diff options
| author | Dave Martin | 2017-10-31 15:51:14 +0000 |
|---|---|---|
| committer | Will Deacon | 2017-11-03 15:24:19 +0000 |
| commit | 2d2123bc7c7f843aa9db87720de159a049839862 (patch) | |
| tree | cc8ad3cccc8d8156382edbf512c4cf1af1d27978 /include/uapi | |
| parent | 43d4da2c45b2f5d62f8a79ff7c6f95089bb24656 (diff) | |
arm64/sve: Add prctl controls for userspace vector length management
This patch adds two arm64-specific prctls, to permit userspace to
control its vector length:
* PR_SVE_SET_VL: set the thread's SVE vector length and vector
length inheritance mode.
* PR_SVE_GET_VL: get the same information.
Although these prctls resemble instruction set features in the SVE
architecture, they provide additional control: the vector length
inheritance mode is Linux-specific and nothing to do with the
architecture, and the architecture does not permit EL0 to set its
own vector length directly. Both can be used in portable tools
without requiring the use of SVE instructions.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Alex Bennée <alex.bennee@linaro.org>
[will: Fixed up prctl constants to avoid clash with PDEATHSIG]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'include/uapi')
| -rw-r--r-- | include/uapi/linux/prctl.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 1b64901ca6b3..f60db5db6e8e 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -198,7 +198,11 @@ struct prctl_mm_map { # define PR_CAP_AMBIENT_CLEAR_ALL 4 /* arm64 Scalable Vector Extension controls */ +/* Flag values must be kept in sync with ptrace NT_ARM_SVE interface */ +#define PR_SVE_SET_VL 50 /* set task vector length */ # define PR_SVE_SET_VL_ONEXEC (1 << 18) /* defer effect until exec */ +#define PR_SVE_GET_VL 51 /* get task vector length */ +/* Bits common to PR_SVE_SET_VL and PR_SVE_GET_VL */ # define PR_SVE_VL_LEN_MASK 0xffff # define PR_SVE_VL_INHERIT (1 << 17) /* inherit across exec */ |