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From:   Sedat Dilek <sedat.dilek@gmail.com>
Date:   Sat, 13 Feb 2021 20:33:27 +0100
Message-ID: <CA+icZUUHu6Qm_xNyXdumi0WjGZn1NQt8CSj=pkh4-2qLxg-n7Q@mail.gmail.com>
Subject: Re: [PATCH v2 0/2] Clean up x86_32 stackprotector
To:     Andy Lutomirski <luto@kernel.org>
Cc:     x86@kernel.org, LKML <linux-kernel@vger.kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Sean Christopherson <seanjc@google.com>,
        Brian Gerst <brgerst@gmail.com>, Joerg Roedel <jroedel@suse.de>
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On Sat, Feb 13, 2021 at 8:19 PM Andy Lutomirski <luto@kernel.org> wrote:
>
> x86_32 stackprotector is a maintenance nightmare.  Clean it up.  This
> disables stackprotector on x86_32 on GCC 8.1 and on all clang
> versions.  Some clang people are cc'd.
>
> Changes from v1:
>  - Changelog fixes.
>  - Comment fixes (mostly from Sean).
>  - Fix the !SMP case.
>
> Andy Lutomirski (2):
>   x86/stackprotector/32: Make the canary into a regular percpu variable
>   x86/entry/32: Remove leftover macros after stackprotector cleanups
>

Thanks Andy for bringing this up as v2.

AFAICS, LLVM bug #47479 was involved here (see [1]).
Maybe Nick can say some words.

After patching my LLVM toolchain I decided to drop this and integrated
the (kernel-side) diff from Nick (see [1]) in my custom patch-series.

Is this your x86/unify_stack_canary Git branch (see [2])?

- Sedat -

[1] https://bugs.llvm.org/show_bug.cgi?id=47479
[2] https://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git/log/?h=x86/unify_stack_canary

>  arch/x86/Kconfig                          |  7 +-
>  arch/x86/Makefile                         |  8 ++
>  arch/x86/entry/entry_32.S                 | 95 +----------------------
>  arch/x86/include/asm/processor.h          | 15 +---
>  arch/x86/include/asm/ptrace.h             |  5 +-
>  arch/x86/include/asm/segment.h            | 30 ++-----
>  arch/x86/include/asm/stackprotector.h     | 79 ++++---------------
>  arch/x86/include/asm/suspend_32.h         |  6 +-
>  arch/x86/kernel/asm-offsets_32.c          |  5 --
>  arch/x86/kernel/cpu/common.c              |  5 +-
>  arch/x86/kernel/doublefault_32.c          |  4 +-
>  arch/x86/kernel/head_32.S                 | 18 +----
>  arch/x86/kernel/setup_percpu.c            |  1 -
>  arch/x86/kernel/tls.c                     |  8 +-
>  arch/x86/kvm/svm/svm.c                    | 10 +--
>  arch/x86/lib/insn-eval.c                  |  4 -
>  arch/x86/platform/pvh/head.S              | 14 ----
>  arch/x86/power/cpu.c                      |  6 +-
>  arch/x86/xen/enlighten_pv.c               |  1 -
>  scripts/gcc-x86_32-has-stack-protector.sh |  6 +-
>  20 files changed, 62 insertions(+), 265 deletions(-)
>
> --
> 2.29.2
>