From: Michael Ellerman <mpe@ellerman•id.au>
To: Torsten Duwe <duwe@lst•de>
Cc: linuxppc-dev@ozlabs•org, bsingharora@gmail•com,
linux-kernel@vger•kernel.org, rostedt@goodmis•org,
kamalesh@linux•vnet.ibm.com, pmladek@suse•com, jeyu@redhat•com,
jkosina@suse•cz, live-patching@vger•kernel.org, mbenes@suse•cz
Subject: Re: [PATCH 04/12] powerpc/ftrace: Prepare for -mprofile-kernel
Date: Fri, 26 Feb 2016 21:14:18 +1100 [thread overview]
Message-ID: <1456481658.25691.6.camel@ellerman.id.au> (raw)
In-Reply-To: <20160225135205.GF21932@lst.de>
On Thu, 2016-02-25 at 14:52 +0100, Torsten Duwe wrote:
> On Thu, Feb 25, 2016 at 01:28:27AM +1100, Michael Ellerman wrote:
> > @@ -450,17 +448,44 @@ static unsigned long stub_for_addr(const Elf64_Shdr *sechdrs,
> > return (unsigned long)&stubs[i];
> > }
> >
> > +#ifdef CC_USING_MPROFILE_KERNEL
> > +static int is_early_mcount_callsite(u32 *instruction)
> > +{
> > + /* -mprofile-kernel sequence starting with
> > + * mflr r0 and maybe std r0, LRSAVE(r1).
> > + */
> > + if ((instruction[-3] == PPC_INST_MFLR &&
> > + instruction[-2] == PPC_INST_STD_LR) ||
> > + instruction[-2] == PPC_INST_MFLR) {
> > + /* Nothing to be done here, it's an _mcount
> > + * call location and r2 will have to be
> > + * restored in the _mcount function.
> > + */
> > + return 1;
> > + }
> > + return 0;
> > +}
> > +#else
>
> *You* said this might page fault :)
It does :) - I fixed it up in patch 6, sorry I realise that's hard to review.
> Did we agree yet whether we insist on a streamlined compiler?
> (GCC commit e95d0248dace required)?
No we didn't really. I think you're right that it's not /too/ hard to support
both sequences. But we may change our mind in future :)
cheers
next prev parent reply other threads:[~2016-02-26 10:14 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-24 14:28 [PATCH 01/12] powerpc/module: Only try to generate the ftrace_caller() stub once Michael Ellerman
2016-02-24 14:28 ` [PATCH 02/12] powerpc/module: Mark module stubs with a magic value Michael Ellerman
2016-02-25 0:04 ` Balbir Singh
2016-02-25 6:43 ` Michael Ellerman
2016-02-25 13:17 ` Torsten Duwe
2016-02-26 10:37 ` Michael Ellerman
2016-02-24 14:28 ` [PATCH 03/12] powerpc/module: Create a special stub for ftrace_caller() Michael Ellerman
2016-02-25 0:08 ` Balbir Singh
2016-02-25 10:48 ` Michael Ellerman
2016-02-25 13:31 ` Torsten Duwe
2016-02-26 10:35 ` Michael Ellerman
2016-02-24 14:28 ` [PATCH 04/12] powerpc/ftrace: Prepare for -mprofile-kernel Michael Ellerman
2016-02-25 0:28 ` Balbir Singh
2016-02-25 10:37 ` Michael Ellerman
2016-02-25 13:52 ` Torsten Duwe
2016-02-26 10:14 ` Michael Ellerman [this message]
2016-02-24 14:28 ` [PATCH 05/12] powerpc/ftrace: ftrace_graph_caller() needs to save/restore toc Michael Ellerman
2016-02-25 0:30 ` Balbir Singh
2016-02-25 10:39 ` Michael Ellerman
2016-02-25 14:02 ` Torsten Duwe
2016-02-24 14:28 ` [PATCH 06/12] powerpc/module: Rework is_early_mcount_callsite() Michael Ellerman
2016-02-24 23:39 ` Balbir Singh
2016-02-25 10:28 ` Michael Ellerman
2016-02-25 14:06 ` Torsten Duwe
2016-02-24 14:28 ` [PATCH 07/12] powerpc/ftrace: FTRACE_WITH_REGS implementation for ppc64le Michael Ellerman
2016-02-25 0:48 ` Balbir Singh
2016-02-25 15:11 ` Torsten Duwe
2016-02-26 10:14 ` Michael Ellerman
2016-02-24 14:28 ` [PATCH 08/12] powerpc/ftrace: Rework ftrace_caller() Michael Ellerman
2016-02-25 1:06 ` Balbir Singh
2016-02-25 14:25 ` Torsten Duwe
2016-02-24 14:28 ` [PATCH 09/12] powerpc/ftrace: Use generic ftrace_modify_all_code() Michael Ellerman
2016-02-25 1:10 ` Balbir Singh
2016-02-24 14:28 ` [PATCH 10/12] powerpc/ftrace: FTRACE_WITH_REGS configuration variables Michael Ellerman
2016-02-25 1:11 ` Balbir Singh
2016-02-25 14:34 ` Torsten Duwe
2016-02-24 14:28 ` [PATCH 11/12] powerpc/ftrace: Rework __ftrace_make_nop() Michael Ellerman
2016-02-24 14:28 ` [PATCH 12/12] powerpc/ftrace: Disable profiling for some files Michael Ellerman
2016-02-25 1:13 ` Balbir Singh
2016-02-24 23:55 ` [PATCH 01/12] powerpc/module: Only try to generate the ftrace_caller() stub once Balbir Singh
2016-02-25 4:36 ` Balbir Singh
2016-02-25 13:08 ` Torsten Duwe
2016-02-25 14:38 ` Kamalesh Babulal
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