Re: [Qemu-devel] [PATCH v2 2/5] linux-user: Add separate aarch64_be uname

[Laurent Vivier <laurent@vivier.eu>]

Le 20/12/2017 à 16:36, Peter Maydell a écrit :
> On 20 December 2017 at 15:20, Laurent Vivier <laurent@vivier.eu> wrote:
>> Le 19/12/2017 à 21:16, Michael Weiser a écrit :
>>> Make big-endian aarch64 systems identify as aarch64_be as expected by
>>> big-endian userland and toolchains.
>>>
>>> Signed-off-by: Michael Weiser <michael.weiser@gmx.de>
>>> ---
>>>  linux-user/aarch64/target_syscall.h | 4 ++++
>>>  1 file changed, 4 insertions(+)
>>>
>>> diff --git a/linux-user/aarch64/target_syscall.h b/linux-user/aarch64/target_syscall.h
>>> index 1b62953eeb..604ab99b14 100644
>>> --- a/linux-user/aarch64/target_syscall.h
>>> +++ b/linux-user/aarch64/target_syscall.h
>>> @@ -8,7 +8,11 @@ struct target_pt_regs {
>>>      uint64_t        pstate;
>>>  };
>>>
>>> +#if defined(TARGET_WORDS_BIGENDIAN)
>>> +#define UNAME_MACHINE "aarch64_be"
>>> +#else
>>>  #define UNAME_MACHINE "aarch64"
>>> +#endif
>>>  #define UNAME_MINIMUM_RELEASE "3.8.0"
>>
>> For aarch64_be, I think the minimum release should be 4.9.0
>> (see kernel commit cfa88c79462d "arm64: Set UTS_MACHINE in the Makefile")
> 
> Isn't the thing that defines what we set the minimum-release
> to glibc, not the kernel? That is, the reason we lie to the
> guest about the kernel version for some architectures is because
> the glibc for those archs insists on a minimum kernel version
> which the host may not have. Unless aarch64_be glibc insists
> on kernel 4.9.0 there's no need to tell the guest that.

As you are the author of the original commit (4a24a75810 "linux-user:
Allow targets to specify a minimum uname release"), I guess you're
right. So ignore my comment...

Thanks,
Laurent