Messages in this thread | | | Subject | Re: [PATCH 5/6] ftrace/x86: Add separate function to save regs | From | Steven Rostedt <> | Date | Wed, 11 Jul 2012 12:22:34 -0400 |
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On Tue, 2012-07-03 at 17:29 +0900, Masami Hiramatsu wrote:
> > > + /* Restore flags */ > > + pushq EFLAGS(%rsp) > > + popfq > > + > > + MCOUNT_RESTORE_FRAME > > Here, if MCOUNT_RESTORE_FRAME has skip too, I think you don't > need to restore flags before restoring other registers, like > below; > > MCOUNT_RESTORE_FRAME 8 > popfq > > And also, this will prevent to modify flags before return by > addq in MCOUNT_RESTORE_FRAME.
Ah, because the addq will modify flags :-/
Grumble, I guess I should implement this, even though it will make it a little more complex. I thought it was better to restore flags explicitly, but that's not the case.
OK, I'll make the update. As MCOUNT_SAVE_FRAME has the skip, I guess it's not so bad to have restore have it too.
-- Steve
> > > + > > + jmp ftrace_return > > +ftrace_restore_flags: > > + popfq > > + jmp ftrace_stub > > + > > +END(ftrace_regs_caller) > > + > > Thank you, > >
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