From: Sathvika Vasireddy <sv@linux.ibm.com> To: linuxppc-dev@lists.ozlabs.org Cc: jpoimboe@redhat.com, peterz@infradead.org, linux-kernel@vger.kernel.org, aik@ozlabs.ru, mpe@ellerman.id.au, mingo@redhat.com, christophe.leroy@csgroup.eu, rostedt@goodmis.org, mbenes@suse.cz, npiggin@gmail.com, chenzhongjin@huawei.com, naveen.n.rao@linux.vnet.ibm.com, sv@linux.ibm.com Subject: [PATCH v2 01/16] powerpc: Replace unreachable() with it's builtin variant in __WARN_FLAGS() Date: Mon, 29 Aug 2022 11:22:08 +0530 [thread overview] Message-ID: <20220829055223.24767-2-sv@linux.ibm.com> (raw) In-Reply-To: <20220829055223.24767-1-sv@linux.ibm.com> objtool is throwing *unannotated intra-function call* warnings in .c files with a few instructions that are marked unreachable. The problem comes from the annotate_unreachable() macro that is called by unreachable(). This annotation is adding a call to a function with size 0, and objtool does not add such symbols to the rbtree. Due to this reason, find_call_destination() function is not able to find the destination symbol for that call. With the annotation (annotate_unreachable()), gcc seems to generate a 'bl' to unreachable symbol with size 0. But with the builtin variant of unreachable (__builtin_unreachable()), gcc does not emit calls to such symbols and the warnings go away. Given that the codegen remains same, and that there are no 'bl' instructions to such symbols emitted, fix these warnings by replacing unreachable() with it's builtin variant in __WARN_FLAGS(). Also, add barrier_before_unreachable() before __builtin_unreachable() to work around a gcc bug [1], for the problem reported at [2]. [1]: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106751 [2]: https://lkml.org/lkml/2022/8/25/418 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
WARNING: multiple messages have this Message-ID (diff)
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 v2 01/16] powerpc: Replace unreachable() with it's builtin variant in __WARN_FLAGS() Date: Mon, 29 Aug 2022 11:22:08 +0530 [thread overview] Message-ID: <20220829055223.24767-2-sv@linux.ibm.com> (raw) In-Reply-To: <20220829055223.24767-1-sv@linux.ibm.com> objtool is throwing *unannotated intra-function call* warnings in .c files with a few instructions that are marked unreachable. The problem comes from the annotate_unreachable() macro that is called by unreachable(). This annotation is adding a call to a function with size 0, and objtool does not add such symbols to the rbtree. Due to this reason, find_call_destination() function is not able to find the destination symbol for that call. With the annotation (annotate_unreachable()), gcc seems to generate a 'bl' to unreachable symbol with size 0. But with the builtin variant of unreachable (__builtin_unreachable()), gcc does not emit calls to such symbols and the warnings go away. Given that the codegen remains same, and that there are no 'bl' instructions to such symbols emitted, fix these warnings by replacing unreachable() with it's builtin variant in __WARN_FLAGS(). Also, add barrier_before_unreachable() before __builtin_unreachable() to work around a gcc bug [1], for the problem reported at [2]. [1]: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106751 [2]: https://lkml.org/lkml/2022/8/25/418 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:[~2022-08-29 5:53 UTC|newest] Thread overview: 128+ 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 ` Sathvika Vasireddy 2022-08-29 5:52 ` Sathvika Vasireddy [this message] 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 2022-08-30 6:15 ` Christophe Leroy 2022-09-05 10:18 ` Naveen N. Rao 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 5:52 ` Sathvika Vasireddy 2022-08-29 13:26 ` Christophe Leroy 2022-08-29 13:26 ` Christophe Leroy 2022-08-29 14:39 ` Sathvika Vasireddy 2022-08-29 14:39 ` Sathvika Vasireddy 2022-08-31 3:24 ` Nicholas Piggin 2022-08-31 3:24 ` Nicholas Piggin 2022-08-31 7:22 ` Michael Ellerman 2022-08-31 7:22 ` Michael Ellerman 2022-09-05 11:03 ` Peter Zijlstra 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 2022-08-29 5:52 ` Sathvika Vasireddy 2022-08-30 6:16 ` Christophe Leroy 2022-08-30 6:16 ` Christophe Leroy 2022-08-30 12:42 ` Christophe Leroy 2022-08-30 12:42 ` Christophe Leroy 2022-09-05 11:02 ` Peter Zijlstra 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 2022-08-29 5:52 ` Sathvika Vasireddy 2022-08-30 6:26 ` Christophe Leroy 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 2022-08-29 5:52 ` Sathvika Vasireddy 2022-08-30 6:26 ` Christophe Leroy 2022-08-30 6:26 ` Christophe Leroy 2022-09-01 19:17 ` Peter Zijlstra 2022-09-01 19:17 ` Peter Zijlstra 2022-09-05 10:47 ` Naveen N. Rao 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 ` Sathvika Vasireddy 2022-08-29 5:52 ` [PATCH v2 07/16] powerpc: Skip objtool from running on VDSO files Sathvika Vasireddy 2022-08-29 5:52 ` Sathvika Vasireddy 2022-08-30 6:27 ` Christophe Leroy 2022-08-30 6:27 ` Christophe Leroy 2022-09-01 19:19 ` Peter Zijlstra 2022-09-01 19:19 ` Peter Zijlstra 2022-09-02 7:40 ` Michael Ellerman 2022-09-02 7:40 ` Michael Ellerman 2022-08-29 5:52 ` [PATCH v2 08/16] objtool: Fix SEGFAULT Sathvika Vasireddy 2022-08-29 5:52 ` Sathvika Vasireddy 2022-09-01 19:20 ` Peter Zijlstra 2022-09-01 19:20 ` Peter Zijlstra 2022-09-02 8:06 ` Christophe Leroy 2022-09-02 8:06 ` Christophe Leroy 2022-09-02 8:42 ` Peter Zijlstra 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 2022-08-29 5:52 ` Sathvika Vasireddy 2022-09-01 19:22 ` Peter Zijlstra 2022-09-01 19:22 ` Peter Zijlstra 2022-08-29 5:52 ` [PATCH v2 10/16] objtool: Use target file class size " Sathvika Vasireddy 2022-08-29 5:52 ` Sathvika Vasireddy 2022-09-01 19:23 ` Peter Zijlstra 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 2022-08-29 5:52 ` Sathvika Vasireddy 2022-08-30 6:28 ` Christophe Leroy 2022-08-30 6:28 ` Christophe Leroy 2022-09-01 19:25 ` Peter Zijlstra 2022-09-01 19:25 ` Peter Zijlstra 2022-09-05 10:55 ` Naveen N. Rao 2022-09-05 10:55 ` Naveen N. Rao 2022-08-29 5:52 ` [PATCH v2 12/16] objtool: Read special sections with alts only when specific options are selected Sathvika Vasireddy 2022-08-29 5:52 ` Sathvika Vasireddy 2022-08-30 6:31 ` Christophe Leroy 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 2022-08-29 5:52 ` Sathvika Vasireddy 2022-08-30 6:33 ` Christophe Leroy 2022-08-30 6:33 ` Christophe Leroy 2022-09-01 19:28 ` Peter Zijlstra 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 2022-08-29 5:52 ` Sathvika Vasireddy 2022-08-30 6:36 ` Christophe Leroy 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 2022-08-29 5:52 ` Sathvika Vasireddy 2022-08-30 6:41 ` Christophe Leroy 2022-08-30 6:41 ` Christophe Leroy 2022-09-05 10:37 ` Naveen N. Rao 2022-09-05 10:37 ` Naveen N. Rao 2023-02-04 8:19 ` Randy Dunlap 2023-02-04 8:19 ` Randy Dunlap 2023-02-04 8:21 ` Randy Dunlap 2023-02-04 8:21 ` Randy Dunlap 2023-02-04 8:30 ` Randy Dunlap 2023-02-04 8:30 ` Randy Dunlap 2023-02-04 11:55 ` Christophe Leroy 2023-02-04 11:55 ` Christophe Leroy 2023-02-04 13:10 ` Christophe Leroy 2023-02-04 13:10 ` Christophe Leroy 2023-02-04 15:47 ` Josh Poimboeuf 2023-02-04 15:47 ` Josh Poimboeuf 2022-09-01 9:32 ` Christophe Leroy 2022-09-01 9:32 ` Christophe Leroy 2022-09-01 15:11 ` Segher Boessenkool 2022-09-01 15:11 ` Segher Boessenkool 2022-09-01 16:38 ` Christophe Leroy 2022-09-01 16:38 ` Christophe Leroy 2022-09-01 19:01 ` Peter Zijlstra 2022-09-01 19:01 ` Peter Zijlstra 2022-08-29 5:52 ` [PATCH v2 16/16] objtool/powerpc: Add --mcount specific implementation Sathvika Vasireddy 2022-08-29 5:52 ` Sathvika Vasireddy 2022-08-30 6:44 ` Christophe Leroy 2022-08-30 6:44 ` Christophe Leroy 2022-08-31 12:50 ` Christophe Leroy 2022-08-31 12:50 ` Christophe Leroy 2022-08-31 17:51 ` Segher Boessenkool 2022-08-31 17:51 ` Segher Boessenkool 2022-09-05 10:45 ` Naveen N. Rao 2022-09-05 10:45 ` Naveen N. Rao 2022-09-05 20:43 ` Segher Boessenkool 2022-09-05 20:43 ` Segher Boessenkool 2022-09-06 6:22 ` Christophe Leroy 2022-09-06 6:22 ` Christophe Leroy
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