Messages in this thread Patch in this message | | | From | Petr Tesarik <> | Subject | [PATCH v2 5/8] x86: mark altinstr-related sections in vDSO as broken | Date | Fri, 12 Jun 2009 15:40:37 +0200 |
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There are several reasons why this does not work for the vDSO.
1. The alt_instr records are not processed by anybody.
The .altinstruction sections end up in the vDSO binary, which is then incorporated verbatim inside a completely different section, so it is not seen by the main kernel.
There is no code to interpret them during vDSO setup either.
2. The pointers in the alt_instr records are wrong.
They point to the instructions and replacements at the prelinked addresses, but that's neither where the vDSO blob is located at startup, nor where it is copied to by the vDSO setup.
The .altinstr_replacement section is not broken per se, but it is useless dead code without the accompanying .alt_instr section.
Signed-off-by: Petr Tesarik <ptesarik@suse.cz> --- arch/x86/vdso/vdso-layout.lds.S | 12 +++++------- 1 files changed, 5 insertions(+), 7 deletions(-)
diff --git a/arch/x86/vdso/vdso-layout.lds.S b/arch/x86/vdso/vdso-layout.lds.S index 7a76159..fc2ad07 100644 --- a/arch/x86/vdso/vdso-layout.lds.S +++ b/arch/x86/vdso/vdso-layout.lds.S @@ -56,13 +56,6 @@ SECTIONS *(.gnu.linkonce.b.*) } - .altinstructions : { - *(.altinstructions) - } - .altinstr_replacement : { - *(.altinstr_replacement) - } - /* * Align the actual code well away from the non-instruction data. * This is the best thing for the I-cache. @@ -80,6 +73,11 @@ SECTIONS * if they get used by accident. */ .broken : { + /* The vDSO setup code does not handle alternative + * instructions. + */ + *(.altinstructions) + *(.altinstr_replacement) } } -- 1.6.0.2
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