2 files changed, 91 insertions, 0 deletions

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index db5a3732f106..253ae1328271 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -194,3 +194,6 @@
                 .stab.index 0 : { *(.stab.index) }                      \
                 .stab.indexstr 0 : { *(.stab.indexstr) }                \
                 .comment 0 : { *(.comment) }
+
+#define NOTES                                                           \
+                .notes : { *(.note.*) } :note
diff --git a/include/linux/elfnote.h b/include/linux/elfnote.h
new file mode 100644
index 000000000000..16f9f8ebffd9
--- /dev/null
+++ b/include/linux/elfnote.h
@@ -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 */