[RFC PATCH 01/10] prctl: Add skeleton for PR_SVE_{SET, GET}_VL controls
From: Dave.Martin@arm.com (Dave Martin)
Date: 2017-01-12 11:26:00
Also in:
linux-arch
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
This patch adds a do-nothing skeleton for the arm64 Scalable Vector
Extension control prctls.
These prctls are only avilable with
CONFIG_ARM64=y
CONFIG_ARM64_SVE=y
Otherwise they will compile out and return -EINVAL if attempted
from userspace.
The backend functions sve_{set,get}_task_vl() will be fleshed out
with actual functionality in subsequent patches.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
---
There will probably also be a call to discover the signal frame size
(MINSIGSTKSZ equivalent) for the current configuration, something like
* PR_GET_MINSIGSTKSZ
This series doesn't add this yet: only the PR_SVE_{SET,GET}_VL prctls
are provided.
arch/arm64/include/asm/fpsimd.h | 19 +++++++++++++++++++
arch/arm64/include/asm/processor.h | 4 ++++
arch/arm64/kernel/fpsimd.c | 13 +++++++++++++
include/uapi/linux/prctl.h | 4 ++++
kernel/sys.c | 12 ++++++++++++
5 files changed, 52 insertions(+)
diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
index 88bcf69..e13259e 100644
--- a/arch/arm64/include/asm/fpsimd.h
+++ b/arch/arm64/include/asm/fpsimd.h@@ -17,6 +17,7 @@ #define __ASM_FP_H #include <asm/ptrace.h> +#include <asm/errno.h> #ifndef __ASSEMBLY__
@@ -110,12 +111,30 @@ extern unsigned int sve_get_vl(void); extern void fpsimd_sync_to_sve(struct task_struct *task); #ifdef CONFIG_ARM64_SVE + extern void fpsimd_sync_to_fpsimd(struct task_struct *task); extern void fpsimd_sync_from_fpsimd_zeropad(struct task_struct *task); +extern int sve_set_task_vl(struct task_struct *task, + unsigned long vector_length, unsigned long flags); +extern int sve_get_task_vl(struct task_struct *task); + #else /* !CONFIG_ARM64_SVE */ + static void __maybe_unused fpsimd_sync_to_fpsimd(struct task_struct *task) { } static void __maybe_unused fpsimd_sync_from_fpsimd_zeropad( struct task_struct *task) { } + +static int __maybe_unused sve_set_task_vl(struct task_struct *task, + unsigned long vector_length, unsigned long flags) +{ + return -EINVAL; +} + +static int __maybe_unused sve_get_task_vl(struct task_struct *task) +{ + return -EINVAL; +} + #endif /* !CONFIG_ARM64_SVE */ #endif
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index 747c65a..6f0f300 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h@@ -190,4 +190,8 @@ int cpu_enable_pan(void *__unused); int cpu_enable_uao(void *__unused); int cpu_enable_cache_maint_trap(void *__unused); +#define SVE_SET_VL(task, vector_length, flags) \ + sve_set_task_vl(task, vector_length, flags) +#define SVE_GET_VL(task) sve_get_task_vl(task) + #endif /* __ASM_PROCESSOR_H */
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 2c113e4..bdacfcd 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c@@ -468,6 +468,19 @@ void fpsimd_sync_from_fpsimd_zeropad(struct task_struct *task) __fpsimd_sync_from_fpsimd_zeropad(task, sve_vq_from_vl(vl)); } +/* PR_SVE_SET_VL */ +int sve_set_task_vl(struct task_struct *task, + unsigned long vector_length, unsigned long flags) +{ + return -EINVAL; +} + +/* PR_SVE_GET_VL */ +int sve_get_task_vl(struct task_struct *task) +{ + return -EINVAL; +} + #endif /* CONFIG_ARM64_SVE */ #ifdef CONFIG_KERNEL_MODE_NEON
diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
index a8d0759..e32e2da 100644
--- a/include/uapi/linux/prctl.h
+++ b/include/uapi/linux/prctl.h@@ -197,4 +197,8 @@ struct prctl_mm_map { # define PR_CAP_AMBIENT_LOWER 3 # define PR_CAP_AMBIENT_CLEAR_ALL 4 +/* arm64 Scalable Vector Extension controls */ +#define PR_SVE_SET_VL 48 /* set task vector length */ +#define PR_SVE_GET_VL 49 /* get task vector length */ + #endif /* _LINUX_PRCTL_H */
diff --git a/kernel/sys.c b/kernel/sys.c
index 842914e..5f50385 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c@@ -103,6 +103,12 @@ #ifndef SET_FP_MODE # define SET_FP_MODE(a,b) (-EINVAL) #endif +#ifndef SVE_SET_VL +# define SVE_SET_VL(a,b,c) (-EINVAL) +#endif +#ifndef SVE_GET_VL +# define SVE_GET_VL(a) (-EINVAL) +#endif /* * this is where the system-wide overflow UID and GID are defined, for
@@ -2261,6 +2267,12 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, case PR_GET_FP_MODE: error = GET_FP_MODE(me); break; + case PR_SVE_SET_VL: + error = SVE_SET_VL(me, arg2, arg3); + break; + case PR_SVE_GET_VL: + error = SVE_GET_VL(me); + break; default: error = -EINVAL; break;
--
2.1.4