From: Sami Tolvanen <samitolvanen@google.com> To: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org>, Jann Horn <jannh@google.com>, "the arch/x86 maintainers" <x86@kernel.org>, Masahiro Yamada <masahiroy@kernel.org>, Steven Rostedt <rostedt@goodmis.org>, Will Deacon <will@kernel.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, "Paul E. McKenney" <paulmck@kernel.org>, Kees Cook <keescook@chromium.org>, Nick Desaulniers <ndesaulniers@google.com>, clang-built-linux <clang-built-linux@googlegroups.com>, Kernel Hardening <kernel-hardening@lists.openwall.com>, linux-arch <linux-arch@vger.kernel.org>, Linux ARM <linux-arm-kernel@lists.infradead.org>, linux-kbuild <linux-kbuild@vger.kernel.org>, kernel list <linux-kernel@vger.kernel.org>, linux-pci@vger.kernel.org Subject: Re: [PATCH v6 22/25] x86/asm: annotate indirect jumps Date: Fri, 13 Nov 2020 12:24:32 -0800 [thread overview] Message-ID: <CABCJKufA-aOcsOqb1NiMQeBGm9Q-JxjoPjsuNpHh0kL4LzfO0w@mail.gmail.com> (raw) In-Reply-To: <20201113195408.atbpjizijnhuinzy@treble> On Fri, Nov 13, 2020 at 11:54 AM Josh Poimboeuf <jpoimboe@redhat.com> wrote: > > On Tue, Nov 10, 2020 at 10:59:55AM -0800, Sami Tolvanen wrote: > > On Tue, Nov 10, 2020 at 9:46 AM Josh Poimboeuf <jpoimboe@redhat.com> wrote: > > > > > > On Mon, Nov 09, 2020 at 08:29:24PM -0600, Josh Poimboeuf wrote: > > > > On Mon, Nov 09, 2020 at 03:11:41PM -0800, Sami Tolvanen wrote: > > > > > CONFIG_XEN > > > > > > > > > > __switch_to_asm()+0x0: undefined stack state > > > > > xen_hypercall_set_trap_table()+0x0: <=== (sym) > > > > > > With your branch + GCC 9 I can recreate all the warnings except this > > > one. > > > > In a gcc build this warning is replaced with a different one: > > > > vmlinux.o: warning: objtool: __startup_secondary_64()+0x7: return with > > modified stack frame > > > > This just seems to depend on which function is placed right after the > > code in xen-head.S. With gcc, the disassembly looks like this: > > > > 0000000000000000 <asm_cpu_bringup_and_idle>: > > 0: e8 00 00 00 00 callq 5 <asm_cpu_bringup_and_idle+0x5> > > 1: R_X86_64_PLT32 cpu_bringup_and_idle-0x4 > > 5: e9 f6 0f 00 00 jmpq 1000 > > <xen_hypercall_set_trap_table> > > ... > > 0000000000001000 <xen_hypercall_set_trap_table>: > > ... > > ... > > 0000000000002000 <__startup_secondary_64>: > > > > With Clang+LTO, we end up with __switch_to_asm here instead of > > __startup_secondary_64. > > I still don't see this warning for some reason. Do you have CONFIG_XEN enabled? I can reproduce this on ToT master as follows: $ git rev-parse HEAD 585e5b17b92dead8a3aca4e3c9876fbca5f7e0ba $ make defconfig && \ ./scripts/config -e HYPERVISOR_GUEST -e PARAVIRT -e XEN && \ make olddefconfig && \ make -j110 ... $ ./tools/objtool/objtool check -arfld vmlinux.o 2>&1 | grep secondary vmlinux.o: warning: objtool: __startup_secondary_64()+0x2: return with modified stack frame > Is it fixed by adding cpu_bringup_and_idle() to global_noreturns[] in > tools/objtool/check.c? No, that didn't fix the warning. Here's what I tested: diff --git a/tools/objtool/check.c b/tools/objtool/check.c index c6ab44543c92..f1f65f5688cf 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -156,6 +156,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func, "machine_real_restart", "rewind_stack_do_exit", "kunit_try_catch_throw", + "cpu_bringup_and_idle", }; if (!func) Sami
WARNING: multiple messages have this Message-ID (diff)
From: Sami Tolvanen <samitolvanen@google.com> To: Josh Poimboeuf <jpoimboe@redhat.com> Cc: linux-arch <linux-arch@vger.kernel.org>, Kees Cook <keescook@chromium.org>, "Paul E. McKenney" <paulmck@kernel.org>, Jann Horn <jannh@google.com>, Peter Zijlstra <peterz@infradead.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Masahiro Yamada <masahiroy@kernel.org>, the arch/x86 maintainers <x86@kernel.org>, Nick Desaulniers <ndesaulniers@google.com>, kernel list <linux-kernel@vger.kernel.org>, Steven Rostedt <rostedt@goodmis.org>, linux-kbuild <linux-kbuild@vger.kernel.org>, clang-built-linux <clang-built-linux@googlegroups.com>, linux-pci@vger.kernel.org, Kernel Hardening <kernel-hardening@lists.openwall.com>, Will Deacon <will@kernel.org>, Linux ARM <linux-arm-kernel@lists.infradead.org> Subject: Re: [PATCH v6 22/25] x86/asm: annotate indirect jumps Date: Fri, 13 Nov 2020 12:24:32 -0800 [thread overview] Message-ID: <CABCJKufA-aOcsOqb1NiMQeBGm9Q-JxjoPjsuNpHh0kL4LzfO0w@mail.gmail.com> (raw) In-Reply-To: <20201113195408.atbpjizijnhuinzy@treble> On Fri, Nov 13, 2020 at 11:54 AM Josh Poimboeuf <jpoimboe@redhat.com> wrote: > > On Tue, Nov 10, 2020 at 10:59:55AM -0800, Sami Tolvanen wrote: > > On Tue, Nov 10, 2020 at 9:46 AM Josh Poimboeuf <jpoimboe@redhat.com> wrote: > > > > > > On Mon, Nov 09, 2020 at 08:29:24PM -0600, Josh Poimboeuf wrote: > > > > On Mon, Nov 09, 2020 at 03:11:41PM -0800, Sami Tolvanen wrote: > > > > > CONFIG_XEN > > > > > > > > > > __switch_to_asm()+0x0: undefined stack state > > > > > xen_hypercall_set_trap_table()+0x0: <=== (sym) > > > > > > With your branch + GCC 9 I can recreate all the warnings except this > > > one. > > > > In a gcc build this warning is replaced with a different one: > > > > vmlinux.o: warning: objtool: __startup_secondary_64()+0x7: return with > > modified stack frame > > > > This just seems to depend on which function is placed right after the > > code in xen-head.S. With gcc, the disassembly looks like this: > > > > 0000000000000000 <asm_cpu_bringup_and_idle>: > > 0: e8 00 00 00 00 callq 5 <asm_cpu_bringup_and_idle+0x5> > > 1: R_X86_64_PLT32 cpu_bringup_and_idle-0x4 > > 5: e9 f6 0f 00 00 jmpq 1000 > > <xen_hypercall_set_trap_table> > > ... > > 0000000000001000 <xen_hypercall_set_trap_table>: > > ... > > ... > > 0000000000002000 <__startup_secondary_64>: > > > > With Clang+LTO, we end up with __switch_to_asm here instead of > > __startup_secondary_64. > > I still don't see this warning for some reason. Do you have CONFIG_XEN enabled? I can reproduce this on ToT master as follows: $ git rev-parse HEAD 585e5b17b92dead8a3aca4e3c9876fbca5f7e0ba $ make defconfig && \ ./scripts/config -e HYPERVISOR_GUEST -e PARAVIRT -e XEN && \ make olddefconfig && \ make -j110 ... $ ./tools/objtool/objtool check -arfld vmlinux.o 2>&1 | grep secondary vmlinux.o: warning: objtool: __startup_secondary_64()+0x2: return with modified stack frame > Is it fixed by adding cpu_bringup_and_idle() to global_noreturns[] in > tools/objtool/check.c? No, that didn't fix the warning. Here's what I tested: diff --git a/tools/objtool/check.c b/tools/objtool/check.c index c6ab44543c92..f1f65f5688cf 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -156,6 +156,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func, "machine_real_restart", "rewind_stack_do_exit", "kunit_try_catch_throw", + "cpu_bringup_and_idle", }; if (!func) Sami _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-11-13 20:24 UTC|newest] Thread overview: 188+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-10-13 0:31 [PATCH v6 00/25] Add support for Clang LTO Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` [PATCH v6 01/25] kbuild: preprocess module linker script Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` [PATCH v6 02/25] objtool: Add a pass for generating __mcount_loc Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-14 16:50 ` Ingo Molnar 2020-10-14 16:50 ` Ingo Molnar 2020-10-14 18:21 ` Peter Zijlstra 2020-10-14 18:21 ` Peter Zijlstra 2020-10-15 20:10 ` Josh Poimboeuf 2020-10-15 20:10 ` Josh Poimboeuf 2020-10-13 0:31 ` [PATCH v6 03/25] objtool: Don't autodetect vmlinux.o Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` [PATCH v6 04/25] tracing: move function tracer options to Kconfig Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` [PATCH v6 05/25] tracing: add support for objtool mcount Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` [PATCH v6 06/25] x86, build: use " Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` [PATCH v6 07/25] treewide: remove DISABLE_LTO Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-14 22:43 ` Kees Cook 2020-10-14 22:43 ` Kees Cook 2020-10-17 1:46 ` Masahiro Yamada 2020-10-17 1:46 ` Masahiro Yamada 2020-10-13 0:31 ` [PATCH v6 08/25] kbuild: add support for Clang LTO Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` [PATCH v6 09/25] kbuild: lto: fix module versioning Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` [PATCH v6 10/25] objtool: Split noinstr validation from --vmlinux Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` [PATCH v6 11/25] kbuild: lto: postpone objtool Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` [PATCH v6 12/25] kbuild: lto: limit inlining Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` [PATCH v6 13/25] kbuild: lto: merge module sections Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-14 22:49 ` Kees Cook 2020-10-14 22:49 ` Kees Cook 2020-10-20 16:42 ` Sami Tolvanen 2020-10-20 16:42 ` Sami Tolvanen 2020-10-20 16:42 ` Sami Tolvanen 2020-10-13 0:31 ` [PATCH v6 14/25] kbuild: lto: remove duplicate dependencies from .mod files Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-14 22:50 ` Kees Cook 2020-10-14 22:50 ` Kees Cook 2020-12-03 17:59 ` Masahiro Yamada 2020-12-03 17:59 ` Masahiro Yamada 2020-12-03 18:47 ` Sami Tolvanen 2020-12-03 18:47 ` Sami Tolvanen 2020-12-03 18:47 ` Sami Tolvanen 2020-10-13 0:31 ` [PATCH v6 15/25] init: lto: ensure initcall ordering Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` [PATCH v6 16/25] init: lto: fix PREL32 relocations Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-14 22:53 ` Kees Cook 2020-10-14 22:53 ` Kees Cook 2020-10-15 0:12 ` Jann Horn 2020-10-15 0:12 ` Jann Horn 2020-10-15 0:12 ` Jann Horn 2020-10-13 0:31 ` [PATCH v6 17/25] PCI: Fix PREL32 relocations for LTO Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-14 22:58 ` Kees Cook 2020-10-14 22:58 ` Kees Cook 2020-10-13 0:31 ` [PATCH v6 18/25] modpost: lto: strip .lto from module names Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` [PATCH v6 19/25] scripts/mod: disable LTO for empty.c Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` [PATCH v6 20/25] efi/libstub: disable LTO Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` [PATCH v6 21/25] drivers/misc/lkdtm: disable LTO for rodata.o Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:31 ` Sami Tolvanen 2020-10-13 0:32 ` [PATCH v6 22/25] x86/asm: annotate indirect jumps Sami Tolvanen 2020-10-13 0:32 ` Sami Tolvanen 2020-10-13 0:32 ` Sami Tolvanen 2020-10-14 22:46 ` Kees Cook 2020-10-14 22:46 ` Kees Cook 2020-10-14 23:23 ` Jann Horn 2020-10-14 23:23 ` Jann Horn 2020-10-14 23:23 ` Jann Horn 2020-10-15 10:22 ` Peter Zijlstra 2020-10-15 10:22 ` Peter Zijlstra 2020-10-15 20:39 ` Josh Poimboeuf 2020-10-15 20:39 ` Josh Poimboeuf 2020-10-20 16:45 ` Sami Tolvanen 2020-10-20 16:45 ` Sami Tolvanen 2020-10-20 16:45 ` Sami Tolvanen 2020-10-20 18:52 ` Josh Poimboeuf 2020-10-20 18:52 ` Josh Poimboeuf 2020-10-20 19:24 ` Sami Tolvanen 2020-10-20 19:24 ` Sami Tolvanen 2020-10-20 19:24 ` Sami Tolvanen 2020-10-21 8:56 ` Peter Zijlstra 2020-10-21 8:56 ` Peter Zijlstra 2020-10-21 9:08 ` Peter Zijlstra 2020-10-21 9:08 ` Peter Zijlstra 2020-10-21 9:32 ` Peter Zijlstra 2020-10-21 9:32 ` Peter Zijlstra 2020-10-21 21:27 ` Josh Poimboeuf 2020-10-21 21:27 ` Josh Poimboeuf 2020-10-22 7:25 ` Peter Zijlstra 2020-10-22 7:25 ` Peter Zijlstra 2020-10-23 17:48 ` Sami Tolvanen 2020-10-23 17:48 ` Sami Tolvanen 2020-10-23 18:04 ` Nick Desaulniers 2020-10-23 18:04 ` Nick Desaulniers 2020-10-23 18:04 ` Nick Desaulniers 2020-10-21 15:01 ` Sami Tolvanen 2020-10-21 15:01 ` Sami Tolvanen 2020-10-21 15:01 ` Sami Tolvanen 2020-10-22 0:22 ` Sami Tolvanen 2020-10-22 0:22 ` Sami Tolvanen 2020-10-22 0:22 ` Sami Tolvanen 2020-10-23 17:36 ` Sami Tolvanen 2020-10-23 17:36 ` Sami Tolvanen 2020-11-09 23:11 ` Sami Tolvanen 2020-11-09 23:11 ` Sami Tolvanen 2020-11-09 23:11 ` Sami Tolvanen 2020-11-10 2:29 ` Josh Poimboeuf 2020-11-10 2:29 ` Josh Poimboeuf 2020-11-10 3:18 ` Nick Desaulniers 2020-11-10 3:18 ` Nick Desaulniers 2020-11-10 3:18 ` Nick Desaulniers 2020-11-10 4:48 ` Sami Tolvanen 2020-11-10 4:48 ` Sami Tolvanen 2020-11-10 4:48 ` Sami Tolvanen 2020-11-10 16:11 ` Josh Poimboeuf 2020-11-10 16:11 ` Josh Poimboeuf 2020-11-10 17:46 ` Josh Poimboeuf 2020-11-10 17:46 ` Josh Poimboeuf 2020-11-10 18:59 ` Sami Tolvanen 2020-11-10 18:59 ` Sami Tolvanen 2020-11-10 18:59 ` Sami Tolvanen 2020-11-13 19:54 ` Josh Poimboeuf 2020-11-13 19:54 ` Josh Poimboeuf 2020-11-13 20:24 ` Sami Tolvanen [this message] 2020-11-13 20:24 ` Sami Tolvanen 2020-11-13 20:24 ` Sami Tolvanen 2020-11-13 20:52 ` Josh Poimboeuf 2020-11-13 20:52 ` Josh Poimboeuf 2020-11-13 22:34 ` Josh Poimboeuf 2020-11-13 22:34 ` Josh Poimboeuf 2020-11-13 22:54 ` Sami Tolvanen 2020-11-13 22:54 ` Sami Tolvanen 2020-11-13 22:54 ` Sami Tolvanen 2020-11-13 22:56 ` Josh Poimboeuf 2020-11-13 22:56 ` Josh Poimboeuf 2020-11-13 23:31 ` Sami Tolvanen 2020-11-13 23:31 ` Sami Tolvanen 2020-11-13 23:31 ` Sami Tolvanen 2020-11-14 0:49 ` Josh Poimboeuf 2020-11-14 0:49 ` Josh Poimboeuf 2020-10-21 9:51 ` Peter Zijlstra 2020-10-21 9:51 ` Peter Zijlstra 2020-10-21 18:30 ` Josh Poimboeuf 2020-10-21 18:30 ` Josh Poimboeuf 2020-10-13 0:32 ` [PATCH v6 23/25] x86, vdso: disable LTO only for vDSO Sami Tolvanen 2020-10-13 0:32 ` Sami Tolvanen 2020-10-13 0:32 ` Sami Tolvanen 2020-10-13 0:32 ` [PATCH v6 24/25] x86, cpu: disable LTO for cpu.c Sami Tolvanen 2020-10-13 0:32 ` Sami Tolvanen 2020-10-13 0:32 ` Sami Tolvanen 2020-10-13 0:32 ` [PATCH v6 25/25] x86, build: allow LTO_CLANG and THINLTO to be selected Sami Tolvanen 2020-10-13 0:32 ` Sami Tolvanen 2020-10-13 0:32 ` Sami Tolvanen
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