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From: Mark Rutland <mark.rutland@arm•com>
To: linux-arm-kernel@lists•infradead.org, kvmarm@lists•linux.dev
Cc: broonie@kernel•org, catalin.marinas@arm•com, james.morse@arm•com,
	mark.rutland@arm•com, maz@kernel•org, oupton@kernel•org,
	tabba@google•com, will@kernel•org
Subject: [PATCH 14/18] arm64: fpsimd: Use opaque type for SME state
Date: Thu, 21 May 2026 14:25:52 +0100	[thread overview]
Message-ID: <20260521132556.584676-15-mark.rutland@arm.com> (raw)
In-Reply-To: <20260521132556.584676-1-mark.rutland@arm.com>

As the SME state size can vary at runtime, we don't have a concrete type
for the in-memory SME state, and pass this around using a pointer to
void.

Using pointer to void means that it's very easy to introduce errors that
cannot be caught by the compiler (e.g. as 'void **' can be assigned to
'void *').

Improve this by adding an opaque 'struct sve_state', and consistently
passing a pointer to this.

Signed-off-by: Mark Rutland <mark.rutland@arm•com>
Cc: Catalin Marinas <catalin.marinas@arm•com>
Cc: Fuad Tabba <tabba@google•com>
Cc: James Morse <james.morse@arm•com>
Cc: Marc Zyngier <maz@kernel•org>
Cc: Mark Brown <broonie@kernel•org>
Cc: Oliver Upton <oupton@kernel•org>
Cc: Will Deacon <will@kernel•org>
---
 arch/arm64/include/asm/fpsimd.h    | 8 ++++----
 arch/arm64/include/asm/processor.h | 3 ++-
 arch/arm64/kernel/fpsimd.c         | 4 ++--
 3 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
index 19e670ae67598..560814acc60c0 100644
--- a/arch/arm64/include/asm/fpsimd.h
+++ b/arch/arm64/include/asm/fpsimd.h
@@ -163,7 +163,7 @@ extern void fpsimd_update_current_state(struct user_fpsimd_state const *state);
 struct cpu_fp_state {
 	struct user_fpsimd_state *st;
 	struct sve_state *sve_state;
-	void *sme_state;
+	struct sme_state *sme_state;
 	u64 *svcr;
 	u64 *fpmr;
 	unsigned int sve_vl;
@@ -199,7 +199,7 @@ static inline void *thread_zt_state(struct thread_struct *thread)
 {
 	/* The ZT register state is stored immediately after the ZA state */
 	unsigned int sme_vq = sve_vq_from_vl(thread_get_sme_vl(thread));
-	return thread->sme_state + ZA_SIG_REGS_SIZE(sme_vq);
+	return (void *)thread->sme_state + ZA_SIG_REGS_SIZE(sme_vq);
 }
 
 static inline unsigned int sve_get_vl(void)
@@ -218,8 +218,8 @@ static inline unsigned int sve_get_vl(void)
 extern void sve_save_state(struct sve_state *state, int save_ffr);
 extern void sve_load_state(const struct sve_state *state, int restore_ffr);
 extern void sve_flush_live(bool flush_ffr, unsigned long vq_minus_1);
-extern void sme_save_state(void *state, int zt);
-extern void sme_load_state(void const *state, int zt);
+extern void sme_save_state(struct sme_state *state, int zt);
+extern void sme_load_state(const struct sme_state *state, int zt);
 
 struct arm64_cpu_capabilities;
 extern void cpu_enable_fpsimd(const struct arm64_cpu_capabilities *__unused);
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index 1c2ffd063baa8..7304d9cca3e85 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -131,6 +131,7 @@ enum fp_type {
 };
 
 struct sve_state;		/* Opaque type */
+struct sme_state;		/* Opaque type */
 
 struct cpu_context {
 	unsigned long x19;
@@ -167,7 +168,7 @@ struct thread_struct {
 	enum fp_type		fp_type;	/* registers FPSIMD or SVE? */
 	unsigned int		fpsimd_cpu;
 	struct sve_state	*sve_state;	/* SVE registers, if any */
-	void			*sme_state;	/* ZA and ZT state, if any */
+	struct sme_state	*sme_state;	/* ZA and ZT state, if any */
 	unsigned int		vl[ARM64_VEC_MAX];	/* vector length */
 	unsigned int		vl_onexec[ARM64_VEC_MAX]; /* vl after next exec */
 	unsigned long		fault_address;	/* fault info */
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 66d880d081671..f9b3eeacf130d 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -808,7 +808,7 @@ static int change_live_vector_length(struct task_struct *task,
 	unsigned int sve_vl = task_get_sve_vl(task);
 	unsigned int sme_vl = task_get_sme_vl(task);
 	struct sve_state *sve_state = NULL;
-	void *sme_state = NULL;
+	struct sme_state *sme_state = NULL;
 
 	if (type == ARM64_VEC_SME)
 		sme_vl = vl;
@@ -1645,7 +1645,7 @@ static void fpsimd_flush_thread_vl(enum vec_type type)
 void fpsimd_flush_thread(void)
 {
 	struct sve_state *sve_state = NULL;
-	void *sme_state = NULL;
+	struct sme_state *sme_state = NULL;
 
 	if (!system_supports_fpsimd())
 		return;
-- 
2.30.2



  parent reply	other threads:[~2026-05-21 13:27 UTC|newest]

Thread overview: 78+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-21 13:25 [PATCH 00/18] arm64+KVM: FPSIMD/SVE/SME cleanups Mark Rutland
2026-05-21 13:25 ` [PATCH 01/18] KVM: arm64: Don't include <asm/fpsimdmacros.h> Mark Rutland
2026-05-26 14:18   ` Mark Brown
2026-05-27 10:10   ` Vladimir Murzin
2026-05-21 13:25 ` [PATCH 02/18] KVM: arm64: Don't override FFR save/restore argument Mark Rutland
2026-05-26 14:27   ` Mark Brown
2026-05-27 10:16   ` Vladimir Murzin
2026-05-21 13:25 ` [PATCH 03/18] KVM: arm64: pkvm: Save host FPMR in host cpu context Mark Rutland
2026-05-27 10:29   ` Vladimir Murzin
2026-05-21 13:25 ` [PATCH 04/18] KVM: arm64: pkvm: Remove struct cpu_sve_state Mark Rutland
2026-05-27 11:58   ` Vladimir Murzin
2026-05-27 16:02     ` Mark Rutland
2026-05-27 16:11       ` Vladimir Murzin
2026-05-28 15:09         ` Mark Rutland
2026-05-28 15:12           ` Vladimir Murzin
2026-05-21 13:25 ` [PATCH 05/18] arm64: fpsimd: Fold sve_init_regs() into do_sve_acc() Mark Rutland
2026-05-26 15:28   ` Mark Brown
2026-05-27 12:05   ` Vladimir Murzin
2026-05-21 13:25 ` [PATCH 06/18] arm64: fpsimd: Remove sve_set_vq() and sme_set_vq() Mark Rutland
2026-05-26 15:42   ` Mark Brown
2026-05-27 12:50   ` Vladimir Murzin
2026-05-21 13:25 ` [PATCH 07/18] arm64: fpsimd: Use assembler for SVE instructions Mark Rutland
2026-05-26 15:43   ` Mark Brown
2026-05-27 12:58   ` Vladimir Murzin
2026-05-27 16:10     ` Mark Rutland
2026-05-21 13:25 ` [PATCH 08/18] arm64: fpsimd: Use assembler for baseline SME instructions Mark Rutland
2026-05-26 15:45   ` Mark Brown
2026-05-27 13:06   ` Vladimir Murzin
2026-05-21 13:25 ` [PATCH 09/18] arm64: fpsimd: Move sve_get_vl() and sme_get_vl() inline Mark Rutland
2026-05-26 15:47   ` Mark Brown
2026-05-27 13:18   ` Vladimir Murzin
2026-05-21 13:25 ` [PATCH 10/18] arm64: sysreg: Add FPCR and FPSR Mark Rutland
2026-05-26 15:55   ` Mark Brown
2026-05-26 16:51     ` Mark Rutland
2026-05-26 16:54       ` Mark Brown
2026-05-21 13:25 ` [PATCH 11/18] arm64: fpsimd: Split FPSR/FPCR from SVE save/restore Mark Rutland
2026-05-26 16:28   ` Mark Brown
2026-05-27 13:51     ` Mark Rutland
2026-05-27 14:13       ` Mark Brown
2026-05-27 16:13         ` Mark Rutland
2026-05-27 13:44   ` Vladimir Murzin
2026-05-21 13:25 ` [PATCH 12/18] arm64: fpsimd: Move fpsimd save/restore inline Mark Rutland
2026-05-26 16:44   ` Mark Brown
2026-05-28 16:15     ` Mark Rutland
2026-05-28 16:39       ` Mark Brown
2026-05-27 14:49   ` Vladimir Murzin
2026-05-27 15:34     ` Mark Rutland
2026-05-27 16:13       ` Vladimir Murzin
2026-05-21 13:25 ` [PATCH 13/18] arm64: fpsimd: Use opaque type for SVE state Mark Rutland
2026-05-26 16:53   ` Mark Brown
2026-05-28  9:45   ` Vladimir Murzin
2026-05-28 16:25     ` Mark Rutland
2026-05-21 13:25 ` Mark Rutland [this message]
2026-05-26 16:56   ` [PATCH 14/18] arm64: fpsimd: Use opaque type for SME state Mark Brown
2026-05-28  9:51   ` Vladimir Murzin
2026-05-21 13:25 ` [PATCH 15/18] arm64: fpsimd: Move SVE save/restore inline Mark Rutland
2026-05-27 12:29   ` Mark Brown
2026-05-28 10:39   ` Vladimir Murzin
2026-05-21 13:25 ` [PATCH 16/18] arm64: fpsimd: Move sve_flush_live() inline Mark Rutland
2026-05-27 12:54   ` Mark Brown
2026-05-27 16:23     ` Mark Rutland
2026-05-28 10:49   ` Vladimir Murzin
2026-05-21 13:25 ` [PATCH 17/18] arm64: fpsimd: Move SME save/restore inline Mark Rutland
2026-05-26 14:08   ` Mark Rutland
2026-05-26 14:39     ` Vladimir Murzin
2026-05-26 15:28       ` Mark Rutland
2026-05-26 16:38         ` Mark Rutland
2026-05-27  9:00           ` Vladimir Murzin
2026-05-29  9:10           ` Mark Rutland
2026-05-28 12:30   ` Vladimir Murzin
2026-05-28 14:39     ` Mark Rutland
2026-05-21 13:25 ` [PATCH 18/18] arm64: fpsimd: Remove <asm/fpsimdmacros.h> Mark Rutland
2026-05-28 13:10   ` Vladimir Murzin
2026-05-27  8:07 ` [PATCH 00/18] arm64+KVM: FPSIMD/SVE/SME cleanups Marc Zyngier
2026-05-27 10:32   ` Mark Rutland
2026-05-27 14:36     ` Will Deacon
2026-05-28 13:21 ` Vladimir Murzin
2026-05-28 16:28   ` Mark Rutland

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