linux-kernel - Re: [PATCH v8 08/28] x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file

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Date:   Wed, 6 Sep 2017 17:54:30 +0200
From:   Borislav Petkov <bp@...e.de>
To:     Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
Cc:     Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Brian Gerst <brgerst@...il.com>,
        Chris Metcalf <cmetcalf@...lanox.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Huang Rui <ray.huang@....com>, Jiri Slaby <jslaby@...e.cz>,
        Jonathan Corbet <corbet@....net>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        Paul Gortmaker <paul.gortmaker@...driver.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Chen Yucong <slaoub@...il.com>,
        "Ravi V. Shankar" <ravi.v.shankar@...el.com>,
        Shuah Khan <shuah@...nel.org>, linux-kernel@...r.kernel.org,
        x86@...nel.org, ricardo.neri@...el.com,
        Adam Buchbinder <adam.buchbinder@...il.com>,
        Colin Ian King <colin.king@...onical.com>,
        Lorenzo Stoakes <lstoakes@...il.com>,
        Qiaowei Ren <qiaowei.ren@...el.com>,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Kees Cook <keescook@...omium.org>,
        Thomas Garnier <thgarnie@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>
Subject: Re: [PATCH v8 08/28] x86/mpx, x86/insn: Relocate insn util functions
 to a new insn-eval file

On Fri, Aug 18, 2017 at 05:27:49PM -0700, Ricardo Neri wrote:
> Other kernel submodules can benefit from using the utility functions
> defined in mpx.c to obtain the addresses and values of operands contained
> in the general purpose registers. An instance of this is the emulation code
> used for instructions protected by the Intel User-Mode Instruction
> Prevention feature.
> 
> Thus, these functions are relocated to a new insn-eval.c file. The reason
> to not relocate these utilities into insn.c is that the latter solely
> analyses instructions given by a struct insn without any knowledge of the
> meaning of the values of instruction operands. This new utility insn-
> eval.c aims to be used to resolve and userspace linear addresses based on
				   ^
				   |

something's missing there - "kernel" maybe?

> the contents of the instruction operands as well as the contents of pt_regs
> structure.
> 
> These utilities come with a separate header. This is to avoid taking insn.c
> out of sync from the instructions decoders under tools/obj and tools/perf.
> This also avoids adding cumbersome #ifdef's for the #include'd files
> required to decode instructions in a kernel context.
> 
> Functions are simply relocated. There are not functional or indentation
> changes.

That text below you don't need to have in the commit message. Patch
handling and other modalities are usually put after the "---" and before
the diffstat below...

> The checkpatch script issues the following warning with this
> commit:
> 
> WARNING: Avoid crashing the kernel - try using WARN_ON & recovery code
> rather than BUG() or BUG_ON()
> +               BUG();
> 
> This warning will be fixed in a subsequent patch.
> 
> Cc: Borislav Petkov <bp@...e.de>
> Cc: Andy Lutomirski <luto@...nel.org>
> Cc: Dave Hansen <dave.hansen@...ux.intel.com>
> Cc: Adam Buchbinder <adam.buchbinder@...il.com>
> Cc: Colin Ian King <colin.king@...onical.com>
> Cc: Lorenzo Stoakes <lstoakes@...il.com>
> Cc: Qiaowei Ren <qiaowei.ren@...el.com>
> Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
> Cc: Masami Hiramatsu <mhiramat@...nel.org>
> Cc: Adrian Hunter <adrian.hunter@...el.com>
> Cc: Kees Cook <keescook@...omium.org>
> Cc: Thomas Garnier <thgarnie@...gle.com>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Cc: Dmitry Vyukov <dvyukov@...gle.com>
> Cc: Ravi V. Shankar <ravi.v.shankar@...el.com>
> Cc: x86@...nel.org
> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
> ---

<--- ... here. Put such notes here.

>  arch/x86/include/asm/insn-eval.h |  16 ++++
>  arch/x86/lib/Makefile            |   2 +-
>  arch/x86/lib/insn-eval.c         | 163 +++++++++++++++++++++++++++++++++++++++
>  arch/x86/mm/mpx.c                | 156 +------------------------------------
>  4 files changed, 182 insertions(+), 155 deletions(-)
>  create mode 100644 arch/x86/include/asm/insn-eval.h
>  create mode 100644 arch/x86/lib/insn-eval.c

Reviewed-by: Borislav Petkov <bp@...e.de>

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--