From 085b30625e39df67d7320f22269796276c6b0c11 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 23 Sep 2016 14:05:12 +0100 Subject: perf/core: Add PERF_AUX_FLAG_COLLISION to report colliding samples The ARM SPE architecture permits an implementation to ignore a sample if the sample is due to be taken whilst another sample is already being produced. In this case, it is desirable to report the collision to userspace, as they may want to lower the sample period. This patch adds a PERF_AUX_FLAG_COLLISION flag, so that such events can be relayed to userspace. Acked-by: Peter Zijlstra Signed-off-by: Will Deacon --- include/uapi/linux/perf_event.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index 140ae638cfd6..7ca1b22ea417 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -941,6 +941,7 @@ enum perf_callchain_context { #define PERF_AUX_FLAG_TRUNCATED 0x01 /* record was truncated to fit */ #define PERF_AUX_FLAG_OVERWRITE 0x02 /* snapshot from overwrite mode */ #define PERF_AUX_FLAG_PARTIAL 0x04 /* record contains gaps */ +#define PERF_AUX_FLAG_COLLISION 0x08 /* sample collided with another */ #define PERF_FLAG_FD_NO_GROUP (1UL << 0) #define PERF_FLAG_FD_OUTPUT (1UL << 1) -- cgit v1.2.3 From 7582e22038a266444eb87bc07c372592ad647439 Mon Sep 17 00:00:00 2001 From: Dave Martin Date: Tue, 31 Oct 2017 15:51:08 +0000 Subject: arm64/sve: Backend logic for setting the vector length MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This patch implements the core logic for changing a task's vector length on request from userspace. This will be used by the ptrace and prctl frontends that are implemented in later patches. The SVE architecture permits, but does not require, implementations to support vector lengths that are not a power of two. To handle this, logic is added to check a requested vector length against a possibly sparse bitmap of available vector lengths at runtime, so that the best supported value can be chosen. Signed-off-by: Dave Martin Reviewed-by: Catalin Marinas Cc: Alex Bennée Signed-off-by: Will Deacon --- include/uapi/linux/prctl.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index a8d0759a9e40..1b64901ca6b3 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -197,4 +197,9 @@ 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_ONEXEC (1 << 18) /* defer effect until exec */ +# define PR_SVE_VL_LEN_MASK 0xffff +# define PR_SVE_VL_INHERIT (1 << 17) /* inherit across exec */ + #endif /* _LINUX_PRCTL_H */ -- cgit v1.2.3 From 43d4da2c45b2f5d62f8a79ff7c6f95089bb24656 Mon Sep 17 00:00:00 2001 From: Dave Martin Date: Tue, 31 Oct 2017 15:51:13 +0000 Subject: arm64/sve: ptrace and ELF coredump support MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This patch defines and implements a new regset NT_ARM_SVE, which describes a thread's SVE register state. This allows a debugger to manipulate the SVE state, as well as being included in ELF coredumps for post-mortem debugging. Because the regset size and layout are dependent on the thread's current vector length, it is not possible to define a C struct to describe the regset contents as is done for existing regsets. Instead, and for the same reasons, NT_ARM_SVE is based on the freeform variable-layout approach used for the SVE signal frame. Additionally, to reduce debug overhead when debugging threads that might or might not have live SVE register state, NT_ARM_SVE may be presented in one of two different formats: the old struct user_fpsimd_state format is embedded for describing the state of a thread with no live SVE state, whereas a new variable-layout structure is embedded for describing live SVE state. This avoids a debugger needing to poll NT_PRFPREG in addition to NT_ARM_SVE, and allows existing userspace code to handle the non-SVE case without too much modification. For this to work, NT_ARM_SVE is defined with a fixed-format header of type struct user_sve_header, which the recipient can use to figure out the content, size and layout of the reset of the regset. Accessor macros are defined to allow the vector-length-dependent parts of the regset to be manipulated. Signed-off-by: Alan Hayward Signed-off-by: Dave Martin Reviewed-by: Catalin Marinas Cc: Alex Bennée Cc: Okamoto Takayuki Signed-off-by: Will Deacon --- include/uapi/linux/elf.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h index b5280db9ef6a..735b8f4d12fc 100644 --- a/include/uapi/linux/elf.h +++ b/include/uapi/linux/elf.h @@ -416,6 +416,7 @@ typedef struct elf64_shdr { #define NT_ARM_HW_BREAK 0x402 /* ARM hardware breakpoint registers */ #define NT_ARM_HW_WATCH 0x403 /* ARM hardware watchpoint registers */ #define NT_ARM_SYSTEM_CALL 0x404 /* ARM system call number */ +#define NT_ARM_SVE 0x405 /* ARM Scalable Vector Extension registers */ #define NT_METAG_CBUF 0x500 /* Metag catch buffer registers */ #define NT_METAG_RPIPE 0x501 /* Metag read pipeline state */ #define NT_METAG_TLS 0x502 /* Metag TLS pointer */ -- cgit v1.2.3 From 2d2123bc7c7f843aa9db87720de159a049839862 Mon Sep 17 00:00:00 2001 From: Dave Martin Date: Tue, 31 Oct 2017 15:51:14 +0000 Subject: arm64/sve: Add prctl controls for userspace vector length management MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Catalin Marinas Cc: Alex Bennée [will: Fixed up prctl constants to avoid clash with PDEATHSIG] Signed-off-by: Will Deacon --- include/uapi/linux/prctl.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/uapi/linux') 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 */ -- cgit v1.2.3