diff options
| author | Andy Lutomirski <luto@amacapital.net> | 2014-06-19 02:59:49 +0400 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2014-06-20 02:45:26 +0400 |
| commit | 0e3727a8839c988a3c56170bc8da76d55a16acad (patch) | |
| tree | bfecd620ea122be019fdf446d4c716244838fdfd /arch/x86/vdso/vdso-layout.lds.S | |
| parent | bfad381c0d1e19cae8461e105d8d4387dd2a14fe (diff) | |
| download | linux-0e3727a8839c988a3c56170bc8da76d55a16acad.tar.xz | |
x86/vdso: Remove some redundant in-memory section headers
.data doesn't need to be separate from .rodata: they're both readonly.
.altinstructions and .altinstr_replacement aren't needed by anything
except vdso2c; strip them from the final image.
While we're at it, rather than aligning the actual executable text,
just shove some unused-at-runtime data in between real data and
text.
My vdso image is still above 4k, but I'm disinclined to try to
trim it harder for 3.16. For future trimming, I suspect that these
sections could be moved to later in the file and dropped from
the in-memory image:
.gnu.version and .gnu.version_d (this may lose versions in gdb)
.eh_frame (should be harmless)
.eh_frame_hdr (I'm not really sure)
.hash (AFAIK nothing needs this section header)
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/2e96d0c49016ea6d026a614ae645e93edd325961.1403129369.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/vdso/vdso-layout.lds.S')
| -rw-r--r-- | arch/x86/vdso/vdso-layout.lds.S | 43 |
1 files changed, 23 insertions, 20 deletions
diff --git a/arch/x86/vdso/vdso-layout.lds.S b/arch/x86/vdso/vdso-layout.lds.S index e4cbc2145bab..9197544eea9a 100644 --- a/arch/x86/vdso/vdso-layout.lds.S +++ b/arch/x86/vdso/vdso-layout.lds.S @@ -14,7 +14,7 @@ # error unknown VDSO target #endif -#define NUM_FAKE_SHDRS 16 +#define NUM_FAKE_SHDRS 13 SECTIONS { @@ -28,15 +28,17 @@ SECTIONS .gnu.version_d : { *(.gnu.version_d) } .gnu.version_r : { *(.gnu.version_r) } - .note : { *(.note.*) } :text :note - - .eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr - .eh_frame : { KEEP (*(.eh_frame)) } :text - .dynamic : { *(.dynamic) } :text :dynamic .rodata : { *(.rodata*) + *(.data*) + *(.sdata*) + *(.got.plt) *(.got) + *(.gnu.linkonce.d.*) + *(.bss*) + *(.dynbss*) + *(.gnu.linkonce.b.*) /* * Ideally this would live in a C file, but that won't @@ -50,28 +52,29 @@ SECTIONS .fake_shstrtab : { *(.fake_shstrtab) } :text - .data : { - *(.data*) - *(.sdata*) - *(.got.plt) *(.got) - *(.gnu.linkonce.d.*) - *(.bss*) - *(.dynbss*) - *(.gnu.linkonce.b.*) - } - .altinstructions : { *(.altinstructions) } - .altinstr_replacement : { *(.altinstr_replacement) } + .note : { *(.note.*) } :text :note + + .eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr + .eh_frame : { KEEP (*(.eh_frame)) } :text + /* - * Align the actual code well away from the non-instruction data. - * This is the best thing for the I-cache. + * Text is well-separated from actual data: there's plenty of + * stuff that isn't used at runtime in between. */ - . = ALIGN(0x100); .text : { *(.text*) } :text =0x90909090, /* + * At the end so that eu-elflint stays happy when vdso2c strips + * these. A better implementation would avoid allocating space + * for these. + */ + .altinstructions : { *(.altinstructions) } :text + .altinstr_replacement : { *(.altinstr_replacement) } :text + + /* * The remainder of the vDSO consists of special pages that are * shared between the kernel and userspace. It needs to be at the * end so that it doesn't overlap the mapping of the actual |