From: Mark Rutland <mark.rutland@arm.com> mainline inclusion from mainline-6.16 commit 3aa4d74438afa1324513a7a6bc30f57e8727ad86 category: feature bugzilla: https://atomgit.com/openeuler/kernel/issues/8904 CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ---------------------------------------------------------------------- There are several issues with the way the native signal handling code manipulates FPSIMD/SVE/SME state. To fix those issues, subsequent patches will rework the native signal handling code to always save+flush the current task's FPSIMD/SVE/SME state before manipulating that state. In preparation for those changes, rework the compat signal handling code to save+flush the current task's FPSIMD state before manipulating it. Subsequent patches will remove fpsimd_signal_preserve_current_state() and fpsimd_update_current_state(). Compat tasks can only have FPSIMD state, and cannot have any SVE or SME state. Thus, the SVE state manipulation present in fpsimd_signal_preserve_current_state() and fpsimd_update_current_state() is not necessary, and it is safe to directly manipulate current->thread.uw.fpsimd_state once it has been saved+flushed. Use fpsimd_save_and_flush_current_state() to save+flush the state for both signal delivery and signal return, before the state is manipulated in any way. While it would be safe for compat_restore_vfp_context() to use fpsimd_flush_task_state(current), there are several extant issues in the native signal code resulting from incorrect use of fpsimd_flush_task_state(), and for consistency it is preferable to use fpsimd_save_and_flush_current_state(). Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Mark Brown <broonie@kernel.org> Cc: Will Deacon <will@kernel.org> Reviewed-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20250409164010.3480271-12-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Conflicts: arch/arm64/kernel/signal32.c [Context conflicts] Signed-off-by: Qinxin Xia <xiaqinxin@huawei.com> Signed-off-by: Hongye Lin <linhongye@h-partners.com> --- arch/arm64/kernel/signal32.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c index 8a0de714cb8e..1c86352cdfe2 100644 --- a/arch/arm64/kernel/signal32.c +++ b/arch/arm64/kernel/signal32.c @@ -82,7 +82,7 @@ static int a32_preserve_vfp_context(struct a32_vfp_sigframe __user *frame) * Note that this also saves V16-31, which aren't visible * in AArch32. */ - fpsimd_signal_preserve_current_state(); + fpsimd_save_and_flush_current_state(); /* Place structure header on the stack */ __put_user_error(magic, &frame->magic, err); @@ -148,14 +148,17 @@ static int a32_restore_vfp_context(struct a32_vfp_sigframe __user *frame) fpsimd.fpsr = fpscr & VFP_FPSCR_STAT_MASK; fpsimd.fpcr = fpscr & VFP_FPSCR_CTRL_MASK; + if (err) + return -EFAULT; + /* * We don't need to touch the exception register, so * reload the hardware state. */ - if (!err) - fpsimd_update_current_state(&fpsimd); + fpsimd_save_and_flush_current_state(); + current->thread.uw.fpsimd_state = fpsimd; - return err ? -EFAULT : 0; + return 0; } static int a32_restore_sigframe(struct pt_regs *regs, -- 2.33.0