Re: [PATCH v2] linux-user: Fix strace output for s390x mmap()

[iii <iii@imap.linux.ibm.com>]

On 2024-11-21 10:00, Philippe Mathieu-Daudé wrote:
> On 20/11/24 22:26, Ilya Leoshkevich wrote:
>> print_mmap() assumes that mmap() receives arguments via memory if
>> mmap2() is present. s390x (as opposed to s390) does not fit this
>> pattern: it does not have mmap2(), but mmap() still receives arguments
>> via memory.
>> 
>> Fix by sharing the detection logic between syscall.c and strace.c.
>> 
>> Cc: qemu-stable@nongnu.org
>> Fixes: d971040c2d16 ("linux-user: Fix strace output for old_mmap")
>> Suggested-by: Richard Henderson <richard.henderson@linaro.org>
>> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
>> ---
>> 
>> v1: 
>> https://lore.kernel.org/qemu-devel/20241119211138.148806-1-iii@linux.ibm.com/
>> v1 -> v2: Share the detection logic between syscall.c and strace.c
>>            (Richard).
>> 
>>   linux-user/strace.c       | 2 +-
>>   linux-user/syscall.c      | 5 +----
>>   linux-user/syscall_defs.h | 7 +++++++
>>   3 files changed, 9 insertions(+), 5 deletions(-)
>> 
>> diff --git a/linux-user/strace.c b/linux-user/strace.c
>> index b70eadc19ef..9c55f39b095 100644
>> --- a/linux-user/strace.c
>> +++ b/linux-user/strace.c
>> @@ -3971,7 +3971,7 @@ print_mmap(CPUArchState *cpu_env, const struct 
>> syscallname *name,
>>   {
>>       return print_mmap_both(cpu_env, name, arg0, arg1, arg2, arg3,
>>                              arg4, arg5,
>> -#if defined(TARGET_NR_mmap2)
>> +#ifdef TARGET_ARCH_WANT_SYS_OLD_MMAP
> 
> We still want to print for mmap2, so:
> 
>   #if defined(TARGET_NR_mmap2) || 
> defined(TARGET_ARCH_WANT_SYS_OLD_MMAP)
> 
>>                               true
>>   #else
>>                               false

mmap2() has its own flow from what I can see:

print_mmap2()
   print_mmap_both(..., is_old_mmap=false)

It should not call print_mmap(), which I'm changing here.

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