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Message-ID: <CAK8P3a0MbxMC9iLe0NGR0ttLY7sZDjsrgKvfRZOXVJLjzDNKmA@mail.gmail.com>
Date: Thu, 28 Jan 2021 17:15:13 +0100
From: Arnd Bergmann <arnd@...nel.org>
To: Nick Desaulniers <ndesaulniers@...gle.com>
Cc: Russell King <linux@...linux.org.uk>,
Arnd Bergmann <arnd@...db.de>,
Ard Biesheuvel <ardb@...nel.org>,
Nathan Chancellor <natechancellor@...il.com>,
Linux ARM <linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
clang-built-linux <clang-built-linux@...glegroups.com>
Subject: Re: [PATCH] ARM: kprobes: rewrite in UAL
On Thu, Jan 28, 2021 at 5:44 AM 'Nick Desaulniers' via Clang Built
Linux <clang-built-linux@...glegroups.com> wrote:
>
> Clang's integrated assembler only accepts UAL syntax, rewrite the
> instructions that were changed by RVCTv2.1.
>
> The document "Assembly language changes after RVCTv2.1" was very
> helpful.
>
> This exposed a bug in Clang's integrated assembler, which hopefully will
> land in clang-12, but is required to test this patch with LLVM_IAS=1.
>
> Link: https://developer.arm.com/documentation/dui0473/c/writing-arm-assembly-language/assembly-language-changes-after-rvctv2-1
> Link: https://github.com/ClangBuiltLinux/linux/issues/1271
> Link: https://reviews.llvm.org/D95586
> Reported-by: Arnd Bergmann <arnd@...db.de>
> Signed-off-by: Nick Desaulniers <ndesaulniers@...gle.com>
> ---
> arch/arm/probes/kprobes/test-arm.c | 288 ++++++++++++++---------------
> 1 file changed, 144 insertions(+), 144 deletions(-)
This mostly works, but I see one extra case in some configurations:
arch/arm/probes/kprobes/test-arm.c:453:2: error: invalid instruction,
did you mean: swpb?
TEST_R( "swpvsb r0, r",1,VAL1,", [sp]")
^
arch/arm/probes/kprobes/test-core.h:235:2: note: expanded from macro 'TEST_R'
TEST_INSTRUCTION(code1 #reg code2) \
^
arch/arm/probes/kprobes/test-core.h:155:17: note: expanded from macro
'TEST_INSTRUCTION'
"50: nop \n\t" \
^
<inline asm>:20:5: note: instantiated into assembly here
1: swpvsb r0, r1, [sp]
^~~~~~
Plus a lot of extra errors when building with CONFIG_THUMB2_KERNEL,
as that uses tests in arch/arm/probes/kprobes/test-thumb.c.
Arnd
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