# HG changeset patch
# User Ian Campbell <ian.campbell@xxxxxxxxxxxxx>
# Date 1180947924 -3600
# Node ID b450c13522c817e47276c2423ebb7d175009a316
# Parent 132f24200f4c5efffa4501c0542750d835e651d8
Imported patch x86-put-note-sections-into-a-pt_note-segment-in-vmlinux.patch
from xen-unstable.hg 15200:bd3d6b4c52ec
---
arch/i386/kernel/vmlinux.lds.S | 12 ++++-
include/asm-generic/vmlinux.lds.h | 3 +
include/linux/elfnote.h | 88 ++++++++++++++++++++++++++++++++++++++
3 files changed, 101 insertions(+), 2 deletions(-)
diff -r 132f24200f4c -r b450c13522c8 arch/i386/kernel/vmlinux.lds.S
--- a/arch/i386/kernel/vmlinux.lds.S Mon Jun 04 10:05:24 2007 +0100
+++ b/arch/i386/kernel/vmlinux.lds.S Mon Jun 04 10:05:24 2007 +0100
@@ -13,6 +13,12 @@ OUTPUT_ARCH(i386)
OUTPUT_ARCH(i386)
ENTRY(phys_startup_32)
jiffies = jiffies_64;
+
+PHDRS {
+ text PT_LOAD FLAGS(5); /* R_E */
+ data PT_LOAD FLAGS(7); /* RWE */
+ note PT_NOTE FLAGS(4); /* R__ */
+}
SECTIONS
{
. = __KERNEL_START;
@@ -26,7 +32,7 @@ SECTIONS
KPROBES_TEXT
*(.fixup)
*(.gnu.warning)
- } = 0x9090
+ } :text = 0x9090
_etext = .; /* End of text section */
@@ -48,7 +54,7 @@ SECTIONS
.data : AT(ADDR(.data) - LOAD_OFFSET) { /* Data */
*(.data)
CONSTRUCTORS
- }
+ } :data
. = ALIGN(4096);
__nosave_begin = .;
@@ -184,4 +190,6 @@ SECTIONS
STABS_DEBUG
DWARF_DEBUG
+
+ NOTES
}
diff -r 132f24200f4c -r b450c13522c8 include/asm-generic/vmlinux.lds.h
--- a/include/asm-generic/vmlinux.lds.h Mon Jun 04 10:05:24 2007 +0100
+++ b/include/asm-generic/vmlinux.lds.h Mon Jun 04 10:05:24 2007 +0100
@@ -194,3 +194,6 @@
.stab.index 0 : { *(.stab.index) } \
.stab.indexstr 0 : { *(.stab.indexstr) } \
.comment 0 : { *(.comment) }
+
+#define NOTES \
+ .notes : { *(.note.*) } :note
diff -r 132f24200f4c -r b450c13522c8 include/linux/elfnote.h
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/include/linux/elfnote.h Mon Jun 04 10:05:24 2007 +0100
@@ -0,0 +1,88 @@
+#ifndef _LINUX_ELFNOTE_H
+#define _LINUX_ELFNOTE_H
+/*
+ * Helper macros to generate ELF Note structures, which are put into a
+ * PT_NOTE segment of the final vmlinux image. These are useful for
+ * including name-value pairs of metadata into the kernel binary (or
+ * modules?) for use by external programs.
+ *
+ * Each note has three parts: a name, a type and a desc. The name is
+ * intended to distinguish the note's originator, so it would be a
+ * company, project, subsystem, etc; it must be in a suitable form for
+ * use in a section name. The type is an integer which is used to tag
+ * the data, and is considered to be within the "name" namespace (so
+ * "FooCo"'s type 42 is distinct from "BarProj"'s type 42). The
+ * "desc" field is the actual data. There are no constraints on the
+ * desc field's contents, though typically they're fairly small.
+ *
+ * All notes from a given NAME are put into a section named
+ * .note.NAME. When the kernel image is finally linked, all the notes
+ * are packed into a single .notes section, which is mapped into the
+ * PT_NOTE segment. Because notes for a given name are grouped into
+ * the same section, they'll all be adjacent the output file.
+ *
+ * This file defines macros for both C and assembler use. Their
+ * syntax is slightly different, but they're semantically similar.
+ *
+ * See the ELF specification for more detail about ELF notes.
+ */
+
+#ifdef __ASSEMBLER__
+/*
+ * Generate a structure with the same shape as Elf{32,64}_Nhdr (which
+ * turn out to be the same size and shape), followed by the name and
+ * desc data with appropriate padding. The 'desc' argument includes
+ * the assembler pseudo op defining the type of the data: .asciz
+ * "hello, world"
+ */
+.macro ELFNOTE name type desc:vararg
+.pushsection ".note.\name"
+ .align 4
+ .long 2f - 1f /* namesz */
+ .long 4f - 3f /* descsz */
+ .long \type
+1:.asciz "\name"
+2:.align 4
+3:\desc
+4:.align 4
+.popsection
+.endm
+#else /* !__ASSEMBLER__ */
+#include <linux/elf.h>
+/*
+ * Use an anonymous structure which matches the shape of
+ * Elf{32,64}_Nhdr, but includes the name and desc data. The size and
+ * type of name and desc depend on the macro arguments. "name" must
+ * be a literal string, and "desc" must be passed by value. You may
+ * only define one note per line, since __LINE__ is used to generate
+ * unique symbols.
+ */
+#define _ELFNOTE_PASTE(a,b) a##b
+#define _ELFNOTE(size, name, unique, type, desc) \
+ static const struct { \
+ struct elf##size##_note _nhdr; \
+ unsigned char _name[sizeof(name)] \
+ __attribute__((aligned(sizeof(Elf##size##_Word)))); \
+ typeof(desc) _desc \
+
__attribute__((aligned(sizeof(Elf##size##_Word)))); \
+ } _ELFNOTE_PASTE(_note_, unique) \
+ __attribute_used__ \
+ __attribute__((section(".note." name), \
+ aligned(sizeof(Elf##size##_Word)), \
+ unused)) = { \
+ { \
+ sizeof(name), \
+ sizeof(desc), \
+ type, \
+ }, \
+ name, \
+ desc \
+ }
+#define ELFNOTE(size, name, type, desc) \
+ _ELFNOTE(size, name, __LINE__, type, desc)
+
+#define ELFNOTE32(name, type, desc) ELFNOTE(32, name, type, desc)
+#define ELFNOTE64(name, type, desc) ELFNOTE(64, name, type, desc)
+#endif /* __ASSEMBLER__ */
+
+#endif /* _LINUX_ELFNOTE_H */
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