qemu-binfmt-conf.sh: mips: allow nonzero EI_ABIVERSION, distinguish o32 and n32

[PATCH for-7.0 v5] qemu-binfmt-conf.sh: mips: allow nonzero EI_ABIVERSION, distinguish o32 and n32

Posted by Andreas K. Hüttel 3 years ago

With the command line flag -mplt and a recent toolchain, ELF binaries
generated by gcc can obtain EI_ABIVERSION=1, 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. Also other
values are technically possible. qemu executes these binaries just
fine, so relax the mask for the EI_ABIVERSION byte at offset 0x08.

In addition, extend magic string to distinguish mips o32 and n32 ABI.
This information is given by the EF_MIPS_ABI2 (0x20) bit in the
e_flags field of the ELF header (a 4-byte value at offset 0x24 for
the here applicable ELFCLASS32).

See-also: ace3d65459
Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: WANG Xuerui <xen0n@gentoo.org>
Cc: Laurent Vivier <laurent@vivier.eu>
Cc: WANG Xuerui <xen0n@gentoo.org>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Alex Bennee <alex.bennee@linaro.org>
Cc: Philippe Mathieu-Daudé <philippe.mathieu.daude@gmail.com>
Closes: https://gitlab.com/qemu-project/qemu/-/issues/843
---

v5: Fully relax mask for EI_ABIVERSION for all of mips; squash patches
    since they touch the same lines
v4: Unchanged repost of v3
v3: Add the magic extension to distinguish n32 and o32
v2: Add the same EI_ABIVERSION fix for little endian as for big endian
v1: Initial version, only handling EI_ABIVERSION=1 on BE

 scripts/qemu-binfmt-conf.sh | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/scripts/qemu-binfmt-conf.sh b/scripts/qemu-binfmt-conf.sh
index e9bfeb94d3..9cb723f443 100755
--- a/scripts/qemu-binfmt-conf.sh
+++ b/scripts/qemu-binfmt-conf.sh
@@ -60,28 +60,28 @@ 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_magic='\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
+mips_mask='\xff\xff\xff\xff\xff\xff\xff\x00\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff\xff\xff\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20'
 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_magic='\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
+mipsel_mask='\xff\xff\xff\xff\xff\xff\xff\x00\x00\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff\xff\xff\xff\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20\x00\x00\x00'
 mipsel_family=mips
 
-mipsn32_magic='\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08'
-mipsn32_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
+mipsn32_magic='\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20'
+mipsn32_mask='\xff\xff\xff\xff\xff\xff\xff\x00\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff\xff\xff\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20'
 mipsn32_family=mips
 
-mipsn32el_magic='\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00'
-mipsn32el_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
+mipsn32el_magic='\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20\x00\x00\x00'
+mipsn32el_mask='\xff\xff\xff\xff\xff\xff\xff\x00\x00\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff\xff\xff\xff\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20\x00\x00\x00'
 mipsn32el_family=mips
 
 mips64_magic='\x7fELF\x02\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08'
-mips64_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
+mips64_mask='\xff\xff\xff\xff\xff\xff\xff\x00\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
 mips64_family=mips
 
 mips64el_magic='\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00'
-mips64el_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
+mips64el_mask='\xff\xff\xff\xff\xff\xff\xff\x00\x00\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
 mips64el_family=mips
 
 sh4_magic='\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x2a\x00'
-- 
2.34.1

Re: [PATCH for-7.0 v5] qemu-binfmt-conf.sh: mips: allow nonzero EI_ABIVERSION, distinguish o32 and n32

Posted by Philippe Mathieu-Daudé 3 years ago

On 28/3/22 22:49, Andreas K. Hüttel wrote:
> With the command line flag -mplt and a recent toolchain, ELF binaries
> generated by gcc can obtain EI_ABIVERSION=1, 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. Also other
> values are technically possible. qemu executes these binaries just
> fine, so relax the mask for the EI_ABIVERSION byte at offset 0x08.
> 
> In addition, extend magic string to distinguish mips o32 and n32 ABI.
> This information is given by the EF_MIPS_ABI2 (0x20) bit in the
> e_flags field of the ELF header (a 4-byte value at offset 0x24 for
> the here applicable ELFCLASS32).
> 
> See-also: ace3d65459
> Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>
> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> Reviewed-by: WANG Xuerui <xen0n@gentoo.org>

v5 changes are too different from v4 to keep these R-b tags IMO.

LGTM but I'd like Xuerui to double-check the R-b stands,
and an Acked-by from Laurent would make me feel safer ;)

> Cc: Laurent Vivier <laurent@vivier.eu>
> Cc: WANG Xuerui <xen0n@gentoo.org>
> Cc: Richard Henderson <richard.henderson@linaro.org>
> Cc: Alex Bennee <alex.bennee@linaro.org>
> Cc: Philippe Mathieu-Daudé <philippe.mathieu.daude@gmail.com>
> Closes: https://gitlab.com/qemu-project/qemu/-/issues/843
> ---
> 
> v5: Fully relax mask for EI_ABIVERSION for all of mips; squash patches
>      since they touch the same lines
> v4: Unchanged repost of v3
> v3: Add the magic extension to distinguish n32 and o32
> v2: Add the same EI_ABIVERSION fix for little endian as for big endian
> v1: Initial version, only handling EI_ABIVERSION=1 on BE
> 
>   scripts/qemu-binfmt-conf.sh | 20 ++++++++++----------
>   1 file changed, 10 insertions(+), 10 deletions(-)
> 
> diff --git a/scripts/qemu-binfmt-conf.sh b/scripts/qemu-binfmt-conf.sh
> index e9bfeb94d3..9cb723f443 100755
> --- a/scripts/qemu-binfmt-conf.sh
> +++ b/scripts/qemu-binfmt-conf.sh
> @@ -60,28 +60,28 @@ 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_magic='\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
> +mips_mask='\xff\xff\xff\xff\xff\xff\xff\x00\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff\xff\xff\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20'
>   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_magic='\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
> +mipsel_mask='\xff\xff\xff\xff\xff\xff\xff\x00\x00\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff\xff\xff\xff\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20\x00\x00\x00'
>   mipsel_family=mips
>   
> -mipsn32_magic='\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08'
> -mipsn32_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
> +mipsn32_magic='\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20'
> +mipsn32_mask='\xff\xff\xff\xff\xff\xff\xff\x00\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff\xff\xff\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20'
>   mipsn32_family=mips
>   
> -mipsn32el_magic='\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00'
> -mipsn32el_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
> +mipsn32el_magic='\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20\x00\x00\x00'
> +mipsn32el_mask='\xff\xff\xff\xff\xff\xff\xff\x00\x00\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff\xff\xff\xff\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20\x00\x00\x00'
>   mipsn32el_family=mips
>   
>   mips64_magic='\x7fELF\x02\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08'
> -mips64_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
> +mips64_mask='\xff\xff\xff\xff\xff\xff\xff\x00\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
>   mips64_family=mips
>   
>   mips64el_magic='\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00'
> -mips64el_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
> +mips64el_mask='\xff\xff\xff\xff\xff\xff\xff\x00\x00\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
>   mips64el_family=mips
>   
>   sh4_magic='\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x2a\x00'

Re: [PATCH for-7.0 v5] qemu-binfmt-conf.sh: mips: allow nonzero EI_ABIVERSION, distinguish o32 and n32

Posted by Laurent Vivier 2 years, 12 months ago

Le 29/03/2022 à 01:39, Philippe Mathieu-Daudé a écrit :
> On 28/3/22 22:49, Andreas K. Hüttel wrote:
>> With the command line flag -mplt and a recent toolchain, ELF binaries
>> generated by gcc can obtain EI_ABIVERSION=1, 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. Also other
>> values are technically possible. qemu executes these binaries just
>> fine, so relax the mask for the EI_ABIVERSION byte at offset 0x08.
>>
>> In addition, extend magic string to distinguish mips o32 and n32 ABI.
>> This information is given by the EF_MIPS_ABI2 (0x20) bit in the
>> e_flags field of the ELF header (a 4-byte value at offset 0x24 for
>> the here applicable ELFCLASS32).
>>
>> See-also: ace3d65459
>> Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>
>> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
>> Reviewed-by: WANG Xuerui <xen0n@gentoo.org>
> 
> v5 changes are too different from v4 to keep these R-b tags IMO.
> 
> LGTM but I'd like Xuerui to double-check the R-b stands,
> and an Acked-by from Laurent would make me feel safer ;)

Sorry, I didn't see your email before.
It's more mips than linux-user, so there is no problem for me.

Thanks,
Laurent

Re: [PATCH for-7.0 v5] qemu-binfmt-conf.sh: mips: allow nonzero EI_ABIVERSION, distinguish o32 and n32

Posted by WANG Xuerui 3 years ago

On 3/29/22 07:39, Philippe Mathieu-Daudé wrote:
> On 28/3/22 22:49, Andreas K. Hüttel wrote:
>> With the command line flag -mplt and a recent toolchain, ELF binaries
>> generated by gcc can obtain EI_ABIVERSION=1, 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. Also other
>> values are technically possible. qemu executes these binaries just
>> fine, so relax the mask for the EI_ABIVERSION byte at offset 0x08.
>>
>> In addition, extend magic string to distinguish mips o32 and n32 ABI.
>> This information is given by the EF_MIPS_ABI2 (0x20) bit in the
>> e_flags field of the ELF header (a 4-byte value at offset 0x24 for
>> the here applicable ELFCLASS32).
>>
>> See-also: ace3d65459
>> Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>
>> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
>> Reviewed-by: WANG Xuerui <xen0n@gentoo.org>
> 
> v5 changes are too different from v4 to keep these R-b tags IMO.
> 
> LGTM but I'd like Xuerui to double-check the R-b stands,
> and an Acked-by from Laurent would make me feel safer ;)

This is just a squash of v4 patches, but I manually double-checked the 
definitions against elf.h for that extra confidence, and they looked 
good. The R-b tags still stand :)

-- 
WANG Xuerui
xen0n@gentoo.org
Gentoo Linux developer
PGP: 7C52 19E3 26A0 7311 3EA3 8806 C01F 7214 BC93 1414

Re: [PATCH for-7.0 v5] qemu-binfmt-conf.sh: mips: allow nonzero EI_ABIVERSION, distinguish o32 and n32

Posted by Philippe Mathieu-Daudé 2 years, 12 months ago

On 29/3/22 04:05, WANG Xuerui wrote:
> On 3/29/22 07:39, Philippe Mathieu-Daudé wrote:
>> On 28/3/22 22:49, Andreas K. Hüttel wrote:
>>> With the command line flag -mplt and a recent toolchain, ELF binaries
>>> generated by gcc can obtain EI_ABIVERSION=1, 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. Also other
>>> values are technically possible. qemu executes these binaries just
>>> fine, so relax the mask for the EI_ABIVERSION byte at offset 0x08.
>>>
>>> In addition, extend magic string to distinguish mips o32 and n32 ABI.
>>> This information is given by the EF_MIPS_ABI2 (0x20) bit in the
>>> e_flags field of the ELF header (a 4-byte value at offset 0x24 for
>>> the here applicable ELFCLASS32).
>>>
>>> See-also: ace3d65459
>>> Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>
>>> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
>>> Reviewed-by: WANG Xuerui <xen0n@gentoo.org>
>>
>> v5 changes are too different from v4 to keep these R-b tags IMO.
>>
>> LGTM but I'd like Xuerui to double-check the R-b stands,
>> and an Acked-by from Laurent would make me feel safer ;)
> 
> This is just a squash of v4 patches, but I manually double-checked the 
> definitions against elf.h for that extra confidence, and they looked 
> good. The R-b tags still stand :)

Thanks for double-checking your R-b!

Patch (already) queued to mips-fixes.

Regards,

Phil.