kernel.git/arch/arm64/include/asm/vdso, branch linux-6.15.y

arm64: vdso: Work around invalid absolute relocations from GCC

2025-05-02T18:57:11Z

All vDSO code needs to be completely position independent. Symbol references are marked as hidden so the compiler emits PC-relative relocations. However GCC emits absolute relocations for symbol-relative references with an offset >= 64KiB. After recent refactorings in the vDSO code this is the case in __arch_get_vdso_u_timens_data() with a page size of 64KiB. Work around the issue by preventing the optimizer from seeing the offsets. Fixes: 83a2a6b8cfc5 ("vdso/gettimeofday: Prepare do_hres_timens() for introduction of struct vdso_clock") Reported-by: Jan Stancek Signed-off-by: Thomas Weißschuh Signed-off-by: Thomas Gleixner Acked-by: Catalin Marinas Link: https://lore.kernel.org/all/20250430-vdso-absolute-reloc-v2-1-5efcc3bc4b26@linutronix.de Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120002 Closes: https://lore.kernel.org/lkml/aApGPAoctq_eoE2g@t14ultra/

vdso: Rework struct vdso_time_data and introduce struct vdso_clock

2025-03-08T13:37:41Z

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 Signed-off-by: Nam Cao Signed-off-by: Thomas Weißschuh Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/20250303-vdso-clock-v1-19-c1b5c69a166f@linutronix.de

arm64/vdso: Prepare introduction of struct vdso_clock

2025-03-08T13:37:41Z

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 array of VDSO clocks. At the moment, vdso_clock is simply a define which maps vdso_clock to vdso_time_data. To prepare for the rework of the data structures, replace the struct vdso_time_data pointer with a struct vdso_clock pointer where applicable. No functional change. Signed-off-by: Nam Cao Signed-off-by: Thomas Weißschuh Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/20250303-vdso-clock-v1-16-c1b5c69a166f@linutronix.de

arm64: vdso: Switch to generic storage implementation

2025-02-21T08:54:01Z

The generic storage implementation provides the same features as the custom one. However it can be shared between architectures, making maintenance easier. This switch also moves the random state data out of the time data page. The currently used hardcoded __VDSO_RND_DATA_OFFSET does not take into account changes to the time data page layout. Co-developed-by: Nam Cao Signed-off-by: Nam Cao Signed-off-by: Thomas Weißschuh Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/20250204-vdso-store-rng-v3-8-13a4669dfc8c@linutronix.de

vdso: Remove timekeeper argument of __arch_update_vsyscall()

2024-10-15T15:50:28Z

No implementation of this hook uses the passed in timekeeper anymore. This avoids including a non-VDSO header while building the VDSO, which can lead to compilation errors. Signed-off-by: Thomas Weißschuh Signed-off-by: Thomas Gleixner Acked-by: Will Deacon Link: https://lore.kernel.org/all/20241010-vdso-generic-arch_update_vsyscall-v1-1-7fe5a3ea4382@linutronix.de

arm64: vDSO: Wire up getrandom() vDSO implementation

2024-09-13T15:28:36Z

Hook up the generic vDSO implementation to the aarch64 vDSO data page. The _vdso_rng_data required data is placed within the _vdso_data vvar page, by using a offset larger than the vdso_data. The vDSO function requires a ChaCha20 implementation that does not write to the stack, and that can do an entire ChaCha20 permutation. The one provided uses NEON on the permute operation, with a fallback to the syscall for chips that do not support AdvSIMD. This also passes the vdso_test_chacha test along with vdso_test_getrandom. The vdso_test_getrandom bench-single result on Neoverse-N1 shows: vdso: 25000000 times in 0.783884250 seconds libc: 25000000 times in 8.780275399 seconds syscall: 25000000 times in 8.786581518 seconds A small fixup to arch/arm64/include/asm/mman.h was required to avoid pulling kernel code into the vDSO, similar to what's already done in arch/arm64/include/asm/rwonce.h. Signed-off-by: Adhemerval Zanella Reviewed-by: Ard Biesheuvel Acked-by: Will Deacon Signed-off-by: Jason A. Donenfeld

arm64: rework compat syscall macros

2024-07-10T12:23:38Z

The generated asm/unistd_compat_32.h header file now contains macros that can be used directly in the vdso and the signal trampolines, so remove the duplicate definitions. Acked-by: Catalin Marinas Signed-off-by: Arnd Bergmann

arm64: vdso: use SYS_CNTVCTSS_EL0 for gettimeofday

2022-09-09T11:27:25Z

If FEAT_ECV is implemented, the self-synchronized counter CNTVCTSS_EL0 can be used, removing the need for an ISB. Signed-off-by: Joey Gouly Cc: Will Deacon Cc: Vincenzo Frascino Cc: Mark Rutland Cc: Andre Przywara Acked-by: Mark Rutland Link: https://lore.kernel.org/r/20220830104833.34636-4-joey.gouly@arm.com Signed-off-by: Catalin Marinas

arm64: vdso32: drop test for -march=armv8-a

2021-10-21T09:31:38Z

As Arnd points out: gcc-4.8 already supported -march=armv8, and we require gcc-5.1 now, so both this #if/#else construct and the corresponding "cc32-option,-march=armv8-a" check should be obsolete now. Link: https://lore.kernel.org/lkml/CAK8P3a3UBEJ0Py2ycz=rHfgog8g3mCOeQOwO0Gmp-iz6Uxkapg@mail.gmail.com/ Suggested-by: Arnd Bergmann Signed-off-by: Nick Desaulniers Reviewed-by: Vincenzo Frascino Reviewed-by: Nathan Chancellor Link: https://lore.kernel.org/r/20211019223646.1146945-3-ndesaulniers@google.com Signed-off-by: Will Deacon

arm64: vdso32: drop the test for dmb ishld

2021-10-21T09:31:38Z

Binutils added support for this instruction in commit e797f7e0b2bedc9328d4a9a0ebc63ca7a2dbbebc which shipped in 2.24 (just missing the 2.23 release) but was cherry-picked into 2.23 in commit 27a50d6755bae906bc73b4ec1a8b448467f0bea1. Thanks to Christian and Simon for helping me with the patch archaeology. According to Documentation/process/changes.rst, the minimum supported version of binutils is 2.23. Since all supported versions of GAS support this instruction, drop the assembler invocation, preprocessor flags/guards, and the cross assembler macro that's now unused. This also avoids a recursive self reference in a follow up cleanup patch. Cc: Christian Biesinger Cc: Simon Marchi Signed-off-by: Nick Desaulniers Reviewed-by: Vincenzo Frascino Reviewed-by: Nathan Chancellor Link: https://lore.kernel.org/r/20211019223646.1146945-2-ndesaulniers@google.com Signed-off-by: Will Deacon