[PATCH] ARM: stackprotector: prefer compiler for TLS based per-task protector

[Nathan Chancellor]

On Thu, Oct 21, 2021 at 04:25:16PM +0200, Ard Biesheuvel wrote:
> Currently, we implement the per-task stack protector for ARM using a GCC
> plugin, due to lack of native compiler support. However, work is
> underway to get this implemented in the compiler, which means we will be
> able to deprecate the GCC plugin at some point.
> 
> In the meantime, we will need to support both, where the native compiler
> implementation is obviously preferred. So let's wire this up in Kconfig
> and the Makefile.
> 
> Cc: Kees Cook <keescook at chromium.org>
> Cc: Nick Desaulniers <ndesaulniers at google.com>
> Signed-off-by: Ard Biesheuvel <ardb at kernel.org>

I see this patch in the KSPP tree as commit 151bbc8be85e ("ARM:
stackprotector: prefer compiler for TLS based per-task protector"),
which breaks booting aspeed_g5_defconfig in QEMU with clang-14. It seems
like this patch depends on Ard's patch "ARM: decompressor: disable stack
protector" [1]; applying that on top of next-20220125 allows me to boot
again.

This patch is still queued up in Russell's devel-stable branch as
commit f05eb1d24eb5 ("ARM: stackprotector: prefer compiler for TLS based
per-task protector") so perhaps this patch should be dropped from the
KSPP tree? I assume once Ard's recent fixes series [2] is applied to
devel-stable, it will be added back to for-next?

[1]: https://lore.kernel.org/r/20220124174744.1054712-9-ardb@kernel.org/
[2]: https://lore.kernel.org/r/20220125091453.1475246-1-ardb@kernel.org/

Cheers,
Nathan