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From: Mark Wielaard <mark@klomp.org>
To: ying.huang@oss.cipunited.com, elfutils-devel@sourceware.org
Subject: Re: [PATCH 1/5] strip: Adapt src/strip -o -f on mips
Date: Tue, 09 May 2023 17:15:00 +0200	[thread overview]
Message-ID: <f35114fdb9b73fe1e374e150292bdfe5a845ca76.camel@klomp.org> (raw)
In-Reply-To: <20230411081141.1762395-2-ying.huang@oss.cipunited.com>

Hi,

On Tue, 2023-04-11 at 16:12 +0800, Ying Huang wrote:
> From: Ying Huang <ying.huang@oss.cipunited.com>
> 
> In mips64 little-endian, r_info consists of four byte fields(contains
> three reloc types) and a 32-bit symbol index. In order to adapt
> GELF_R_SYM and GELF_R_TYPE, need convert raw data to get correct symbol
> index and type.

Is there a spec that describes this?

I see you adjusted elf.h to include:

+#define ELF64_MIPS_R_TYPE(i)		((i) & 0xff)
+#define ELF64_MIPS_R_TYPE2(i)           (((i) >> 8) & 0xff)
+#define ELF64_MIPS_R_TYPE3(i)           (((i) >> 16) & 0xff)

And various new relocation types for MIPS variants.
Our elf.h comes from the glibc project. Have you also submitted these
changes to libc-alpha@sourceware.org ?

>   libelf/elf_getdata.c: Some eu-utils use read-mmap method to map file,
> so we need to malloc and memcpy raw data to avoid segment fault. After
> modification, the correct value are saved in the malloced memory not in
> process address space.

Where do these segfaults show up?

>   libelf/elf_updata.c: Because we converted the relocation info in mips
> order when we call elf_getdata.c, so we need to convert the modified data
> in original order bits before writing the data to the file.

It feels like this is in the wrong place and doesn't take into account
whether the program itself is running on a big or little endian
machine.

Maybe I am misunderstanding why this conversion is needed always. But I
would have expected a specific conversion function for MIPS for
ELF_T_REL and/or ELF_T_RELA (which are currently generic).

Cheers,

Mark

  reply	other threads:[~2023-05-09 15:15 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-11  8:12 [PATCH 0/5] Add support for MIPS Ying Huang
2023-04-11  8:12 ` [PATCH 1/5] strip: Adapt src/strip -o -f on mips Ying Huang
2023-05-09 15:15   ` Mark Wielaard [this message]
2023-05-16  6:38     ` Ying Huang
2023-05-21 21:13       ` Mark Wielaard
2023-05-24  6:21         ` Ying Huang
2023-05-16  6:46     ` Ying Huang
2023-05-16  7:34       ` Ying Huang
2023-05-21 21:14         ` Mark Wielaard
2023-05-26  2:48           ` Ying Huang
2023-05-16  8:05     ` [EXTERNAL] " Luke Diamand
2023-04-11  8:12 ` [PATCH 2/5] readelf: Adapt src/readelf -h/-S/-r/-w/-l/-d/-a " Ying Huang
2023-05-11 14:31   ` Mark Wielaard
2023-05-16  8:01     ` Ying Huang
2023-07-24  8:35     ` Ying Huang
2023-07-25  8:15       ` Ying Huang
2023-07-27  6:08         ` Ying Huang
2023-08-01 21:43           ` Mark Wielaard
2023-08-01 13:14         ` Mark Wielaard
2023-08-01  9:25       ` Mark Wielaard
2023-04-11  8:12 ` [PATCH 3/5] elflint: Fix invalid type of relocation info and other issues " Ying Huang
2023-05-11 15:59   ` Mark Wielaard
2023-05-17  9:14     ` Ying Huang
2023-04-11  8:12 ` [PATCH 4/5] stack: Fix stack unwind failure " Ying Huang
2023-05-11 16:07   ` Mark Wielaard
2023-05-18  6:14     ` Ying Huang
2023-04-11  8:12 ` [PATCH 5/5] backends: Fix run-native-test.sh and run-funcretval++11.sh run fail " Ying Huang
2023-05-11 16:38   ` Mark Wielaard
2023-05-18  9:06     ` Ying Huang
2023-05-04  2:24 ` [PATCH 0/5] Add support for MIPS 黄莺

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