1 files changed, 58 insertions, 44 deletions

diff --git a/include/uapi/linux/rseq.h b/include/uapi/linux/rseq.h
index d620fa43756c..9a402fdb60e9 100644
--- a/include/uapi/linux/rseq.h
+++ b/include/uapi/linux/rseq.h
@@ -10,13 +10,8 @@
  * Copyright (c) 2015-2018 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  */
 
-#ifdef __KERNEL__
-# include <linux/types.h>
-#else
-# include <stdint.h>
-#endif
-
-#include <linux/types_32_64.h>
+#include <linux/types.h>
+#include <asm/byteorder.h>
 
 enum rseq_cpu_id_state {
         RSEQ_CPU_ID_UNINITIALIZED               = -1,
@@ -52,10 +47,10 @@ struct rseq_cs {
         __u32 version;
         /* enum rseq_cs_flags */
         __u32 flags;
-        LINUX_FIELD_u32_u64(start_ip);
+        __u64 start_ip;
         /* Offset from start_ip. */
-        LINUX_FIELD_u32_u64(post_commit_offset);
-        LINUX_FIELD_u32_u64(abort_ip);
+        __u64 post_commit_offset;
+        __u64 abort_ip;
 } __attribute__((aligned(4 * sizeof(__u64))));
 
 /*
@@ -67,28 +62,30 @@ struct rseq_cs {
 struct rseq {
         /*
          * Restartable sequences cpu_id_start field. Updated by the
-         * kernel, and read by user-space with single-copy atomicity
-         * semantics. Aligned on 32-bit. Always contains a value in the
-         * range of possible CPUs, although the value may not be the
-         * actual current CPU (e.g. if rseq is not initialized). This
-         * CPU number value should always be compared against the value
-         * of the cpu_id field before performing a rseq commit or
-         * returning a value read from a data structure indexed using
-         * the cpu_id_start value.
+         * 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. Always
+         * contains a value in the range of possible CPUs, although the
+         * value may not be the actual current CPU (e.g. if rseq is not
+         * initialized). This CPU number value should always be compared
+         * against the value of the cpu_id field before performing a rseq
+         * commit or returning a value read from a data structure indexed
+         * using the cpu_id_start value.
          */
         __u32 cpu_id_start;
         /*
-         * Restartable sequences cpu_id field. Updated by the kernel,
-         * and read by user-space with single-copy atomicity semantics.
-         * Aligned on 32-bit. Values RSEQ_CPU_ID_UNINITIALIZED and
-         * RSEQ_CPU_ID_REGISTRATION_FAILED have a special semantic: the
-         * former means "rseq uninitialized", and latter means "rseq
-         * initialization failed". This value is meant to be read within
-         * rseq critical sections and compared with the cpu_id_start
-         * value previously read, before performing the commit instruction,
-         * or read and compared with the cpu_id_start value before returning
-         * a value loaded from a data structure indexed using the
-         * cpu_id_start value.
+         * Restartable sequences cpu_id 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. Values
+         * RSEQ_CPU_ID_UNINITIALIZED and RSEQ_CPU_ID_REGISTRATION_FAILED
+         * have a special semantic: the former means "rseq uninitialized",
+         * and latter means "rseq initialization failed". This value is
+         * meant to be read within rseq critical sections and compared
+         * with the cpu_id_start value previously read, before performing
+         * the commit instruction, or read and compared with the
+         * cpu_id_start value before returning a value loaded from a data
+         * structure indexed using the cpu_id_start value.
          */
         __u32 cpu_id;
         /*
@@ -105,27 +102,44 @@ struct rseq {
          * targeted by the rseq_cs. Also needs to be set to NULL by user-space
          * before reclaiming memory that contains the targeted struct rseq_cs.
          *
-         * Read and set by the kernel with single-copy atomicity semantics.
-         * Set by user-space with single-copy atomicity semantics. Aligned
-         * on 64-bit.
+         * Read and set by the kernel. Set by user-space with single-copy
+         * atomicity semantics. This field should only be updated by the
+         * thread which registered this data structure. Aligned on 64-bit.
          */
-        LINUX_FIELD_u32_u64(rseq_cs);
+        union {
+                __u64 ptr64;
+#ifdef __LP64__
+                __u64 ptr;
+#else
+                struct {
+#if (defined(__BYTE_ORDER) && (__BYTE_ORDER == __BIG_ENDIAN)) || defined(__BIG_ENDIAN)
+                        __u32 padding;          /* Initialized to zero. */
+                        __u32 ptr32;
+#else /* LITTLE */
+                        __u32 ptr32;
+                        __u32 padding;          /* Initialized to zero. */
+#endif /* ENDIAN */
+                } ptr;
+#endif
+        } rseq_cs;
+
         /*
-         * - RSEQ_DISABLE flag:
+         * Restartable sequences flags field.
+         *
+         * This field should only be updated by the thread which
+         * registered this data structure. Read by the kernel.
+         * Mainly used for single-stepping through rseq critical sections
+         * with debuggers.
          *
-         * Fallback fast-track flag for single-stepping.
-         * Set by user-space if lack of progress is detected.
-         * Cleared by user-space after rseq finish.
-         * Read by the kernel.
          * - RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT
-         *     Inhibit instruction sequence block restart and event
-         *     counter increment on preemption for this thread.
+         *     Inhibit instruction sequence block restart on preemption
+         *     for this thread.
          * - RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL
-         *     Inhibit instruction sequence block restart and event
-         *     counter increment on signal delivery for this thread.
+         *     Inhibit instruction sequence block restart on signal
+         *     delivery for this thread.
          * - RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE
-         *     Inhibit instruction sequence block restart and event
-         *     counter increment on migration for this thread.
+         *     Inhibit instruction sequence block restart on migration for
+         *     this thread.
          */
         __u32 flags;
 } __attribute__((aligned(4 * sizeof(__u64))));