Commit 95338648 authored by Mark Brown's avatar Mark Brown Committed by Will Deacon
Browse files

arm64/sme: Restore SME registers on exit from suspend 



The fields in SMCR_EL1 and SMPRI_EL1 reset to an architecturally UNKNOWN
value. Since we do not otherwise manage the traps configured in this
register at runtime we need to reconfigure them after a suspend in case
nothing else was kind enough to preserve them for us.

The vector length will be restored as part of restoring the SME state for
the next SME using task.

Fixes: a1f4ccd2 ("arm64/sme: Provide Kconfig for SME")
Reported-by: default avatarJackson Cooper-Driver <Jackson.Cooper-Driver@arm.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240213-arm64-sme-resume-v3-1-17e05e493471@kernel.org


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent a6b3eb30

arch/arm64/include/asm/fpsimd.h

+2 −0
Original line number Diff line number Diff line
@@ -386,6 +386,7 @@ extern void sme_alloc(struct task_struct *task, bool flush); 
extern unsigned int sme_get_vl(void);

extern int sme_set_current_vl(unsigned long arg);

extern int sme_get_current_vl(void);

extern void sme_suspend_exit(void);



/*

 * Return how many bytes of memory are required to store the full SME
@@ -421,6 +422,7 @@ static inline int sme_max_vl(void) { return 0; } 
static inline int sme_max_virtualisable_vl(void) { return 0; }

static inline int sme_set_current_vl(unsigned long arg) { return -EINVAL; }

static inline int sme_get_current_vl(void) { return -EINVAL; }

static inline void sme_suspend_exit(void) { }



static inline size_t sme_state_size(struct task_struct const *task)

{

arch/arm64/kernel/fpsimd.c

+14 −0
Original line number Diff line number Diff line
@@ -1311,6 +1311,20 @@ void __init sme_setup(void) 
		get_sme_default_vl());

}



void sme_suspend_exit(void)

{

	u64 smcr = 0;



	if (!system_supports_sme())

		return;



	if (system_supports_fa64())

		smcr |= SMCR_ELx_FA64;



	write_sysreg_s(smcr, SYS_SMCR_EL1);

	write_sysreg_s(0, SYS_SMPRI_EL1);

}



#endif /* CONFIG_ARM64_SME */



static void sve_init_regs(void)

arch/arm64/kernel/suspend.c

+3 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <asm/daifflags.h>

#include <asm/debug-monitors.h>

#include <asm/exec.h>

#include <asm/fpsimd.h>

#include <asm/mte.h>

#include <asm/memory.h>

#include <asm/mmu_context.h>
@@ -80,6 +81,8 @@ void notrace __cpu_suspend_exit(void) 
	 */

	spectre_v4_enable_mitigation(NULL);



	sme_suspend_exit();



	/* Restore additional feature-specific configuration */

	ptrauth_suspend_exit();

}