diff options
| -rw-r--r-- | include/uapi/linux/rseq.h | 9 | ||||
| -rw-r--r-- | kernel/rseq.c | 11 |
2 files changed, 19 insertions, 1 deletions
diff --git a/include/uapi/linux/rseq.h b/include/uapi/linux/rseq.h index 1cb90a435c5c..c233aae5eac9 100644 --- a/include/uapi/linux/rseq.h +++ b/include/uapi/linux/rseq.h @@ -140,6 +140,15 @@ struct rseq { __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[]; diff --git a/kernel/rseq.c b/kernel/rseq.c index 193cfcc94ddc..9de6e35fe679 100644 --- a/kernel/rseq.c +++ b/kernel/rseq.c @@ -90,12 +90,15 @@ static int rseq_update_cpu_node_id(struct task_struct *t) struct rseq __user *rseq = t->rseq; u32 cpu_id = raw_smp_processor_id(); u32 node_id = cpu_to_node(cpu_id); + u32 mm_cid = task_mm_cid(t); + WARN_ON_ONCE((int) mm_cid < 0); if (!user_write_access_begin(rseq, t->rseq_len)) goto efault; unsafe_put_user(cpu_id, &rseq->cpu_id_start, efault_end); unsafe_put_user(cpu_id, &rseq->cpu_id, efault_end); unsafe_put_user(node_id, &rseq->node_id, efault_end); + unsafe_put_user(mm_cid, &rseq->mm_cid, efault_end); /* * Additional feature fields added after ORIG_RSEQ_SIZE * need to be conditionally updated only if @@ -113,7 +116,8 @@ efault: static int rseq_reset_rseq_cpu_node_id(struct task_struct *t) { - u32 cpu_id_start = 0, cpu_id = RSEQ_CPU_ID_UNINITIALIZED, node_id = 0; + u32 cpu_id_start = 0, cpu_id = RSEQ_CPU_ID_UNINITIALIZED, node_id = 0, + mm_cid = 0; /* * Reset cpu_id_start to its initial state (0). @@ -133,6 +137,11 @@ static int rseq_reset_rseq_cpu_node_id(struct task_struct *t) if (put_user(node_id, &t->rseq->node_id)) return -EFAULT; /* + * Reset mm_cid to its initial state (0). + */ + if (put_user(mm_cid, &t->rseq->mm_cid)) + return -EFAULT; + /* * Additional feature fields added after ORIG_RSEQ_SIZE * need to be conditionally reset only if * t->rseq_len != ORIG_RSEQ_SIZE. |