* Re: [tip:tracing/core] x86/tracing: comment need for atomic nop [not found] <tip-fc06b8520b3bf9aaeb2e27debe6719c215bd4916@git.kernel.org> @ 2009-09-12 13:45 ` Mathieu Desnoyers 2009-09-12 18:05 ` Steven Rostedt 0 siblings, 1 reply; 2+ messages in thread From: Mathieu Desnoyers @ 2009-09-12 13:45 UTC (permalink / raw) To: linux-kernel, mingo, hpa, rostedt, srostedt, tglx; +Cc: linux-tip-commits * tip-bot for Steven Rostedt (srostedt@redhat.com) wrote: > Commit-ID: fc06b8520b3bf9aaeb2e27debe6719c215bd4916 > Gitweb: http://git.kernel.org/tip/fc06b8520b3bf9aaeb2e27debe6719c215bd4916 > Author: Steven Rostedt <srostedt@redhat.com> > AuthorDate: Thu, 10 Sep 2009 17:22:44 -0400 > Committer: Steven Rostedt <rostedt@goodmis.org> > CommitDate: Thu, 10 Sep 2009 17:22:44 -0400 > > x86/tracing: comment need for atomic nop > > The dynamic function tracer relys on the macro P6_NOP5 always being > an atomic NOP. If for some reason it is changed to be two operations > (like a nop2 nop3) it can faults within the kernel when the function > tracer modifies the code. > > This patch adds a comment to note that the P6_NOPs are expected to > be atomic. This will hopefully prevent anyone from changing that. > > Reported-by: Mathieu Desnoyer <mathieu.desnoyers@polymtl.ca> With an added "s" to my last name, that will be good. Thanks ! Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> > Signed-off-by: Steven Rostedt <rostedt@goodmis.org> > > > --- > arch/x86/include/asm/nops.h | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/arch/x86/include/asm/nops.h b/arch/x86/include/asm/nops.h > index ad2668e..6d8723a 100644 > --- a/arch/x86/include/asm/nops.h > +++ b/arch/x86/include/asm/nops.h > @@ -65,6 +65,8 @@ > 6: osp nopl 0x00(%eax,%eax,1) > 7: nopl 0x00000000(%eax) > 8: nopl 0x00000000(%eax,%eax,1) > + Note: All the above are assumed to be a single instruction. > + There is kernel code that depends on this. > */ > #define P6_NOP1 GENERIC_NOP1 > #define P6_NOP2 ".byte 0x66,0x90\n" -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 ^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [tip:tracing/core] x86/tracing: comment need for atomic nop 2009-09-12 13:45 ` [tip:tracing/core] x86/tracing: comment need for atomic nop Mathieu Desnoyers @ 2009-09-12 18:05 ` Steven Rostedt 0 siblings, 0 replies; 2+ messages in thread From: Steven Rostedt @ 2009-09-12 18:05 UTC (permalink / raw) To: Mathieu Desnoyers Cc: linux-kernel, mingo, hpa, srostedt, tglx, linux-tip-commits On Sat, 2009-09-12 at 09:45 -0400, Mathieu Desnoyers wrote: > * tip-bot for Steven Rostedt (srostedt@redhat.com) wrote: > > Commit-ID: fc06b8520b3bf9aaeb2e27debe6719c215bd4916 > > Gitweb: http://git.kernel.org/tip/fc06b8520b3bf9aaeb2e27debe6719c215bd4916 > > Author: Steven Rostedt <srostedt@redhat.com> > > AuthorDate: Thu, 10 Sep 2009 17:22:44 -0400 > > Committer: Steven Rostedt <rostedt@goodmis.org> > > CommitDate: Thu, 10 Sep 2009 17:22:44 -0400 > > > > x86/tracing: comment need for atomic nop > > > > The dynamic function tracer relys on the macro P6_NOP5 always being > > an atomic NOP. If for some reason it is changed to be two operations > > (like a nop2 nop3) it can faults within the kernel when the function > > tracer modifies the code. > > > > This patch adds a comment to note that the P6_NOPs are expected to > > be atomic. This will hopefully prevent anyone from changing that. > > > > Reported-by: Mathieu Desnoyer <mathieu.desnoyers@polymtl.ca> > > With an added "s" to my last name, that will be good. Oops, sorry. I seem to always do that to your name. I was too busy concentrating in getting your email correct (wrote the commit on a different box than my email client) that I didn't notice your name was wrong. -- Steve > > Thanks ! > > Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> > > > Signed-off-by: Steven Rostedt <rostedt@goodmis.org> ^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2009-09-12 18:05 UTC | newest] Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- [not found] <tip-fc06b8520b3bf9aaeb2e27debe6719c215bd4916@git.kernel.org> 2009-09-12 13:45 ` [tip:tracing/core] x86/tracing: comment need for atomic nop Mathieu Desnoyers 2009-09-12 18:05 ` Steven Rostedt
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.