[PATCH] Add VM_ALWAYSDUMP

This patch adds the VM_ALWAYSDUMP flag for vm_flags in vm_area_struct.  This
provides a clean explicit way to have a vma always included in core dumps, as
is needed for vDSO's.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 5 insertions, 0 deletions

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 7cb28720f90e..6fec8bfa6bac 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1178,6 +1178,10 @@ static int dump_seek(struct file *file, loff_t off)
  */
 static int maydump(struct vm_area_struct *vma)
 {
+        /* The vma can be set up to tell us the answer directly.  */
+        if (vma->vm_flags & VM_ALWAYSDUMP)
+                return 1;
+
         /* Do not dump I/O mapped devices or special mappings */
         if (vma->vm_flags & (VM_IO | VM_RESERVED))
                 return 0;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 76912231af41..2d2c08d5f473 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -168,6 +168,7 @@ extern unsigned int kobjsize(const void *objp);
 #define VM_NONLINEAR    0x00800000      /* Is non-linear (remap_file_pages) */
 #define VM_MAPPED_COPY  0x01000000      /* T if mapped copy of data (nommu mmap) */
 #define VM_INSERTPAGE   0x02000000      /* The vma has had "vm_insert_page()" done on it */
+#define VM_ALWAYSDUMP   0x04000000      /* Always include in core dumps */
 
 #ifndef VM_STACK_DEFAULT_FLAGS          /* arch can override this */
 #define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS