x86: make arch/x86/kernel/acpi/wakeup_32.S use a separate

While examining vmlinux namelist on i386 (nm -v vmlinux) I noticed :

c01021d0 t es7000_rename_gsi
c010221a T es7000_start_cpu
<Big Hole>
c0103000 T thread_saved_pc

and

c0113218 T acpi_restore_state_mem
c0113219 T acpi_save_state_mem
<Big Hole>
c0114000 t wakeup_code

This is because arch/x86/kernel/acpi/wakeup_32.S forces a .text alignment
of 4096 bytes. (I have no idea if it is really needed, since
arch/x86/kernel/acpi/wakeup_64.S uses a 16 bytes alignment *only*)

So arch/x86/kernel/built-in.o also has this alignment

arch/x86/kernel/built-in.o:     file format elf32-i386

Sections:
Idx Name          Size      VMA       LMA       File off  Algn
  0 .text         00018c94  00000000  00000000  00001000  2**12
                  CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE

But as arch/x86/kernel/acpi/wakeup_32.o is not the first object linked
into arch/x86/kernel/built-in.o, linker had to build several holes to meet
alignement requirements, because of .o nestings in the kbuild process.

This can be solved by using a special section, .text.page_aligned, so that
no holes are needed.

# size vmlinux.before vmlinux.after
   text    data     bss     dec     hex filename
4619942  422838  458752 5501532  53f25c vmlinux.before
4610534  422838  458752 5492124  53cd9c vmlinux.after

This saves 9408 bytes

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/kernel/acpi/wakeup_32.S b/arch/x86/kernel/acpi/wakeup_32.S
index 1e931aaf2ef6db657ec4bc471d17ab169a4aa975..f53e3277f8e500512d1c86a3aa9c2b718715a6f3 100644 (file)
--- a/arch/x86/kernel/acpi/wakeup_32.S
+++ b/arch/x86/kernel/acpi/wakeup_32.S
@@ -1,4 +1,4 @@
-.text
+       .section .text.page_aligned
 #include <linux/linkage.h>
 #include <asm/segment.h>
 #include <asm/page.h>

diff --git a/arch/x86/kernel/vmlinux_32.lds.S b/arch/x86/kernel/vmlinux_32.lds.S
index ec072588ff0137f30a2d63752dad59e02be3b65c..f1148ac8abe307ae425127e5275f78dd31db5531 100644 (file)
--- a/arch/x86/kernel/vmlinux_32.lds.S
+++ b/arch/x86/kernel/vmlinux_32.lds.S
@@ -38,6 +38,8 @@ SECTIONS
 
   /* read-only */
   .text : AT(ADDR(.text) - LOAD_OFFSET) {
+       . = ALIGN(4096); /* not really needed, already page aligned */
+       *(.text.page_aligned)
        TEXT_TEXT
        SCHED_TEXT
        LOCK_TEXT