diff options
| -rw-r--r-- | include/linux/rseq.h | 7 | ||||
| -rw-r--r-- | include/linux/rseq_types.h | 21 | ||||
| -rw-r--r-- | include/trace/events/rseq.h | 4 | ||||
| -rw-r--r-- | kernel/rseq.c | 4 |
4 files changed, 32 insertions, 4 deletions
diff --git a/include/linux/rseq.h b/include/linux/rseq.h index ab91b1e6bb4a..d315a92afb36 100644 --- a/include/linux/rseq.h +++ b/include/linux/rseq.h @@ -57,6 +57,7 @@ static inline void rseq_virt_userspace_exit(void) static inline void rseq_reset(struct task_struct *t) { memset(&t->rseq, 0, sizeof(t->rseq)); + t->rseq.ids.cpu_cid = ~0ULL; } static inline void rseq_execve(struct task_struct *t) @@ -70,10 +71,12 @@ static inline void rseq_execve(struct task_struct *t) */ static inline void rseq_fork(struct task_struct *t, u64 clone_flags) { - if (clone_flags & CLONE_VM) + if (clone_flags & CLONE_VM) { rseq_reset(t); - else + } else { t->rseq = current->rseq; + t->rseq.ids.cpu_cid = ~0ULL; + } } #else /* CONFIG_RSEQ */ diff --git a/include/linux/rseq_types.h b/include/linux/rseq_types.h index f7a60c8eddc9..40901b033b92 100644 --- a/include/linux/rseq_types.h +++ b/include/linux/rseq_types.h @@ -31,17 +31,38 @@ struct rseq_event { }; /** + * struct rseq_ids - Cache for ids, which need to be updated + * @cpu_cid: Compound of @cpu_id and @mm_cid to make the + * compiler emit a single compare on 64-bit + * @cpu_id: The CPU ID which was written last to user space + * @mm_cid: The MM CID which was written last to user space + * + * @cpu_id and @mm_cid are updated when the data is written to user space. + */ +struct rseq_ids { + union { + u64 cpu_cid; + struct { + u32 cpu_id; + u32 mm_cid; + }; + }; +}; + +/** * struct rseq_data - Storage for all rseq related data * @usrptr: Pointer to the registered user space RSEQ memory * @len: Length of the RSEQ region * @sig: Signature of critial section abort IPs * @event: Storage for event management + * @ids: Storage for cached CPU ID and MM CID */ struct rseq_data { struct rseq __user *usrptr; u32 len; u32 sig; struct rseq_event event; + struct rseq_ids ids; }; #else /* CONFIG_RSEQ */ diff --git a/include/trace/events/rseq.h b/include/trace/events/rseq.h index 823b47d1ba1e..ce85d650bf4b 100644 --- a/include/trace/events/rseq.h +++ b/include/trace/events/rseq.h @@ -21,9 +21,9 @@ TRACE_EVENT(rseq_update, ), TP_fast_assign( - __entry->cpu_id = raw_smp_processor_id(); + __entry->cpu_id = t->rseq.ids.cpu_id; __entry->node_id = cpu_to_node(__entry->cpu_id); - __entry->mm_cid = task_mm_cid(t); + __entry->mm_cid = t->rseq.ids.mm_cid; ), TP_printk("cpu_id=%d node_id=%d mm_cid=%d", __entry->cpu_id, diff --git a/kernel/rseq.c b/kernel/rseq.c index aae62661e6bb..ad1e7cecd527 100644 --- a/kernel/rseq.c +++ b/kernel/rseq.c @@ -184,6 +184,10 @@ static int rseq_update_cpu_node_id(struct task_struct *t) rseq_unsafe_put_user(t, node_id, node_id, efault_end); rseq_unsafe_put_user(t, mm_cid, mm_cid, efault_end); + /* Cache the user space values */ + t->rseq.ids.cpu_id = cpu_id; + t->rseq.ids.mm_cid = mm_cid; + /* * Additional feature fields added after ORIG_RSEQ_SIZE * need to be conditionally updated only if |