diff options
| author | Mark Rutland <mark.rutland@arm.com> | 2025-04-09 17:40:08 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2025-04-09 18:06:31 +0100 |
| commit | 3aa4d74438afa1324513a7a6bc30f57e8727ad86 (patch) | |
| tree | e1572e5e7ed71ed8dc67bb615648811b1f8aa2a0 | |
| parent | d3a181588df9401d319fe2dc24bf1a364a687cc2 (diff) | |
arm64/fpsimd: signal32: Always save+flush state early
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>
| -rw-r--r-- | arch/arm64/kernel/signal32.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c index 81e798b6dada..bb3b526ff43f 100644 --- a/arch/arm64/kernel/signal32.c +++ b/arch/arm64/kernel/signal32.c @@ -103,7 +103,7 @@ static int compat_preserve_vfp_context(struct compat_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); @@ -169,14 +169,17 @@ static int compat_restore_vfp_context(struct compat_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 compat_restore_sigframe(struct pt_regs *regs, |