Re: [PATCH] x86, relocs: add percpu fixup for GNU ld 2.23

From: Kees Cook
Date: Wed Oct 16 2013 - 10:55:22 EST


On Tue, Oct 15, 2013 at 11:51 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> On 10/15/2013 11:43 PM, Kees Cook wrote:
>> The GNU linker tries to put __per_cpu_load into the percpu area, resulting
>> in a lack of its relocation. Force this symbol to be relocated. Seen
>> starting with GNU ld 2.23 and later.
>>
>> Reported-by: Ingo Molnar <mingo@xxxxxxxxxx>
>> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
>> ---
>> arch/x86/tools/relocs.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
>> index 1fa291f..7a85f29 100644
>> --- a/arch/x86/tools/relocs.c
>> +++ b/arch/x86/tools/relocs.c
>> @@ -729,6 +729,7 @@ static void percpu_init(void)
>> *
>> * The GNU linker incorrectly associates:
>> * __init_begin
>> + * __per_cpu_load
>> *
>> * The "gold" linker incorrectly associates:
>> * init_per_cpu__irq_stack_union
>> @@ -738,6 +739,7 @@ static int is_percpu_sym(ElfW(Sym) *sym, const char *symname)
>> {
>> return (sym->st_shndx == per_cpu_shndx) &&
>> strcmp(symname, "__init_begin") &&
>> + strcmp(symname, "__per_cpu_load") &&
>> strncmp(symname, "init_per_cpu_", 13);
>> }
>>
>>
>
> Why isn't this list using a regex like other symbol classes?

I assume because it was initially a single item and it has grown
slowly. Would you like me to convert it to a regex instead?

-Kees

--
Kees Cook
Chrome OS Security
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