linux-kernel - Re: [PATCH 0/2] Support kexec/kdump for clang built kernel

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Message-ID: <CAKwvOdm_D1RnbzP6ZSuyOjm5DuNFrST4s8ihwVfOyAXm6wOc_g@mail.gmail.com>
Date:   Thu, 18 Jul 2019 14:29:58 -0700
From:   Nick Desaulniers <ndesaulniers@...gle.com>
To:     Vaibhav Rustagi <vaibhavrustagi@...gle.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Vivek Goyal <vgoyal@...hat.com>,
        "# 3.4.x" <stable@...r.kernel.org>
Subject: Re: [PATCH 0/2] Support kexec/kdump for clang built kernel

On Wed, Jul 17, 2019 at 5:02 PM Vaibhav Rustagi
<vaibhavrustagi@...gle.com> wrote:
>
> This patch series includes the following:
>
> 1. Adding compiler options to not use XMM registers in the purgatory code.
> 2. Reuse the implementation of memcpy and memset instead of relying on
> __builtin_memcpy and __builtin_memset as it causes infinite recursion
> in clang.

Thanks for the series, and debugging and finding the issue.  These
would explain why I couldn't get kexec to work with Clang built
kernels.  Comments/reviews inbound on the individual patches.

>
> Nick Desaulniers (1):
>   x86/purgatory: do not use __builtin_memcpy and __builtin_memset.
>
> Vaibhav Rustagi (1):
>   x86/purgatory: add -mno-sse, -mno-mmx, -mno-sse2 to Makefile
>
>  arch/x86/purgatory/Makefile    |  4 ++++
>  arch/x86/purgatory/purgatory.c |  6 ++++++
>  arch/x86/purgatory/string.c    | 23 -----------------------
>  3 files changed, 10 insertions(+), 23 deletions(-)
>  delete mode 100644 arch/x86/purgatory/string.c
>
> --
> 2.22.0.510.g264f2c817a-goog
>


-- 
Thanks,
~Nick Desaulniers