perf: Pass protection and flags bits through mmap2 interface

The mmap2 interface was missing the protection and flags bits needed to
accurately determine if a mmap memory area was shared or private and
if it was readable or not.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
[tweaked patch to compile and wrote changelog]
Signed-off-by: Don Zickus <dzickus@redhat.com>
Link: http://lkml.kernel.org/r/1400526833-141779-2-git-send-email-dzickus@redhat.com
Signed-off-by: Jiri Olsa <jolsa@kernel.org>

2 files changed, 34 insertions, 0 deletions

diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 5312fae47218..9269de254874 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -705,6 +705,7 @@ enum perf_event_type {
          *      u32                             min;
          *      u64                             ino;
          *      u64                             ino_generation;
+         *      u32                             prot, flags;
          *      char                            filename[];
          *      struct sample_id                sample_id;
          * };
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 7da5e561e89a..eea1955c7868 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -40,6 +40,7 @@
 #include <linux/mm_types.h>
 #include <linux/cgroup.h>
 #include <linux/module.h>
+#include <linux/mman.h>
 
 #include "internal.h"
 
@@ -5127,6 +5128,7 @@ struct perf_mmap_event {
         int                     maj, min;
         u64                     ino;
         u64                     ino_generation;
+        u32                     prot, flags;
 
         struct {
                 struct perf_event_header        header;
@@ -5168,6 +5170,8 @@ static void perf_event_mmap_output(struct perf_event *event,
                 mmap_event->event_id.header.size += sizeof(mmap_event->min);
                 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
                 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
+                mmap_event->event_id.header.size += sizeof(mmap_event->prot);
+                mmap_event->event_id.header.size += sizeof(mmap_event->flags);
         }
 
         perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
@@ -5186,6 +5190,8 @@ static void perf_event_mmap_output(struct perf_event *event,
                 perf_output_put(&handle, mmap_event->min);
                 perf_output_put(&handle, mmap_event->ino);
                 perf_output_put(&handle, mmap_event->ino_generation);
+                perf_output_put(&handle, mmap_event->prot);
+                perf_output_put(&handle, mmap_event->flags);
         }
 
         __output_copy(&handle, mmap_event->file_name,
@@ -5204,6 +5210,7 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
         struct file *file = vma->vm_file;
         int maj = 0, min = 0;
         u64 ino = 0, gen = 0;
+        u32 prot = 0, flags = 0;
         unsigned int size;
         char tmp[16];
         char *buf = NULL;
@@ -5234,6 +5241,28 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
                 gen = inode->i_generation;
                 maj = MAJOR(dev);
                 min = MINOR(dev);
+
+                if (vma->vm_flags & VM_READ)
+                        prot |= PROT_READ;
+                if (vma->vm_flags & VM_WRITE)
+                        prot |= PROT_WRITE;
+                if (vma->vm_flags & VM_EXEC)
+                        prot |= PROT_EXEC;
+
+                if (vma->vm_flags & VM_MAYSHARE)
+                        flags = MAP_SHARED;
+                else
+                        flags = MAP_PRIVATE;
+
+                if (vma->vm_flags & VM_DENYWRITE)
+                        flags |= MAP_DENYWRITE;
+                if (vma->vm_flags & VM_MAYEXEC)
+                        flags |= MAP_EXECUTABLE;
+                if (vma->vm_flags & VM_LOCKED)
+                        flags |= MAP_LOCKED;
+                if (vma->vm_flags & VM_HUGETLB)
+                        flags |= MAP_HUGETLB;
+
                 goto got_name;
         } else {
                 name = (char *)arch_vma_name(vma);
@@ -5274,6 +5303,8 @@ got_name:
         mmap_event->min = min;
         mmap_event->ino = ino;
         mmap_event->ino_generation = gen;
+        mmap_event->prot = prot;
+        mmap_event->flags = flags;
 
         if (!(vma->vm_flags & VM_EXEC))
                 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
@@ -5314,6 +5345,8 @@ void perf_event_mmap(struct vm_area_struct *vma)
                 /* .min (attr_mmap2 only) */
                 /* .ino (attr_mmap2 only) */
                 /* .ino_generation (attr_mmap2 only) */
+                /* .prot (attr_mmap2 only) */
+                /* .flags (attr_mmap2 only) */
         };
 
         perf_event_mmap_event(&mmap_event);