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From: Segher Boessenkool <segher@kernel.crashing.org>
To: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Marc Zyngier <maz@kernel.org>,
	Sathvika Vasireddy <sv@linux.vnet.ibm.com>,
	"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"rostedt@goodmis.org" <rostedt@goodmis.org>,
	"aik@ozlabs.ru" <aik@ozlabs.ru>,
	"mingo@redhat.com" <mingo@redhat.com>,
	Sathvika Vasireddy <sv@linux.ibm.com>,
	"jpoimboe@redhat.com" <jpoimboe@redhat.com>,
	"paulus@samba.org" <paulus@samba.org>,
	"naveen.n.rao@linux.vnet.ibm.com"
	<naveen.n.rao@linux.vnet.ibm.com>,
	"mbenes@suse.cz" <mbenes@suse.cz>,
	Chen Zhongjin <chenzhongjin@huawei.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC PATCH v3 11/12] powerpc: Remove unreachable() from WARN_ON()
Date: Tue, 5 Jul 2022 10:48:52 -0500	[thread overview]
Message-ID: <20220705154852.GR25951@gate.crashing.org> (raw)
In-Reply-To: <6ab46ef2-6bbd-e758-a7ff-5f62fdf1ca96@csgroup.eu>

On Mon, Jul 04, 2022 at 12:34:08PM +0000, Christophe Leroy wrote:
> Le 04/07/2022 à 13:45, Peter Zijlstra a écrit :
> > I'm somewhat confused; how is an empty STT_FUNC a valid construct on
> > Power?
> 
> So am I. It is likely not a valid construct, but that's what GCC seems 
> to generate when you call annotate_unreachable().

It is a valid construct on (almost) all targets.  If the user chooses to
have executable code terminate in limbo, that is what the compiler will
do (and this can result in a code symbol with size 0).  Compare this to
data symbols with no size, the situation is quite similar.


Segher

  reply	other threads:[~2022-07-05 15:52 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-24 18:32 [RFC PATCH v3 00/12] objtool: Enable and implement --mcount option on powerpc Sathvika Vasireddy
2022-06-24 18:32 ` [RFC PATCH v3 01/12] objtool: Fix SEGFAULT Sathvika Vasireddy
2022-07-08 15:10   ` Christophe Leroy
2022-06-24 18:32 ` [RFC PATCH v3 02/12] objtool: Use target file endianness instead of a compiled constant Sathvika Vasireddy
2022-06-24 18:32 ` [RFC PATCH v3 03/12] objtool: Use target file class size " Sathvika Vasireddy
2022-07-08 17:35   ` Christophe Leroy
2022-06-24 18:32 ` [RFC PATCH v3 04/12] objtool: Add --mnop as an option to --mcount Sathvika Vasireddy
2022-06-24 18:32 ` [RFC PATCH v3 05/12] powerpc: Skip objtool from running on VDSO files Sathvika Vasireddy
2022-06-24 18:32 ` [RFC PATCH v3 06/12] objtool: Read special sections with alts only when specific options are selected Sathvika Vasireddy
2022-06-24 18:32 ` [RFC PATCH v3 07/12] objtool: Use macros to define arch specific reloc types Sathvika Vasireddy
2022-07-04 11:14   ` Peter Zijlstra
2022-07-04 15:53     ` Christophe Leroy
2022-07-04 16:18       ` Peter Zijlstra
2022-06-24 18:32 ` [RFC PATCH v3 08/12] objtool: Add arch specific function arch_ftrace_match() Sathvika Vasireddy
2022-06-24 18:32 ` [RFC PATCH v3 09/12] objtool/powerpc: Enable objtool to be built on ppc Sathvika Vasireddy
2022-06-24 18:32 ` [RFC PATCH v3 10/12] objtool/powerpc: Add --mcount specific implementation Sathvika Vasireddy
2022-06-24 18:32 ` [RFC PATCH v3 11/12] powerpc: Remove unreachable() from WARN_ON() Sathvika Vasireddy
2022-06-25  6:46   ` Christophe Leroy
2022-06-27 15:21     ` Sathvika Vasireddy
2022-06-27 15:35     ` Sathvika Vasireddy
2022-06-27 15:46       ` Christophe Leroy
2022-06-29 18:30       ` Christophe Leroy
2022-06-30  8:05         ` Naveen N. Rao
2022-06-30  9:58           ` Christophe Leroy
2022-06-30 10:33             ` Christophe Leroy
2022-06-30 10:37             ` Naveen N. Rao
2022-06-30 15:58               ` Segher Boessenkool
2022-07-04 12:01                 ` Peter Zijlstra
2022-07-04 11:43               ` Peter Zijlstra
2022-07-01  2:13           ` Chen Zhongjin
2022-07-01  6:56             ` Sathvika Vasireddy
2022-07-01 11:40               ` [RFC PATCH v3 11/12] powerpc: Remove unreachable() from WARN_ON() (gcc issue ?) Christophe Leroy
2022-07-04 11:45         ` [RFC PATCH v3 11/12] powerpc: Remove unreachable() from WARN_ON() Peter Zijlstra
2022-07-04 12:34           ` Christophe Leroy
2022-07-05 15:48             ` Segher Boessenkool [this message]
2022-07-04 12:05     ` Peter Zijlstra
2022-07-04 12:44       ` Christophe Leroy
2022-07-04 14:19         ` Peter Zijlstra
2022-06-24 18:32 ` [RFC PATCH v3 12/12] objtool/powerpc: Fix unannotated intra-function call warnings Sathvika Vasireddy
2022-07-08 15:06 ` [RFC PATCH v3 00/12] objtool: Enable and implement --mcount option on powerpc Christophe Leroy
2022-07-08 15:42   ` Christophe Leroy

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