+#define RB_CRASH_DUMP_ABI_LEN 256
+#define RB_RING_BUFFER_PADDING 60
+
+#define RB_CRASH_DUMP_ABI_MAGIC_LEN 16
+
+/*
+ * The 128-bit magic number is xor'd in the process data so it does not
+ * cause a false positive when searching for buffers by scanning memory.
+ * The actual magic number is:
+ * 0x17, 0x7B, 0xF1, 0x77, 0xBF, 0x17, 0x7B, 0xF1,
+ * 0x77, 0xBF, 0x17, 0x7B, 0xF1, 0x77, 0xBF, 0x17,
+ */
+#define RB_CRASH_DUMP_ABI_MAGIC_XOR \
+ { \
+ 0x17 ^ 0xFF, 0x7B ^ 0xFF, 0xF1 ^ 0xFF, 0x77 ^ 0xFF, \
+ 0xBF ^ 0xFF, 0x17 ^ 0xFF, 0x7B ^ 0xFF, 0xF1 ^ 0xFF, \
+ 0x77 ^ 0xFF, 0xBF ^ 0xFF, 0x17 ^ 0xFF, 0x7B ^ 0xFF, \
+ 0xF1 ^ 0xFF, 0x77 ^ 0xFF, 0xBF ^ 0xFF, 0x17 ^ 0xFF, \
+ }
+
+#define RB_CRASH_ENDIAN 0x1234
+
+#define RB_CRASH_DUMP_ABI_MAJOR 0
+#define RB_CRASH_DUMP_ABI_MINOR 0
+
+enum lttng_crash_type {
+ LTTNG_CRASH_TYPE_UST = 0,
+ LTTNG_CRASH_TYPE_KERNEL = 1,
+};
+
+struct lttng_crash_abi {
+ uint8_t magic[RB_CRASH_DUMP_ABI_MAGIC_LEN];
+ uint64_t mmap_length; /* Overall lenght of crash record */
+ uint16_t endian; /*
+ * { 0x12, 0x34 }: big endian
+ * { 0x34, 0x12 }: little endian
+ */
+ uint16_t major; /* Major number. */
+ uint16_t minor; /* Minor number. */
+ uint8_t word_size; /* Word size (bytes). */
+ uint8_t layout_type; /* enum lttng_crash_type */
+
+ struct {
+ uint32_t prod_offset;
+ uint32_t consumed_offset;
+ uint32_t commit_hot_array;
+ uint32_t commit_hot_seq;
+ uint32_t buf_wsb_array;
+ uint32_t buf_wsb_id;
+ uint32_t sb_array;
+ uint32_t sb_array_shmp_offset;
+ uint32_t sb_backend_p_offset;
+ uint32_t content_size;
+ uint32_t packet_size;
+ } __attribute__((packed)) offset;
+ struct {
+ uint8_t prod_offset;
+ uint8_t consumed_offset;
+ uint8_t commit_hot_seq;
+ uint8_t buf_wsb_id;
+ uint8_t sb_array_shmp_offset;
+ uint8_t sb_backend_p_offset;
+ uint8_t content_size;
+ uint8_t packet_size;
+ } __attribute__((packed)) length;
+ struct {
+ uint32_t commit_hot_array;
+ uint32_t buf_wsb_array;
+ uint32_t sb_array;
+ } __attribute__((packed)) stride;
+
+ uint64_t buf_size; /* Size of the buffer */
+ uint64_t subbuf_size; /* Sub-buffer size */
+ uint64_t num_subbuf; /* Number of sub-buffers for writer */
+ uint32_t mode; /* Buffer mode: 0: overwrite, 1: discard */
+} __attribute__((packed));
+
+struct lttng_ust_lib_ring_buffer {
+ /* First 32 bytes are for the buffer crash dump ABI */
+ struct lttng_crash_abi crash_abi;
+
+ /* 32 bytes cache-hot cacheline */
+ union v_atomic __attribute__((aligned(32))) offset;
+ /* Current offset in the buffer */