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FROMGIT: arm64/fpsimd: ptrace: Save task state before generating SVE header

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As sve_init_header_from_task() consumes the saved value of PSTATE.SM and
the saved fp_type, both must be saved before the header is generated.

When generating a coredump for the current task, sve_get_common() calls
sve_init_header_from_task() before saving the task's state. Consequently
the header may be bogus, and the contents of the regset may be
misleading.

Fix this by saving the task's state before generting the header.

Fixes: e12310a0d3 ("arm64/sme: Implement ptrace support for streaming mode SVE registers")
Fixes: b017a0cea6 ("arm64/ptrace: Use saved floating point state type to determine SVE layout")
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/20250508132644.1395904-17-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
(cherry picked from commit 054d627c5554bdd38228174b275d62113124e3ad
 https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git
 for-next/sme-fixes)
Bug: 393087661
Signed-off-by: Will Deacon <willdeacon@google.com>
Change-Id: Idb971c6a96b45098aedec363b00c202f6560ab44
This commit is contained in:
Mark Rutland
2025-05-08 14:26:36 +01:00
committed by Will Deacon
parent 3baa9071c3
commit 958a94681f
1 changed files with 3 additions and 3 deletions
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6
arch/arm64/kernel/ptrace.c
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@@ -821,15 +821,15 @@ static int sve_get_common(struct task_struct *target,
unsigned int vq;
unsigned long start, end;
if (target == current)
fpsimd_preserve_current_state();
/* Header */
sve_init_header_from_task(&header, target, type);
vq = sve_vq_from_vl(header.vl);
membuf_write(&to, &header, sizeof(header));
if (target == current)
fpsimd_preserve_current_state();
BUILD_BUG_ON(SVE_PT_FPSIMD_OFFSET != sizeof(header));
BUILD_BUG_ON(SVE_PT_SVE_OFFSET != sizeof(header));