RE: [PATCH perf 3/4] perf tools: Fix unused variables: x86_{32,64}_regoffset_table

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From	平松雅巳 / HIRAMATU，MASAMI <masami.hiramatsu.pt@hitachi.com>
Newsgroups	linux.kernel
Subject	RE: [PATCH perf 3/4] perf tools: Fix unused variables: x86_{32,64}_regoffset_table
Date	Fri, 22 Jan 2016 09:10:02 +0100
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X-Original-To	"'Wangnan (F)'" <wangnan0@huawei.com>, Arnaldo Carvalho de Melo <acme@kernel.org>, Ben Hutchings <ben@decadent.org.uk>, He Kuang <hekuang@huawei.com>
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>From: Wangnan (F) [mailto:wangnan0@huawei.com]
>On 2016/1/22 13:56, 平松雅巳 / HIRAMATU，MASAMI wrote:
>>> From: Wangnan (F) [mailto:wangnan0@huawei.com]
>>> I think this problem is not introduced by my patch. In fact
>>> there's a fundamental problem in get_arch_regstr() that it is
>>> impossible to switch sub ISA.
>> Right, but I guess this can fixed by switching %sp (for x86-64)
>> and +0(%sp) (for x86-32) instead of $stack.
>>
>
>It may not work.
>
>No matter how we change regoffset_table, when get_arch_regstr()
>get a register number 4, how can it know whether we are looking
>for x86_32 register and return $stack or return %si for x86_64?

I think we can also use elf header to get the ISA of the
target binary.

>The fundamental problem is: we need a way to map dwarf's register
>number to register names so uprobe know which register we are
>looking for, but the API we designed for this can't distinguish
>the sub ISAs dwarf are using.

As I said, we can read the elf header and get the Class or Machine
and switch the table according to it. Can't it?

Thanks,

Thread

[PATCH perf 0/4] Build fixes for gcc 6 Ben Hutchings <ben@decadent.org.uk> - 2016-01-19 22:40 +0100
  [PATCH perf 4/4] perf tests: Delete mis-indented dead code that  causes build failure with gcc 6 Ben Hutchings <ben@decadent.org.uk> - 2016-01-19 22:40 +0100
  [PATCH perf 3/4] perf tools: Fix unused variables:  x86_{32,64}_regoffset_table Ben Hutchings <ben@decadent.org.uk> - 2016-01-19 22:40 +0100
    Re: [PATCH perf 3/4] perf tools: Fix unused variables:  x86_{32,64}_regoffset_table Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-20 15:00 +0100
      Re: [PATCH perf 3/4] perf tools: Fix unused variables: x86_{32,64}_regoffset_table "Wangnan (F)" <wangnan0@huawei.com> - 2016-01-21 05:50 +0100
        Re: [PATCH perf 3/4] perf tools: Fix unused variables:  x86_{32,64}_regoffset_table Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-21 16:40 +0100
          Re: [PATCH perf 3/4] perf tools: Fix unused variables:  x86_{32,64}_regoffset_table Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-21 16:50 +0100
            Re: [PATCH perf 3/4] perf tools: Fix unused variables: x86_{32,64}_regoffset_table "Wangnan (F)" <wangnan0@huawei.com> - 2016-01-22 02:40 +0100
        RE: [PATCH perf 3/4] perf tools: Fix unused variables:  x86_{32,64}_regoffset_table 平松雅巳 / HIRAMATU，MASAMI   <masami.hiramatsu.pt@hitachi.com> - 2016-01-22 07:00 +0100
          Re: [PATCH perf 3/4] perf tools: Fix unused variables: x86_{32,64}_regoffset_table "Wangnan (F)" <wangnan0@huawei.com> - 2016-01-22 07:30 +0100
            RE: [PATCH perf 3/4] perf tools: Fix unused variables:  x86_{32,64}_regoffset_table 平松雅巳 / HIRAMATU，MASAMI   <masami.hiramatsu.pt@hitachi.com> - 2016-01-22 09:10 +0100
  [PATCH perf 2/4] perf top: Fix behaviour of Shift-Tab in annotated  view with nothing focussed Ben Hutchings <ben@decadent.org.uk> - 2016-01-19 22:40 +0100
  [PATCH perf 1/4] perf tools: Fix wrong indentation and build failure  with gcc 6 Ben Hutchings <ben@decadent.org.uk> - 2016-01-19 22:40 +0100
  Re: [PATCH perf 0/4] Build fixes for gcc 6 Markus Trippelsdorf <markus@trippelsdorf.de> - 2016-01-19 22:50 +0100
    Re: [PATCH perf 0/4] Build fixes for gcc 6 Ben Hutchings <ben@decadent.org.uk> - 2016-01-19 23:00 +0100
      Re: [PATCH perf 0/4] Build fixes for gcc 6 Ben Hutchings <ben@decadent.org.uk> - 2016-01-19 23:10 +0100
      Re: [PATCH perf 0/4] Build fixes for gcc 6 Markus Trippelsdorf <markus@trippelsdorf.de> - 2016-01-19 23:10 +0100
        Re: [PATCH perf 0/4] Build fixes for gcc 6 Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-19 23:30 +0100
          Re: [PATCH perf 0/4] Build fixes for gcc 6 Markus Trippelsdorf <markus@trippelsdorf.de> - 2016-01-19 23:40 +0100
            Re: [PATCH perf 0/4] Build fixes for gcc 6 Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-20 14:30 +0100
          Re: [PATCH perf 0/4] Build fixes for gcc 6 Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-19 23:40 +0100
            Re: [PATCH perf 0/4] Build fixes for gcc 6 Markus Trippelsdorf <markus@trippelsdorf.de> - 2016-01-19 23:50 +0100

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