On Thu 2008-01-03 21:04:26, Eric Dumazet wrote:
> 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 <[EMAIL PROTECTED]>
Seems okay to me, but I did not test it.
> 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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