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From: Torsten Duwe <duwe@lst.de>
To: Balbir Singh <bsingharora@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
	linuxppc-dev@ozlabs.org, pmladek@suse.com, jeyu@redhat.com,
	jkosina@suse.cz, linux-kernel@vger.kernel.org,
	rostedt@goodmis.org, kamalesh@linux.vnet.ibm.com,
	live-patching@vger.kernel.org, mbenes@suse.cz
Subject: Re: [PATCH 07/12] powerpc/ftrace: FTRACE_WITH_REGS implementation for ppc64le
Date: Thu, 25 Feb 2016 16:11:13 +0100	[thread overview]
Message-ID: <20160225151113.GK21932@lst.de> (raw)
In-Reply-To: <56CE4F7B.7050704@gmail.com>

On Thu, Feb 25, 2016 at 11:48:59AM +1100, Balbir Singh wrote:
> > @@ -608,6 +621,9 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
> >  					return -ENOENT;
> >  				if (!restore_r2((u32 *)location + 1, me))
> >  					return -ENOEXEC;
> > +				/* Squash the TOC saver for profiler calls */
> > +				if (!strcmp("_mcount", strtab+sym->st_name))
> > +					SQUASH_TOC_SAVE_INSN(value);
> I don't think we need this anymore, do we?

I'm not sure. Once a module is loaded, are all the "bl _mcount"s NOPed out
before any of its functions are run? If not, the _mcount trampoline will
be used, and it must not save R2!

	Torsten

  reply	other threads:[~2016-02-25 15:11 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
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 [this message]
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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