Thread (11 messages) flat view 11 messages, 5 authors, 2015-07-21

Re: BUG: perf error on syscalls for powerpc64.

From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2015-07-16 09:04:34
Also in: lkml

On Thu, 2015-07-16 at 13:57 +0800, Zumeng Chen wrote:
Hi All,

1028ccf5 did a change for sys_call_table from a pointer to an array of
unsigned long, I think it's not proper, here is my reason:

sys_call_table defined as a label in assembler should be pointer array
rather than an array as described in 1028ccf5. If we defined it as an
array, then arch_syscall_addr will return the address of sys_call_table[],
actually the content of sys_call_table[] is demanded by arch_syscall_addr.
so 'perf list' will ignore all syscalls since find_syscall_meta will
return null
in init_ftrace_syscalls because of the wrong arch_syscall_addr.

Did I miss something, or Gcc compiler has done something newer ?
Hi Zumeng,

It works for me with the code as it is in mainline.

I don't quite follow your explanation, so if you're seeing a bug please send
some information about what you're actually seeing. And include the disassembly
of arch_syscall_addr() and your compiler version etc.

cheers
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