perf_counter: Generate mmap events for install_special_mapping()

In order to track the vdso also generate mmap events for
install_special_mapping().

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

3 files changed, 33 insertions, 20 deletions

diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index 6ca403acd419..40dc0e273d9c 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -617,8 +617,13 @@ static inline int is_software_counter(struct perf_counter *counter)
 
 extern void perf_swcounter_event(u32, u64, int, struct pt_regs *, u64);
 
-extern void perf_counter_mmap(unsigned long addr, unsigned long len,
-                              unsigned long pgoff, struct file *file);
+extern void __perf_counter_mmap(struct vm_area_struct *vma);
+
+static inline void perf_counter_mmap(struct vm_area_struct *vma)
+{
+        if (vma->vm_flags & VM_EXEC)
+                __perf_counter_mmap(vma);
+}
 
 extern void perf_counter_comm(struct task_struct *tsk);
 extern void perf_counter_fork(struct task_struct *tsk);
@@ -668,10 +673,7 @@ static inline void
 perf_swcounter_event(u32 event, u64 nr, int nmi,
                      struct pt_regs *regs, u64 addr)                    { }
 
-static inline void
-perf_counter_mmap(unsigned long addr, unsigned long len,
-                  unsigned long pgoff, struct file *file)               { }
-
+static inline void perf_counter_mmap(struct vm_area_struct *vma)        { }
 static inline void perf_counter_comm(struct task_struct *tsk)           { }
 static inline void perf_counter_fork(struct task_struct *tsk)           { }
 static inline void perf_counter_init(void)                              { }
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index a5d3e2aedd2f..37a5a241ca7e 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -2255,7 +2255,7 @@ out:
 }
 
 static void perf_output_copy(struct perf_output_handle *handle,
-                             void *buf, unsigned int len)
+                             const void *buf, unsigned int len)
 {
         unsigned int pages_mask;
         unsigned int offset;
@@ -2681,9 +2681,10 @@ void perf_counter_comm(struct task_struct *task)
  */
 
 struct perf_mmap_event {
-        struct file     *file;
-        char            *file_name;
-        int             file_size;
+        struct vm_area_struct   *vma;
+
+        const char              *file_name;
+        int                     file_size;
 
         struct {
                 struct perf_event_header        header;
@@ -2744,11 +2745,12 @@ static void perf_counter_mmap_event(struct perf_mmap_event *mmap_event)
 {
         struct perf_cpu_context *cpuctx;
         struct perf_counter_context *ctx;
-        struct file *file = mmap_event->file;
+        struct vm_area_struct *vma = mmap_event->vma;
+        struct file *file = vma->vm_file;
         unsigned int size;
         char tmp[16];
         char *buf = NULL;
-        char *name;
+        const char *name;
 
         if (file) {
                 buf = kzalloc(PATH_MAX, GFP_KERNEL);
@@ -2762,6 +2764,15 @@ static void perf_counter_mmap_event(struct perf_mmap_event *mmap_event)
                         goto got_name;
                 }
         } else {
+                name = arch_vma_name(mmap_event->vma);
+                if (name)
+                        goto got_name;
+
+                if (!vma->vm_mm) {
+                        name = strncpy(tmp, "[vdso]", sizeof(tmp));
+                        goto got_name;
+                }
+
                 name = strncpy(tmp, "//anon", sizeof(tmp));
                 goto got_name;
         }
@@ -2791,8 +2802,7 @@ got_name:
         kfree(buf);
 }
 
-void perf_counter_mmap(unsigned long addr, unsigned long len,
-                       unsigned long pgoff, struct file *file)
+void __perf_counter_mmap(struct vm_area_struct *vma)
 {
         struct perf_mmap_event mmap_event;
 
@@ -2800,12 +2810,12 @@ void perf_counter_mmap(unsigned long addr, unsigned long len,
                 return;
 
         mmap_event = (struct perf_mmap_event){
-                .file   = file,
+                .vma    = vma,
                 .event  = {
                         .header = { .type = PERF_EVENT_MMAP, },
-                        .start  = addr,
-                        .len    = len,
-                        .pgoff  = pgoff,
+                        .start  = vma->vm_start,
+                        .len    = vma->vm_end - vma->vm_start,
+                        .pgoff  = vma->vm_pgoff,
                 },
         };
 
diff --git a/mm/mmap.c b/mm/mmap.c
index 6451ce2854b9..8101de490c73 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1220,8 +1220,7 @@ munmap_back:
         if (correct_wcount)
                 atomic_inc(&inode->i_writecount);
 out:
-        if (vm_flags & VM_EXEC)
-                perf_counter_mmap(addr, len, pgoff, file);
+        perf_counter_mmap(vma);
 
         mm->total_vm += len >> PAGE_SHIFT;
         vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
@@ -2309,6 +2308,8 @@ int install_special_mapping(struct mm_struct *mm,
 
         mm->total_vm += len >> PAGE_SHIFT;
 
+        perf_counter_mmap(vma);
+
         return 0;
 }