Re: [PATCH v3] linux-user: Fix /proc/cpuinfo output for sparc and hppa

[Laurent Vivier]

Le 28/12/2022 à 22:09, Helge Deller a écrit :
> The sparc and hppa 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
>
> Avoid such issues by adding a "processor:" line for each of the online
> CPUs.
>
> Signed-off-by: Helge Deller <deller@gmx.de>
>
> ---
> v3:
> - add trailing newline at end of /proc/cpuinfo file (needed by procps)
>
> v2:
> - drop m68k part (based on feedback from Laurent Vivier <laurent@vivier.eu>)
> - change commit message
>
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index afb24fd0b9..5ec11a3683 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -8310,7 +8310,13 @@ static int open_net_route(CPUArchState *cpu_env, int fd)
>   #if defined(TARGET_SPARC)
>   static int open_cpuinfo(CPUArchState *cpu_env, int fd)
>   {
> -    dprintf(fd, "type\t\t: sun4u\n");
> +    int i, num_cpus;
> +
> +    num_cpus = sysconf(_SC_NPROCESSORS_ONLN);
> +    for (i = 0; i < num_cpus; i++) {
> +        dprintf(fd, "processor\t: %d\n", i);
> +        dprintf(fd, "type\t\t: sun4u\n\n");
> +    }

I'm sorry, kernel on real hardware doesn't use the "processor:" entry on sparc.
See show_cpuinfo() in arch/sparc/kernel/cpu.c.

In this case, fix the userspace application, as it would not work on the real 
hardware too.

>       return 0;
>   }
>   #endif
> @@ -8318,11 +8324,17 @@ static int open_cpuinfo(CPUArchState *cpu_env, int fd)
>   #if defined(TARGET_HPPA)
>   static int open_cpuinfo(CPUArchState *cpu_env, int fd)
>   {
> -    dprintf(fd, "cpu family\t: PA-RISC 1.1e\n");
> -    dprintf(fd, "cpu\t\t: PA7300LC (PCX-L2)\n");
> -    dprintf(fd, "capabilities\t: os32\n");
> -    dprintf(fd, "model\t\t: 9000/778/B160L\n");
> -    dprintf(fd, "model name\t: Merlin L2 160 QEMU (9000/778/B160L)\n");
> +    int i, num_cpus;
> +
> +    num_cpus = sysconf(_SC_NPROCESSORS_ONLN);
> +    for (i = 0; i < num_cpus; i++) {
> +        dprintf(fd, "processor\t: %d\n", i);
> +        dprintf(fd, "cpu family\t: PA-RISC 1.1e\n");
> +        dprintf(fd, "cpu\t\t: PA7300LC (PCX-L2)\n");
> +        dprintf(fd, "capabilities\t: os32\n");
> +        dprintf(fd, "model\t\t: 9000/778/B160L - "
> +                    "Merlin L2 160 QEMU (9000/778/B160L)\n\n");
> +    }
>       return 0;
>   }
>   #endif

It's good for hppa. Please, send a v4 with only hppa.

Thanks,
Laurent