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From: "Philippe Mathieu-Daudé" <philippe.mathieu.daude@gmail.com>
To: "Andreas K. Hüttel" <dilfridge@gentoo.org>, qemu-devel@nongnu.org
Cc: Richard Henderson <richard.henderson@linaro.org>,
	Laurent Vivier <laurent@vivier.eu>
Subject: Re: [PATCH v2] qemu-binfmt-conf.sh: allow elf EI_ABIVERSION=1 for mips
Date: Mon, 7 Mar 2022 00:54:44 +0100	[thread overview]
Message-ID: <28ad3f08-6b08-1a92-a71b-4019e4c662a1@gmail.com> (raw)
In-Reply-To: <b54bb834-84e9-6342-ecac-643cbd11549b@gmail.com>

(Cc'ing Richard)

On 5/3/22 01:18, Philippe Mathieu-Daudé wrote:
> Cc'ing Laurent:
> 
> $ ./scripts/get_maintainer.pl -f scripts/qemu-binfmt-conf.sh
> Laurent Vivier <laurent@vivier.eu> (maintainer:Linux user)
> qemu-devel@nongnu.org (open list:All patches CC here)
> 
> On 5/3/22 01:06, Andreas K. Hüttel wrote:
>> With the command line flag -mplt and a recent toolchain, ELF binaries
>> generated by gcc can obtain EI_ABIVERSION=1, see below, which makes, 
>> e.g.,
>> gcc three-stage bootstrap in a mips-unknown-linux-gnu qemu-user chroot
>> fail since the binfmt-misc magic does not match anymore.
>>
>> qemu executes these binaries just fine, so relax the mask slightly.
>>
>> CHOST=mips-unknown-linux-gnu (and also mipsel-unknown-linux-gnu)
>> CFLAGS="-O2 -march=mips32 -mabi=32 -mplt -pipe"
>> gcc-11.2, binutils-2.37, glibc-2.34
>>
>> |  /*
>> | - * ELF dump of './prev-gcc/build/gengenrtl'
>> | - *     29608 (0x73A8) bytes
>> | + * ELF dump of './gcc/build/gengenrtl'
>> | + *     54532 (0xD504) bytes
>> |   */
>> |
>> |  Elf32_Dyn dumpedelf_dyn_0[];
>> |  struct {
>> |         Elf32_Ehdr ehdr;
>> |         Elf32_Phdr phdrs[12];
>> | -       Elf32_Shdr shdrs[33];
>> | +       Elf32_Shdr shdrs[44];
>> |         Elf32_Dyn *dyns;
>> |  } dumpedelf_0 = {
>> |
>> |  .ehdr = {
>> |         .e_ident = { /* (EI_NIDENT bytes) */
>> |                 /* [0] EI_MAG:        */ 0x7F,'E','L','F',
>> |                 /* [4] EI_CLASS:      */ 1 , /* (ELFCLASS32) */
>> |                 /* [5] EI_DATA:       */ 2 , /* (ELFDATA2MSB) */
>> |                 /* [6] EI_VERSION:    */ 1 , /* (EV_CURRENT) */
>> |                 /* [7] EI_OSABI:      */ 0 , /* (ELFOSABI_NONE) */
>> | -               /* [8] EI_ABIVERSION: */ 0 ,
>> | +               /* [8] EI_ABIVERSION: */ 1 ,
>> |                 /* [9-15] EI_PAD:     */ 0x0, 0x0, 0x0, 0x0, 0x0, 
>> 0x0, 0x0,
>> |         },
>> |         .e_type      = 2          , /* (ET_EXEC) */
>> |         .e_machine   = 8          , /* (EM_MIPS) */
>> |         .e_version   = 1          , /* (EV_CURRENT) */
>> | (...)
>>
>> Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>
>> ---
>>
>> v2: Add the same fix for little endian as for big endian
>>
>>   scripts/qemu-binfmt-conf.sh | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)

Acked-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

>> diff --git a/scripts/qemu-binfmt-conf.sh b/scripts/qemu-binfmt-conf.sh
>> index e9bfeb94d3..fc2f856800 100755
>> --- a/scripts/qemu-binfmt-conf.sh
>> +++ b/scripts/qemu-binfmt-conf.sh
>> @@ -61,11 +61,11 @@ m68k_family=m68k
>>   # FIXME: We could use the other endianness on a MIPS host.
>>   
>> mips_magic='\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08' 
>>
>> -mips_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff' 
>>
>> +mips_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff' 
>>
>>   mips_family=mips
>>   
>> mipsel_magic='\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00' 
>>
>> -mipsel_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff' 
>>
>> +mipsel_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xfe\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff' 
>>
>>   mipsel_family=mips
>>   
>> mipsn32_magic='\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08' 
>>
> 



  reply	other threads:[~2022-03-06 23:56 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-03 10:17 [PATCH] qemu-binfmt-conf.sh: allow elf EI_ABIVERSION=1 for mips Andreas K. Hüttel
2022-03-05  0:06 ` [PATCH v2] " Andreas K. Hüttel
2022-03-05  0:18   ` Philippe Mathieu-Daudé
2022-03-06 23:54     ` Philippe Mathieu-Daudé [this message]
2022-03-14 21:33   ` qemu-binfmt-conf.sh: mips improvements Andreas K. Hüttel
2022-03-14 21:33     ` [PATCH v3 1/2] qemu-binfmt-conf.sh: allow elf EI_ABIVERSION=1 for mips Andreas K. Hüttel
2022-03-23 11:00       ` [PATCH-for-7.0 " Philippe Mathieu-Daudé
2022-03-14 21:33     ` [PATCH v3 2/2] qemu-binfmt-conf.sh: Extend magic to distinguish mips o32 and n32 ABI Andreas K. Hüttel
2022-03-22 10:35       ` Philippe Mathieu-Daudé

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