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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: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-12-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Mark Brown 2022-04-19 12:22:19 +01:00 committed by Catalin Marinas
parent 12f1bacfc5
commit 9e4ab6c891
6 changed files with 61 additions and 1 deletions
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4
arch/arm64/include/asm/fpsimd.h
View File

@ -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 */

4
arch/arm64/include/asm/processor.h
View File

@ -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)

1
arch/arm64/include/asm/thread_info.h
View File

@ -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)

32
arch/arm64/kernel/fpsimd.c
View File

@ -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))
{

9
include/uapi/linux/prctl.h
View File

@ -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

12
kernel/sys.c
View File

@ -117,6 +117,12 @@
#ifndef SVE_GET_VL
# define SVE_GET_VL() (-EINVAL)
#endif
#ifndef SME_SET_VL
# define SME_SET_VL(a) (-EINVAL)
#endif
#ifndef SME_GET_VL
# define SME_GET_VL() (-EINVAL)
#endif
#ifndef PAC_RESET_KEYS
# define PAC_RESET_KEYS(a, b) (-EINVAL)
#endif
@ -2541,6 +2547,12 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
case PR_SVE_GET_VL:
error = SVE_GET_VL();
break;
case PR_SME_SET_VL:
error = SME_SET_VL(arg2);
break;
case PR_SME_GET_VL:
error = SME_GET_VL();
break;
case PR_GET_SPECULATION_CTRL:
if (arg3 || arg4 || arg5)
return -EINVAL;