1 files changed, 67 insertions, 70 deletions

diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index f79b0d5f71ac..a360e52db02f 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -594,7 +594,7 @@ static int __fpr_get(struct task_struct *target,
 {
 	struct user_fpsimd_state *uregs;
 
-	sve_sync_to_fpsimd(target);
+	fpsimd_sync_from_effective_state(target);
 
 	uregs = &target->thread.uw.fpsimd_state;
 
@@ -626,7 +626,7 @@ static int __fpr_set(struct task_struct *target,
 	 * Ensure target->thread.uw.fpsimd_state is up to date, so that a
 	 * short copyin can't resurrect stale data.
 	 */
-	sve_sync_to_fpsimd(target);
+	fpsimd_sync_from_effective_state(target);
 
 	newstate = target->thread.uw.fpsimd_state;
 
@@ -653,7 +653,7 @@ static int fpr_set(struct task_struct *target, const struct user_regset *regset,
 	if (ret)
 		return ret;
 
-	sve_sync_from_fpsimd_zeropad(target);
+	fpsimd_sync_to_effective_state_zeropad(target);
 	fpsimd_flush_task_state(target);
 
 	return ret;
@@ -775,6 +775,11 @@ static void sve_init_header_from_task(struct user_sve_header *header,
 		task_type = ARM64_VEC_SVE;
 	active = (task_type == type);
 
+	if (active && target->thread.fp_type == FP_STATE_SVE)
+		header->flags = SVE_PT_REGS_SVE;
+	else
+		header->flags = SVE_PT_REGS_FPSIMD;
+
 	switch (type) {
 	case ARM64_VEC_SVE:
 		if (test_tsk_thread_flag(target, TIF_SVE_VL_INHERIT))
@@ -789,19 +794,14 @@ static void sve_init_header_from_task(struct user_sve_header *header,
 		return;
 	}
 
-	if (active) {
-		if (target->thread.fp_type == FP_STATE_FPSIMD) {
-			header->flags |= SVE_PT_REGS_FPSIMD;
-		} else {
-			header->flags |= SVE_PT_REGS_SVE;
-		}
-	}
-
 	header->vl = task_get_vl(target, type);
 	vq = sve_vq_from_vl(header->vl);
 
 	header->max_vl = vec_max_vl(type);
-	header->size = SVE_PT_SIZE(vq, header->flags);
+	if (active)
+		header->size = SVE_PT_SIZE(vq, header->flags);
+	else
+		header->size = sizeof(header);
 	header->max_size = SVE_PT_SIZE(sve_vq_from_vl(header->max_vl),
 				      SVE_PT_REGS_SVE);
 }
@@ -820,18 +820,25 @@ static int sve_get_common(struct task_struct *target,
 	unsigned int vq;
 	unsigned long start, end;
 
+	if (target == current)
+		fpsimd_preserve_current_state();
+
 	/* Header */
 	sve_init_header_from_task(&header, target, type);
 	vq = sve_vq_from_vl(header.vl);
 
 	membuf_write(&to, &header, sizeof(header));
 
-	if (target == current)
-		fpsimd_preserve_current_state();
-
 	BUILD_BUG_ON(SVE_PT_FPSIMD_OFFSET != sizeof(header));
 	BUILD_BUG_ON(SVE_PT_SVE_OFFSET != sizeof(header));
 
+	/*
+	 * When the requested vector type is not active, do not present data
+	 * from the other mode to userspace.
+	 */
+	if (header.size == sizeof(header))
+		return 0;
+
 	switch ((header.flags & SVE_PT_REGS_MASK)) {
 	case SVE_PT_REGS_FPSIMD:
 		return __fpr_get(target, regset, to);
@@ -859,7 +866,7 @@ static int sve_get_common(struct task_struct *target,
 		return membuf_zero(&to, end - start);
 
 	default:
-		return 0;
+		BUILD_BUG();
 	}
 }
 
@@ -883,6 +890,9 @@ static int sve_set_common(struct task_struct *target,
 	struct user_sve_header header;
 	unsigned int vq;
 	unsigned long start, end;
+	bool fpsimd;
+
+	fpsimd_flush_task_state(target);
 
 	/* Header */
 	if (count < sizeof(header))
@@ -890,7 +900,16 @@ static int sve_set_common(struct task_struct *target,
 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &header,
 				 0, sizeof(header));
 	if (ret)
-		goto out;
+		return ret;
+
+	/*
+	 * Streaming SVE data is always stored and presented in SVE format.
+	 * Require the user to provide SVE formatted data for consistency, and
+	 * to avoid the risk that we configure the task into an invalid state.
+	 */
+	fpsimd = (header.flags & SVE_PT_REGS_MASK) == SVE_PT_REGS_FPSIMD;
+	if (fpsimd && type == ARM64_VEC_SME)
+		return -EINVAL;
 
 	/*
 	 * Apart from SVE_PT_REGS_MASK, all SVE_PT_* flags are consumed by
@@ -899,7 +918,21 @@ static int sve_set_common(struct task_struct *target,
 	ret = vec_set_vector_length(target, type, header.vl,
 		((unsigned long)header.flags & ~SVE_PT_REGS_MASK) << 16);
 	if (ret)
-		goto out;
+		return ret;
+
+	/* Allocate SME storage if necessary, preserving any existing ZA/ZT state */
+	if (type == ARM64_VEC_SME) {
+		sme_alloc(target, false);
+		if (!target->thread.sme_state)
+			return -ENOMEM;
+	}
+
+	/* Allocate SVE storage if necessary, zeroing any existing SVE state */
+	if (!fpsimd) {
+		sve_alloc(target, true);
+		if (!target->thread.sve_state)
+			return -ENOMEM;
+	}
 
 	/*
 	 * Actual VL set may be different from what the user asked
@@ -910,81 +943,47 @@ static int sve_set_common(struct task_struct *target,
 
 	/* Enter/exit streaming mode */
 	if (system_supports_sme()) {
-		u64 old_svcr = target->thread.svcr;
-
 		switch (type) {
 		case ARM64_VEC_SVE:
 			target->thread.svcr &= ~SVCR_SM_MASK;
+			set_tsk_thread_flag(target, TIF_SVE);
 			break;
 		case ARM64_VEC_SME:
 			target->thread.svcr |= SVCR_SM_MASK;
-
-			/*
-			 * Disable traps and ensure there is SME storage but
-			 * preserve any currently set values in ZA/ZT.
-			 */
-			sme_alloc(target, false);
 			set_tsk_thread_flag(target, TIF_SME);
 			break;
 		default:
 			WARN_ON_ONCE(1);
-			ret = -EINVAL;
-			goto out;
+			return -EINVAL;
 		}
-
-		/*
-		 * If we switched then invalidate any existing SVE
-		 * state and ensure there's storage.
-		 */
-		if (target->thread.svcr != old_svcr)
-			sve_alloc(target, true);
 	}
 
+	/* Always zero V regs, FPSR, and FPCR */
+	memset(&current->thread.uw.fpsimd_state, 0,
+	       sizeof(current->thread.uw.fpsimd_state));
+
 	/* Registers: FPSIMD-only case */
 
 	BUILD_BUG_ON(SVE_PT_FPSIMD_OFFSET != sizeof(header));
-	if ((header.flags & SVE_PT_REGS_MASK) == SVE_PT_REGS_FPSIMD) {
-		ret = __fpr_set(target, regset, pos, count, kbuf, ubuf,
-				SVE_PT_FPSIMD_OFFSET);
+	if (fpsimd) {
 		clear_tsk_thread_flag(target, TIF_SVE);
 		target->thread.fp_type = FP_STATE_FPSIMD;
-		goto out;
+		ret = __fpr_set(target, regset, pos, count, kbuf, ubuf,
+				SVE_PT_FPSIMD_OFFSET);
+		return ret;
 	}
 
-	/*
-	 * Otherwise: no registers or full SVE case.  For backwards
-	 * compatibility reasons we treat empty flags as SVE registers.
-	 */
+	/* Otherwise: no registers or full SVE case. */
+
+	target->thread.fp_type = FP_STATE_SVE;
 
 	/*
 	 * If setting a different VL from the requested VL and there is
 	 * register data, the data layout will be wrong: don't even
 	 * try to set the registers in this case.
 	 */
-	if (count && vq != sve_vq_from_vl(header.vl)) {
-		ret = -EIO;
-		goto out;
-	}
-
-	sve_alloc(target, true);
-	if (!target->thread.sve_state) {
-		ret = -ENOMEM;
-		clear_tsk_thread_flag(target, TIF_SVE);
-		target->thread.fp_type = FP_STATE_FPSIMD;
-		goto out;
-	}
-
-	/*
-	 * Ensure target->thread.sve_state is up to date with target's
-	 * FPSIMD regs, so that a short copyin leaves trailing
-	 * registers unmodified.  Only enable SVE if we are
-	 * configuring normal SVE, a system with streaming SVE may not
-	 * have normal SVE.
-	 */
-	fpsimd_sync_to_sve(target);
-	if (type == ARM64_VEC_SVE)
-		set_tsk_thread_flag(target, TIF_SVE);
-	target->thread.fp_type = FP_STATE_SVE;
+	if (count && vq != sve_vq_from_vl(header.vl))
+		return -EIO;
 
 	BUILD_BUG_ON(SVE_PT_SVE_OFFSET != sizeof(header));
 	start = SVE_PT_SVE_OFFSET;
@@ -993,7 +992,7 @@ static int sve_set_common(struct task_struct *target,
 				 target->thread.sve_state,
 				 start, end);
 	if (ret)
-		goto out;
+		return ret;
 
 	start = end;
 	end = SVE_PT_SVE_FPSR_OFFSET(vq);
@@ -1009,8 +1008,6 @@ static int sve_set_common(struct task_struct *target,
 				 &target->thread.uw.fpsimd_state.fpsr,
 				 start, end);
 
-out:
-	fpsimd_flush_task_state(target);
 	return ret;
 }