------------
   ftrace failed to modify
   [<c000000000bf8e5c>] napi_busy_loop+0xc/0x390
    actual:   11:3b:47:4b
   Setting ftrace call site to call ftrace function
   ftrace record flags: 80000001
    (1)
    expected tramp: c00000000006c96c
   ------------[ cut here ]------------
   WARNING: CPU: 4 PID: 809 at kernel/trace/ftrace.c:2065 ftrace_bug+0x28c/0x2e8
   Modules linked in: nop_module(PO-) [last unloaded: nop_module]
   CPU: 4 PID: 809 Comm: sh Tainted: P           O      5.10.0-rc5-01360-gf878ccaf250a #1
   NIP:  c00000000024f334 LR: c00000000024f330 CTR: c0000000001a5af0
   REGS: c000000004c8b760 TRAP: 0700   Tainted: P           O       (5.10.0-rc5-01360-gf878ccaf250a)
   MSR:  900000000282b033 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE>  CR: 28008848  XER: 20040000
   CFAR: c0000000001a9c98 IRQMASK: 0
   GPR00: c00000000024f330 c000000004c8b9f0 c000000002770600 0000000000000022
   GPR04: 00000000ffff7fff c000000004c8b6d0 0000000000000027 c0000007fe9bcdd8
   GPR08: 0000000000000023 ffffffffffffffd8 0000000000000027 c000000002613118
   GPR12: 0000000000008000 c0000007fffdca00 0000000000000000 0000000000000000
   GPR16: 0000000023ec37c5 0000000000000000 0000000000000000 0000000000000008
   GPR20: c000000004c8bc90 c0000000027a2d20 c000000004c8bcd0 c000000002612fe8
   GPR24: 0000000000000038 0000000000000030 0000000000000028 0000000000000020
   GPR28: c000000000ff1b68 c000000000bf8e5c c00000000312f700 c000000000fbb9b0
   NIP ftrace_bug+0x28c/0x2e8
   LR  ftrace_bug+0x288/0x2e8
   Call Trace:
     ftrace_bug+0x288/0x2e8 (unreliable)
     ftrace_modify_all_code+0x168/0x210
     arch_ftrace_update_code+0x18/0x30
     ftrace_run_update_code+0x44/0xc0
     ftrace_startup+0xf8/0x1c0
     register_ftrace_function+0x4c/0xc0
     function_trace_init+0x80/0xb0
     tracing_set_tracer+0x2a4/0x4f0
     tracing_set_trace_write+0xd4/0x130
     vfs_write+0xf0/0x330
     ksys_write+0x84/0x140
     system_call_exception+0x14c/0x230
     system_call_common+0xf0/0x27c

To fix this when updating kernel memory PTEs using ptesync.

Fixes: f1cb8f9beb ("powerpc/64s/radix: avoid ptesync after set_pte and ptep_set_access_flags")
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Tidy up change log slightly]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210208032957.1232102-1-jniethe5@gmail.com
2021-04-08 21:17:42 +10:00
Bhaskar Chowdhury
4763d37827 powerpc: Spelling/typo fixes
Various spelling/typo fixes.

Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2021-04-08 21:17:42 +10:00
Nicholas Piggin
1479e3d3b7 powerpc/64s: Fix hash fault to use TRAP accessor
Hash faults use the trap vector to decide whether this is an
instruction or data fault. This should use the TRAP accessor
rather than open access regs->trap.

This won't cause a problem at the moment because 64s only uses
trap flags for system call interrupts (the norestart flag), but
that could change if any other trap flags get used in future.

Fixes: a4922f5442 ("powerpc/64s: move the hash fault handling logic to C")
Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210316105205.407767-1-npiggin@gmail.com
2021-03-29 13:22:15 +11:00
Christophe Leroy
98c26a7275 powerpc/mm: Remove unneeded #ifdef CONFIG_PPC_MEM_KEYS
In fault.c, #ifdef CONFIG_PPC_MEM_KEYS is not needed because all
functions are always defined, and arch_vma_access_permitted()
always returns true when CONFIG_PPC_MEM_KEYS is not defined so
access_pkey_error() will return false so bad_access_pkey()
will never be called.

Include linux/pkeys.h to get a definition of vma_pkeys() for
bad_access_pkey().

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/8038392f38d81f2ad169347efac29146f553b238.1615819955.git.christophe.leroy@csgroup.eu
2021-03-29 13:22:15 +11:00
Michael Ellerman
c2a2a5d027 powerpc/64s: Fold update_current_thread_[i]amr() into their only callers
lkp reported warnings in some configuration due to
update_current_thread_amr() being unused:

  arch/powerpc/mm/book3s64/pkeys.c:284:20: error: unused function 'update_current_thread_amr'
  static inline void update_current_thread_amr(u64 value)

Which is because it's only use is inside an ifdef. We could move it
inside the ifdef, but it's a single line function and only has one
caller, so just fold it in.

Similarly update_current_thread_iamr() is small and only called once,
so fold it in also.

Fixes: 48a8ab4eeb ("powerpc/book3s64/pkeys: Don't update SPRN_AMR when in kernel mode.")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210314093320.132331-1-mpe@ellerman.id.au
2021-03-29 13:22:14 +11:00
Bhaskar Chowdhury
7a7d744ffe powerpc/mm/book3s64: Fix a typo in mmu_context.c
s/detalis/details/

Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210312112537.4585-1-unixbhaskar@gmail.com
2021-03-29 13:22:12 +11:00
Christophe Leroy
b5efec00b6 powerpc/32s: Move KUEP locking/unlocking in C
This can be done in C, do it.

Unrolling the loop gains approx. 15% performance.

From now on, prepare_transfer_to_handler() is only for
interrupts from kernel.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/4eadd873927e9a73c3d1dfe2f9497353465514cf.1615552867.git.christophe.leroy@csgroup.eu
2021-03-29 13:22:10 +11:00
Christophe Leroy
af6f2ce84b powerpc/32: Call bad_page_fault() from do_page_fault()
Now that non volatile registers are saved at all time, no
need to split bad_page_fault() out of do_page_fault().

Remove handle_page_fault() and use do_page_fault() directly.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/cfb95be8863204cc2bf45a22ea44dd1d0dc16b7f.1615552867.git.christophe.leroy@csgroup.eu
2021-03-29 13:22:08 +11:00
Christophe Leroy
7aa8dd67f1 powerpc/32: Always enable data translation in exception prolog
If the code can use a stack in vm area, it can also use a
stack in linear space.

Simplify code by removing old non VMAP stack code on PPC32.

That means the data translation is now re-enabled early in
exception prolog in all cases, not only when using VMAP stacks.

While we are touching EXCEPTION_PROLOG macros, remove the
unused for_rtas parameter in EXCEPTION_PROLOG_1.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7cd6440c60a7e8f4f035b245c57720f51e225aae.1615552866.git.christophe.leroy@csgroup.eu
2021-03-29 13:22:05 +11:00
Christophe Leroy
90cbac0e99 powerpc: Enable KFENCE for PPC32
Add architecture specific implementation details for KFENCE and enable
KFENCE for the ppc32 architecture. In particular, this implements the
required interface in <asm/kfence.h>.

KFENCE requires that attributes for pages from its memory pool can
individually be set. Therefore, force the Read/Write linear map to be
mapped at page granularity.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Marco Elver <elver@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/8dfe1bd2abde26337c1d8c1ad0acfcc82185e0d5.1614868445.git.christophe.leroy@csgroup.eu
2021-03-24 14:09:30 +11:00
Sebastian Andrzej Siewior
9be77e11da powerpc/mm: Move the linear_mapping_mutex to the ifdef where it is used
The mutex linear_mapping_mutex is defined at the of the file while its
only two user are within the CONFIG_MEMORY_HOTPLUG block.
A compile without CONFIG_MEMORY_HOTPLUG set fails on PREEMPT_RT because
its mutex implementation is smart enough to realize that it is unused.

Move the definition of linear_mapping_mutex to ifdef block where it is
used.

Fixes: 1f73ad3e8d ("powerpc/mm: print warning in arch_remove_linear_mapping()")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210219165648.2505482-1-bigeasy@linutronix.de
2021-03-24 14:09:29 +11:00
Linus Torvalds
b12b472496 powerpc updates for 5.12
A large series adding wrappers for our interrupt handlers, so that irq/nmi/user
 tracking can be isolated in the wrappers rather than spread in each handler.
 
 Conversion of the 32-bit syscall handling into C.
 
 A series from Nick to streamline our TLB flushing when using the Radix MMU.
 
 Switch to using queued spinlocks by default for 64-bit server CPUs.
 
 A rework of our PCI probing so that it happens later in boot, when more generic
 infrastructure is available.
 
 Two small fixes to allow 32-bit little-endian processes to run on 64-bit
 kernels.
 
 Other smaller features, fixes & cleanups.
 
 Thanks to:
   Alexey Kardashevskiy, Ananth N Mavinakayanahalli, Aneesh Kumar K.V, Athira
   Rajeev, Bhaskar Chowdhury, Cédric Le Goater, Chengyang Fan, Christophe Leroy,
   Christopher M. Riedl, Fabiano Rosas, Florian Fainelli, Frederic Barrat, Ganesh
   Goudar, Hari Bathini, Jiapeng Chong, Joseph J Allen, Kajol Jain, Markus
   Elfring, Michal Suchanek, Nathan Lynch, Naveen N. Rao, Nicholas Piggin, Oliver
   O'Halloran, Pingfan Liu, Po-Hsu Lin, Qian Cai, Ram Pai, Randy Dunlap, Sandipan
   Das, Stephen Rothwell, Tyrel Datwyler, Will Springer, Yury Norov, Zheng
   Yongjun.
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Merge tag 'powerpc-5.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:

 - A large series adding wrappers for our interrupt handlers, so that
   irq/nmi/user tracking can be isolated in the wrappers rather than
   spread in each handler.

 - Conversion of the 32-bit syscall handling into C.

 - A series from Nick to streamline our TLB flushing when using the
   Radix MMU.

 - Switch to using queued spinlocks by default for 64-bit server CPUs.

 - A rework of our PCI probing so that it happens later in boot, when
   more generic infrastructure is available.

 - Two small fixes to allow 32-bit little-endian processes to run on
   64-bit kernels.

 - Other smaller features, fixes & cleanups.

Thanks to: Alexey Kardashevskiy, Ananth N Mavinakayanahalli, Aneesh
Kumar K.V, Athira Rajeev, Bhaskar Chowdhury, Cédric Le Goater, Chengyang
Fan, Christophe Leroy, Christopher M. Riedl, Fabiano Rosas, Florian
Fainelli, Frederic Barrat, Ganesh Goudar, Hari Bathini, Jiapeng Chong,
Joseph J Allen, Kajol Jain, Markus Elfring, Michal Suchanek, Nathan
Lynch, Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran, Pingfan Liu,
Po-Hsu Lin, Qian Cai, Ram Pai, Randy Dunlap, Sandipan Das, Stephen
Rothwell, Tyrel Datwyler, Will Springer, Yury Norov, and Zheng Yongjun.

* tag 'powerpc-5.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (188 commits)
  powerpc/perf: Adds support for programming of Thresholding in P10
  powerpc/pci: Remove unimplemented prototypes
  powerpc/uaccess: Merge raw_copy_to_user_allowed() into raw_copy_to_user()
  powerpc/uaccess: Merge __put_user_size_allowed() into __put_user_size()
  powerpc/uaccess: get rid of small constant size cases in raw_copy_{to,from}_user()
  powerpc/64: Fix stack trace not displaying final frame
  powerpc/time: Remove get_tbl()
  powerpc/time: Avoid using get_tbl()
  spi: mpc52xx: Avoid using get_tbl()
  powerpc/syscall: Avoid storing 'current' in another pointer
  powerpc/32: Handle bookE debugging in C in syscall entry/exit
  powerpc/syscall: Do not check unsupported scv vector on PPC32
  powerpc/32: Remove the counter in global_dbcr0
  powerpc/32: Remove verification of MSR_PR on syscall in the ASM entry
  powerpc/syscall: implement system call entry/exit logic in C for PPC32
  powerpc/32: Always save non volatile GPRs at syscall entry
  powerpc/syscall: Change condition to check MSR_RI
  powerpc/syscall: Save r3 in regs->orig_r3
  powerpc/syscall: Use is_compat_task()
  powerpc/syscall: Make interrupt.c buildable on PPC32
  ...
2021-02-22 14:34:00 -08:00
Aneesh Kumar K.V
2ac02e5ece powerpc/mm: Remove dcache flush from memory remove.
We added dcache flush on memory add/remove in commit
fb5924fddf ("powerpc/mm: Flush cache on memory hot(un)plug") to
handle crashes on GPU hotplug. Instead of adding dcache flush in
generic memory add/remove routine which is used even for regular
memory, we should handle these devices specific flush in the device
driver code.

memtrace did handle this in the driver and that was removed by commit
7fd6641de2 ("powerpc/powernv/memtrace: Let the arch hotunplug code
flush cache"). This patch reverts that commit.

The dcache flush in memory add was removed by commit
ea458effa8 ("powerpc: Don't flush caches when adding memory") which
I don't think is correct. The reason why we require dcache flush in
memtrace is to make sure we don't have a dirty cache when we remap a
pfn to cache inhibited. We should do that when the memtrace module
removes the memory and make the pfn available for HTM traces to map it
as cache inhibited.

The other device mentioned in commit fb5924fddf ("powerpc/mm: Flush
cache on memory hot(un)plug") is nvlink device with coherent memory.
The support for that was removed in commit
7eb3cf7619 ("powerpc/powernv: remove unused NPU DMA code") and
commit 25b2995a35 ("mm: remove MEMORY_DEVICE_PUBLIC support")

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210203045812.234439-3-aneesh.kumar@linux.ibm.com
2021-02-11 23:35:07 +11:00
Aneesh Kumar K.V
ec94b9b23d powerpc/mm: Add PG_dcache_clean to indicate dcache clean state
This just add a better name for PG_arch_1. No functional change in this patch.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210203045812.234439-2-aneesh.kumar@linux.ibm.com
2021-02-11 23:35:06 +11:00
Aneesh Kumar K.V
c7ba2d6363 powerpc/mm: Enable compound page check for both THP and HugeTLB
THP config results in compound pages. Make sure the kernel enables
the PageCompound() check with CONFIG_HUGETLB_PAGE disabled and
CONFIG_TRANSPARENT_HUGEPAGE enabled.

This makes sure we correctly flush the icache with THP pages.
flush_dcache_icache_page only matter for platforms that don't support
COHERENT_ICACHE.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210203045812.234439-1-aneesh.kumar@linux.ibm.com
2021-02-11 23:35:06 +11:00
Michael Ellerman
2bb421a3d9 powerpc/mm/64s: Fix no previous prototype warning
As reported by lkp:

  arch/powerpc/mm/book3s64/radix_tlb.c:646:6: warning: no previous
  prototype for function 'exit_lazy_flush_tlb'

Fix it by moving the prototype into the existing header.

Fixes: 032b7f0893 ("powerpc/64s/radix: serialize_against_pte_lookup IPIs trim mm_cpumask")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210210130804.3190952-2-mpe@ellerman.id.au
2021-02-11 23:28:51 +11:00
Nicholas Piggin
e4bb64c7a4 powerpc: remove interrupt handler functions from the noinstr section
The allyesconfig ppc64 kernel fails to link with relocations unable to
fit after commit 3a96570ffc ("powerpc: convert interrupt handlers to
use wrappers"), which is due to the interrupt handler functions being
put into the .noinstr.text section, which the linker script places on
the opposite side of the main .text section from the interrupt entry
asm code which calls the handlers.

This results in a lot of linker stubs that overwhelm the 252-byte sized
space we allow for them, or in the case of BE a .opd relocation link
error for some reason.

It's not required to put interrupt handlers in the .noinstr section,
previously they used NOKPROBE_SYMBOL, so take them out and replace
with a NOKPROBE_SYMBOL in the wrapper macro. Remove the explicit
NOKPROBE_SYMBOL macros in the interrupt handler functions. This makes
a number of interrupt handlers nokprobe that were not prior to the
interrupt wrappers commit, but since that commit they were made
nokprobe due to being in .noinstr.text, so this fix does not change
that.

The fixes tag is different to the commit that first exposes the problem
because it is where the wrapper macros were introduced.

Fixes: 8d41fc618a ("powerpc: interrupt handler wrapper functions")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Slightly fix up comment wording]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210211063636.236420-1-npiggin@gmail.com
2021-02-11 23:28:34 +11:00
Christophe Leroy
179ae57dba powerpc/32s: mfsrin()/mtsrin() become mfsr()/mtsr()
Function names should tell what the function does, not how.

mfsrin() and mtsrin() are read/writing segment registers.

They are called that way because they are using mfsrin and mtsrin
instructions, but it doesn't matter for the caller.

In preparation of following patch, change their name to mfsr() and mtsr()
in order to make it obvious they manipulate segment registers without
messing up with how they do it.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/f92d99f4349391b77766745900231aa880a0efb5.1612612022.git.christophe.leroy@csgroup.eu
2021-02-09 01:10:15 +11:00
Nicholas Piggin
032b7f0893 powerpc/64s/radix: serialize_against_pte_lookup IPIs trim mm_cpumask
serialize_against_pte_lookup() performs IPIs to all CPUs in mm_cpumask.
Take this opportunity to try trim the CPU out of mm_cpumask. This can
reduce the cost of future serialize_against_pte_lookup() and/or the
cost of future TLB flushes.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201217134731.488135-7-npiggin@gmail.com
2021-02-09 01:09:45 +11:00
Nicholas Piggin
9393544842 powerpc/64s/radix: occasionally attempt to trim mm_cpumask
A single-threaded process that is flushing its own address space is
so far the only case where the mm_cpumask is attempted to be trimmed.
This patch expands that to flush in other situations, multi-threaded
processes and external sources. For now it's a relatively simple
occasional trim attempt. The main aim is to add the mechanism,
tweaking and tuning can come with more data.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201217134731.488135-6-npiggin@gmail.com
2021-02-09 01:09:45 +11:00
Nicholas Piggin
780de40601 powerpc/64s/radix: Allow mm_cpumask trimming from external sources
mm_cpumask trimming is currently restricted to be issued by the current
thread of a single-threaded mm. This patch relaxes that and allows the
mask to be trimmed from any context.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201217134731.488135-5-npiggin@gmail.com
2021-02-09 01:09:44 +11:00
Nicholas Piggin
54bb503345 powerpc/64s/radix: Check for no TLB flush required
If there are no CPUs in mm_cpumask, no TLB flush is required at all.
This patch adds a check for this case.

Currently it's not tested for, in fact mm_is_thread_local() returns
false if the current CPU is not in mm_cpumask, so it's treated as a
global flush.

This can come up in some cases like exec failure before the new mm has
ever been switched to. This patch reduces TLBIE instructions required
to build a kernel from about 120,000 to 45,000. Another situation it
could help is page reclaim, KSM, THP, etc., (i.e., asynch operations
external to the process) where the process is sleeping and has all TLBs
flushed out of all CPUs.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201217134731.488135-4-npiggin@gmail.com
2021-02-09 01:09:44 +11:00
Nicholas Piggin
26418b36a1 powerpc/64s/radix: refactor TLB flush type selection
The logic to decide what kind of TLB flush is required (local, global,
or IPI) is spread multiple times over the several kinds of TLB flushes.

Move it all into a single function which may issue IPIs if necessary,
and also returns a flush type that is to be used.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201217134731.488135-3-npiggin@gmail.com
2021-02-09 01:09:44 +11:00
Nicholas Piggin
a2496049f1 powerpc/64s/radix: add warning and comments in mm_cpumask trim
Add a comment explaining part of the logic for mm_cpumask trimming, and
add a (hopefully graceful) check and warning in case something gets it
wrong.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201217134731.488135-2-npiggin@gmail.com
2021-02-09 01:09:44 +11:00
Nicholas Piggin
540d4d34be powerpc/64: context tracking move to interrupt wrappers
This moves exception_enter/exit calls to wrapper functions for
synchronous interrupts. More interrupt handlers are covered by
this than previously.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-33-npiggin@gmail.com
2021-02-09 00:10:46 +11:00
Nicholas Piggin
a008f8f9fd powerpc/64s/hash: improve context tracking of hash faults
This moves the 64s/hash context tracking from hash_page_mm() to
__do_hash_fault(), so it's no longer called by OCXL / SPU
accelerators, which was certainly the wrong thing to be doing,
because those callers are not low level interrupt handlers, so
should have entered a kernel context tracking already.

Then remain in kernel context for the duration of the fault,
rather than enter/exit for the hash fault then enter/exit for
the page fault, which is pointless.

Even still, calling exception_enter/exit in __do_hash_fault seems
questionable because that's touching per-cpu variables, tracing,
etc., which might have been interrupted by this hash fault or
themselves cause hash faults. But maybe I miss something because
hash_page_mm very deliberately calls trace_hash_fault too, for
example. So for now go with it, it's no worse than before, in this
regard.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-32-npiggin@gmail.com
2021-02-09 00:02:12 +11:00
Nicholas Piggin
e6f8a6c86c powerpc: add interrupt_cond_local_irq_enable helper
Simple helper for synchronous interrupt handlers (i.e., process-context)
to enable interrupts if it was taken in an interrupts-enabled context.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-30-npiggin@gmail.com
2021-02-09 00:02:12 +11:00
Nicholas Piggin
3a96570ffc powerpc: convert interrupt handlers to use wrappers
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-29-npiggin@gmail.com
2021-02-09 00:02:12 +11:00
Nicholas Piggin
e44370abb2 powerpc/64s: slb comment update
This makes a small improvement to the description of the SLB interrupt
environment. Move the memory access restrictions into one paragraph,
and the interrupt restrictions into the next rather than mix them.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-18-npiggin@gmail.com
2021-02-09 00:02:10 +11:00
Nicholas Piggin
31d6490ccb powerpc/mm: Remove stale do_page_fault comment referring to SLB faults
SLB faults no longer call do_page_fault, this was removed somewhere
between 2.6.0 and 2.6.12.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-17-npiggin@gmail.com
2021-02-09 00:02:10 +11:00
Nicholas Piggin
bf0e2374aa powerpc/64s: split do_hash_fault
This is required for subsequent interrupt wrapper implementation.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-16-npiggin@gmail.com
2021-02-09 00:02:10 +11:00
Nicholas Piggin
f4c03b0e52 powerpc/64s: move bad_page_fault handling to C
This simplifies code, and it is also useful when introducing
interrupt handler wrappers when introducing wrapper functionality
that doesn't cope with asm entry code calling into more than one
handler function.

32-bit and 64e still have some such cases, which limits some ways
they can use interrupt wrappers.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-15-npiggin@gmail.com
2021-02-09 00:02:10 +11:00
Nicholas Piggin
4cb8428465 powerpc: rearrange do_page_fault error case to be inside exception_enter
This keeps the context tracking over the entire interrupt handler which
helps later with moving context tracking into interrupt wrappers.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-14-npiggin@gmail.com
2021-02-09 00:02:09 +11:00
Nicholas Piggin
71f47976fa powerpc/64s: add do_bad_page_fault_segv handler
This function acts like an interrupt handler so it needs to follow
the standard interrupt handler function signature which will be
introduced in a future change.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-13-npiggin@gmail.com
2021-02-09 00:02:09 +11:00
Nicholas Piggin
8458c628a5 powerpc: bad_page_fault get registers from regs
Similar to the previous patch this makes interrupt handler function
types more regular so they can be wrapped with the next patch.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-12-npiggin@gmail.com
2021-02-09 00:02:09 +11:00
Nicholas Piggin
a01a3f2ddb powerpc: remove arguments from fault handler functions
Make mm fault handlers all just take the pt_regs * argument and load
DAR/DSISR from that. Make those that return a value return long.

This is done to make the function signatures match other handlers, which
will help with a future patch to add wrappers. Explicit arguments could
be added for performance but that would require more wrapper macro
variants.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-7-npiggin@gmail.com
2021-02-09 00:02:08 +11:00
Nicholas Piggin
a4922f5442 powerpc/64s: move the hash fault handling logic to C
The fault handling still has some complex logic particularly around
hash table handling, in asm. Implement most of this in C.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-6-npiggin@gmail.com
2021-02-09 00:02:08 +11:00
Aneesh Kumar K.V
8c511eff18 powerpc/kuap: Allow kernel thread to access userspace after kthread_use_mm
This fix the bad fault reported by KUAP when io_wqe_worker access userspace.

 Bug: Read fault blocked by KUAP!
 WARNING: CPU: 1 PID: 101841 at arch/powerpc/mm/fault.c:229 __do_page_fault+0x6b4/0xcd0
 NIP [c00000000009e7e4] __do_page_fault+0x6b4/0xcd0
 LR [c00000000009e7e0] __do_page_fault+0x6b0/0xcd0
..........
 Call Trace:
 [c000000016367330] [c00000000009e7e0] __do_page_fault+0x6b0/0xcd0 (unreliable)
 [c0000000163673e0] [c00000000009ee3c] do_page_fault+0x3c/0x120
 [c000000016367430] [c00000000000c848] handle_page_fault+0x10/0x2c
 --- interrupt: 300 at iov_iter_fault_in_readable+0x148/0x6f0
..........
 NIP [c0000000008e8228] iov_iter_fault_in_readable+0x148/0x6f0
 LR [c0000000008e834c] iov_iter_fault_in_readable+0x26c/0x6f0
 interrupt: 300
 [c0000000163677e0] [c0000000007154a0] iomap_write_actor+0xc0/0x280
 [c000000016367880] [c00000000070fc94] iomap_apply+0x1c4/0x780
 [c000000016367990] [c000000000710330] iomap_file_buffered_write+0xa0/0x120
 [c0000000163679e0] [c00800000040791c] xfs_file_buffered_aio_write+0x314/0x5e0 [xfs]
 [c000000016367a90] [c0000000006d74bc] io_write+0x10c/0x460
 [c000000016367bb0] [c0000000006d80e4] io_issue_sqe+0x8d4/0x1200
 [c000000016367c70] [c0000000006d8ad0] io_wq_submit_work+0xc0/0x250
 [c000000016367cb0] [c0000000006e2578] io_worker_handle_work+0x498/0x800
 [c000000016367d40] [c0000000006e2cdc] io_wqe_worker+0x3fc/0x4f0
 [c000000016367da0] [c0000000001cb0a4] kthread+0x1c4/0x1d0
 [c000000016367e10] [c00000000000dbf0] ret_from_kernel_thread+0x5c/0x6c

The kernel consider thread AMR value for kernel thread to be
AMR_KUAP_BLOCKED. Hence access to userspace is denied. This
of course not correct and we should allow userspace access after
kthread_use_mm(). To be precise, kthread_use_mm() should inherit the
AMR value of the operating address space. But, the AMR value is
thread-specific and we inherit the address space and not thread
access restrictions. Because of this ignore AMR value when accessing
userspace via kernel thread.

current_thread_amr/iamr() are updated, because we use them in the
below stack.
....
[  530.710838] CPU: 13 PID: 5587 Comm: io_wqe_worker-0 Tainted: G      D           5.11.0-rc6+ #3
....

 NIP [c0000000000aa0c8] pkey_access_permitted+0x28/0x90
 LR [c0000000004b9278] gup_pte_range+0x188/0x420
 --- interrupt: 700
 [c00000001c4ef3f0] [0000000000000000] 0x0 (unreliable)
 [c00000001c4ef490] [c0000000004bd39c] gup_pgd_range+0x3ac/0xa20
 [c00000001c4ef5a0] [c0000000004bdd44] internal_get_user_pages_fast+0x334/0x410
 [c00000001c4ef620] [c000000000852028] iov_iter_get_pages+0xf8/0x5c0
 [c00000001c4ef6a0] [c0000000007da44c] bio_iov_iter_get_pages+0xec/0x700
 [c00000001c4ef770] [c0000000006a325c] iomap_dio_bio_actor+0x2ac/0x4f0
 [c00000001c4ef810] [c00000000069cd94] iomap_apply+0x2b4/0x740
 [c00000001c4ef920] [c0000000006a38b8] __iomap_dio_rw+0x238/0x5c0
 [c00000001c4ef9d0] [c0000000006a3c60] iomap_dio_rw+0x20/0x80
 [c00000001c4ef9f0] [c008000001927a30] xfs_file_dio_aio_write+0x1f8/0x650 [xfs]
 [c00000001c4efa60] [c0080000019284dc] xfs_file_write_iter+0xc4/0x130 [xfs]
 [c00000001c4efa90] [c000000000669984] io_write+0x104/0x4b0
 [c00000001c4efbb0] [c00000000066cea4] io_issue_sqe+0x3d4/0xf50
 [c00000001c4efc60] [c000000000670200] io_wq_submit_work+0xb0/0x2f0
 [c00000001c4efcb0] [c000000000674268] io_worker_handle_work+0x248/0x4a0
 [c00000001c4efd30] [c0000000006746e8] io_wqe_worker+0x228/0x2a0
 [c00000001c4efda0] [c00000000019d994] kthread+0x1b4/0x1c0

Fixes: 48a8ab4eeb ("powerpc/book3s64/pkeys: Don't update SPRN_AMR when in kernel mode.")
Reported-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210206025634.521979-1-aneesh.kumar@linux.ibm.com
2021-02-06 23:13:04 +11:00
Christophe Leroy
259149cf7c powerpc/32s: Only build hash code when CONFIG_PPC_BOOK3S_604 is selected
It is now possible to only build book3s/32 kernel for
CPUs without hash table.

Opt out hash related code when CONFIG_PPC_BOOK3S_604 is not selected.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/62df436454ef06e104cc334a0859a2878d7888d5.1608274548.git.christophe.leroy@csgroup.eu
2021-01-31 22:35:50 +11:00
Qian Cai
b5952f8125 powerpc/mm/book3s64/iommu: fix some RCU-list locks
It is safe to traverse mm->context.iommu_group_mem_list with either
mem_list_mutex or the RCU read lock held. Silence a few RCU-list false
positive warnings and fix a few missing RCU read locks.

 arch/powerpc/mm/book3s64/iommu_api.c:330 RCU-list traversed in non-reader section!!

 other info that might help us debug this:

 rcu_scheduler_active = 2, debug_locks = 1
 2 locks held by qemu-kvm/4305:
  #0: c000000bc3fe4d68 (&container->lock){+.+.}-{3:3}, at: tce_iommu_ioctl.part.9+0xc7c/0x1870 [vfio_iommu_spapr_tce]
  #1: c000000001501910 (mem_list_mutex){+.+.}-{3:3}, at: mm_iommu_get+0x50/0x190

 ====
 arch/powerpc/mm/book3s64/iommu_api.c:132 RCU-list traversed in non-reader section!!

 other info that might help us debug this:

 rcu_scheduler_active = 2, debug_locks = 1
 2 locks held by qemu-kvm/4305:
  #0: c000000bc3fe4d68 (&container->lock){+.+.}-{3:3}, at: tce_iommu_ioctl.part.9+0xc7c/0x1870 [vfio_iommu_spapr_tce]
  #1: c000000001501910 (mem_list_mutex){+.+.}-{3:3}, at: mm_iommu_do_alloc+0x120/0x5f0

 ====
 arch/powerpc/mm/book3s64/iommu_api.c:292 RCU-list traversed in non-reader section!!

 other info that might help us debug this:

 rcu_scheduler_active = 2, debug_locks = 1
 2 locks held by qemu-kvm/4312:
  #0: c000000ecafe23c8 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0xdc/0x950 [kvm]
  #1: c000000045e6c468 (&kvm->srcu){....}-{0:0}, at: kvmppc_h_put_tce+0x88/0x340 [kvm]

 ====
 arch/powerpc/mm/book3s64/iommu_api.c:424 RCU-list traversed in non-reader section!!

 other info that might help us debug this:

 rcu_scheduler_active = 2, debug_locks = 1
 2 locks held by qemu-kvm/4312:
  #0: c000000ecafe23c8 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0xdc/0x950 [kvm]
  #1: c000000045e6c468 (&kvm->srcu){....}-{0:0}, at: kvmppc_h_put_tce+0x88/0x340 [kvm]

Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200510051559.1959-1-cai@lca.pw
2021-01-31 22:35:49 +11:00
Cédric Le Goater
94b87d72fc powerpc/mm/hugetlb: Make pseries_alloc_bootmem_huge_page() static
pseries_alloc_bootmem_huge_page() is only used locally in
alloc_bootmem_huge_page() and does not need to be external.

It fixes this W=1 compile error :

../arch/powerpc/mm/hugetlbpage.c:220:12: error: no previous prototype for ‘pseries_alloc_bootmem_huge_page’ [-Werror=missing-prototypes]
  220 | int __init pseries_alloc_bootmem_huge_page(struct hstate *hstate)
      |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210104143206.695198-16-clg@kaod.org
2021-01-30 11:39:30 +11:00
Cédric Le Goater
11f9c1d2fb powerpc/mm: Move hpte_insert_repeating() prototype
It fixes this W=1 compile error :

../arch/powerpc/mm/book3s64/hash_utils.c:1867:6: error: no previous prototype for ‘hpte_insert_repeating’ [-Werror=missing-prototypes]
 1867 | long hpte_insert_repeating(unsigned long hash, unsigned long vpn,
      |      ^~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210104143206.695198-14-clg@kaod.org
2021-01-30 11:39:29 +11:00
Cédric Le Goater
d25da505c3 powerpc/mm: Include __find_linux_pte() prototype
It fixes this W=1 compile error :

../arch/powerpc/mm/pgtable.c:337:8: error: no previous prototype for ‘__find_linux_pte’ [-Werror=missing-prototypes]
  337 | pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
      |        ^~~~~~~~~~~~~~~~

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210104143206.695198-2-clg@kaod.org
2021-01-30 11:39:26 +11:00
Linus Torvalds
8a5be36b93 powerpc updates for 5.11
- Switch to the generic C VDSO, as well as some cleanups of our VDSO
    setup/handling code.
 
  - Support for KUAP (Kernel User Access Prevention) on systems using the hashed
    page table MMU, using memory protection keys.
 
  - Better handling of PowerVM SMT8 systems where all threads of a core do not
    share an L2, allowing the scheduler to make better scheduling decisions.
 
  - Further improvements to our machine check handling.
 
  - Show registers when unwinding interrupt frames during stack traces.
 
  - Improvements to our pseries (PowerVM) partition migration code.
 
  - Several series from Christophe refactoring and cleaning up various parts of
    the 32-bit code.
 
  - Other smaller features, fixes & cleanups.
 
 Thanks to:
   Alan Modra, Alexey Kardashevskiy, Andrew Donnellan, Aneesh Kumar K.V, Ard
   Biesheuvel, Athira Rajeev, Balamuruhan S, Bill Wendling, Cédric Le Goater,
   Christophe Leroy, Christophe Lombard, Colin Ian King, Daniel Axtens, David
   Hildenbrand, Frederic Barrat, Ganesh Goudar, Gautham R. Shenoy, Geert
   Uytterhoeven, Giuseppe Sacco, Greg Kurz, Harish, Jan Kratochvil, Jordan
   Niethe, Kaixu Xia, Laurent Dufour, Leonardo Bras, Madhavan Srinivasan, Mahesh
   Salgaonkar, Mathieu Desnoyers, Nathan Lynch, Nicholas Piggin, Oleg Nesterov,
   Oliver O'Halloran, Oscar Salvador, Po-Hsu Lin, Qian Cai, Qinglang Miao, Randy
   Dunlap, Ravi Bangoria, Sachin Sant, Sandipan Das, Sebastian Andrzej Siewior ,
   Segher Boessenkool, Srikar Dronamraju, Tyrel Datwyler, Uwe Kleine-König,
   Vincent Stehlé, Youling Tang, Zhang Xiaoxu.
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Merge tag 'powerpc-5.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:

 - Switch to the generic C VDSO, as well as some cleanups of our VDSO
   setup/handling code.

 - Support for KUAP (Kernel User Access Prevention) on systems using the
   hashed page table MMU, using memory protection keys.

 - Better handling of PowerVM SMT8 systems where all threads of a core
   do not share an L2, allowing the scheduler to make better scheduling
   decisions.

 - Further improvements to our machine check handling.

 - Show registers when unwinding interrupt frames during stack traces.

 - Improvements to our pseries (PowerVM) partition migration code.

 - Several series from Christophe refactoring and cleaning up various
   parts of the 32-bit code.

 - Other smaller features, fixes & cleanups.

Thanks to: Alan Modra, Alexey Kardashevskiy, Andrew Donnellan, Aneesh
Kumar K.V, Ard Biesheuvel, Athira Rajeev, Balamuruhan S, Bill Wendling,
Cédric Le Goater, Christophe Leroy, Christophe Lombard, Colin Ian King,
Daniel Axtens, David Hildenbrand, Frederic Barrat, Ganesh Goudar,
Gautham R. Shenoy, Geert Uytterhoeven, Giuseppe Sacco, Greg Kurz,
Harish, Jan Kratochvil, Jordan Niethe, Kaixu Xia, Laurent Dufour,
Leonardo Bras, Madhavan Srinivasan, Mahesh Salgaonkar, Mathieu
Desnoyers, Nathan Lynch, Nicholas Piggin, Oleg Nesterov, Oliver
O'Halloran, Oscar Salvador, Po-Hsu Lin, Qian Cai, Qinglang Miao, Randy
Dunlap, Ravi Bangoria, Sachin Sant, Sandipan Das, Sebastian Andrzej
Siewior , Segher Boessenkool, Srikar Dronamraju, Tyrel Datwyler, Uwe
Kleine-König, Vincent Stehlé, Youling Tang, and Zhang Xiaoxu.

* tag 'powerpc-5.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (304 commits)
  powerpc/32s: Fix cleanup_cpu_mmu_context() compile bug
  powerpc: Add config fragment for disabling -Werror
  powerpc/configs: Add ppc64le_allnoconfig target
  powerpc/powernv: Rate limit opal-elog read failure message
  powerpc/pseries/memhotplug: Quieten some DLPAR operations
  powerpc/ps3: use dma_mapping_error()
  powerpc: force inlining of csum_partial() to avoid multiple csum_partial() with GCC10
  powerpc/perf: Fix Threshold Event Counter Multiplier width for P10
  powerpc/mm: Fix hugetlb_free_pmd_range() and hugetlb_free_pud_range()
  KVM: PPC: Book3S HV: Fix mask size for emulated msgsndp
  KVM: PPC: fix comparison to bool warning
  KVM: PPC: Book3S: Assign boolean values to a bool variable
  powerpc: Inline setup_kup()
  powerpc/64s: Mark the kuap/kuep functions non __init
  KVM: PPC: Book3S HV: XIVE: Add a comment regarding VP numbering
  powerpc/xive: Improve error reporting of OPAL calls
  powerpc/xive: Simplify xive_do_source_eoi()
  powerpc/xive: Remove P9 DD1 flag XIVE_IRQ_FLAG_EOI_FW
  powerpc/xive: Remove P9 DD1 flag XIVE_IRQ_FLAG_MASK_FW
  powerpc/xive: Remove P9 DD1 flag XIVE_IRQ_FLAG_SHIFT_BUG
  ...
2020-12-17 13:34:25 -08:00
Christophe Leroy
2198d4934e powerpc/mm: Fix hugetlb_free_pmd_range() and hugetlb_free_pud_range()
Commit 7bfe54b5f1 ("powerpc/mm: Refactor the floor/ceiling check in
hugetlb range freeing functions") inadvertely removed the mask
applied to start parameter in those two functions, leading to the
following crash on power9.

  LTP: starting hugemmap05_1 (hugemmap05 -m)
  ------------[ cut here ]------------
  kernel BUG at arch/powerpc/mm/book3s64/pgtable.c:387!
  Oops: Exception in kernel mode, sig: 5 [#1]
  LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=256 NUMA PowerNV
  ...
  CPU: 99 PID: 308 Comm: ksoftirqd/99 Tainted: G           O      5.10.0-rc7-next-20201211 #1
  NIP:  c00000000005dbec LR: c0000000003352f4 CTR: 0000000000000000
  REGS: c00020000bb6f830 TRAP: 0700   Tainted: G           O       (5.10.0-rc7-next-20201211)
  MSR:  900000000282b033 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE>  CR: 24002284  XER: 20040000
  GPR00: c0000000003352f4 c00020000bb6fad0 c000000007f70b00 c0002000385b3ff0
  GPR04: 0000000000000000 0000000000000003 c00020000bb6f8b4 0000000000000001
  GPR08: 0000000000000001 0000000000000009 0000000000000008 0000000000000002
  GPR12: 0000000024002488 c000201fff649c00 c000000007f2a20c 0000000000000000
  GPR16: 0000000000000007 0000000000000000 c000000000194d10 c000000000194d10
  GPR24: 0000000000000014 0000000000000015 c000201cc6e72398 c000000007fac4b4
  GPR28: c000000007f2bf80 c000000007fac2f8 0000000000000008 c000200033870000
  NIP [c00000000005dbec] __tlb_remove_table+0x1dc/0x1e0
                         pgtable_free at arch/powerpc/mm/book3s64/pgtable.c:387
                         (inlined by) __tlb_remove_table at arch/powerpc/mm/book3s64/pgtable.c:405
  LR [c0000000003352f4] tlb_remove_table_rcu+0x54/0xa0
  Call Trace:
    __tlb_remove_table+0x13c/0x1e0 (unreliable)
    tlb_remove_table_rcu+0x54/0xa0
    __tlb_remove_table_free at mm/mmu_gather.c:101
    (inlined by) tlb_remove_table_rcu at mm/mmu_gather.c:156
    rcu_core+0x35c/0xbb0
    rcu_do_batch at kernel/rcu/tree.c:2502
    (inlined by) rcu_core at kernel/rcu/tree.c:2737
    __do_softirq+0x480/0x704
    run_ksoftirqd+0x74/0xd0
    run_ksoftirqd at kernel/softirq.c:651
    (inlined by) run_ksoftirqd at kernel/softirq.c:642
    smpboot_thread_fn+0x278/0x320
    kthread+0x1c4/0x1d0
    ret_from_kernel_thread+0x5c/0x80

Properly apply the masks before calling pmd_free_tlb() and
pud_free_tlb() respectively.

Fixes: 7bfe54b5f1 ("powerpc/mm: Refactor the floor/ceiling check in hugetlb range freeing functions")
Reported-by: Qian Cai <qcai@redhat.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/56feccd7b6fcd98e353361a233fa7bb8e67c3164.1607780469.git.christophe.leroy@csgroup.eu
2020-12-15 22:22:07 +11:00
Linus Torvalds
edd7ab7684 The new preemtible kmap_local() implementation:
- Consolidate all kmap_atomic() internals into a generic implementation
     which builds the base for the kmap_local() API and make the
     kmap_atomic() interface wrappers which handle the disabling/enabling of
     preemption and pagefaults.
 
   - Switch the storage from per-CPU to per task and provide scheduler
     support for clearing mapping when scheduling out and restoring them
     when scheduling back in.
 
   - Merge the migrate_disable/enable() code, which is also part of the
     scheduler pull request. This was required to make the kmap_local()
     interface available which does not disable preemption when a mapping
     is established. It has to disable migration instead to guarantee that
     the virtual address of the mapped slot is the same accross preemption.
 
   - Provide better debug facilities: guard pages and enforced utilization
     of the mapping mechanics on 64bit systems when the architecture allows
     it.
 
   - Provide the new kmap_local() API which can now be used to cleanup the
     kmap_atomic() usage sites all over the place. Most of the usage sites
     do not require the implicit disabling of preemption and pagefaults so
     the penalty on 64bit and 32bit non-highmem systems is removed and quite
     some of the code can be simplified. A wholesale conversion is not
     possible because some usage depends on the implicit side effects and
     some need to be cleaned up because they work around these side effects.
 
     The migrate disable side effect is only effective on highmem systems
     and when enforced debugging is enabled. On 64bit and 32bit non-highmem
     systems the overhead is completely avoided.
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Merge tag 'core-mm-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull kmap updates from Thomas Gleixner:
 "The new preemtible kmap_local() implementation:

   - Consolidate all kmap_atomic() internals into a generic
     implementation which builds the base for the kmap_local() API and
     make the kmap_atomic() interface wrappers which handle the
     disabling/enabling of preemption and pagefaults.

   - Switch the storage from per-CPU to per task and provide scheduler
     support for clearing mapping when scheduling out and restoring them
     when scheduling back in.

   - Merge the migrate_disable/enable() code, which is also part of the
     scheduler pull request. This was required to make the kmap_local()
     interface available which does not disable preemption when a
     mapping is established. It has to disable migration instead to
     guarantee that the virtual address of the mapped slot is the same
     across preemption.

   - Provide better debug facilities: guard pages and enforced
     utilization of the mapping mechanics on 64bit systems when the
     architecture allows it.

   - Provide the new kmap_local() API which can now be used to cleanup
     the kmap_atomic() usage sites all over the place. Most of the usage
     sites do not require the implicit disabling of preemption and
     pagefaults so the penalty on 64bit and 32bit non-highmem systems is
     removed and quite some of the code can be simplified. A wholesale
     conversion is not possible because some usage depends on the
     implicit side effects and some need to be cleaned up because they
     work around these side effects.

     The migrate disable side effect is only effective on highmem
     systems and when enforced debugging is enabled. On 64bit and 32bit
     non-highmem systems the overhead is completely avoided"

* tag 'core-mm-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits)
  ARM: highmem: Fix cache_is_vivt() reference
  x86/crashdump/32: Simplify copy_oldmem_page()
  io-mapping: Provide iomap_local variant
  mm/highmem: Provide kmap_local*
  sched: highmem: Store local kmaps in task struct
  x86: Support kmap_local() forced debugging
  mm/highmem: Provide CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP
  mm/highmem: Provide and use CONFIG_DEBUG_KMAP_LOCAL
  microblaze/mm/highmem: Add dropped #ifdef back
  xtensa/mm/highmem: Make generic kmap_atomic() work correctly
  mm/highmem: Take kmap_high_get() properly into account
  highmem: High implementation details and document API
  Documentation/io-mapping: Remove outdated blurb
  io-mapping: Cleanup atomic iomap
  mm/highmem: Remove the old kmap_atomic cruft
  highmem: Get rid of kmap_types.h
  xtensa/mm/highmem: Switch to generic kmap atomic
  sparc/mm/highmem: Switch to generic kmap atomic
  powerpc/mm/highmem: Switch to generic kmap atomic
  nds32/mm/highmem: Switch to generic kmap atomic
  ...
2020-12-14 18:35:53 -08:00