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Subject[PATCH] i386 : Make arch/x86/kernel/acpi/wakeup_32.S use a separate text section
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>

diff --git a/arch/x86/kernel/acpi/wakeup_32.S b/arch/x86/kernel/acpi/wakeup_32.S
index 1e931aa..f53e327 100644
--- 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 7d72cce..113a831 100644
--- a/arch/x86/kernel/vmlinux_32.lds.S
+++ b/arch/x86/kernel/vmlinux_32.lds.S
@@ -44,6 +44,8 @@ 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


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