[PATCH v2] linux-user: Fix /proc/cpuinfo output for sparc and hppa

[PATCH v2] linux-user: Fix /proc/cpuinfo output for sparc and hppa

[Helge Deller]

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>

---
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 9e2c0a18fc..d58e9b8d10 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -8299,7 +8299,13 @@ 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, "%sprocessor\t: %d\n", (i > 0) ? "\n":"", i);
+        dprintf(fd, "type\t\t: sun4u\n");
+    }
     return 0;
 }
 #endif
@@ -8307,11 +8313,17 @@ 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, "%sprocessor\t: %d\n", (i > 0) ? "\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");
+    }
     return 0;
 }
 #endif

Re: [PATCH v2] linux-user: Fix /proc/cpuinfo output for sparc and hppa

[Helge Deller]

On 12/13/22 22:26, Helge Deller wrote:
> 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>
>
> ---
> 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 9e2c0a18fc..d58e9b8d10 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -8299,7 +8299,13 @@ 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, "%sprocessor\t: %d\n", (i > 0) ? "\n":"", i);

it turned out, that the procps tools expect the /proc/cpuinfo file
to have a trailing \n at the end of the file.
So, I'll respin this patch and send a v3 version to replace this
conditional \n-output.

Same applies for the hppa arch.....


> +        dprintf(fd, "type\t\t: sun4u\n");
> +    }
>       return 0;
>   }
>   #endif
> @@ -8307,11 +8313,17 @@ 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, "%sprocessor\t: %d\n", (i > 0) ? "\n":"", i);

^^  here.

Helge

> +        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");
> +    }
>       return 0;
>   }
>   #endif