From: Will Deacon <will@kernel.org>
To: Julien Thierry <jthierry@redhat.com>
Cc: peterz@infradead.org, catalin.marinas@arm.com,
linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com,
raphael.gault@arm.com, jpoimboe@redhat.com,
Nathan Chancellor <natechancellor@gmail.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC v5 00/57] objtool: Add support for arm64
Date: Tue, 21 Jan 2020 10:31:01 +0000 [thread overview]
Message-ID: <20200121103101.GE11154@willie-the-truck> (raw)
In-Reply-To: <d5bf34f0-22cc-ba46-41b4-96a52d7acfa4@redhat.com>
On Mon, Jan 13, 2020 at 07:57:48AM +0000, Julien Thierry wrote:
> On 1/12/20 8:42 AM, Nathan Chancellor wrote:
> > The 0day bot reported a couple of issues with clang with this series;
> > the full report is available here (clang reports are only sent to our
> > mailing lists for manual triage for the time being):
> >
> > https://groups.google.com/d/msg/clang-built-linux/MJbl_xPxawg/mWjgDgZgBwAJ
> >
>
> Thanks, I'll have a look at those.
>
> > The first obvious issue is that this series appears to depend on a GCC
> > plugin? I'll be quite honest, objtool and everything it does is rather
> > over my head but I see this warning during configuration (allyesconfig):
> >
> > WARNING: unmet direct dependencies detected for GCC_PLUGIN_SWITCH_TABLES
> > Depends on [n]: GCC_PLUGINS [=n] && ARM64 [=y]
> > Selected by [y]:
> > - ARM64 [=y] && STACK_VALIDATION [=y]
> >
> > Followed by the actual error:
> >
> > error: unable to load plugin
> > './scripts/gcc-plugins/arm64_switch_table_detection_plugin.so':
> > './scripts/gcc-plugins/arm64_switch_table_detection_plugin.so: cannot
> > open shared object file: No such file or directory'
> >
> > If this plugin is absolutely necessary and can't be implemented in
> > another way so that clang can be used, seems like STACK_VALIDATION
> > should only be selected on ARM64 when CONFIG_CC_IS_GCC is not zero.
> >
>
> So currently the plugin is necessary for proper validation. One option can
> be to just let objtool output false positives on files containing jump
> tables when the plugin cannot be used. But overall I guess it makes more
> sense to disable stack validation for non-gcc builds, for now.
Alternatively, could we add '-fno-jump-tables' to the KBUILD_CFLAGS if
STACK_VALIDATION is selected but we're not using GCC? Is that sufficient
to prevent generation of these things?
Will
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next prev parent reply other threads:[~2020-01-21 10:31 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-09 16:02 [RFC v5 00/57] objtool: Add support for arm64 Julien Thierry
2020-01-09 16:02 ` [RFC v5 01/57] objtool: check: Remove redundant checks on operand type Julien Thierry
2020-01-09 16:02 ` [RFC v5 02/57] objtool: check: Clean instruction state before each function validation Julien Thierry
2020-01-09 16:02 ` [RFC v5 03/57] objtool: check: Use arch specific values in restore_reg() Julien Thierry
2020-01-09 16:02 ` [RFC v5 04/57] objtool: check: Ignore empty alternative groups Julien Thierry
2020-01-21 16:30 ` Josh Poimboeuf
2020-01-23 11:45 ` Julien Thierry
2020-01-09 16:02 ` [RFC v5 05/57] objtool: Add abstraction for computation of symbols offsets Julien Thierry
2020-01-09 16:02 ` [RFC v5 06/57] objtool: Give ORC functions consistent name Julien Thierry
2020-01-09 16:02 ` [RFC v5 07/57] objtool: orc: Refactor ORC API for other architectures to implement Julien Thierry
2020-01-09 16:02 ` [RFC v5 08/57] objtool: Make ORC support optional Julien Thierry
2020-01-21 16:37 ` Josh Poimboeuf
2020-01-23 11:45 ` Julien Thierry
2020-01-09 16:02 ` [RFC v5 09/57] objtool: Move registers and control flow to arch-dependent code Julien Thierry
2020-01-09 16:02 ` [RFC v5 10/57] objtool: Split generic and arch specific CFI definitions Julien Thierry
2020-01-09 16:02 ` [RFC v5 11/57] objtool: Abstract alternative special case handling Julien Thierry
2020-01-20 14:54 ` Peter Zijlstra
2020-01-23 11:45 ` Julien Thierry
2020-01-09 16:02 ` [RFC v5 12/57] objtool: check: Allow jumps from an alternative group to itself Julien Thierry
2020-01-20 14:56 ` Peter Zijlstra
2020-01-21 10:30 ` Will Deacon
2020-01-21 17:33 ` Josh Poimboeuf
2020-01-23 13:42 ` Julien Thierry
2020-01-09 16:02 ` [RFC v5 13/57] objtool: Refactor switch-tables code to support other architectures Julien Thierry
2020-01-09 16:02 ` [RFC v5 14/57] objtool: Do not look for STT_NOTYPE symbols Julien Thierry
2020-01-13 10:20 ` Julien Thierry
2020-01-09 16:02 ` [RFC v5 15/57] objtool: Support addition to set frame pointer Julien Thierry
2020-01-09 16:02 ` [RFC v5 16/57] objtool: Support restoring BP from the stack without POP Julien Thierry
2020-01-09 16:02 ` [RFC v5 17/57] objtool: Make stack validation more generic Julien Thierry
2020-01-09 16:02 ` [RFC v5 18/57] objtool: Support multiple stack_op per instruction Julien Thierry
2020-01-09 16:02 ` [RFC v5 19/57] objtool: arm64: Add required implementation for supporting the aarch64 architecture in objtool Julien Thierry
2020-01-09 16:02 ` [RFC v5 20/57] objtool: arm64: Decode unknown instructions Julien Thierry
2020-01-09 16:02 ` [RFC v5 21/57] objtool: arm64: Decode simple data processing instructions Julien Thierry
2020-01-09 16:02 ` [RFC v5 22/57] objtool: arm64: Decode add/sub immediate instructions Julien Thierry
2020-01-09 16:02 ` [RFC v5 23/57] objtool: arm64: Decode logical data processing instructions Julien Thierry
2020-01-09 16:02 ` [RFC v5 24/57] objtool: arm64: Decode system instructions not affecting the flow Julien Thierry
2020-01-09 16:02 ` [RFC v5 25/57] objtool: arm64: Decode calls to higher EL Julien Thierry
2020-01-09 16:02 ` [RFC v5 26/57] objtool: arm64: Decode brk instruction Julien Thierry
2020-01-09 16:02 ` [RFC v5 27/57] objtool: arm64: Decode instruction triggering context switch Julien Thierry
2020-01-09 16:02 ` [RFC v5 28/57] objtool: arm64: Decode branch instructions with PC relative immediates Julien Thierry
2020-01-09 16:02 ` [RFC v5 29/57] objtool: arm64: Decode branch to register instruction Julien Thierry
2020-01-09 16:02 ` [RFC v5 30/57] objtool: arm64: Decode basic load/stores Julien Thierry
2020-01-09 16:02 ` [RFC v5 31/57] objtool: arm64: Decode load/store with register offset Julien Thierry
2020-01-09 16:02 ` [RFC v5 32/57] objtool: arm64: Decode load/store register pair instructions Julien Thierry
2020-01-09 16:02 ` [RFC v5 33/57] objtool: arm64: Decode FP/SIMD load/store instructions Julien Thierry
2020-01-09 16:02 ` [RFC v5 34/57] objtool: arm64: Decode load/store exclusive Julien Thierry
2020-01-09 16:02 ` [RFC v5 35/57] objtool: arm64: Decode atomic load/store Julien Thierry
2020-01-09 16:02 ` [RFC v5 36/57] objtool: arm64: Decode pointer auth load instructions Julien Thierry
2020-01-09 16:02 ` [RFC v5 37/57] objtool: arm64: Decode load acquire/store release Julien Thierry
2020-01-09 16:02 ` [RFC v5 38/57] objtool: arm64: Decode load/store with memory tag Julien Thierry
2020-01-09 16:02 ` [RFC v5 39/57] objtool: arm64: Decode load literal Julien Thierry
2020-01-09 16:02 ` [RFC v5 40/57] objtool: arm64: Decode register data processing instructions Julien Thierry
2020-01-09 16:02 ` [RFC v5 41/57] objtool: arm64: Decode FP/SIMD " Julien Thierry
2020-01-09 16:02 ` [RFC v5 42/57] objtool: arm64: Decode SVE instructions Julien Thierry
2020-01-09 16:02 ` [RFC v5 43/57] gcc-plugins: objtool: Add plugin to detect switch table on arm64 Julien Thierry
2020-01-09 16:02 ` [RFC v5 44/57] objtool: arm64: Implement functions to add switch tables alternatives Julien Thierry
2020-01-15 16:37 ` Raphael Gault
2020-01-17 8:28 ` Julien Thierry
2020-01-09 16:02 ` [RFC v5 45/57] objtool: arm64: Enable stack validation for arm64 Julien Thierry
2020-01-09 16:02 ` [RFC v5 46/57] arm64: alternative: Mark .altinstr_replacement as containing executable instructions Julien Thierry
2020-01-09 16:02 ` [RFC v5 47/57] arm64: assembler: Add macro to annotate asm function having non standard stack-frame Julien Thierry
2020-01-21 10:30 ` Will Deacon
2020-01-23 13:45 ` Julien Thierry
2020-01-23 14:40 ` Will Deacon
2020-01-09 16:02 ` [RFC v5 48/57] arm64: sleep: Prevent stack frame warnings from objtool Julien Thierry
2020-01-09 16:02 ` [RFC v5 49/57] arm64: kvm: Annotate non-standard stack frame functions Julien Thierry
2020-01-09 16:02 ` [RFC v5 50/57] arm64: kernel: Add exception on kuser32 to prevent stack analysis Julien Thierry
2020-01-09 16:02 ` [RFC v5 51/57] arm64: crypto: Add exceptions for crypto object " Julien Thierry
2020-01-09 16:02 ` [RFC v5 52/57] arm64: kernel: Annotate non-standard stack frame functions Julien Thierry
2020-01-09 16:02 ` [RFC v5 53/57] arm64: Generate no-ops to pad executable section Julien Thierry
2020-01-09 16:02 ` [RFC v5 54/57] arm64: Move constant to rodata Julien Thierry
2020-01-09 16:02 ` [RFC v5 55/57] arm64: Mark sigreturn32.o as containing non standard code Julien Thierry
2020-01-09 16:02 ` [RFC v5 56/57] arm64: entry: Avoid empty alternatives entries Julien Thierry
2020-01-09 16:51 ` Mark Rutland
2020-01-21 10:30 ` Will Deacon
2020-01-09 16:03 ` [RFC v5 57/57] arm64: crypto: Remove redundant branch Julien Thierry
2020-01-12 8:42 ` [RFC v5 00/57] objtool: Add support for arm64 Nathan Chancellor
2020-01-13 7:57 ` Julien Thierry
2020-01-21 10:31 ` Will Deacon [this message]
2020-01-21 17:08 ` Nick Desaulniers
2020-01-21 18:06 ` Will Deacon
2020-01-21 18:30 ` Josh Poimboeuf
2020-01-22 14:47 ` Will Deacon
2020-01-13 17:18 ` Nick Desaulniers
2020-01-20 15:07 ` Peter Zijlstra
2020-01-21 17:50 ` Josh Poimboeuf
2020-01-23 13:56 ` Julien Thierry
2020-01-21 10:30 ` Will Deacon
2020-01-23 13:52 ` Julien Thierry
2020-01-23 14:35 ` Will Deacon
2020-01-23 15:11 ` Julien Thierry
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