* tip-bot for Steven Rostedt (srostedt@xxxxxxxxxx) wrote: > Commit-ID: fc06b8520b3bf9aaeb2e27debe6719c215bd4916 > Gitweb: http://git.kernel.org/tip/fc06b8520b3bf9aaeb2e27debe6719c215bd4916 > Author: Steven Rostedt <srostedt@xxxxxxxxxx> > AuthorDate: Thu, 10 Sep 2009 17:22:44 -0400 > Committer: Steven Rostedt <rostedt@xxxxxxxxxxx> > 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@xxxxxxxxxx> With an added "s" to my last name, that will be good. Thanks ! Acked-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx> > Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx> > > > --- > 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 -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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