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Re: TLS details on Linux for x86 and x64
On 03/12/17 10:50, Jakub Jelinek wrote:
> On Sat, Dec 02, 2017 at 05:00:23PM +0000, Andrew Haley wrote:
>> On 02/12/17 14:04, Liu Hao wrote:
>>>
>>> 0) What is the magical `@tpoff` suffix supposed to do? The `@ntpoff` and
>>> `@dtpoff` things are documented in System V ABI but there doesn't seem
>>> to be anything about `@tpoff`.
>>> 1) How does LD tell that `b` (a thread-local integer) is different from
>>> `a` (a static integer)? `a` is apparently offset from RIP, but what
>>> thing is `b` offset from?
>>> 2) TLS initializers are placed into specially named sections. The
>>> sections will have the names like `.tls$XXX` where `$XXX` is used to
>>> sort these sections and discarded thereafter. How is LD supposed to
>>> associate the section containing the initializer with the symbol of
>>> object being initialized, without disordering?
>>>
>>> Any help will be appreciated.
>>
>> Have you read
>>
>> https://www.fsfla.org/~lxoliva/writeups/TLS/RFC-TLSDESC-x86.txt
>>
>> ?
>
> Well, for GNU TLS (rather than GNU2) you want to read
> https://www.akkadia.org/drepper/tls.pdf
Ah, thanks. I thought that it was much the same.
--
Andrew Haley
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
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