linux-kernel - [PATCH 4.14 012/237] arm64: ptrace: nofpsimd: Fail FP/SIMD regset operations

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Date:   Thu, 27 Feb 2020 14:33:46 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Will Deacon <will@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Ard Biesheuvel <ardb@...nel.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.14 012/237] arm64: ptrace: nofpsimd: Fail FP/SIMD regset operations

From: Suzuki K Poulose <suzuki.poulose@....com>

commit c9d66999f064947e6b577ceacc1eb2fbca6a8d3c upstream

When fp/simd is not supported on the system, fail the operations
of FP/SIMD regsets.

Cc: stable@...r.kernel.org # v4.14
Cc: Will Deacon <will@...nel.org>
Cc: Mark Rutland <mark.rutland@....com>
Reviewed-by: Ard Biesheuvel <ardb@...nel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@....com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/arm64/kernel/ptrace.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 242527f29c410..e230b4dff9602 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -624,6 +624,13 @@ static int gpr_set(struct task_struct *target, const struct user_regset *regset,
 	return 0;
 }
 
+static int fpr_active(struct task_struct *target, const struct user_regset *regset)
+{
+	if (!system_supports_fpsimd())
+		return -ENODEV;
+	return regset->n;
+}
+
 /*
  * TODO: update fp accessors for lazy context switching (sync/flush hwstate)
  */
@@ -634,6 +641,9 @@ static int fpr_get(struct task_struct *target, const struct user_regset *regset,
 	struct user_fpsimd_state *uregs;
 	uregs = &target->thread.fpsimd_state.user_fpsimd;
 
+	if (!system_supports_fpsimd())
+		return -EINVAL;
+
 	if (target == current)
 		fpsimd_preserve_current_state();
 
@@ -648,6 +658,9 @@ static int fpr_set(struct task_struct *target, const struct user_regset *regset,
 	struct user_fpsimd_state newstate =
 		target->thread.fpsimd_state.user_fpsimd;
 
+	if (!system_supports_fpsimd())
+		return -EINVAL;
+
 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newstate, 0, -1);
 	if (ret)
 		return ret;
@@ -740,6 +753,7 @@ static const struct user_regset aarch64_regsets[] = {
 		 */
 		.size = sizeof(u32),
 		.align = sizeof(u32),
+		.active = fpr_active,
 		.get = fpr_get,
 		.set = fpr_set
 	},
@@ -914,6 +928,9 @@ static int compat_vfp_get(struct task_struct *target,
 	compat_ulong_t fpscr;
 	int ret, vregs_end_pos;
 
+	if (!system_supports_fpsimd())
+		return -EINVAL;
+
 	uregs = &target->thread.fpsimd_state.user_fpsimd;
 
 	if (target == current)
@@ -947,6 +964,9 @@ static int compat_vfp_set(struct task_struct *target,
 	compat_ulong_t fpscr;
 	int ret, vregs_end_pos;
 
+	if (!system_supports_fpsimd())
+		return -EINVAL;
+
 	uregs = &target->thread.fpsimd_state.user_fpsimd;
 
 	vregs_end_pos = VFP_STATE_SIZE - sizeof(compat_ulong_t);
@@ -1004,6 +1024,7 @@ static const struct user_regset aarch32_regsets[] = {
 		.n = VFP_STATE_SIZE / sizeof(compat_ulong_t),
 		.size = sizeof(compat_ulong_t),
 		.align = sizeof(compat_ulong_t),
+		.active = fpr_active,
 		.get = compat_vfp_get,
 		.set = compat_vfp_set
 	},
-- 
2.20.1