Expose the auxiliary clocks through the vDSO.
Architectures not using the generic vDSO time framework,
namely SPARC64, are not supported.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250701-vdso-auxclock-v1-12-df7d9f87b9b8@linutronix.de
Expose the auxiliary clock data so it can be read from the vDSO.
Architectures not using the generic vDSO time framework,
namely SPARC64, are not supported.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250701-vdso-auxclock-v1-11-df7d9f87b9b8@linutronix.de
Auxiliary clocks will have their vDSO data in a dedicated 'struct vdso_clock',
which needs to be synchronized independently.
Add a helper to synchronize a single vDSO clock.
[ tglx: Move the SMP memory barriers to the call sites and get rid of the
confusing first/last arguments and conditional barriers ]
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250701-vdso-auxclock-v1-4-df7d9f87b9b8@linutronix.de
Compiling the kernel with gcc12.3 W=2 results in shadowing warnings:
warning: declaration of '__pptr' shadows a previous local [-Wshadow]
const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr);
note: in definition of macro '__put_unaligned_t'
__pptr->x = (val);
note: in expansion of macro '__get_unaligned_t'
__put_unaligned_t(type, __get_unaligned_t(type, src), dst);
__get_unaligned_t() and __put_unaligned_t() use a local variable named
'__pptr', which can lead to variable shadowing when these macros are used in
the same scope. This results in a -Wshadow warning during compilation.
To address this issue, rename the local variables within the macros to
ensure uniqueness.
Signed-off-by: Peng Jiang <jiang.peng9@zte.com.cn>
Signed-off-by: Shao Mingyin <shao.mingyin@zte.com.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250324191230477zpGtgIRSH4mEHdtxGtgx9@zte.com.cn
To support multiple PTP clocks, the VDSO data structure needs to be
reworked. All clock specific data will end up in struct vdso_clock and in
struct vdso_time_data there will be an array of VDSO clocks.
Now that all preparatory changes are in place:
Split the clock related struct members into a separate struct
vdso_clock. Make sure all users are aware, that vdso_time_data is no longer
initialized as an array and vdso_clock is now the array inside
vdso_data. Remove the vdso_clock define, which mapped it to vdso_time_data
for the transition.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250303-vdso-clock-v1-19-c1b5c69a166f@linutronix.de
Architecture related vdso data is required in the fast path when reading
CLOCK_MONOTONIC or CLOCK_REALTIME. At the moment, this information is
located at the end of the vdso_time_data structure, which is a suboptimal
cache layout.
Move the architecture specific VDSO data right before the basetime
information, which is always required. This change does not have an impact
on architectures with CONFIG_ARCH_HAS_VDSO_DATA=n. Architectures, which
have it enabled, gain a better cache layout.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250303-vdso-clock-v1-18-c1b5c69a166f@linutronix.de
To support multiple PTP clocks, the VDSO data structure needs to be
reworked. All clock specific data will end up in struct vdso_clock and in
struct vdso_time_data there will be an array of VDSO clocks. For now,
vdso_clock is simply a define which maps vdso_clock to vdso_time_data.
Prepare all functions which need the pointer to the vdso_clock array to
work well after the structures get reworked. Replace the struct vdso_time_data
pointer with a struct vdso_clock pointer where applicable.
No functional change.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250303-vdso-clock-v1-5-c1b5c69a166f@linutronix.de
Multiple PTP clocks, which are independent of timekeeping, are required for
systems, which utilize PTP for synchronizing e.g. automation systems
independent of clock TAI.
PTP clocks are slow to access, but applications require fast access to the
relevant time similar to the regular timekeeping relevant clocks.
To prepare for that the VDSO data representation must be reworked. For
transition to the new structure of the vdso, add a define which maps
vdso_clock to vdso_data. This will be removed when all users are updated
step by step.
No functional change.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250303-vdso-clock-v1-4-c1b5c69a166f@linutronix.de
vdso_time_data is not cacheline aligned at the moment. When instantiating
an array, the start of the second array member is not cache line aligned.
This increases the number of the required cache lines which needs to be
read when handling e.g. CLOCK_MONOTONIC_RAW, because the data spawns an
extra cache line if the previous data does not end at a cache line
boundary.
Therefore make struct vdso_time_data cacheline aligned.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250303-vdso-clock-v1-3-c1b5c69a166f@linutronix.de
The vDSO implementation can only include headers from the vdso/
namespace. To enable the usage of ____cacheline_aligned from
the vDSO, move it and its dependencies into a new header vdso/cache.h.
Keep compatibility by including vdso/cache.h from linux/cache.h.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250303-vdso-clock-v1-1-c1b5c69a166f@linutronix.de
All users of the time releated parts of the vDSO are now using the generic
storage implementation. Remove the therefore unnecessary compatibility
accessor functions and symbols.
Co-developed-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250204-vdso-store-rng-v3-18-13a4669dfc8c@linutronix.de
All users of the random vDSO are using the generic storage
implementation. Remove the now unnecessary compatibility accessor
functions and symbols.
Co-developed-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250204-vdso-store-rng-v3-17-13a4669dfc8c@linutronix.de
Some architectures need to expose architecture-specific data to the vDSO.
Enable the generic vDSO storage mechanism to both store and map this
data. Some architectures require more than a single page, like LoongArch,
so prepare for that usecase, too.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250204-vdso-store-rng-v3-7-13a4669dfc8c@linutronix.de
Extend the generic vDSO data storage with a page for the random state data.
The random state data is stored in a dedicated page, as the existing
storage page is only meant for time-related, time-namespace-aware data.
This simplifies to access logic to not need to handle time namespaces
anymore and also frees up more space in the time-related page.
In case further generic vDSO data store is required it can be added to
the random state page.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250204-vdso-store-rng-v3-6-13a4669dfc8c@linutronix.de
Historically each architecture defined their own way to store the vDSO
data page. Add a generic mechanism to provide storage for that page.
Furthermore this generic storage will be extended to also provide
uniform storage for *non*-time-related data, like the random state or
architecture-specific data. These will have their own pages and data
structures, so rename 'vdso_data' into 'vdso_time_data' to make that
split clear from the name.
Also introduce a new consistent naming scheme for the symbols related to
the vDSO, which makes it clear if the symbol is accessible from
userspace or kernel space and the type of data behind the symbol.
The generic fault handler contains an optimization to prefault the vvar
page when the timens page is accessed. This was lifted from s390 and x86.
Co-developed-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250204-vdso-store-rng-v3-5-13a4669dfc8c@linutronix.de
The vDSO implementation can only include headers from the vdso/
namespace. To enable the usage of the ALIGN() macro from the vDSO, move
linux/align.h to vdso/align.h wholly.
As the only dependency linux/const.h is only a wrapper around
vdso/const.h anyways adapt that dependency.
Also provide a compatibility wrapper linux/align.h.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250204-vdso-store-rng-v3-3-13a4669dfc8c@linutronix.de
The struct arch_vdso_data is only about vdso time data. So rename it to
arch_vdso_time_data to make it obvious.
Non time-related data will be migrated out of these structs soon.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # s390
Link: https://lore.kernel.org/all/20241010-vdso-generic-base-v1-28-b64f0842d512@linutronix.de
With the introduction of an architecture-independent defintion of
PAGE_MASK, we had to make a choice between defining it as 'unsigned long'
as on 64-bit architectures, or as signed 'long' as required for
architectures with a 64-bit phys_addr_t.
To reduce the risk for regressions and minimize the changes in behavior,
the result was using the signed value only when CONFIG_PHYS_ADDR_T_64BIT
is set, but that ended up causing a regression after all in the
early_init_dt_add_memory_arch() function that uses 64-bit integers for
address calculation.
Presumably the same regression also affects mips32 and powerpc32 when
dealing with large amounts of memory on DT platforms: like arm32, they were
using the signed version unconditionally.
The two most sensible options for addressing the regression are either to
go back to an architecture specific definition, using a signed constant on
arm/powerpc/mips and unsigned on the others, or to use the same definition
everywhere.
Use the simpler of those two and change them all to the signed version, in
the hope that this does not cause a different type of bug. Most of the
other 32-bit architectures have no large physical address support and are
rarely used, so it seems more likely that using the same definition helps
than hurts here.
In particular, x86-32 does have physical addressing extensions, so it
already changed to the signed version after the previous patch, so it makes
sense to use the same version on non-PAE as well.
Fixes: efe8419ae7 ("vdso: Introduce vdso/page.h")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lore.kernel.org/all/20241024133447.3117273-1-arnd@kernel.org
Link: https://lore.kernel.org/lkml/CA+G9fYt86bUAu_v5dXPWnDUwQNVipj+Wq3Djir1KUSKdr9QLNg@mail.gmail.com/
The VDSO implementation includes headers from outside of the
vdso/ namespace.
Introduce vdso/page.h to make sure that the generic library
uses only the allowed namespace.
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k
Link: https://lore.kernel.org/all/20241014151340.1639555-3-vincenzo.frascino@arm.com
Without a prototype, we'll have to add a prototype for each architecture
implementing vDSO getrandom. As most architectures will likely have the
vDSO getrandom implemented in a near future, and we'd like to keep the
declarations compatible everywhere (to ease the libc implementor work),
we should really just have one copy of the prototype.
This also is what's already done inside of include/vdso/gettime.h for
those vDSO functions, so this continues that convention.
Suggested-by: Huacai Chen <chenhuacai@kernel.org>
Signed-off-by: Xi Ruoyao <xry111@xry111.site>
Acked-by: Huacai Chen <chenhuacai@kernel.org>
[Jason: rewrite docbook comment for prototype.]
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Depending on the architecture, building a 32-bit vDSO on a 64-bit kernel
is problematic when some system headers are included.
Minimise the amount of headers by moving needed items, such as
__{get,put}_unaligned_t, into dedicated common headers and in general
use more specific headers, similar to what was done in commit
8165b57bca ("linux/const.h: Extract common header for vDSO") and
commit 8c59ab839f ("lib/vdso: Enable common headers").
On some architectures this results in missing PAGE_SIZE, as was
described by commit 8b3843ae36 ("vdso/datapage: Quick fix - use
asm/page-def.h for ARM64"), so define this if necessary, in the same way
as done prior by commit cffaefd15a ("vdso: Use CONFIG_PAGE_SHIFT in
vdso/datapage.h").
Removing linux/time64.h leads to missing 'struct timespec64' in
x86's asm/pvclock.h. Add a forward declaration of that struct in
that file.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Having the prototype for __arch_chacha20_blocks_nostack in
arch/x86/include/asm/vdso/getrandom.h meant that the prototype and large
doc comment were cloned by every architecture, which has been causing
unnecessary churn. Instead move it into include/vdso/getrandom.h, where
it can be shared by all archs implementing it.
As a side bonus, this then lets us use that prototype in the
vdso_test_chacha self test, to ensure that it matches the source, and
indeed doing so turned up some inconsistencies, which are rectified
here.
Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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Merge tag 'random-6.11-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random
Pull random number generator updates from Jason Donenfeld:
"This adds getrandom() support to the vDSO.
First, it adds a new kind of mapping to mmap(2), MAP_DROPPABLE, which
lets the kernel zero out pages anytime under memory pressure, which
enables allocating memory that never gets swapped to disk but also
doesn't count as being mlocked.
Then, the vDSO implementation of getrandom() is introduced in a
generic manner and hooked into random.c.
Next, this is implemented on x86. (Also, though it's not ready for
this pull, somebody has begun an arm64 implementation already)
Finally, two vDSO selftests are added.
There are also two housekeeping cleanup commits"
* tag 'random-6.11-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
MAINTAINERS: add random.h headers to RNG subsection
random: note that RNDGETPOOL was removed in 2.6.9-rc2
selftests/vDSO: add tests for vgetrandom
x86: vdso: Wire up getrandom() vDSO implementation
random: introduce generic vDSO getrandom() implementation
mm: add MAP_DROPPABLE for designating always lazily freeable mappings
Provide a generic C vDSO getrandom() implementation, which operates on
an opaque state returned by vgetrandom_alloc() and produces random bytes
the same way as getrandom(). This has the following API signature:
ssize_t vgetrandom(void *buffer, size_t len, unsigned int flags,
void *opaque_state, size_t opaque_len);
The return value and the first three arguments are the same as ordinary
getrandom(), while the last two arguments are a pointer to the opaque
allocated state and its size. Were all five arguments passed to the
getrandom() syscall, nothing different would happen, and the functions
would have the exact same behavior.
The actual vDSO RNG algorithm implemented is the same one implemented by
drivers/char/random.c, using the same fast-erasure techniques as that.
Should the in-kernel implementation change, so too will the vDSO one.
It requires an implementation of ChaCha20 that does not use any stack,
in order to maintain forward secrecy if a multi-threaded program forks
(though this does not account for a similar issue with SA_SIGINFO
copying registers to the stack), so this is left as an
architecture-specific fill-in. Stack-less ChaCha20 is an easy algorithm
to implement on a variety of architectures, so this shouldn't be too
onerous.
Initially, the state is keyless, and so the first call makes a
getrandom() syscall to generate that key, and then uses it for
subsequent calls. By keeping track of a generation counter, it knows
when its key is invalidated and it should fetch a new one using the
syscall. Later, more than just a generation counter might be used.
Since MADV_WIPEONFORK is set on the opaque state, the key and related
state is wiped during a fork(), so secrets don't roll over into new
processes, and the same state doesn't accidentally generate the same
random stream. The generation counter, as well, is always >0, so that
the 0 counter is a useful indication of a fork() or otherwise
uninitialized state.
If the kernel RNG is not yet initialized, then the vDSO always calls the
syscall, because that behavior cannot be emulated in userspace, but
fortunately that state is short lived and only during early boot. If it
has been initialized, then there is no need to inspect the `flags`
argument, because the behavior does not change post-initialization
regardless of the `flags` value.
Since the opaque state passed to it is mutated, vDSO getrandom() is not
reentrant, when used with the same opaque state, which libc should be
mindful of.
The function works over an opaque per-thread state of a particular size,
which must be marked VM_WIPEONFORK, VM_DONTDUMP, VM_NORESERVE, and
VM_DROPPABLE for proper operation. Over time, the nuances of these
allocations may change or grow or even differ based on architectural
features.
The opaque state passed to vDSO getrandom() must be allocated using the
mmap_flags and mmap_prot parameters provided by the vgetrandom_opaque_params
struct, which also contains the size of each state. That struct can be
obtained with a call to vgetrandom(NULL, 0, 0, ¶ms, ~0UL). Then,
libc can call mmap(2) and slice up the returned array into a state per
each thread, while ensuring that no single state straddles a page
boundary. Libc is expected to allocate a chunk of these on first use,
and then dole them out to threads as they're created, allocating more
when needed.
vDSO getrandom() provides the ability for userspace to generate random
bytes quickly and safely, and is intended to be integrated into libc's
thread management. As an illustrative example, the introduced code in
the vdso_test_getrandom self test later in this series might be used to
do the same outside of libc. In a libc the various pthread-isms are
expected to be elided into libc internals.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
struct vdso_data is optimized for fast access to the often required struct
members. The optimization is not documented in the struct description but
it should be kept in mind, when working with the vdso_data struct.
Add a comment to the struct description.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lore.kernel.org/r/20240701-vdso-cleanup-v1-2-36eb64e7ece2@linutronix.de
Add vdso_data::max_cycles in preparation to use it to detect potential
multiplication overflow.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240325064023.2997-7-adrian.hunter@intel.com
Provide mul_u64_u32_add_u64_shr() which is a calculation that will be used
by timekeeping and VDSO.
Place #include <vdso/math64.h> after #include <asm/div64.h> to allow
architecture-specific overrides, at least for the kernel.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240325064023.2997-6-adrian.hunter@intel.com
Both the vdso rework and the CONFIG_PAGE_SHIFT changes were merged during
the v6.9 merge window, so it is now possible to use CONFIG_PAGE_SHIFT
instead of including asm/page.h in the vdso.
This avoids the workaround for arm64 - commit 8b3843ae36 ("vdso/datapage:
Quick fix - use asm/page-def.h for ARM64") and addresses a build warning
for powerpc64:
In file included from <built-in>:4:
In file included from /home/arnd/arm-soc/arm-soc/lib/vdso/gettimeofday.c:5:
In file included from ../include/vdso/datapage.h:25:
arch/powerpc/include/asm/page.h:230:9: error: result of comparison of constant 13835058055282163712 with expression of type 'unsigned long' is always true [-Werror,-Wtautological-constant-out-of-range-compare]
230 | return __pa(kaddr) >> PAGE_SHIFT;
| ^~~~~~~~~~~
arch/powerpc/include/asm/page.h:217:37: note: expanded from macro '__pa'
217 | VIRTUAL_WARN_ON((unsigned long)(x) < PAGE_OFFSET); \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~
arch/powerpc/include/asm/page.h:202:73: note: expanded from macro 'VIRTUAL_WARN_ON'
202 | #define VIRTUAL_WARN_ON(x) WARN_ON(IS_ENABLED(CONFIG_DEBUG_VIRTUAL) && (x))
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
arch/powerpc/include/asm/bug.h:88:25: note: expanded from macro 'WARN_ON'
88 | int __ret_warn_on = !!(x); \
| ^
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Link: https://lore.kernel.org/r/20240320180228.136371-1-arnd@kernel.org
The vdso rework for the generic union vdso_data_store broke compat VDSO on
arm64:
In file included from arch/arm64/include/asm/lse.h:5,
from arch/arm64/include/asm/cmpxchg.h:14,
from arch/arm64/include/asm/atomic.h:16,
from include/linux/atomic.h:7,
from include/asm-generic/bitops/atomic.h:5,
from arch/arm64/include/asm/bitops.h:25,
from include/linux/bitops.h:68,
from arch/arm64/include/asm/memory.h:209,
from arch/arm64/include/asm/page.h:46,
from include/vdso/datapage.h:22,
from lib/vdso/gettimeofday.c:5,
from <command-line>:
arch/arm64/include/asm/atomic_ll_sc.h:298:9: error: unknown type name 'u128'
298 | u128 full;
| ^~~~
arch/arm64/include/asm/atomic_ll_sc.h:305:24: error: unknown type name 'u128'
305 | static __always_inline u128
\
|
The reason is the include of asm/page.h which in turn includes headers
which are outside the scope of compat VDSO. The only reason for the
asm/page.h include is the required definition of PAGE_SIZE. But as arm64
defines PAGE_SIZE in asm/page-def.h without extra header includes, this
could be used instead.
Caution: this is a quick fix only! The final fix is an upcoming cleanup of
Arnd which consolidates PAGE_SIZE definition. After the cleanup, the
include of asm/page.h to access PAGE_SIZE is no longer required.
Fixes: a0d2fcd62a ("vdso/ARM: Make union vdso_data_store available for all architectures")
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240226175023.56679-1-anna-maria@linutronix.de
Link: https://lore.kernel.org/lkml/CA+G9fYtrXXm_KO9fNPz3XaRxHV7UD_yQp-TEuPQrNRHU+_0W_Q@mail.gmail.com/
The vDSO data page "union vdso_data_store" is defined in an ARM specific
header file and also defined in several other places.
Move the definition from the ARM header file into the generic vdso datapage
header to make it also usable for others and to prevent code duplication.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20240219153939.75719-5-anna-maria@linutronix.de
The VDSO functions are defined as globals in the kernel sources but intended
to be called from userspace, so there is no need to declare them in a kernel
side header.
Without a prototype, this now causes warnings such as
arch/mips/vdso/vgettimeofday.c:14:5: error: no previous prototype for '__vdso_clock_gettime' [-Werror=missing-prototypes]
arch/mips/vdso/vgettimeofday.c:28:5: error: no previous prototype for '__vdso_gettimeofday' [-Werror=missing-prototypes]
arch/mips/vdso/vgettimeofday.c:36:5: error: no previous prototype for '__vdso_clock_getres' [-Werror=missing-prototypes]
arch/mips/vdso/vgettimeofday.c:42:5: error: no previous prototype for '__vdso_clock_gettime64' [-Werror=missing-prototypes]
arch/sparc/vdso/vclock_gettime.c:254:1: error: no previous prototype for '__vdso_clock_gettime' [-Werror=missing-prototypes]
arch/sparc/vdso/vclock_gettime.c:282:1: error: no previous prototype for '__vdso_clock_gettime_stick' [-Werror=missing-prototypes]
arch/sparc/vdso/vclock_gettime.c:307:1: error: no previous prototype for '__vdso_gettimeofday' [-Werror=missing-prototypes]
arch/sparc/vdso/vclock_gettime.c:343:1: error: no previous prototype for '__vdso_gettimeofday_stick' [-Werror=missing-prototypes]
Most architectures have already added workarounds for these by adding
declarations somewhere, but since these are all compatible, we should
really just have one copy, with an #ifdef check for the 32-bit vs
64-bit variant and use that everywhere.
Unfortunately, the sparc an um versions are currently incompatible
since they never added support for __vdso_clock_gettime64() in 32-bit
userland. For the moment, I'm leaving this one out, as I can't
easily test it and it requires a larger rework.
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
The minimization done in 3945ff37d2 ("linux/bits.h: Extract common header
for vDSO") was required to isolate the VDSO build from the larger kernel
header impact.
The split added some inconsistency since BIT() and BIT_ULL() are now
defined in the different files which confuses unprepared reader.
Move BIT_ULL() to vdso/bits.h. No functional change.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20221128141003.77929-1-andriy.shevchenko@linux.intel.com
We have currently three users of the PSEC_PER_SEC each of them defining it
individually. Instead, move it to time64.h to be available for everyone.
There is a new user coming with the same constant in use. It will also
make its life easier.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
The initial assumption that all VDSO related data can be completely generic
does not hold. S390 needs architecture specific storage to access the clock
steering information.
Add struct arch_vdso_data to the vdso data struct. For architectures which
do not need extra data this defaults to an empty struct. Architectures
which require it, enable CONFIG_ARCH_HAS_VDSO_DATA and provide their
specific struct in asm/vdso/data.h.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200804150124.41692-2-svens@linux.ibm.com
Architectures can have the requirement to add additional architecture
specific data to the VDSO data page which needs to be updated independent
of the timekeeper updates.
To protect these updates vs. concurrent readers and a conflicting update
through timekeeping, provide helper functions to make such updates safe.
vdso_update_begin() takes the timekeeper_lock to protect against a
potential update from timekeeper code and increments the VDSO sequence
count to signal data inconsistency to concurrent readers. vdso_update_end()
makes the sequence count even again to signal data consistency and drops
the timekeeper lock.
[ Sven: Add interrupt disable handling to the functions ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200804150124.41692-3-svens@linux.ibm.com
Allocate the time namespace page among VVAR pages. Provide
__arch_get_timens_vdso_data() helper for VDSO code to get the
code-relative position of VVARs on that special page.
If a task belongs to a time namespace then the VVAR page which contains
the system wide VDSO data is replaced with a namespace specific page
which has the same layout as the VVAR page. That page has vdso_data->seq
set to 1 to enforce the slow path and vdso_data->clock_mode set to
VCLOCK_TIMENS to enforce the time namespace handling path.
The extra check in the case that vdso_data->seq is odd, e.g. a concurrent
update of the VDSO data is in progress, is not really affecting regular
tasks which are not part of a time namespace as the task is spin waiting
for the update to finish and vdso_data->seq to become even again.
If a time namespace task hits that code path, it invokes the corresponding
time getter function which retrieves the real VVAR page, reads host time
and then adds the offset for the requested clock which is stored in the
special VVAR page.
The time-namespace page isn't allocated on !CONFIG_TIME_NAMESPACE, but
vma is the same size, which simplifies criu/vdso migration between
different kernel configs.
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Dmitry Safonov <dima@arista.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20200624083321.144975-4-avagin@gmail.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
While the explanation for time namespace <-> vdso interactions is very
helpful it uses the wrong name in the comment when describing the clock
mode making grepping a bit annoying.
This seems like an accidental oversight when moving from VCLOCK_TIMENS
to VDSO_CLOCKMODE_TIMENS. It seems that
660fd04f93 ("lib/vdso: Prepare for time namespace support") misspelled
VCLOCK_TIMENS as VLOCK_TIMENS which explains why it got missed when
VCLOCK_TIMENS became VDSO_CLOCKMODE_TIMENS in
2d6b01bd88 ("lib/vdso: Move VCLOCK_TIMENS to vdso_clock_modes").
Update the comment to use VDSO_CLOCKMODE_TIMENS.
Fixes: 660fd04f93 ("lib/vdso: Prepare for time namespace support")
Fixes: 2d6b01bd88 ("lib/vdso: Move VCLOCK_TIMENS to vdso_clock_modes")
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andrei Vagin <avagin@gmail.com>
Acked-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lkml.kernel.org/r/20200420100615.1549804-1-christian.brauner@ubuntu.com
CONFIG_GENERIC_GETTIMEOFDAY is a sufficient condition to verify if an
architecture implements asm/vdso/clocksource.h or not. The current
implementation wrongly assumes that the same is true for the config
option CONFIG_ARCH_CLOCKSOURCE_DATA.
This results in a series of build errors on ia64/sparc/sparc64 like this:
In file included from ./include/linux/clocksource.h:31,
from ./include/linux/clockchips.h:14,
from ./include/linux/tick.h:8,
from fs/proc/stat.c:15:
./include/vdso/clocksource.h:9:10: fatal error: asm/vdso/clocksource.h:
No such file or directory
9 | #include <asm/vdso/clocksource.h>
| ^~~~~~~~~~~~~~~~~~~~~~~~
Fix the issue removing the unneeded config condition.
Fixes: 14ee2ac618 ("linux/clocksource.h: Extract common header for vDSO")
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200323133920.46546-1-vincenzo.frascino@arm.com
The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.
Refactor the unified vdso code to use the common headers.
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200320145351.32292-26-vincenzo.frascino@arm.com
The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.
Introduce processor.h to contain all the processor specific functions
that are suitable for vDSO inclusion.
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200320145351.32292-16-vincenzo.frascino@arm.com
The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.
Split ktime.h into linux and common headers to make the latter suitable
for inclusion in the vDSO library.
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200320145351.32292-15-vincenzo.frascino@arm.com
The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.
Split jiffies.h into linux and common headers to make the latter suitable
for inclusion in the vDSO library.
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200320145351.32292-14-vincenzo.frascino@arm.com
The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.
Split time64.h into linux and common headers to make the latter suitable
for inclusion in the vDSO library.
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200320145351.32292-13-vincenzo.frascino@arm.com
The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.
Split time32.h into linux and common headers to make the latter suitable
for inclusion in the vDSO library.
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200320145351.32292-12-vincenzo.frascino@arm.com
The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.
Split time.h into linux and common headers to make the latter suitable
for inclusion in the vDSO library.
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200320145351.32292-11-vincenzo.frascino@arm.com
The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.
Split math64.h into linux and common headers to make the latter suitable
for inclusion in the vDSO library.
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200320145351.32292-10-vincenzo.frascino@arm.com
The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.
Split clocksource.h into linux and common headers to make the latter
suitable for inclusion in the vDSO library.
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200320145351.32292-9-vincenzo.frascino@arm.com
