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Subject[PATCH v2 6/7] arm64: signal: nofpsimd: Handle fp/simd context for signal frames
Date
Make sure we try to save/restore the vfp/fpsimd context for signal
handling only when the fp/simd support is available. Otherwise, skip
the frames.

Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
arch/arm64/kernel/signal.c | 17 +++++++++++++++--
arch/arm64/kernel/signal32.c | 11 +++++++++--
2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index dd2cdc0d5be2..c648f7627035 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -173,6 +173,10 @@ static int preserve_fpsimd_context(struct fpsimd_context __user *ctx)
&current->thread.uw.fpsimd_state;
int err;

+ /* This must not be called when FP/SIMD support is missing */
+ if (WARN_ON(!system_supports_fpsimd()))
+ return -EINVAL;
+
/* copy the FP and status/control registers */
err = __copy_to_user(ctx->vregs, fpsimd->vregs, sizeof(fpsimd->vregs));
__put_user_error(fpsimd->fpsr, &ctx->fpsr, err);
@@ -191,6 +195,10 @@ static int restore_fpsimd_context(struct fpsimd_context __user *ctx)
__u32 magic, size;
int err = 0;

+ /* This must not be called when FP/SIMD support is missing */
+ if (WARN_ON(!system_supports_fpsimd()))
+ return -EINVAL;
+
/* check the magic/size information */
__get_user_error(magic, &ctx->head.magic, err);
__get_user_error(size, &ctx->head.size, err);
@@ -261,6 +269,9 @@ static int restore_sve_fpsimd_context(struct user_ctxs *user)
struct user_fpsimd_state fpsimd;
struct sve_context sve;

+ if (WARN_ON(!system_supports_fpsimd()))
+ return -EINVAL;
+
if (__copy_from_user(&sve, user->sve, sizeof(sve)))
return -EFAULT;

@@ -371,6 +382,8 @@ static int parse_user_sigframe(struct user_ctxs *user,
goto done;

case FPSIMD_MAGIC:
+ if (!system_supports_fpsimd())
+ goto invalid;
if (user->fpsimd)
goto invalid;

@@ -506,7 +519,7 @@ static int restore_sigframe(struct pt_regs *regs,
if (err == 0)
err = parse_user_sigframe(&user, sf);

- if (err == 0) {
+ if (err == 0 && system_supports_fpsimd()) {
if (!user.fpsimd)
return -EINVAL;

@@ -623,7 +636,7 @@ static int setup_sigframe(struct rt_sigframe_user_layout *user,

err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));

- if (err == 0) {
+ if (err == 0 && system_supports_fpsimd()) {
struct fpsimd_context __user *fpsimd_ctx =
apply_user_offset(user, user->fpsimd_offset);
err |= preserve_fpsimd_context(fpsimd_ctx);
diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c
index 12a585386c2f..97ace6919bc2 100644
--- a/arch/arm64/kernel/signal32.c
+++ b/arch/arm64/kernel/signal32.c
@@ -100,6 +100,9 @@ static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame)
compat_ulong_t fpscr, fpexc;
int i, err = 0;

+ /* This must not be called when the FP/SIMD is missing */
+ if (WARN_ON(!system_supports_fpsimd()))
+ return -EINVAL;
/*
* Save the hardware registers to the fpsimd_state structure.
* Note that this also saves V16-31, which aren't visible
@@ -149,6 +152,10 @@ static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame)
compat_ulong_t fpscr;
int i, err = 0;

+ /* This must not be called when the FP/SIMD is missing */
+ if (WARN_ON(!system_supports_fpsimd()))
+ return -EINVAL;
+
__get_user_error(magic, &frame->magic, err);
__get_user_error(size, &frame->size, err);

@@ -223,7 +230,7 @@ static int compat_restore_sigframe(struct pt_regs *regs,
err |= !valid_user_regs(&regs->user_regs, current);

aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace;
- if (err == 0)
+ if (err == 0 && system_supports_fpsimd())
err |= compat_restore_vfp_context(&aux->vfp);

return err;
@@ -419,7 +426,7 @@ static int compat_setup_sigframe(struct compat_sigframe __user *sf,

aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace;

- if (err == 0)
+ if (err == 0 && system_supports_fpsimd())
err |= compat_preserve_vfp_context(&aux->vfp);
__put_user_error(0, &aux->end_magic, err);

--
2.23.0
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