perf: Factor __output_copy to be usable with specific copy function

Adding a generic way to use __output_copy function with specific copy
function via DEFINE_PERF_OUTPUT_COPY macro.

Using this to add new __output_copy_user function, that provides output
copy from user pointers. For x86 the copy_from_user_nmi function is used
and __copy_from_user_inatomic for the rest of the architectures.

This new function will be used in user stack dump on sample, coming in
next patches.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Arun Sharma <asharma@fb.com>
Cc: Benjamin Redelings <benjamin.redelings@nescent.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Ulrich Drepper <drepper@gmail.com>
Link: http://lkml.kernel.org/r/1344345647-11536-4-git-send-email-jolsa@redhat.com
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index cb4e43b..4fabcdf 100644 (file)
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -262,4 +262,6 @@ static inline void perf_check_microcode(void) { }
  static inline void amd_pmu_disable_virt(void) { }
 #endif
 
+#define arch_perf_out_copy_user copy_from_user_nmi
+
 #endif /* _ASM_X86_PERF_EVENT_H */

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 3d4d847..d41394a 100644 (file)
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1319,7 +1319,7 @@ static inline bool has_branch_stack(struct perf_event *event)
 extern int perf_output_begin(struct perf_output_handle *handle,
                             struct perf_event *event, unsigned int size);
 extern void perf_output_end(struct perf_output_handle *handle);
-extern void perf_output_copy(struct perf_output_handle *handle,
+extern unsigned int perf_output_copy(struct perf_output_handle *handle,
                             const void *buf, unsigned int len);
 extern int perf_swevent_get_recursion_context(void);
 extern void perf_swevent_put_recursion_context(int rctx);

diff --git a/kernel/events/internal.h b/kernel/events/internal.h
index a096c19..7fd5408 100644 (file)
--- a/kernel/events/internal.h
+++ b/kernel/events/internal.h
@@ -2,6 +2,7 @@
 #define _KERNEL_EVENTS_INTERNAL_H
 
 #include <linux/hardirq.h>
+#include <linux/uaccess.h>
 
 /* Buffer handling */
 
@@ -76,30 +77,49 @@ static inline unsigned long perf_data_size(struct ring_buffer *rb)
        return rb->nr_pages << (PAGE_SHIFT + page_order(rb));
 }
 
-static inline void
-__output_copy(struct perf_output_handle *handle,
-                  const void *buf, unsigned int len)
+#define DEFINE_OUTPUT_COPY(func_name, memcpy_func)                     \
+static inline unsigned int                                             \
+func_name(struct perf_output_handle *handle,                           \
+         const void *buf, unsigned int len)                            \
+{                                                                      \
+       unsigned long size, written;                                    \
+                                                                       \
+       do {                                                            \
+               size = min_t(unsigned long, handle->size, len);         \
+                                                                       \
+               written = memcpy_func(handle->addr, buf, size);         \
+                                                                       \
+               len -= written;                                         \
+               handle->addr += written;                                \
+               buf += written;                                         \
+               handle->size -= written;                                \
+               if (!handle->size) {                                    \
+                       struct ring_buffer *rb = handle->rb;            \
+                                                                       \
+                       handle->page++;                                 \
+                       handle->page &= rb->nr_pages - 1;               \
+                       handle->addr = rb->data_pages[handle->page];    \
+                       handle->size = PAGE_SIZE << page_order(rb);     \
+               }                                                       \
+       } while (len && written == size);                               \
+                                                                       \
+       return len;                                                     \
+}
+
+static inline int memcpy_common(void *dst, const void *src, size_t n)
 {
-       do {
-               unsigned long size = min_t(unsigned long, handle->size, len);
-
-               memcpy(handle->addr, buf, size);
-
-               len -= size;
-               handle->addr += size;
-               buf += size;
-               handle->size -= size;
-               if (!handle->size) {
-                       struct ring_buffer *rb = handle->rb;
-
-                       handle->page++;
-                       handle->page &= rb->nr_pages - 1;
-                       handle->addr = rb->data_pages[handle->page];
-                       handle->size = PAGE_SIZE << page_order(rb);
-               }
-       } while (len);
+       memcpy(dst, src, n);
+       return n;
 }
 
+DEFINE_OUTPUT_COPY(__output_copy, memcpy_common)
+
+#ifndef arch_perf_out_copy_user
+#define arch_perf_out_copy_user __copy_from_user_inatomic
+#endif
+
+DEFINE_OUTPUT_COPY(__output_copy_user, arch_perf_out_copy_user)
+
 /* Callchain handling */
 extern struct perf_callchain_entry *
 perf_callchain(struct perf_event *event, struct pt_regs *regs);

diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 6ddaba4..b4c2ad3 100644 (file)
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -182,10 +182,10 @@ out:
        return -ENOSPC;
 }
 
-void perf_output_copy(struct perf_output_handle *handle,
+unsigned int perf_output_copy(struct perf_output_handle *handle,
                      const void *buf, unsigned int len)
 {
-       __output_copy(handle, buf, len);
+       return __output_copy(handle, buf, len);
 }
 
 void perf_output_end(struct perf_output_handle *handle)