From: Ralf Baechle <ralf@linux-mips.org>
To: Alan Cooper <alcooperx@gmail.com>
Cc: Petri Gynther <pgynther@google.com>,
linux-mips@linux-mips.org, Steven Rostedt <rostedt@goodmis.org>,
cminyard@mvista.com
Subject: Re: [PATCH] MIPS: Ftrace: Fix dynamic tracing of kernel modules
Date: Thu, 7 Aug 2014 23:25:14 +0200 [thread overview]
Message-ID: <20140807212514.GD29898@linux-mips.org> (raw)
In-Reply-To: <CAOGqxeW8+cdfUuGqy8d6Ewcyy9oC7ZCsdd1p4aX_-zko38BAuA@mail.gmail.com>
On Wed, Aug 06, 2014 at 01:12:06PM -0400, Alan Cooper wrote:
> Actually , there's no reason to write the second NOP when nop'ing the
> mcount call site in a module. This was done to remove the stack adjust
> instruction which only exists at this location for internal kernel
> routines. The following diff seems like a simpler way to solve issue
> #1:
Oh?
$ mips-linux-objdump -d --reloc net/sctp/sctp.ko
[...]
00000000 <sctp_sm_lookup_event>:
0: 27bdffe8 addiu sp,sp,-24
4: afbf0014 sw ra,20(sp)
8: 3c030000 lui v1,0x0
8: R_MIPS_HI16 _mcount
c: 24630000 addiu v1,v1,0
c: R_MIPS_LO16 _mcount
10: 03e00821 move at,ra
14: 27ac0014 addiu t4,sp,20
18: 0060f809 jalr v1
1c: 27bdfff8 addiu sp,sp,-8 <====
[...]
64: 27bd0018 addiu sp,sp,24
68: 03e00008 jr ra
[...]
So the stack adjustment also exists for modules.
Or am I missunderstanding something?
Ralf
next prev parent reply other threads:[~2014-08-07 21:25 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-24 5:55 [PATCH] MIPS: Ftrace: Fix dynamic tracing of kernel modules Petri Gynther
2014-08-05 16:41 ` Alan Cooper
[not found] ` <CAGXr9JE7v9-hS3irmdgeaEU2iGLZHshEr_N-Do1UAsZhyzMe2g@mail.gmail.com>
2014-08-06 17:12 ` Alan Cooper
2014-08-07 21:25 ` Ralf Baechle [this message]
2014-08-08 4:11 ` Tony Wu
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