@@ -168,6 +168,7 @@ struct thread_struct {
u64 mte_ctrl;
#endif
u64 sctlr_user;
+ u64 svcr;
u64 tpidr2_el0;
};
@@ -81,6 +81,7 @@ int arch_dup_task_struct(struct task_struct *dst,
#define TIF_SVE_VL_INHERIT 24 /* Inherit SVE vl_onexec across exec */
#define TIF_SSBD 25 /* Wants SSB mitigation */
#define TIF_TAGGED_ADDR 26 /* Allow tagged user addresses */
+#define TIF_SME 27 /* SME in use */
#define TIF_SME_VL_INHERIT 28 /* Inherit SME vl_onexec across exec */
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
@@ -355,6 +355,9 @@ static void task_fpsimd_load(void)
WARN_ON(!system_supports_fpsimd());
WARN_ON(!have_cpu_fpsimd_context());
+ if (IS_ENABLED(CONFIG_ARM64_SME) && test_thread_flag(TIF_SME))
+ write_sysreg_s(current->thread.svcr, SYS_SVCR_EL0);
+
if (IS_ENABLED(CONFIG_ARM64_SVE) && test_thread_flag(TIF_SVE)) {
sve_set_vq(sve_vq_from_vl(task_get_sve_vl(current)) - 1);
sve_load_state(sve_pffr(¤t->thread),
@@ -380,6 +383,10 @@ static void fpsimd_save(void)
if (test_thread_flag(TIF_FOREIGN_FPSTATE))
return;
+ if (IS_ENABLED(CONFIG_ARM64_SME) &&
+ test_thread_flag(TIF_SME))
+ current->thread.svcr = read_sysreg_s(SYS_SVCR_EL0);
+
if (IS_ENABLED(CONFIG_ARM64_SVE) &&
test_thread_flag(TIF_SVE)) {
if (WARN_ON(sve_get_vl() != last->sve_vl)) {
@@ -731,6 +738,10 @@ int vec_set_vector_length(struct task_struct *task, enum vec_type type,
if (test_and_clear_tsk_thread_flag(task, TIF_SVE))
sve_to_fpsimd(task);
+ if (system_supports_sme() && type == ARM64_VEC_SME)
+ task->thread.svcr &= ~(SYS_SVCR_EL0_SM_MASK |
+ SYS_SVCR_EL0_ZA_MASK);
+
if (task == current)
put_cpu_fpsimd_context();
@@ -309,6 +309,8 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
dst->thread.sve_state = NULL;
clear_tsk_thread_flag(dst, TIF_SVE);
+ dst->thread.svcr = 0;
+
/* clear any pending asynchronous tag fault raised by the parent */
clear_tsk_thread_flag(dst, TIF_MTE_ASYNC_FAULT);
In SME the use of both streaming SVE mode and ZA are tracked through PSTATE.SM and PSTATE.ZA, visible through the system register SVCR. In order to context switch the floating point state for SME we need to context switch the contents of this register as part of context switching the floating point state. Since changing the vector length exits streaming SVE mode and disables ZA we also make sure we update SVCR appropriately when setting vector length, and similarly ensure that new threads have streaming SVE mode and ZA disabled. Signed-off-by: Mark Brown <broonie@kernel.org> --- arch/arm64/include/asm/processor.h | 1 + arch/arm64/include/asm/thread_info.h | 1 + arch/arm64/kernel/fpsimd.c | 11 +++++++++++ arch/arm64/kernel/process.c | 2 ++ 4 files changed, 15 insertions(+)