arm64: fpsimd: Use opaque type for SME state

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 arm64_sme_state', and
consistently passing a pointer to this.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Vladimir Murzin <vladimir.murzin@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: Oliver Upton <oupton@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
index 581661a759a3ff1bffbe1210a6f04249f595baf5..fff6d54afd9fe1edb56f2c7eb0120fd328850ae8 100644 (file)
--- 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 arm64_sve_state *sve_state;
-       void *sme_state;
+       struct arm64_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 arm64_sve_state *state, int save_ffr);
 extern void sve_load_state(const struct arm64_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 arm64_sme_state *state, int zt);
+extern void sme_load_state(const struct arm64_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 96c0c30eac50f4c8ca91c039c9cb898bc8c3c1b0..c2a627f393144a92c23a2c2c09cab4822db7748d 100644 (file)
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -131,6 +131,7 @@ enum fp_type {
 };
 
 struct arm64_sve_state;                /* Opaque type */
+struct arm64_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 arm64_sve_state  *sve_state;     /* SVE registers, if any */
-       void                    *sme_state;     /* ZA and ZT state, if any */
+       struct arm64_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 0da2f75de5ddec868b9192c95e16b2b1fabbf9f5..b9506422d29c66d1e8ec093e0cdd8cfb6ec041c2 100644 (file)
--- 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 arm64_sve_state *sve_state = NULL;
-       void *sme_state = NULL;
+       struct arm64_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 arm64_sve_state *sve_state = NULL;
-       void *sme_state = NULL;
+       struct arm64_sme_state *sme_state = NULL;
 
        if (!system_supports_fpsimd())
                return;