Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

User visible changes:

- Enhance the error reporting of tracepoint event parsing, e.g.:

    $ oldperf record -e sched:sched_switc usleep 1
    event syntax error: 'sched:sched_switc'
                         \___ unknown tracepoint
    Run 'perf list' for a list of valid events

  Now we get the much nicer:

    $ perf record -e sched:sched_switc ls
    event syntax error: 'sched:sched_switc'
                         \___ can't access trace events

    Error: No permissions to read /sys/kernel/debug/tracing/events/sched/sched_switc
    Hint:  Try 'sudo mount -o remount,mode=755 /sys/kernel/debug'

  And after we have those mount point permissions fixed:

    $ perf record -e sched:sched_switc ls
    event syntax error: 'sched:sched_switc'
                         \___ unknown tracepoint

    Error: File /sys/kernel/debug/tracing/events/sched/sched_switc not found.
    Hint:  Perhaps this kernel misses some CONFIG_ setting to enable this feature?.

  Now its just a matter of using what git uses to suggest alternatives when we
  make a typo, i.e. that it is just an 'h' missing :-)

  I.e. basically now the event parsing routing uses the strerror_open()
  routines introduced by and used in 'perf trace' work. (Jiri Olsa)

Infrastructure changes:

- Export init/exit_probe_symbol_maps() from 'perf probe' for use in eBPF.
  (Namhyung Kim)

- Free perf_probe_event in cleanup_perf_probe_events(). (Namhyung Kim)

- regs_query_register_offset() infrastructure + implementation for x86.
  First user will be the perf/eBPF code. (Wang Nan)

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 49 insertions, 0 deletions

diff --git a/tools/include/linux/err.h b/tools/include/linux/err.h
new file mode 100644
index 000000000000..c9ada48f5156
--- /dev/null
+++ b/tools/include/linux/err.h
@@ -0,0 +1,49 @@
+#ifndef __TOOLS_LINUX_ERR_H
+#define __TOOLS_LINUX_ERR_H
+
+#include <linux/compiler.h>
+#include <linux/types.h>
+
+#include <asm/errno.h>
+
+/*
+ * Original kernel header comment:
+ *
+ * Kernel pointers have redundant information, so we can use a
+ * scheme where we can return either an error code or a normal
+ * pointer with the same return value.
+ *
+ * This should be a per-architecture thing, to allow different
+ * error and pointer decisions.
+ *
+ * Userspace note:
+ * The same principle works for userspace, because 'error' pointers
+ * fall down to the unused hole far from user space, as described
+ * in Documentation/x86/x86_64/mm.txt for x86_64 arch:
+ *
+ * 0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm hole caused by [48:63] sign extension
+ * ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole
+ *
+ * It should be the same case for other architectures, because
+ * this code is used in generic kernel code.
+ */
+#define MAX_ERRNO	4095
+
+#define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)
+
+static inline void * __must_check ERR_PTR(long error)
+{
+	return (void *) error;
+}
+
+static inline long __must_check PTR_ERR(__force const void *ptr)
+{
+	return (long) ptr;
+}
+
+static inline bool __must_check IS_ERR(__force const void *ptr)
+{
+	return IS_ERR_VALUE((unsigned long)ptr);
+}
+
+#endif /* _LINUX_ERR_H */