diff options
Diffstat (limited to 'include/uapi/linux/userfaultfd.h')
| -rw-r--r-- | include/uapi/linux/userfaultfd.h | 70 |
1 files changed, 55 insertions, 15 deletions
diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h index 330206016249..a5f8825381ef 100644 --- a/include/uapi/linux/userfaultfd.h +++ b/include/uapi/linux/userfaultfd.h @@ -11,9 +11,15 @@ #include <linux/types.h> +#include <linux/compiler.h> + #define UFFD_API ((__u64)0xAA) -/* FIXME: add "|UFFD_FEATURE_WP" to UFFD_API_FEATURES after implementing it */ -#define UFFD_API_FEATURES (UFFD_FEATURE_WRITE_BIT) +/* + * After implementing the respective features it will become: + * #define UFFD_API_FEATURES (UFFD_FEATURE_PAGEFAULT_FLAG_WP | \ + * UFFD_FEATURE_EVENT_FORK) + */ +#define UFFD_API_FEATURES (0) #define UFFD_API_IOCTLS \ ((__u64)1 << _UFFDIO_REGISTER | \ (__u64)1 << _UFFDIO_UNREGISTER | \ @@ -45,26 +51,60 @@ #define UFFDIO_WAKE _IOR(UFFDIO, _UFFDIO_WAKE, \ struct uffdio_range) -/* - * Valid bits below PAGE_SHIFT in the userfault address read through - * the read() syscall. - */ -#define UFFD_BIT_WRITE (1<<0) /* this was a write fault, MISSING or WP */ -#define UFFD_BIT_WP (1<<1) /* handle_userfault() reason VM_UFFD_WP */ -#define UFFD_BITS 2 /* two above bits used for UFFD_BIT_* mask */ +/* read() structure */ +struct uffd_msg { + __u8 event; + + __u8 reserved1; + __u16 reserved2; + __u32 reserved3; + + union { + struct { + __u64 flags; + __u64 address; + } pagefault; + + struct { + /* unused reserved fields */ + __u64 reserved1; + __u64 reserved2; + __u64 reserved3; + } reserved; + } arg; +} __packed; /* - * Features reported in uffdio_api.features field + * Start at 0x12 and not at 0 to be more strict against bugs. */ -#define UFFD_FEATURE_WRITE_BIT (1<<0) /* Corresponds to UFFD_BIT_WRITE */ -#define UFFD_FEATURE_WP_BIT (1<<1) /* Corresponds to UFFD_BIT_WP */ +#define UFFD_EVENT_PAGEFAULT 0x12 +#if 0 /* not available yet */ +#define UFFD_EVENT_FORK 0x13 +#endif + +/* flags for UFFD_EVENT_PAGEFAULT */ +#define UFFD_PAGEFAULT_FLAG_WRITE (1<<0) /* If this was a write fault */ +#define UFFD_PAGEFAULT_FLAG_WP (1<<1) /* If reason is VM_UFFD_WP */ struct uffdio_api { - /* userland asks for an API number */ + /* userland asks for an API number and the features to enable */ __u64 api; - - /* kernel answers below with the available features for the API */ + /* + * Kernel answers below with the all available features for + * the API, this notifies userland of which events and/or + * which flags for each event are enabled in the current + * kernel. + * + * Note: UFFD_EVENT_PAGEFAULT and UFFD_PAGEFAULT_FLAG_WRITE + * are to be considered implicitly always enabled in all kernels as + * long as the uffdio_api.api requested matches UFFD_API. + */ +#if 0 /* not available yet */ +#define UFFD_FEATURE_PAGEFAULT_FLAG_WP (1<<0) +#define UFFD_FEATURE_EVENT_FORK (1<<1) +#endif __u64 features; + __u64 ioctls; }; |