linux-kernel - Re: [PATCH 4/5] MIPS: Support R_MIPS

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 3 Feb 2016 13:25:57 +0300
From:	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To:	Paul Burton <paul.burton@...tec.com>, linux-mips@...ux-mips.org,
	Ralf Baechle <ralf@...ux-mips.org>
Cc:	Andrey Konovalov <adech.fo@...il.com>,
	Andrey Ryabinin <ryabinin.a.a@...il.com>,
	linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH 4/5] MIPS: Support R_MIPS_PC16 rel-style reloc

Hello.

On 2/3/2016 6:44 AM, Paul Burton wrote:

> MIPS32 code uses rel-style relocs, and MIPS32r6 modules may include the
> R_MIPS_PC16 relocation. We thus need to support R_MIPS_PC16 rel-style
> relocations in order to load MIPS32r6 kernel modules. This patch adds
> such support, which is similar to the rela-style R_MIPS_PC16 support but

     R_MIPS_LO16, you mean?

> making use of the implicit addend from the instruction encoding.
>
> Signed-off-by: Paul Burton <paul.burton@...tec.com>
> ---
>
>   arch/mips/kernel/module.c | 14 +++++++++++++-
>   1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/arch/mips/kernel/module.c b/arch/mips/kernel/module.c
> index 2adf572..f2de9b8 100644
> --- a/arch/mips/kernel/module.c
> +++ b/arch/mips/kernel/module.c
> @@ -183,13 +183,25 @@ out_danger:
>   	return -ENOEXEC;
>   }
>
> +static int apply_r_mips_pc16_rel(struct module *me, u32 *location, Elf_Addr v)
> +{
> +	u16 val;
> +
> +	val = *location;
> +	val += (v - (Elf_Addr)location) >> 2;
> +	*location = (*location & 0xffff0000) | val;
> +
> +	return 0;
> +}
> +
>   static int (*reloc_handlers_rel[]) (struct module *me, u32 *location,
>   				Elf_Addr v) = {
>   	[R_MIPS_NONE]		= apply_r_mips_none,
>   	[R_MIPS_32]		= apply_r_mips_32_rel,
>   	[R_MIPS_26]		= apply_r_mips_26_rel,
>   	[R_MIPS_HI16]		= apply_r_mips_hi16_rel,
> -	[R_MIPS_LO16]		= apply_r_mips_lo16_rel
> +	[R_MIPS_LO16]		= apply_r_mips_lo16_rel,
> +	[R_MIPS_PC16]		= apply_r_mips_pc16_rel,
>   };
>
>   int apply_relocate(Elf_Shdr *sechdrs, const char *strtab,

MBR, Sergei