Re: [PATCH] linux-user: Enhance /proc/cpuinfo output for sparc, hppa and m68k

[Laurent Vivier]

Le 13/12/2022 à 17:10, Helge Deller a écrit :
> The sparc, hppa and m68k architectures provide an own output for the
> emulated /proc/cpuinfo file.
>
> Some userspace applications count (even if that's not the recommended
> way) the number of lines which start with "processor:" and assume that
> this number then reflects the number of online CPUs. Since those 3
> architectures don't provide any such line, applications may assume "0"
> CPUs.  One such issue can be seen in debian bug report:
> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1024653

Why don't they use something like system("getconf _NPROCESSORS_CONF") ?

> Avoid such issues by adding a "processor:" line for each of the online
> CPUs.
>
> Signed-off-by: Helge Deller <deller@gmx.de>
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 9e2c0a18fc..d58e9b8d10 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
...
> @@ -8319,6 +8331,7 @@ static int open_cpuinfo(CPUArchState *cpu_env, int fd)
>   #if defined(TARGET_M68K)
>   static int open_hardware(CPUArchState *cpu_env, int fd)
>   {
> +    dprintf(fd, "processor\t: 0\n");
>       dprintf(fd, "Model:\t\tqemu-m68k\n");
>       return 0;
>   }

This is /proc/hardware, not /proc/cpuinfo.

root@debian10-vm1:~# cat /proc/hardware
Model:          Macintosh Quadra 800
System Memory:  1025024K
root@debian10-vm1:~# cat /proc/cpuinfo
CPU:            68040
MMU:            68040
FPU:            68040
Clocking:       1529.8MHz
BogoMips:       1019.90
Calibration:    5099520 loops

And on m68k, no one expects to have a "processor" line.

Thanks,
Laurent