Messages in this thread Patch in this message | | | Date | Thu, 3 Jan 2008 21:04:26 +0100 | From | Eric Dumazet <> | Subject | [PATCH] i386 : Make arch/x86/kernel/acpi/wakeup_32.S use a separate text section |
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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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