From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>,
Sathvika Vasireddy <sv@linux.ibm.com>
Cc: aik@ozlabs.ru, chenzhongjin@huawei.com, npiggin@gmail.com,
linux-kernel@vger.kernel.org, mingo@redhat.com,
rostedt@goodmis.org, jpoimboe@redhat.com, mbenes@suse.cz,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 11/16] objtool: Add --mnop as an option to --mcount
Date: Mon, 05 Sep 2022 16:25:42 +0530 [thread overview]
Message-ID: <1662374882.xll36f5qp9.naveen@linux.ibm.com> (raw)
In-Reply-To: <YxEHM8ZL1XAFsj4H@hirez.programming.kicks-ass.net>
Peter Zijlstra wrote:
> On Mon, Aug 29, 2022 at 11:22:18AM +0530, Sathvika Vasireddy wrote:
>> Architectures can select HAVE_NOP_MCOUNT if they choose
>> to nop out mcount call sites. If that config option is
>> selected, then --mnop is passed as an option to objtool,
>> along with --mcount.
>>
>> Also, make sure that --mnop can be passed as an option
>> to objtool only when --mcount is passed.
>>
>> Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com>
>
> IIRC you want to nop the things yourself because PLT entries or
> something?
For two reasons:
1. We want to maintain a pointer to 'struct module' as part of the
ftrace rec so that we can patch ftrace sites in modules to go to module
stubs.
2. We depend on compiler generated long branches to support large
kernels.
>
> Anyway, patch looks fine, even though the Changelog doesn't relaly
> justify the change.
Sure. We should add that powerpc kernel does not support nop'ed out
ftrace locations.
>
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
>
Thanks,
Naveen
next prev parent reply other threads:[~2022-09-05 10:56 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-29 5:52 [PATCH v2 00/16] objtool: Enable and implement --mcount option on powerpc Sathvika Vasireddy
2022-08-29 5:52 ` [PATCH v2 01/16] powerpc: Replace unreachable() with it's builtin variant in __WARN_FLAGS() Sathvika Vasireddy
2022-08-30 6:15 ` Christophe Leroy
2022-09-05 10:18 ` Naveen N. Rao
2022-08-29 5:52 ` [PATCH v2 02/16] powerpc: override __ALIGN() and __ALIGN_STR() macros Sathvika Vasireddy
2022-08-29 13:26 ` Christophe Leroy
2022-08-29 14:39 ` Sathvika Vasireddy
2022-08-31 3:24 ` Nicholas Piggin
2022-08-31 7:22 ` Michael Ellerman
2022-09-05 11:03 ` Peter Zijlstra
2022-08-29 5:52 ` [PATCH v2 03/16] powerpc: Fix objtool unannotated intra-function call warnings Sathvika Vasireddy
2022-08-30 6:16 ` Christophe Leroy
2022-08-30 12:42 ` Christophe Leroy
2022-09-05 11:02 ` Peter Zijlstra
2022-08-29 5:52 ` [PATCH v2 04/16] powerpc: Curb objtool unannotated intra-function warnings Sathvika Vasireddy
2022-08-30 6:26 ` Christophe Leroy
2022-08-29 5:52 ` [PATCH v2 05/16] powerpc: Skip objtool from running on drivers/crypto/vmx/aesp8-ppc.o Sathvika Vasireddy
2022-08-30 6:26 ` Christophe Leroy
2022-09-01 19:17 ` Peter Zijlstra
2022-09-05 10:47 ` Naveen N. Rao
2022-08-29 5:52 ` [PATCH v2 06/16] powerpc: Fix objtool unannotated intra-function call warnings on PPC32 Sathvika Vasireddy
2022-08-29 5:52 ` [PATCH v2 07/16] powerpc: Skip objtool from running on VDSO files Sathvika Vasireddy
2022-08-30 6:27 ` Christophe Leroy
2022-09-01 19:19 ` Peter Zijlstra
2022-09-02 7:40 ` Michael Ellerman
2022-08-29 5:52 ` [PATCH v2 08/16] objtool: Fix SEGFAULT Sathvika Vasireddy
2022-09-01 19:20 ` Peter Zijlstra
2022-09-02 8:06 ` Christophe Leroy
2022-09-02 8:42 ` Peter Zijlstra
2022-08-29 5:52 ` [PATCH v2 09/16] objtool: Use target file endianness instead of a compiled constant Sathvika Vasireddy
2022-09-01 19:22 ` Peter Zijlstra
2022-08-29 5:52 ` [PATCH v2 10/16] objtool: Use target file class size " Sathvika Vasireddy
2022-09-01 19:23 ` Peter Zijlstra
2022-08-29 5:52 ` [PATCH v2 11/16] objtool: Add --mnop as an option to --mcount Sathvika Vasireddy
2022-08-30 6:28 ` Christophe Leroy
2022-09-01 19:25 ` Peter Zijlstra
2022-09-05 10:55 ` Naveen N. Rao [this message]
2022-08-29 5:52 ` [PATCH v2 12/16] objtool: Read special sections with alts only when specific options are selected Sathvika Vasireddy
2022-08-30 6:31 ` Christophe Leroy
2022-08-29 5:52 ` [PATCH v2 13/16] objtool: Use macros to define arch specific reloc types Sathvika Vasireddy
2022-08-30 6:33 ` Christophe Leroy
2022-09-01 19:28 ` Peter Zijlstra
2022-08-29 5:52 ` [PATCH v2 14/16] objtool: Add arch specific function arch_ftrace_match() Sathvika Vasireddy
2022-08-30 6:36 ` Christophe Leroy
2022-08-29 5:52 ` [PATCH v2 15/16] objtool/powerpc: Enable objtool to be built on ppc Sathvika Vasireddy
2022-08-30 6:41 ` Christophe Leroy
2022-09-05 10:37 ` Naveen N. Rao
2023-02-04 8:19 ` Randy Dunlap
2023-02-04 8:21 ` Randy Dunlap
2023-02-04 8:30 ` Randy Dunlap
2023-02-04 11:55 ` Christophe Leroy
2023-02-04 13:10 ` Christophe Leroy
2023-02-04 15:47 ` Josh Poimboeuf
2022-09-01 9:32 ` Christophe Leroy
2022-09-01 15:11 ` Segher Boessenkool
2022-09-01 16:38 ` Christophe Leroy
2022-09-01 19:01 ` Peter Zijlstra
2022-08-29 5:52 ` [PATCH v2 16/16] objtool/powerpc: Add --mcount specific implementation Sathvika Vasireddy
2022-08-30 6:44 ` Christophe Leroy
2022-08-31 12:50 ` Christophe Leroy
2022-08-31 17:51 ` Segher Boessenkool
2022-09-05 10:45 ` Naveen N. Rao
2022-09-05 20:43 ` Segher Boessenkool
2022-09-06 6:22 ` Christophe Leroy
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