From: Sathvika Vasireddy <sv@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: peterz@infradead.org, npiggin@gmail.com,
linux-kernel@vger.kernel.org, aik@ozlabs.ru, mingo@redhat.com,
sv@linux.ibm.com, rostedt@goodmis.org, jpoimboe@redhat.com,
naveen.n.rao@linux.vnet.ibm.com, mbenes@suse.cz,
chenzhongjin@huawei.com
Subject: [PATCH v3 01/16] powerpc: Fix __WARN_FLAGS() for use with Objtool
Date: Mon, 12 Sep 2022 13:50:05 +0530 [thread overview]
Message-ID: <20220912082020.226755-2-sv@linux.ibm.com> (raw)
In-Reply-To: <20220912082020.226755-1-sv@linux.ibm.com>
Commit 1e688dd2a3d675 ("powerpc/bug: Provide better flexibility to
WARN_ON/__WARN_FLAGS() with asm goto") updated __WARN_FLAGS() to use asm
goto, and added a call to 'unreachable()' after the asm goto for optimal
code generation. With CONFIG_OBJTOOL enabled, 'annotate_unreachable()'
statement in 'unreachable()' tries to note down the location of the
subsequent instruction in a separate elf section to aid code flow
analysis. However, on powerpc, this results in gcc emitting a call to a
symbol of size 0. This results in objtool complaining of "unannotated
intra-function call" since the target symbol is not a valid function
call destination.
Objtool wants this annotation for code flow analysis, which we are not
yet enabling on powerpc. As such, expand the call to 'unreachable()' in
__WARN_FLAGS() without annotate_unreachable():
barrier_before_unreachable();
__builtin_unreachable();
This still results in optimal code generation for __WARN_FLAGS(), while
getting rid of the objtool warning.
We still need barrier_before_unreachable() to work around gcc bugs 82365
and 106751:
- https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365
- https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106751
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com>
---
arch/powerpc/include/asm/bug.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h
index 61a4736355c2..ef42adb44aa3 100644
--- a/arch/powerpc/include/asm/bug.h
+++ b/arch/powerpc/include/asm/bug.h
@@ -99,7 +99,8 @@
__label__ __label_warn_on; \
\
WARN_ENTRY("twi 31, 0, 0", BUGFLAG_WARNING | (flags), __label_warn_on); \
- unreachable(); \
+ barrier_before_unreachable(); \
+ __builtin_unreachable(); \
\
__label_warn_on: \
break; \
--
2.31.1
next prev parent reply other threads:[~2022-09-12 8:22 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-12 8:20 [PATCH v3 00/16] objtool: Enable and implement --mcount option on powerpc Sathvika Vasireddy
2022-09-12 8:20 ` Sathvika Vasireddy [this message]
2022-09-12 8:20 ` [PATCH v3 02/16] powerpc: Override __ALIGN and __ALIGN_STR macros Sathvika Vasireddy
2022-09-13 12:03 ` Peter Zijlstra
2022-09-13 12:21 ` Christophe Leroy
2022-09-13 13:15 ` Peter Zijlstra
2022-09-12 8:20 ` [PATCH v3 03/16] powerpc: Fix objtool unannotated intra-function call warnings Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 04/16] powerpc: Curb objtool unannotated intra-function warnings Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 05/16] powerpc: Skip objtool from running on drivers/crypto/vmx/aesp8-ppc.o Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 06/16] powerpc: Fix objtool unannotated intra-function call warnings on PPC32 Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 07/16] powerpc: Skip objtool from running on VDSO files Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 08/16] objtool: Fix SEGFAULT Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 09/16] objtool: Use target file endianness instead of a compiled constant Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 10/16] objtool: Use target file class size " Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 11/16] objtool: Add --mnop as an option to --mcount Sathvika Vasireddy
2022-09-12 18:55 ` kernel test robot
2022-09-15 6:56 ` Naveen N. Rao
2022-09-17 19:12 ` kernel test robot
2022-09-28 0:48 ` [objtool] ca5e2b42c0: kernel_BUG_at_arch/x86/kernel/jump_label.c kernel test robot
2022-09-28 15:44 ` Nathan Chancellor
2022-09-28 19:13 ` Josh Poimboeuf
2022-09-28 20:45 ` Nathan Chancellor
2022-09-12 8:20 ` [PATCH v3 12/16] objtool: Read special sections with alts only when specific options are selected Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 13/16] objtool: Use macros to define arch specific reloc types Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 14/16] objtool: Add arch specific function arch_ftrace_match() Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 15/16] objtool/powerpc: Enable objtool to be built on ppc Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 16/16] objtool/powerpc: Add --mcount specific implementation Sathvika Vasireddy
2022-09-13 10:00 ` Christophe Leroy
2022-09-13 14:13 ` [PATCH v3 00/16] objtool: Enable and implement --mcount option on powerpc Peter Zijlstra
2022-09-14 0:15 ` Josh Poimboeuf
2022-09-21 9:10 ` Sathvika Vasireddy
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