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-rw-r--r--fs/userfaultfd.c8
-rw-r--r--include/uapi/linux/userfaultfd.h10
2 files changed, 13 insertions, 5 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 5fd4d846691f..665bf7a930b2 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -178,7 +178,8 @@ static inline void msg_init(struct uffd_msg *msg)
static inline struct uffd_msg userfault_msg(unsigned long address,
unsigned int flags,
- unsigned long reason)
+ unsigned long reason,
+ unsigned int features)
{
struct uffd_msg msg;
msg_init(&msg);
@@ -202,6 +203,8 @@ static inline struct uffd_msg userfault_msg(unsigned long address,
* write protect fault.
*/
msg.arg.pagefault.flags |= UFFD_PAGEFAULT_FLAG_WP;
+ if (features & UFFD_FEATURE_THREAD_ID)
+ msg.arg.pagefault.ptid = task_pid_vnr(current);
return msg;
}
@@ -422,7 +425,8 @@ int handle_userfault(struct vm_fault *vmf, unsigned long reason)
init_waitqueue_func_entry(&uwq.wq, userfaultfd_wake_function);
uwq.wq.private = current;
- uwq.msg = userfault_msg(vmf->address, vmf->flags, reason);
+ uwq.msg = userfault_msg(vmf->address, vmf->flags, reason,
+ ctx->features);
uwq.ctx = ctx;
uwq.waken = false;
diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h
index d39d5db56771..2b24c28d99a7 100644
--- a/include/uapi/linux/userfaultfd.h
+++ b/include/uapi/linux/userfaultfd.h
@@ -24,7 +24,8 @@
UFFD_FEATURE_EVENT_UNMAP | \
UFFD_FEATURE_MISSING_HUGETLBFS | \
UFFD_FEATURE_MISSING_SHMEM | \
- UFFD_FEATURE_SIGBUS)
+ UFFD_FEATURE_SIGBUS | \
+ UFFD_FEATURE_THREAD_ID)
#define UFFD_API_IOCTLS \
((__u64)1 << _UFFDIO_REGISTER | \
(__u64)1 << _UFFDIO_UNREGISTER | \
@@ -79,6 +80,7 @@ struct uffd_msg {
struct {
__u64 flags;
__u64 address;
+ __u32 ptid;
} pagefault;
struct {
@@ -158,8 +160,9 @@ struct uffdio_api {
* UFFD_FEATURE_SIGBUS feature means no page-fault
* (UFFD_EVENT_PAGEFAULT) event will be delivered, instead
* a SIGBUS signal will be sent to the faulting process.
- * The application process can enable this behavior by adding
- * it to uffdio_api.features.
+ *
+ * UFFD_FEATURE_THREAD_ID pid of the page faulted task_struct will
+ * be returned, if feature is not requested 0 will be returned.
*/
#define UFFD_FEATURE_PAGEFAULT_FLAG_WP (1<<0)
#define UFFD_FEATURE_EVENT_FORK (1<<1)
@@ -169,6 +172,7 @@ struct uffdio_api {
#define UFFD_FEATURE_MISSING_SHMEM (1<<5)
#define UFFD_FEATURE_EVENT_UNMAP (1<<6)
#define UFFD_FEATURE_SIGBUS (1<<7)
+#define UFFD_FEATURE_THREAD_ID (1<<8)
__u64 features;
__u64 ioctls;