[PATCH v4] linux-user: Fix /proc/cpuinfo output for hppa

From: Helge Deller <deller@gmx.de>
To: Laurent Vivier <laurent@vivier.eu>
Cc: Helge Deller <deller@gmx.de>,
	Richard Henderson <richard.henderson@linaro.org>,
	qemu-devel@nongnu.org
Subject: [PATCH v4] linux-user: Fix /proc/cpuinfo output for hppa
Date: Fri, 27 Jan 2023 21:10:49 +0100	[thread overview]
Message-ID: <Y9QvyRSq1I1k5/JW@p100> (raw)
In-Reply-To: <b645585a-1093-fb97-60a1-5acc40b17271@vivier.eu>

The hppa architectures provides 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>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
v4:
- Drop sparc changes

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..5fa2ae6c8a 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -8318,11 +8318,17 @@ 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

