From: Sedat Dilek <sedat.dilek@gmail.com>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>,
Sami Tolvanen <samitolvanen@google.com>, X86 ML <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Kees Cook <keescook@chromium.org>,
Clang-Built-Linux ML <clang-built-linux@googlegroups.com>,
Miroslav Benes <mbenes@suse.cz>,
Fangrui Song <maskray@google.com>,
Peter Collingbourne <pcc@google.com>
Subject: Re: [PATCH v2 00/20] objtool: vmlinux.o and CLANG LTO support
Date: Sat, 23 Jan 2021 03:50:21 +0100 [thread overview]
Message-ID: <CA+icZUVSiL5tCTjNaCjuRwF7U5Z6OcXMVoODhNfzuLePN+1SFA@mail.gmail.com> (raw)
In-Reply-To: <20210123024634.qu62tyq3nkqusken@treble>
On Sat, Jan 23, 2021 at 3:46 AM Josh Poimboeuf <jpoimboe@redhat.com> wrote:
>
> On Sat, Jan 23, 2021 at 03:31:20AM +0100, Sedat Dilek wrote:
> > On Sat, Jan 23, 2021 at 3:26 AM Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> > >
> > > On Fri, Jan 22, 2021 at 05:32:43PM -0800, Nick Desaulniers wrote:
> > > > > In this specific case, find_func_by_offset returns NULL for
> > > > > .text..L.cfi.jumptable.43 at addend 0x8, because Clang doesn't emit
> > > > > jump table symbols for static functions:
> > > > >
> > > > > 0000000000000000 <__typeid__ZTSFjmiE_global_addr>:
> > > > > 0: e9 00 00 00 00 jmpq 5 <__typeid__ZTSFjmiE_global_addr+0x5>
> > > > > 1: R_X86_64_PLT32 io_serial_in-0x4
> > > > > 5: cc int3
> > > > > 6: cc int3
> > > > > 7: cc int3
> > > > > 8: e9 00 00 00 00 jmpq d <__typeid__ZTSFjmiE_global_addr+0xd>
> > > > > 9: R_X86_64_PLT32 mem32_serial_in-0x4
> > > > > d: cc int3
> > > > > e: cc int3
> > > > > f: cc int3
> > > > >
> > > > > Nick, do you remember if there were plans to change this?
> > > >
> > > > Do you have a link to any previous discussion to help jog my mind; I
> > > > don't really remember this one.
> > > >
> > > > Is it that `__typeid__ZTSFjmiE_global_addr` is the synthesized jump
> > > > table, and yet there is no `__typeid__ZTSFjmiE_global_addr` entry in
> > > > the symbol table?
> > >
> > > I think he means there's not a 'mem32_serial_in.cfi_jt' symbol at
> > > '__typeid__ZTSFjmiE_global_addr+8'. Probably more aggressive symbol
> > > pruning from the assembler.
> > >
> > > It's fine though. I just need to rewrite the CFI support a bit.
> > >
> > > But that can come later. For now I'll just drop the two CFI-related
> > > patches from this set so I can merge the others next week.
> > >
> >
> > Two CFI-related patches?
> >
> > What's the other than "objtool: Add CONFIG_CFI_CLANG support"?
>
> I was referring to patches 10 and 11:
>
> objtool: Move unsuffixed symbol conversion to a helper function
> objtool: Add CONFIG_CFI_CLANG support
>
OK, thanks.
I will test with a revert of these two patches in another scenario
where I have problems with Clang's IAS but not with GNU AS.
- Sedat -
> You can just drop those patches from your testing (and don't test with
> CFI).
>
> > Do you plan (or offer) a v3 of objtool-vmlinux?
>
> Not unless there are any more comments.
>
> --
> Josh
>
> --
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next prev parent reply other threads:[~2021-01-23 2:51 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-21 21:29 [PATCH v2 00/20] objtool: vmlinux.o and CLANG LTO support Josh Poimboeuf
2021-01-21 21:29 ` [PATCH v2 01/20] objtool: Fix error handling for STD/CLD warnings Josh Poimboeuf
2021-01-21 21:29 ` [PATCH v2 02/20] objtool: Fix retpoline detection in asm code Josh Poimboeuf
2021-01-21 21:29 ` [PATCH v2 03/20] objtool: Fix ".cold" section suffix check for newer versions of GCC Josh Poimboeuf
2021-01-21 21:29 ` [PATCH v2 04/20] objtool: Support retpoline jump detection for vmlinux.o Josh Poimboeuf
2021-01-21 21:29 ` [PATCH v2 05/20] x86/ftrace: Add UNWIND_HINT_FUNC annotation for ftrace_stub Josh Poimboeuf
2021-01-21 21:29 ` [PATCH v2 06/20] objtool: Assume only ELF functions do sibling calls Josh Poimboeuf
2021-01-21 21:29 ` [PATCH v2 07/20] objtool: Add asm version of STACK_FRAME_NON_STANDARD Josh Poimboeuf
2021-01-21 21:29 ` [PATCH v2 08/20] objtool: Combine UNWIND_HINT_RET_OFFSET and UNWIND_HINT_FUNC Josh Poimboeuf
2021-01-21 21:29 ` [PATCH v2 09/20] objtool: Add xen_start_kernel() to noreturn list Josh Poimboeuf
2021-01-21 21:29 ` [PATCH v2 10/20] objtool: Move unsuffixed symbol conversion to a helper function Josh Poimboeuf
2021-01-21 21:29 ` [PATCH v2 11/20] objtool: Add CONFIG_CFI_CLANG support Josh Poimboeuf
2021-01-21 21:29 ` [PATCH v2 12/20] x86/xen: Support objtool validation in xen-asm.S Josh Poimboeuf
2021-01-21 21:29 ` [PATCH v2 13/20] x86/xen: Support objtool vmlinux.o validation in xen-head.S Josh Poimboeuf
2021-01-21 21:29 ` [PATCH v2 14/20] x86/xen/pvh: Annotate indirect branch as safe Josh Poimboeuf
2021-01-22 5:17 ` Jürgen Groß
2021-01-21 21:29 ` [PATCH v2 15/20] x86/ftrace: Support objtool vmlinux.o validation in ftrace_64.S Josh Poimboeuf
2021-01-21 21:29 ` [PATCH v2 16/20] x86/acpi: Annotate indirect branch as safe Josh Poimboeuf
2021-01-21 21:29 ` [PATCH v2 17/20] x86/acpi: Support objtool validation in wakeup_64.S Josh Poimboeuf
2021-01-21 21:29 ` [PATCH v2 18/20] x86/power: Annotate indirect branches as safe Josh Poimboeuf
2021-01-21 21:29 ` [PATCH v2 19/20] x86/power: Move restore_registers() to top of the file Josh Poimboeuf
2021-01-21 21:29 ` [PATCH v2 20/20] x86/power: Support objtool validation in hibernate_asm_64.S Josh Poimboeuf
2021-01-21 22:38 ` [PATCH v2 00/20] objtool: vmlinux.o and CLANG LTO support Sedat Dilek
2021-01-22 15:41 ` Josh Poimboeuf
2021-01-22 21:17 ` Sami Tolvanen
2021-01-23 1:32 ` Nick Desaulniers
2021-01-23 2:26 ` Josh Poimboeuf
2021-01-23 2:31 ` Sedat Dilek
2021-01-23 2:46 ` Josh Poimboeuf
2021-01-23 2:50 ` Sedat Dilek [this message]
2021-01-25 22:43 ` Sami Tolvanen
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