(2012/07/12 1:28), Steven Rostedt wrote: > On Wed, 2012-07-11 at 12:22 -0400, Steven Rostedt wrote: >> 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. >> > > I know why I did this. Do you want kprobes to be able to modify flags? > If so, then I need to add, before the restore: > > movq EFLAGS(%rsp), %rax > movq %rax, SS(%rsp)
Yes, kprobes might be used for modifying flags, so, please :) Thank you, -- Masami HIRAMATSU Software Platform Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: [email protected] -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
