Re: [PATCH v7 21/21] scripts: add loongarch64 binfmt config

[Song Gao]

Hi, Xuerui

On 10/18/2021 11:49 PM, WANG Xuerui wrote:
> Hi Song,
> 
> On 10/18/21 20:47, Song Gao wrote:
>> Signed-off-by: Song Gao <gaosong@loongson.cn>
>> Signed-off-by: Xiaojuan Yang <yangxiaojuan@loongson.cn>
>> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
>> ---
>>   scripts/qemu-binfmt-conf.sh | 6 +++++-
>>   1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/scripts/qemu-binfmt-conf.sh b/scripts/qemu-binfmt-conf.sh
>> index 7de996d..5575bdd 100755
>> --- a/scripts/qemu-binfmt-conf.sh
>> +++ b/scripts/qemu-binfmt-conf.sh
>> @@ -4,7 +4,7 @@
>>   qemu_target_list="i386 i486 alpha arm armeb sparc sparc32plus sparc64 \
>>   ppc ppc64 ppc64le m68k mips mipsel mipsn32 mipsn32el mips64 mips64el \
>>   sh4 sh4eb s390x aarch64 aarch64_be hppa riscv32 riscv64 xtensa xtensaeb \
>> -microblaze microblazeel or1k x86_64 hexagon"
>> +microblaze microblazeel or1k x86_64 hexagon loongarch64"
>>     
>> i386_magic='\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x03\x00'
>>   
>> i386_mask='\xff\xff\xff\xff\xff\xfe\xfe\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
>> @@ -140,6 +140,10 @@ 
>> hexagon_magic='\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x
>>   
>> hexagon_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
>>   hexagon_family=hexagon
>>   
>> +loongarch64_magic='\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x02\x01'
>> +loongarch64_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
> 
> Here the EI_OSABI (7th, 0-based offset) byte is ignored which is okay (we 
> want at least ELFOSABI_SYSV=0 and ELFOSABI_GNU=3 but not others, mask of this 
> byte could be "\xfc" to exclude values > 3).
> 
The EI_OSABI can not be modified. If we support FreeBSD and OpenBSD in the 
future.
> However, the EI_ABIVERSION (8th) byte is fixed to be zero; according to the 
> draft LoongArch ELF psABI spec [1] there might be future revision(s) to 
> necessitate a bump of ABI version, but it's highly unlikely to in turn 
> require modifications to QEMU code, with almost all logic happening in the 
> dynamic loader. I suggest unmasking this whole byte (setting mask for this 
> byte to "\x00").
>That's a good suggestion， thank you very much.


Thanks
Song Gao