From: Will Deacon <will@kernel.org>
To: Mark Brown <broonie@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Vincenzo Frascino <Vincenzo.Frascino@arm.com>,
Kees Cook <keescook@chromium.org>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 02/10] arm64: asm: Override SYM_FUNC_START when building the kernel with BTI
Date: Tue, 5 May 2020 17:08:53 +0100 [thread overview]
Message-ID: <20200505160852.GF24239@willie-the-truck> (raw)
In-Reply-To: <20200505151806.GG5377@sirena.org.uk>
On Tue, May 05, 2020 at 04:18:06PM +0100, Mark Brown wrote:
> On Tue, May 05, 2020 at 03:56:42PM +0100, Will Deacon wrote:
> > On Wed, Apr 29, 2020 at 10:16:33PM +0100, Mark Brown wrote:
>
> > > +#define SYM_INNER_LABEL(name, linkage) \
> > > + .type name SYM_T_NONE ASM_NL \
> > > + SYM_ENTRY(name, linkage, SYM_A_NONE) \
> > > + BTI_J
>
> > This break building the compat vDSO:
>
> Right, fixed locally.
Thanks!
> > I also see a scary linker warning about the native VDSO:
>
> > aarch64-none-linux-gnu-ld: arch/arm64/kernel/vdso/vgettimeofday.o: warning: BTI turned on by -z force-bti when all inputs do not have BTI in NOTE section.
>
> I can't reproduce this, I am using clang-10 as well... can you share
> your exact command line and config? I'm using
>
> make -j56 ARCH=arm64 CROSS_COMPILE=aarch64-none-linux-gnu- CC=clang-10
>
> which is the same clang version as you, not that I'd expect that to make
> a difference. This looks like the C code isn't being built with BTI
> enabled but I can't see how you're managing to do that and I'm not -
> this is the warning that "arm64: vdso: Force the VDSO to be linked as
> BTI when built for BTI" is intended to trigger if something goes wrong
> so I guess it's a good job I enabled that :/
Just been debugging this, and it seems that not all clangs are created
equal. Updating mine from 10.0.2 to 11.0.1 means I now get the
'.note.gnu.property' sections emitted for C files compiled using
'-mbranch-protection=pac-ret+leaf+bti', whereas I didn't before.
Cheers,
Will
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next prev parent reply other threads:[~2020-05-05 16:09 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-29 21:16 [PATCH v2 00/10] arm64: BTI kernel and vDSO support Mark Brown
2020-04-29 21:16 ` [PATCH v2 01/10] arm64: bti: Support building kernel C code using BTI Mark Brown
2020-05-05 16:50 ` Dave Martin
2020-05-05 17:31 ` Mark Brown
2020-05-06 12:24 ` Amit Kachhap
2020-04-29 21:16 ` [PATCH v2 02/10] arm64: asm: Override SYM_FUNC_START when building the kernel with BTI Mark Brown
2020-05-05 14:56 ` Will Deacon
2020-05-05 15:18 ` Mark Brown
2020-05-05 16:08 ` Will Deacon [this message]
2020-05-05 17:21 ` Mark Brown
2020-05-06 7:10 ` Will Deacon
2020-05-06 10:41 ` Mark Brown
2020-05-06 10:50 ` Will Deacon
2020-05-06 11:43 ` Mark Brown
2020-05-06 12:27 ` Will Deacon
2020-05-06 13:03 ` Mark Brown
2020-05-06 13:40 ` Dave Martin
2020-05-06 14:45 ` Will Deacon
2020-05-06 15:25 ` Mark Brown
2020-05-06 15:48 ` Will Deacon
2020-05-06 15:33 ` Dave Martin
2020-04-29 21:16 ` [PATCH v2 03/10] arm64: Set GP bit in kernel page tables to enable BTI for the kernel Mark Brown
2020-04-29 21:16 ` [PATCH v2 04/10] arm64: bpf: Annotate JITed code for BTI Mark Brown
2020-04-29 21:16 ` [PATCH v2 05/10] arm64: mm: Mark executable text as guarded pages Mark Brown
2020-04-29 21:16 ` [PATCH v2 06/10] arm64: bti: Provide Kconfig for kernel mode BTI Mark Brown
2020-04-29 21:16 ` [PATCH v2 07/10] arm64: asm: Provide a mechanism for generating ELF note for BTI Mark Brown
2020-05-05 14:58 ` Will Deacon
2020-05-05 16:51 ` Dave Martin
2020-05-05 17:06 ` Mark Brown
2020-05-06 11:26 ` Will Deacon
2020-05-06 12:38 ` Mark Brown
2020-05-06 13:44 ` Will Deacon
2020-05-06 15:39 ` Mark Brown
2020-04-29 21:16 ` [PATCH v2 08/10] arm64: vdso: Annotate " Mark Brown
2020-04-29 21:16 ` [PATCH v2 09/10] arm64: vdso: Force the vDSO to be linked as BTI when built " Mark Brown
2020-04-29 21:16 ` [PATCH v2 10/10] arm64: vdso: Map the vDSO text with guarded pages " Mark Brown
2020-04-30 17:18 ` [PATCH v2 00/10] arm64: BTI kernel and vDSO support Catalin Marinas
2020-04-30 17:23 ` Mark Brown
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