Commit 54b8c7cb authored by Julien Grall's avatar Julien Grall Committed by Catalin Marinas
Browse files

arm64/fpsimd: Introduce fpsimd_save_and_flush_cpu_state() and use it 



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: default avatarDave Martin <Dave.Martin@arm.com>
Acked-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarJulien Grall <julien.grall@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 6fa9b41f

arch/arm64/include/asm/fpsimd.h

+1 −3
Original line number Diff line number Diff line
@@ -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

arch/arm64/kernel/fpsimd.c

+13 −4
Original line number Diff line number Diff line
@@ -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;

arch/arm64/kvm/fpsimd.c

+1 −3
Original line number Diff line number Diff line
@@ -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);

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