TLS on amd64

Daniel Müller Daniel.Mueller at mailbox.tu-dresden.de
Thu Jul 14 20:39:48 CEST 2011


On 13.07.2011 22:38, Adam Lackorzynski wrote:
> On Wed Jul 13, 2011 at 22:10:15 +0200, Daniel Müller wrote:
>> I want to use the __thread keyword gcc provides. I was told this was
>> recently adjusted to work (at least in the private repository which I am
>> using). It appears to be working when building for IA32 but when I
>> compile the same program for amd64 I get a page fault when running it
>> (it is a simple program just incrementing a __thread declared int).
>>
>> It faults at 10010f4 (the first access of the variable).
>>
>> 00000000010010f0 <main>:
>>  10010f0:    48 83 ec 08              sub    rsp,0x8
>>  10010f4:    64 c7 04 25 fc ff ff     mov    DWORD PTR
>> fs:0xfffffffffffffffc,0x0
>>  10010fb:    ff 00 00 00 00
>>  1001100:    bf 60 48 01 01           mov    edi,0x1014860
>>  1001105:    e8 36 88 00 00           call   1009940 <puts>
>>  100110a:    64 83 04 25 fc ff ff     add    DWORD PTR
>> fs:0xfffffffffffffffc,0x1
>>  1001111:    ff 01
>>  1001113:    bf 01 00 00 00           mov    edi,0x1
>>  1001118:    e8 d3 71 00 00           call   10082f0 <sleep>
>>  100111d:    eb e1                    jmp    1001100 <main+0x10>
>>  100111f:    90                       nop
>>
>> Is TLS for amd64 supposed to work? Any idea on the problem?
> It's currently only supposed to work on x86-32, other archs haven't been
> done yet.
This is unfortunate. Are there plans to fix this in the near future?

Daniel




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