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[Xen-changelog] [linux-2.6.18-xen] Imported patch x86-put-note-sections-into-a-pt_note-segment-in-vmlinux.patch from xen-unstable.hg 15200:bd3d6b4c52ec



# 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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