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From:   Huacai Chen <chenhuacai@gmail.com>
Date:   Thu, 14 Oct 2021 11:01:08 +0800
Message-ID: <CAAhV-H5-8yPjZhOkV2+v+XB85+2qs5342hDdTYAV1ctPAdb7+A@mail.gmail.com>
Subject: Re: [PATCH V5 15/22] LoongArch: Add elf and module support
To:     Luis Chamberlain <mcgrof@kernel.org>
Cc:     Huacai Chen <chenhuacai@loongson.cn>,
        Arnd Bergmann <arnd@arndb.de>,
        Andy Lutomirski <luto@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        David Airlie <airlied@linux.ie>,
        Jonathan Corbet <corbet@lwn.net>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-arch <linux-arch@vger.kernel.org>,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Xuefeng Li <lixuefeng@loongson.cn>,
        Yanteng Si <siyanteng@loongson.cn>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>,
        Jessica Yu <jeyu@kernel.org>
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Hi, Luis,

On Wed, Oct 13, 2021 at 8:56 PM Luis Chamberlain <mcgrof@kernel.org> wrote:
>
> On Wed, Oct 13, 2021 at 03:11:10PM +0800, Huacai Chen wrote:
> > diff --git a/arch/loongarch/include/asm/vermagic.h b/arch/loongarch/include/asm/vermagic.h
> > new file mode 100644
> > index 000000000000..9882dfd4702a
> > --- /dev/null
> > +++ b/arch/loongarch/include/asm/vermagic.h
> > @@ -0,0 +1,19 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
> > + */
> > +#ifndef _ASM_VERMAGIC_H
> > +#define _ASM_VERMAGIC_H
> > +
> > +#define MODULE_PROC_FAMILY "LOONGARCH "
>
> I take it this not a mips arch? There are other longarchs under
> arch/mips/include/asm/vermagic.h which is why I ask.
Yes, LoongArch is not compatible with MIPS, old Loongson is MIPS and
new Loongson isn't.

>
> > diff --git a/arch/loongarch/kernel/module.c b/arch/loongarch/kernel/module.c
> > new file mode 100644
> > index 000000000000..af7c403b032b
> > --- /dev/null
> > +++ b/arch/loongarch/kernel/module.c
> > @@ -0,0 +1,652 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Author: Hanlu Li <lihanlu@loongson.cn>
> > + *         Huacai Chen <chenhuacai@loongson.cn>
> > + *
> > + * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
> > + */
> > +
> > +#undef DEBUG
>
> Please remove this undef DEBUG line.
OK, thanks.

>
> > +
> > +#include <linux/moduleloader.h>
> > +#include <linux/elf.h>
> > +#include <linux/mm.h>
> > +#include <linux/vmalloc.h>
> > +#include <linux/slab.h>
> > +#include <linux/fs.h>
> > +#include <linux/string.h>
> > +#include <linux/kernel.h>
> > +
> > +static int rela_stack_push(s64 stack_value, s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > +     if (*rela_stack_top >= RELA_STACK_DEPTH)
> > +             return -ENOEXEC;
> > +
> > +     rela_stack[(*rela_stack_top)++] = stack_value;
> > +     pr_debug("%s stack_value = 0x%llx\n", __func__, stack_value);
>
> If you are going to use pr_debug() so much you may want to add
> a define for #define pr_fmt(fmt) at the very top.
OK, thanks.

>
> > +int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
> > +                    unsigned int symindex, unsigned int relsec,
> > +                    struct module *me)
> > +{
>
> Nit: Please use struct module *mod, it is much more common in other places.
>
OK, thanks.

> Other than that, this looks fine to me.
>
> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
>
>   Luis