Commit 9e4ab6c8 authored by Mark Brown's avatar Mark Brown Committed by Catalin Marinas
Browse files

arm64/sme: Implement vector length configuration prctl()s 



As for SVE provide a prctl() interface which allows processes to
configure their SME vector length.

Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-12-broonie@kernel.org


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 12f1bacf

arch/arm64/include/asm/fpsimd.h

+4 −0
Original line number Diff line number Diff line
@@ -288,6 +288,8 @@ static inline int sme_max_virtualisable_vl(void) 
}



extern unsigned int sme_get_vl(void);

extern int sme_set_current_vl(unsigned long arg);

extern int sme_get_current_vl(void);



#else
@@ -299,6 +301,8 @@ static inline void sme_setup(void) { } 
static inline unsigned int sme_get_vl(void) { return 0; }

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; }



#endif /* ! CONFIG_ARM64_SME */

arch/arm64/include/asm/processor.h

+3 −1
Original line number Diff line number Diff line
@@ -355,9 +355,11 @@ extern void __init minsigstksz_setup(void); 
 */

#include <asm/fpsimd.h>



/* Userspace interface for PR_SVE_{SET,GET}_VL prctl()s: */

/* Userspace interface for PR_S[MV]E_{SET,GET}_VL prctl()s: */

#define SVE_SET_VL(arg)	sve_set_current_vl(arg)

#define SVE_GET_VL()	sve_get_current_vl()

#define SME_SET_VL(arg)	sme_set_current_vl(arg)

#define SME_GET_VL()	sme_get_current_vl()



/* PR_PAC_RESET_KEYS prctl */

#define PAC_RESET_KEYS(tsk, arg)	ptrauth_prctl_reset_keys(tsk, arg)

arch/arm64/include/asm/thread_info.h

+1 −0
Original line number Diff line number Diff line
@@ -82,6 +82,7 @@ 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_VL_INHERIT	28	/* Inherit SME vl_onexec across exec */



#define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)

#define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)

arch/arm64/kernel/fpsimd.c

+32 −0
Original line number Diff line number Diff line
@@ -149,6 +149,8 @@ static unsigned int vec_vl_inherit_flag(enum vec_type type) 
	switch (type) {

	case ARM64_VEC_SVE:

		return TIF_SVE_VL_INHERIT;

	case ARM64_VEC_SME:

		return TIF_SME_VL_INHERIT;

	default:

		WARN_ON_ONCE(1);

		return 0;
@@ -807,6 +809,36 @@ int sve_get_current_vl(void) 
	return vec_prctl_status(ARM64_VEC_SVE, 0);

}



#ifdef CONFIG_ARM64_SME

/* PR_SME_SET_VL */

int sme_set_current_vl(unsigned long arg)

{

	unsigned long vl, flags;

	int ret;



	vl = arg & PR_SME_VL_LEN_MASK;

	flags = arg & ~vl;



	if (!system_supports_sme() || is_compat_task())

		return -EINVAL;



	ret = vec_set_vector_length(current, ARM64_VEC_SME, vl, flags);

	if (ret)

		return ret;



	return vec_prctl_status(ARM64_VEC_SME, flags);

}



/* PR_SME_GET_VL */

int sme_get_current_vl(void)

{

	if (!system_supports_sme() || is_compat_task())

		return -EINVAL;



	return vec_prctl_status(ARM64_VEC_SME, 0);

}

#endif /* CONFIG_ARM64_SME */



static void vec_probe_vqs(struct vl_info *info,

			  DECLARE_BITMAP(map, SVE_VQ_MAX))

{

include/uapi/linux/prctl.h

+9 −0
Original line number Diff line number Diff line
@@ -272,6 +272,15 @@ struct prctl_mm_map { 
# define PR_SCHED_CORE_SCOPE_THREAD_GROUP	1

# define PR_SCHED_CORE_SCOPE_PROCESS_GROUP	2



/* arm64 Scalable Matrix Extension controls */

/* Flag values must be in sync with SVE versions */

#define PR_SME_SET_VL			63	/* set task vector length */

# define PR_SME_SET_VL_ONEXEC		(1 << 18) /* defer effect until exec */

#define PR_SME_GET_VL			64	/* get task vector length */

/* Bits common to PR_SME_SET_VL and PR_SME_GET_VL */

# define PR_SME_VL_LEN_MASK		0xffff

# define PR_SME_VL_INHERIT		(1 << 17) /* inherit across exec */



#define PR_SET_VMA		0x53564d41

# define PR_SET_VMA_ANON_NAME		0