Messages in this thread | | | Date | Mon, 26 Jan 2015 09:37:01 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCH/RFC 2/3] ftrace: introduce nohotpatch function attribute |
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On Mon, 26 Jan 2015 13:54:53 +0100 Heiko Carstens <heiko.carstens@de.ibm.com> wrote:
> gcc supports an s390 specific function attribute called "hotpatch". > It can be used to specify the number of halfwords that shall be added before > and after a function that shall be filled with nops for runtime patching. > > s390 will use the hotpatch attribute for function tracing, therefore > introduce a nohotpatch define, depending on CC_USING_HOTPATCH, and add it > to the existing notrace define.
Are the two mutually exclusive? That is, can you have -pg and hotpatch together? Reason why I ask is, if you have either -pg or hotpatch, then we only need "no_instrument_function" or "hotpatch" in the notrace define, not both. But I could be wrong.
-- Steve
> > Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> > --- > include/linux/compiler.h | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/include/linux/compiler.h b/include/linux/compiler.h > index b4fd7013c9f4..b4ab98e0e10b 100644 > --- a/include/linux/compiler.h > +++ b/include/linux/compiler.h > @@ -54,7 +54,13 @@ extern void __chk_io_ptr(const volatile void __iomem *); > #include <linux/compiler-gcc.h> > #endif > > -#define notrace __attribute__((no_instrument_function)) > +#ifdef CC_USING_HOTPATCH > +#define nohotpatch __attribute__((hotpatch(0,0))) > +#else > +#define nohotpatch > +#endif > + > +#define notrace __attribute__((no_instrument_function)) nohotpatch > > /* Intel compiler defines __GNUC__. So we will overwrite implementations > * coming from above header files here
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