From a90878f297d3dba906a6261deccb1bd4a791ba52 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Wed, 9 Apr 2025 17:40:05 +0100 Subject: [PATCH] arm64/fpsimd: Reset FPMR upon exec() An exec() is expected to reset all FPSIMD/SVE/SME state, and barring special handling of the vector lengths, the state is expected to reset to zero. This reset is handled in fpsimd_flush_thread(), which the core exec() code calls via flush_thread(). When support was added for FPMR, no logic was added to fpsimd_flush_thread() to reset the FPMR value, and thus it is erroneously inherited across an exec(). Add the missing reset of FPMR. Fixes: 203f2b95a882 ("arm64/fpsimd: Support FEAT_FPMR") Signed-off-by: Mark Rutland Cc: Marc Zyngier Cc: Mark Brown Cc: Will Deacon Reviewed-by: Mark Brown Link: https://lore.kernel.org/r/20250409164010.3480271-9-mark.rutland@arm.com Signed-off-by: Catalin Marinas --- arch/arm64/kernel/fpsimd.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 4a0b0bb3a3fa..0b6fda5b7bad 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -1638,6 +1638,9 @@ void fpsimd_flush_thread(void) current->thread.svcr = 0; } + if (system_supports_fpmr()) + current->thread.uw.fpmr = 0; + current->thread.fp_type = FP_STATE_FPSIMD; put_cpu_fpsimd_context(); -- 2.50.1