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arm64/fpsimd: Introduce fpsimd_save_and_flush_cpu_state() and use it

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The only external user of fpsimd_save() and fpsimd_flush_cpu_state() is
the KVM FPSIMD code.

A following patch will introduce a mechanism to acquire owernship of the
FPSIMD/SVE context for performing context management operations. Rather
than having to export the new helpers to get/put the context, we can just
introduce a new function to combine fpsimd_save() and
fpsimd_flush_cpu_state().

This has also the advantage to remove any external call of fpsimd_save()
and fpsimd_flush_cpu_state(), so they can be turned static.

Lastly, the new function can also be used in the PM notifier.

Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Julien Grall <julien.grall@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Julien Grall 2019-05-21 18:21:38 +01:00 committed by Catalin Marinas
parent 6fa9b41f6f
commit 54b8c7cbc5
3 changed files with 15 additions and 10 deletions
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4
arch/arm64/include/asm/fpsimd.h
View File

@ -48,8 +48,6 @@ struct task_struct;
extern void fpsimd_save_state(struct user_fpsimd_state *state);
extern void fpsimd_load_state(struct user_fpsimd_state *state);
extern void fpsimd_save(void);
extern void fpsimd_thread_switch(struct task_struct *next);
extern void fpsimd_flush_thread(void);
@ -63,7 +61,7 @@ extern void fpsimd_bind_state_to_cpu(struct user_fpsimd_state *state,
void *sve_state, unsigned int sve_vl);
extern void fpsimd_flush_task_state(struct task_struct *target);
extern void fpsimd_flush_cpu_state(void);
extern void fpsimd_save_and_flush_cpu_state(void);
/* Maximum VL that SVE VL-agnostic software can transparently support */
#define SVE_VL_ARCH_MAX 0x100

17
arch/arm64/kernel/fpsimd.c
View File

@ -246,7 +246,7 @@ static void task_fpsimd_load(void)
*
* Softirqs (and preemption) must be disabled.
*/
void fpsimd_save(void)
static void fpsimd_save(void)
{
struct fpsimd_last_state_struct const *last =
this_cpu_ptr(&fpsimd_last_state);
@ -1122,12 +1122,22 @@ void fpsimd_flush_task_state(struct task_struct *t)
* Invalidate any task's FPSIMD state that is present on this cpu.
* This function must be called with softirqs disabled.
*/
void fpsimd_flush_cpu_state(void)
static void fpsimd_flush_cpu_state(void)
{
__this_cpu_write(fpsimd_last_state.st, NULL);
set_thread_flag(TIF_FOREIGN_FPSTATE);
}
/*
* Save the FPSIMD state to memory and invalidate cpu view.
* This function must be called with softirqs (and preemption) disabled.
*/
void fpsimd_save_and_flush_cpu_state(void)
{
fpsimd_save();
fpsimd_flush_cpu_state();
}
#ifdef CONFIG_KERNEL_MODE_NEON
DEFINE_PER_CPU(bool, kernel_neon_busy);
@ -1284,8 +1294,7 @@ static int fpsimd_cpu_pm_notifier(struct notifier_block *self,
{
switch (cmd) {
case CPU_PM_ENTER:
fpsimd_save();
fpsimd_flush_cpu_state();
fpsimd_save_and_flush_cpu_state();
break;
case CPU_PM_EXIT:
break;

4
arch/arm64/kvm/fpsimd.c
View File

@ -112,9 +112,7 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)
if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) {
u64 *guest_zcr = &vcpu->arch.ctxt.sys_regs[ZCR_EL1];
/* Clean guest FP state to memory and invalidate cpu view */
fpsimd_save();
fpsimd_flush_cpu_state();
fpsimd_save_and_flush_cpu_state();
if (guest_has_sve)
*guest_zcr = read_sysreg_s(SYS_ZCR_EL12);