In preparation for adding Clang sanitizer coverage stack depth tracking
that can support stack depth callbacks:
- Add the new top-level CONFIG_KSTACK_ERASE option which will be
implemented either with the stackleak GCC plugin, or with the Clang
stack depth callback support.
- Rename CONFIG_GCC_PLUGIN_STACKLEAK as needed to CONFIG_KSTACK_ERASE,
but keep it for anything specific to the GCC plugin itself.
- Rename all exposed "STACKLEAK" names and files to "KSTACK_ERASE" (named
for what it does rather than what it protects against), but leave as
many of the internals alone as possible to avoid even more churn.
While here, also split "prev_lowest_stack" into CONFIG_KSTACK_ERASE_METRICS,
since that's the only place it is referenced from.
Suggested-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250717232519.2984886-1-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
- Large rework of the protected key crypto code to allow for asynchronous
handling without memory allocation
- Speed up system call entry/exit path by re-implementing lazy ASCE
handling
- Add module autoload support for the diag288_wdt watchdog device driver
- Get rid of s390 specific strcpy() and strncpy() implementations, and
switch all remaining users to strscpy() when possible
- Various other small fixes and improvements
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Merge tag 's390-6.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 updates from Heiko Carstens:
- Large rework of the protected key crypto code to allow for
asynchronous handling without memory allocation
- Speed up system call entry/exit path by re-implementing lazy ASCE
handling
- Add module autoload support for the diag288_wdt watchdog device
driver
- Get rid of s390 specific strcpy() and strncpy() implementations, and
switch all remaining users to strscpy() when possible
- Various other small fixes and improvements
* tag 's390-6.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (51 commits)
s390/pci: Serialize device addition and removal
s390/pci: Allow re-add of a reserved but not yet removed device
s390/pci: Prevent self deletion in disable_slot()
s390/pci: Remove redundant bus removal and disable from zpci_release_device()
s390/crypto: Extend protected key conversion retry loop
s390/pci: Fix __pcilg_mio_inuser() inline assembly
s390/ptrace: Always inline regs_get_kernel_stack_nth() and regs_get_register()
s390/thread_info: Cleanup header includes
s390/extmem: Add workaround for DCSS unload diag
s390/crypto: Rework protected key AES for true asynch support
s390/cpacf: Rework cpacf_pcc() to return condition code
s390/mm: Fix potential use-after-free in __crst_table_upgrade()
s390/mm: Add mmap_assert_write_locked() check to crst_table_upgrade()
s390/string: Remove strcpy() implementation
s390/con3270: Use strscpy() instead of strcpy()
s390/boot: Use strspcy() instead of strcpy()
s390: Simple strcpy() to strscpy() conversions
s390/pkey/crypto: Introduce xflags param for pkey in-kernel API
s390/pkey: Provide and pass xflags within pkey and zcrypt layers
s390/uv: Remove uv_get_secret_metadata function
...
In case of stack corruption stack_invalid() is called and the expectation
is that register r10 contains the last breaking event address. This
dependency is quite subtle and broke a couple of years ago without that
anybody noticed.
Fix this by getting rid of the dependency and read the last breaking event
address from lowcore.
Fixes: 56e62a7370 ("s390: convert to generic entry")
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Reduce system call overhead time (round trip time for invoking a
non-existent system call) by 25%.
With the removal of set_fs() [1] lazy control register handling was removed
in order to keep kernel entry and exit simple. However this made system
calls slower.
With the conversion to generic entry [2] and numerous follow up changes
which simplified the entry code significantly, adding support for lazy asce
handling doesn't add much complexity to the entry code anymore.
In particular this means:
- On kernel entry the primary asce is not modified and contains the user
asce
- Kernel accesses which require secondary-space mode (for example futex
operations) are surrounded by enable_sacf_uaccess() and
disable_sacf_uaccess() calls. enable_sacf_uaccess() sets the primary asce
to kernel asce so that the sacf instruction can be used to switch to
secondary-space mode. The primary asce is changed back to user asce with
disable_sacf_uaccess().
The state of the control register which contains the primary asce is
reflected with a new TIF_ASCE_PRIMARY bit. This is required on context
switch so that the correct asce is restored for the scheduled in process.
In result address spaces are now setup like this:
CPU running in | %cr1 ASCE | %cr7 ASCE | %cr13 ASCE
-----------------------------|-----------|-----------|-----------
user space | user | user | kernel
kernel (no sacf) | user | user | kernel
kernel (during sacf uaccess) | kernel | user | kernel
kernel (kvm guest execution) | guest | user | kernel
In result cr1 control register content is not changed except for:
- futex system calls
- legacy s390 PCI system calls
- the kvm specific cmpxchg_user_key() uaccess helper
This leads to faster system call execution.
[1] 87d5986345 ("s390/mm: remove set_fs / rework address space handling")
[2] 56e62a7370 ("s390: convert to generic entry")
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
When lowcore relocation is enabled, the machine check handler doesn't
use the lowcore address when setting _CIF_MCCK_GUEST. Fix this by
adding the missing base register.
Fixes: 0001b7bbc5 ("s390/entry: Make mchk_int_handler() ready for lowcore relocation")
Reported-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
When the kernel stack pointer is pointing to invalid memory,
a 'Kernel stack overflow' message is printed, which is misleading.
Change the message to actually say that the stack pointer is invalid
instead.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
A few include directives use the local search variant even though the files
to be included aren't local. Therefore use the normal system header file
variant of the include directive.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Convert the explicit relocated lowcore alternative type to a more
generic machine feature. This only reduces the number of alternative
types, but has no impact on code generation.
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
There is no point in supporting !VMAP_STACK kernel builds. VMAP_STACK has
proven to work since many years. Also, since KASAN_VMALLOC is supported,
kernels built with !VMAP_STACK are completely untested.
Therefore select VMAP_STACK unconditionally and remove all config options
and code required for !VMAP_STACK builds.
Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
The stack depot filters out everything outside of the top interrupt
context as an uninteresting or irrelevant part of the stack traces. This
helps with stack trace de-duplication, avoiding an explosion of saved
stack traces that share the same IRQ context code path but originate
from different randomly interrupted points, eventually exhausting the
stack depot.
Filtering uses in_irqentry_text() to identify functions within the
.irqentry.text and .softirqentry.text sections, which then become the
last stack trace entries being saved.
While __do_softirq() is placed into the .softirqentry.text section by
common code, populating .irqentry.text is architecture-specific.
Currently, the .irqentry.text section on s390 is empty, which prevents
stack depot filtering and de-duplication and could result in warnings
like:
Stack depot reached limit capacity
WARNING: CPU: 0 PID: 286113 at lib/stackdepot.c:252 depot_alloc_stack+0x39a/0x3c8
with PREEMPT and KASAN enabled.
Fix this by moving the IO/EXT interrupt handlers from .kprobes.text into
the .irqentry.text section and updating the kprobes blacklist to include
the .irqentry.text section.
This is done only for asynchronous interrupts and explicitly not for
program checks, which are synchronous and where the context beyond the
program check is important to preserve. Despite machine checks being
somewhat in between, they are extremely rare, and preserving context
when possible is also of value.
SVCs and Restart Interrupts are not relevant, one being always at the
boundary to user space and the other being a one-time thing.
IRQ entries filtering is also optionally used in ftrace function graph,
where the same logic applies.
Cc: stable@vger.kernel.org # 5.15+
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Any program interrupt that happens in the host during the execution of
a KVM guest will now short circuit the fault handler and return to KVM
immediately. Guest fault handling (including pfault) will happen
entirely inside KVM.
When sie64a() returns zero, current->thread.gmap_int_code will contain
the program interrupt number that caused the exit, or zero if the exit
was not caused by a host program interrupt.
KVM will now take care of handling all guest faults in vcpu_post_run().
Since gmap faults will not be visible by the rest of the kernel, remove
GMAP_FAULT, the linux fault handlers for secure execution faults, the
exception table entries for the sie instruction, the nop padding after
the sie instruction, and all other references to guest faults from the
s390 code.
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Co-developed-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20241022120601.167009-6-imbrenda@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Now that the guest ASCE is passed as a parameter to __sie64a(),
_PIF_GUEST_FAULT can be used again to determine whether the fault was a
guest or host fault.
Since the guest ASCE will not be taken from the gmap pointer in lowcore
anymore, __GMAP_ASCE can be removed. For the same reason the guest
ASCE needs now to be saved into the cr1 save area unconditionally.
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20241022120601.167009-2-imbrenda@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
- Optimize ftrace and kprobes code patching and avoid stop machine for
kprobes if sequential instruction fetching facility is available
- Add hiperdispatch feature to dynamically adjust CPU capacity in
vertical polarization to improve scheduling efficiency and overall
performance. Also add infrastructure for handling warning track
interrupts (WTI), allowing for graceful CPU preemption
- Rework crypto code pkey module and split it into separate, independent
modules for sysfs, PCKMO, CCA, and EP11, allowing modules to load only
when the relevant hardware is available
- Add hardware acceleration for HMAC modes and the full AES-XTS cipher,
utilizing message-security assist extensions (MSA) 10 and 11. It
introduces new shash implementations for HMAC-SHA224/256/384/512 and
registers the hardware-accelerated AES-XTS cipher as the preferred
option. Also add clear key token support
- Add MSA 10 and 11 processor activity instrumentation counters to perf
and update PAI Extension 1 NNPA counters
- Cleanup cpu sampling facility code and rework debug/WARN_ON_ONCE
statements
- Add support for SHA3 performance enhancements introduced with MSA 12
- Add support for the query authentication information feature of
MSA 13 and introduce the KDSA CPACF instruction. Provide query and query
authentication information in sysfs, enabling tools like cpacfinfo to
present this data in a human-readable form
- Update kernel disassembler instructions
- Always enable EXPOLINE_EXTERN if supported by the compiler to ensure
kpatch compatibility
- Add missing warning handling and relocated lowcore support to the
early program check handler
- Optimize ftrace_return_address() and avoid calling unwinder
- Make modules use kernel ftrace trampolines
- Strip relocs from the final vmlinux ELF file to make it roughly 2
times smaller
- Dump register contents and call trace for early crashes to the console
- Generate ptdump address marker array dynamically
- Fix rcu_sched stalls that might occur when adding or removing large
amounts of pages at once to or from the CMM balloon
- Fix deadlock caused by recursive lock of the AP bus scan mutex
- Unify sync and async register save areas in entry code
- Cleanup debug prints in crypto code
- Various cleanup and sanitizing patches for the decompressor
- Various small ftrace cleanups
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Merge tag 's390-6.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 updates from Vasily Gorbik:
- Optimize ftrace and kprobes code patching and avoid stop machine for
kprobes if sequential instruction fetching facility is available
- Add hiperdispatch feature to dynamically adjust CPU capacity in
vertical polarization to improve scheduling efficiency and overall
performance. Also add infrastructure for handling warning track
interrupts (WTI), allowing for graceful CPU preemption
- Rework crypto code pkey module and split it into separate,
independent modules for sysfs, PCKMO, CCA, and EP11, allowing modules
to load only when the relevant hardware is available
- Add hardware acceleration for HMAC modes and the full AES-XTS cipher,
utilizing message-security assist extensions (MSA) 10 and 11. It
introduces new shash implementations for HMAC-SHA224/256/384/512 and
registers the hardware-accelerated AES-XTS cipher as the preferred
option. Also add clear key token support
- Add MSA 10 and 11 processor activity instrumentation counters to perf
and update PAI Extension 1 NNPA counters
- Cleanup cpu sampling facility code and rework debug/WARN_ON_ONCE
statements
- Add support for SHA3 performance enhancements introduced with MSA 12
- Add support for the query authentication information feature of MSA
13 and introduce the KDSA CPACF instruction. Provide query and query
authentication information in sysfs, enabling tools like cpacfinfo to
present this data in a human-readable form
- Update kernel disassembler instructions
- Always enable EXPOLINE_EXTERN if supported by the compiler to ensure
kpatch compatibility
- Add missing warning handling and relocated lowcore support to the
early program check handler
- Optimize ftrace_return_address() and avoid calling unwinder
- Make modules use kernel ftrace trampolines
- Strip relocs from the final vmlinux ELF file to make it roughly 2
times smaller
- Dump register contents and call trace for early crashes to the
console
- Generate ptdump address marker array dynamically
- Fix rcu_sched stalls that might occur when adding or removing large
amounts of pages at once to or from the CMM balloon
- Fix deadlock caused by recursive lock of the AP bus scan mutex
- Unify sync and async register save areas in entry code
- Cleanup debug prints in crypto code
- Various cleanup and sanitizing patches for the decompressor
- Various small ftrace cleanups
* tag 's390-6.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (84 commits)
s390/crypto: Display Query and Query Authentication Information in sysfs
s390/crypto: Add Support for Query Authentication Information
s390/crypto: Rework RRE and RRF CPACF inline functions
s390/crypto: Add KDSA CPACF Instruction
s390/disassembler: Remove duplicate instruction format RSY_RDRU
s390/boot: Move boot_printk() code to own file
s390/boot: Use boot_printk() instead of sclp_early_printk()
s390/boot: Rename decompressor_printk() to boot_printk()
s390/boot: Compile all files with the same march flag
s390: Use MARCH_HAS_*_FEATURES defines
s390: Provide MARCH_HAS_*_FEATURES defines
s390/facility: Disable compile time optimization for decompressor code
s390/boot: Increase minimum architecture to z10
s390/als: Remove obsolete comment
s390/sha3: Fix SHA3 selftests failures
s390/pkey: Add AES xts and HMAC clear key token support
s390/cpacf: Add MSA 10 and 11 new PCKMO functions
s390/mm: Add cond_resched() to cmm_alloc/free_pages()
s390/pai_ext: Update PAI extension 1 counters
s390/pai_crypto: Add support for MSA 10 and 11 pai counters
...
Patch all alternatives which depend on facilities from the decompressor.
There is no technical reason which enforces to split patching of such
alternatives to the decompressor and the kernel.
This simplifies alternative handling a bit, since one alternative type is
removed.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
In the past two save areas existed because interrupt handlers
and system call / program check handlers where entered with
interrupts enabled. To prevent a handler from overwriting the
save areas from the previous handler, interrupts used the async
save area, while system call and program check handler used the
sync save area.
Since the removal of critical section cleanup from entry.S, handlers are
entered with interrupts disabled. When the interrupts are re-enabled,
the save area is no longer need. Therefore merge both save areas into one.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Save some bytes and move early_pgm_check_handler() to init text
section.
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Add the missing pieces so the early program check handler also works
with a relocated lowcore. Right now the result of an early program
check in case of a relocated lowcore would be a program check loop.
Fixes: 8f1e70adb1 ("s390/boot: Add cmdline option to relocate lowcore")
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Have all program check handlers in one file to make future changes easy.
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
In preparation of having lowcore at different address than zero,
add the base register to all lowcore accesses in system_call().
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
In preparation of having lowcore at different address than zero,
add the base register to all lowcore accesses in ret_from_fork().
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
In preparation of having lowcore at different address than zero,
add the base register to all lowcore accesses in __switch_to().
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
In preparation of having lowcore at different address than zero,
add the base register to all lowcore accesses in restart_int_handler().
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
In preparation of having lowcore at different address than zero,
add the base register to all lowcore accesses in mcck_int_handler().
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
In preparation of having lowcore at different address than zero,
add the base register to all lowcore accesses in the ext/io interrupt
handlers.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
In preparation of having lowcore at different address than zero,
add the base register to all lowcore accesses in pgm_check_handler().
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
In preparation of having lowcore at different address than zero,
add the base register to CHECK_VMAP_STACK and CHECK_STACK. No
functional change, because %r0 is passed to the macro.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
In preparation of having lowcore at different address than zero,
add the base register to SIEEXIT. No functional change, because
%r0 is passed to the macro.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
In preparation of having lowcore at different address than zero,
add the base register to MBEAR. No functional change, because
%r0 is passed to the macro.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
In preparation of having lowcore at different address than zero,
add the base register to all lowcore accesses in __sie64a().
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
CIF_SIE indicates if a thread is running in SIE context. This is the
state of a thread and not the CPU. Therefore move this indicator to
thread info.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
The low level machine check handler code fills the ptregs structure
partially with the register contents present at machine check handler
entry and partially with contents from the machine check save area.
In case of a machine check the contents of all general purpose
registers are saved by the CPU to the machine check save area.
Therefore simplify the code and fill the ptregs structure by only
using the machine check save area as source.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
The nospec implementation is deeply integrated into the alternatives
code: only for nospec an alternative facility list is implemented and
used by the alternative code, while it is modified by nospec specific
needs.
Push down the nospec alternative handling into the nospec by
introducing a new alternative type and a specific nospec callback to
decide if alternatives should be applied.
Also introduce a new global nobp variable which together with facility
82 can be used to decide if nobp is enabled or not.
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Tested-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Rework alternatives to allow for callbacks. With this every
alternative entry has additional data encoded:
- When (aka context) an alternative is supposed to be applied
- The type of an alternative, which allows for type specific handling
and callbacks
- Extra type specific payload (patch information), which can be passed
to callbacks in order to decide if an alternative should be applied
or not
With this only the "late" context is implemented, which means there is
no change to the previous behaviour. All code is just converted to the
more generic new infrastructure.
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Tested-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
The two alternative header files must stay in sync. This is easier to
achieve within one header file. Therefore merge both of them and have
only one file, like most other architectures.
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Tested-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
To allow testing flags for offline CPUs, move the CIF flags
to struct pcpu. To avoid having to calculate the array index
for each access, add a pointer to the pcpu member for the current
cpu to lowcore.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Pass the guest ASCE explicitly as parameter, instead of having sie64a()
take it from lowcore.
This removes hidden state from lowcore, and makes things look cleaner.
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
Link: https://lore.kernel.org/r/20240703155900.103783-2-imbrenda@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
To ease maintenance and further enhancements, convert
the psw_idle() function to C.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
The recently added check to figure out if a fault happened on gmap ASCE
dereferences the gmap pointer in lowcore without checking that it is not
NULL. For all non-KVM processes the pointer is NULL, so that some value
from lowcore will be read. With the current layouts of struct gmap and
struct lowcore the read value (aka ASCE) is zero, so that this doesn't lead
to any observable bug; at least currently.
Fix this by adding the missing NULL pointer check.
Fixes: 64c3431808 ("s390/entry: compare gmap asce to determine guest/host fault")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Align system call table on 8 bytes. With sys_call_table entry size
of 8 bytes that eliminates the possibility of a system call pointer
crossing cache line boundary.
Cc: stable@kernel.org
Suggested-by: Ulrich Weigand <ulrich.weigand@de.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
With the current implementation, there are some cornercases where
a host fault would be treated as a guest fault, for example
when the sie instruction causes a program check. Therefore store
the gmap asce in ptregs, and use that to compare the primary asce
from the fault instead of matching instruction addresses.
Suggested-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
With only one OUTSIDE user left, remove the macro and move the code
directly to the machine check handler. This has the advantage that
it is much easier to determine which registers are used.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
When a program check, interrupt or machine check is triggered, the
PSW address is compared to a certain range of the sie64a() function
to figure out whether SIE was interrupted and a cleanup of SIE is
needed.
This doesn't work with kprobes: If kprobes probes an instruction, it
copies the instruction to the kprobes instruction page and overwrites the
original instruction with an undefind instruction (Opcode 00). When this
instruction is hit later, kprobes single-steps the instruction on the
kprobes_instruction page.
However, if this instruction is a relative branch instruction it will now
point to a different location in memory due to being moved to the kprobes
instruction page. If the new branch target points into sie64a() the kernel
assumes it interrupted SIE when processing the breakpoint and will crash
trying to access the SIE control block.
Instead of comparing the address, introduce a new CIF_SIE flag which
indicates whether SIE was interrupted.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Suggested-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
KVM modifies the kernel fpu's regs pointer to its own area to implement its
custom version of preemtible kernel fpu context. With general support for
preemptible kernel fpu context there is no need for the extra complexity in
KVM code anymore.
Therefore convert KVM to a regular kernel fpu user. In particular this
means that all TIF_FPU checks can be removed, since the fpu register
context will never be changed by other kernel fpu users, and also the fpu
register context will be restored if a thread is preempted.
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
The FPU state, as represented by the CIF_FPU flag reflects the FPU state of
a task, not the CPU it is running on. Therefore convert the flag to a
regular TIF flag.
This removes the magic in switch_to() where a save_fpu_regs() call for the
currently (previous) running task sets the per-cpu CIF_FPU flag, which is
required to restore FPU register contents of the next task, when it returns
to user space.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Move, rename, and merge the fpu and vx header files. This way fpu header
files have a consistent naming scheme (fpu*.h).
Also get rid of the fpu subdirectory and move header files to asm
directory, so that all fpu and vx header files can be found at the same
location.
Merge internal.h header file into other header files, since the internal
helpers are used at many locations. so those helper functions are really
not internal.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Remove the historic machine check handler code which validates registers.
Registers are automatically validated as part of the machine check handling
sequence (see Principles of Operation, Machine-Check Handling chapter,
Validation).
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Move the switch_to() implementation to process.c and use the generic
switch_to.h header file instead, like some other architectures.
This addresses also the oddity that the old switch_to() implementation
assigns the return value of __switch_to() to 'prev' instead of 'last',
like it should.
Remove also all includes of switch_to.h from C files, except process.c.
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Commit ddb5cdbafa ("kbuild: generate KSYMTAB entries by modpost")
deprecated <asm/export.h>, which is now a wrapper of <linux/export.h>.
Replace #include <asm/export.h> with #include <linux/export.h>.
After all the <asm/export.h> lines are converted, <asm/export.h> and
<asm-generic/export.h> will be removed.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20230806151641.394720-2-masahiroy@kernel.org
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
In the past machine checks where accounted as irq time. With the conversion
to generic entry, it was decided to account machine checks to the current
context. The stckf at the beginning of the machine check handler and the
lowcore member is no longer required, therefore remove it.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Instead of enforcing PSW_MASK_DAT bit on previously stored
in lowcore restart_psw.mask use the PSW_KERNEL_BITS mask
(which contains PSW_MASK_DAT) directly.
As result, the PSW mask stored in lowcore is only used to
enter the CPU restart routine, while PSW_KERNEL_BITS is
used to enter the kernel code - similarily to commit
64ea2977add2 ("s390/mm: start kernel with DAT enabled").
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
