linux-kernel - [PATCH v3 6/7] arm64: signal: nofpsimd: Handle fp/simd context for signal frames

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Message-Id: <20200113233023.928028-7-suzuki.poulose@arm.com>
Date:   Mon, 13 Jan 2020 23:30:22 +0000
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     linux-kernel@...r.kernel.org, will@...nel.org, maz@...nel.org,
        catalin.marinas@....com, ard.biesheuvel@...aro.org,
        mark.rutland@....com, Suzuki K Poulose <suzuki.poulose@....com>
Subject: [PATCH v3 6/7] arm64: signal: nofpsimd: Handle fp/simd context for signal frames

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@...nel.org>
Cc: Mark Rutland <mark.rutland@....com>
Cc: Catalin Marinas <catalin.marinas@....com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
---
Changes since v2:
  - Remove WARN_ON() from static functions already checked for
    the presence of fpsmid.
---
 arch/arm64/kernel/signal.c   | 6 ++++--
 arch/arm64/kernel/signal32.c | 4 ++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index dd2cdc0d5be2..339882db5a91 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -371,6 +371,8 @@ 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 +508,7 @@ 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 +625,7 @@ 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..82feca6f7052 100644
--- a/arch/arm64/kernel/signal32.c
+++ b/arch/arm64/kernel/signal32.c
@@ -223,7 +223,7 @@ 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 +419,7 @@ 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);
 
-- 
2.24.1