Mark Rutland 78b23877db kselftest/arm64: fp-ptrace: Fix expected FPMR value when PSTATE.SM is changed ... The fp-ptrace test suite expects that FPMR is set to zero when PSTATE.SM is changed via ptrace, but ptrace has never altered FPMR in this way, and the test logic erroneously relies upon (and has concealed) a bug where task_fpsimd_load() would unexpectedly and non-deterministically clobber FPMR. Using ptrace, FPMR can only be altered by writing to the NT_ARM_FPMR regset. The value of PSTATE.SM can be altered by writing to the NT_ARM_SVE or NT_ARM_SSVE regsets, and/or by changing the SME vector length (when writing to the NT_ARM_SVE, NT_ARM_SSVE, or NT_ARM_ZA regsets), but none of these writes will change the value of FPMR. The task_fpsimd_load() bug was introduced with the initial FPMR support in commit: 203f2b95a8 ("arm64/fpsimd: Support FEAT_FPMR") The incorrect FPMR test code was introduced in commit: 7dbd26d0b2 ("kselftest/arm64: Add FPMR coverage to fp-ptrace") Subsequently, the task_fpsimd_load() bug was fixed in commit: e5fa85fce0 ("arm64/fpsimd: Don't corrupt FPMR when streaming mode changes") ... whereupon the fp-ptrace FPMR tests started failing reliably, e.g. | # # Mismatch in saved FPMR: 915058000 != 0 | # not ok 25 SVE write, SVE 64->64, SME 64/0->64/1 Fix this by changing the test to expect that FPMR is *NOT* changed when PSTATE.SM is changed via ptrace, matching the extant behaviour. I've chosen to update the test code rather than modifying ptrace to zero FPMR when PSTATE.SM changes. Not zeroing FPMR is simpler overall, and allows the NT_ARM_FPMR regset to be handled independently from other regsets, leaving less scope for error. Fixes: 7dbd26d0b2 ("kselftest/arm64: Add FPMR coverage to fp-ptrace") Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Spickett <david.spickett@arm.com> Cc: Luis Machado <luis.machado@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Mark Brown <broonie@kernel.org> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20250508132644.1395904-22-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org>		2025-05-08 15:45:24 +01:00
..
crypto/chacha20-s390	crypto: lib/chacha - remove unused arch-specific init support	2025-03-21 17:39:06 +08:00
cxl	cxl for v6.15	2025-04-02 20:04:43 -07:00
fault-injection
ktest	ktest: Fix Test Failures Due to Missing LOG_FILE Directories	2025-03-27 09:34:00 -04:00
kunit	Landlock update for v6.15-rc1	2025-03-28 12:37:13 -07:00
memblock
nvdimm	Get rid of 'remove_new' relic from platform driver struct	2024-12-01 15:12:43 -08:00
radix-tree	xarray: add xas_try_split() to split a multi-index entry	2025-03-17 22:06:59 -07:00
rbtree	lib/interval_tree: add test case for span iteration	2025-03-17 12:17:01 -07:00
scatterlist
selftests	kselftest/arm64: fp-ptrace: Fix expected FPMR value when PSTATE.SM is changed	2025-05-08 15:45:24 +01:00
shared	lib/rbtree: enable userland test suite for rbtree related data structure	2025-03-17 12:17:00 -07:00
vma	mm: make vma cache SLAB_TYPESAFE_BY_RCU	2025-03-16 22:06:21 -07:00
vsock	vsock/test: Add test for SO_LINGER null ptr deref	2025-02-12 20:01:29 -08:00