diff options
Diffstat (limited to 'include/uapi/linux/rseq.h')
| -rw-r--r-- | include/uapi/linux/rseq.h | 43 |
1 files changed, 29 insertions, 14 deletions
diff --git a/include/uapi/linux/rseq.h b/include/uapi/linux/rseq.h index 77ee207623a9..1b76d508400c 100644 --- a/include/uapi/linux/rseq.h +++ b/include/uapi/linux/rseq.h @@ -114,22 +114,37 @@ struct rseq { /* * Restartable sequences flags field. * - * This field should only be updated by the thread which - * registered this data structure. Read by the kernel. - * Mainly used for single-stepping through rseq critical sections - * with debuggers. - * - * - RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT - * Inhibit instruction sequence block restart on preemption - * for this thread. - * - RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL - * Inhibit instruction sequence block restart on signal - * delivery for this thread. - * - RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE - * Inhibit instruction sequence block restart on migration for - * this thread. + * This field was initially intended to allow event masking for + * single-stepping through rseq critical sections with debuggers. + * The kernel does not support this anymore and the relevant bits + * are checked for being always false: + * - RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT + * - RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL + * - RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE */ __u32 flags; + + /* + * Restartable sequences node_id field. Updated by the kernel. Read by + * user-space with single-copy atomicity semantics. This field should + * only be read by the thread which registered this data structure. + * Aligned on 32-bit. Contains the current NUMA node ID. + */ + __u32 node_id; + + /* + * Restartable sequences mm_cid field. Updated by the kernel. Read by + * user-space with single-copy atomicity semantics. This field should + * only be read by the thread which registered this data structure. + * Aligned on 32-bit. Contains the current thread's concurrency ID + * (allocated uniquely within a memory map). + */ + __u32 mm_cid; + + /* + * Flexible array member at end of structure, after last feature field. + */ + char end[]; } __attribute__((aligned(4 * sizeof(__u64)))); #endif /* _UAPI_LINUX_RSEQ_H */ |