[PATCH] i386 vDSO: add PT_NOTE segment

This patch adds an ELF note to the vDSO giving the LINUX_VERSION_CODE
value.  Having this in the vDSO lets the dynamic linker avoid the `uname'
syscall it now always does at startup to ascertain the kernel ABI
available.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/arch/i386/kernel/vsyscall-note.S b/arch/i386/kernel/vsyscall-note.S
new file mode 100644
index 000000000000..d4b5be4f3d5f
--- /dev/null
+++ b/arch/i386/kernel/vsyscall-note.S
@@ -0,0 +1,25 @@
+/*
+ * This supplies .note.* sections to go into the PT_NOTE inside the vDSO text.
+ * Here we can supply some information useful to userland.
+ */
+
+#include <linux/uts.h>
+#include <linux/version.h>
+
+#define ASM_ELF_NOTE_BEGIN(name, flags, vendor, type)                         \
+        .section name, flags;                                                 \
+        .balign 4;                                                            \
+        .long 1f - 0f;          /* name length */                             \
+        .long 3f - 2f;          /* data length */                             \
+        .long type;             /* note type */                               \
+0:      .asciz vendor;          /* vendor name */                             \
+1:      .balign 4;                                                            \
+2:
+
+#define ASM_ELF_NOTE_END                                                      \
+3:      .balign 4;              /* pad out section */                         \
+        .previous
+
+        ASM_ELF_NOTE_BEGIN(".note.kernel-version", "a", UTS_SYSNAME, 0)
+        .long LINUX_VERSION_CODE
+        ASM_ELF_NOTE_END