linux-toradex.git/include/vdso, branch v6.9-rc5

vdso: Use CONFIG_PAGE_SHIFT in vdso/datapage.h

2024-04-03T19:50:04+00:00

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 8b3843ae3634 ("vdso/datapage:
Quick fix - use asm/page-def.h for ARM64") and addresses a build warning
for powerpc64:

In file included from :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 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Kees Cook 
Acked-by: Michael Ellerman  (powerpc)
Link: https://lore.kernel.org/r/20240320180228.136371-1-arnd@kernel.org

vdso/datapage: Quick fix - use asm/page-def.h for ARM64

2024-02-26T22:13:41+00:00

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 :
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: a0d2fcd62ac2 ("vdso/ARM: Make union vdso_data_store available for all architectures")
Reported-by: Linux Kernel Functional Testing 
Signed-off-by: Anna-Maria Behnsen 
Signed-off-by: Thomas Gleixner 
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/

vdso/ARM: Make union vdso_data_store available for all architectures

2024-02-20T19:56:00+00:00

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 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Vincenzo Frascino 
Reviewed-by: Kees Cook 
Link: https://lore.kernel.org/r/20240219153939.75719-5-anna-maria@linutronix.de

vdso/helpers: Fix grammar in comments

2024-02-20T19:56:00+00:00

Signed-off-by: Anna-Maria Behnsen 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Vincenzo Frascino 
Reviewed-by: Kees Cook 
Link: https://lore.kernel.org/r/20240219153939.75719-2-anna-maria@linutronix.de

arch: vdso: consolidate gettime prototypes

2023-11-23T10:32:32+00:00

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 
Signed-off-by: Arnd Bergmann

vdso/bits.h: Add BIT_ULL() for the sake of consistency

2023-01-31T13:42:10+00:00

The minimization done in 3945ff37d2f4 ("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 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20221128141003.77929-1-andriy.shevchenko@linux.intel.com

time64.h: Consolidated PSEC_PER_SEC definition

2021-04-06T23:32:17+00:00

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 
Acked-by: Heiko Stuebner 
Signed-off-by: David S. Miller

lib/vdso: Allow to add architecture-specific vdso data

2020-08-06T08:57:30+00:00

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 
Signed-off-by: Thomas Gleixner 
Link: https://lkml.kernel.org/r/20200804150124.41692-2-svens@linux.ibm.com

timekeeping/vsyscall: Provide vdso_update_begin/end()

2020-08-06T08:57:30+00:00

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 
Signed-off-by: Sven Schnelle 
Signed-off-by: Thomas Gleixner 
Link: https://lkml.kernel.org/r/20200804150124.41692-3-svens@linux.ibm.com

arm64/vdso: Add time namespace page

2020-07-24T12:15:20+00:00

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 
Reviewed-by: Vincenzo Frascino 
Reviewed-by: Dmitry Safonov 
Cc: Mark Rutland 
Link: https://lore.kernel.org/r/20200624083321.144975-4-avagin@gmail.com
Signed-off-by: Catalin Marinas