[PATCH] linux-user: Emulate /proc/cpuinfo on aarch64 and arm

[Helge Deller <deller@gmx.de>]

Add emulation for /proc/cpuinfo for arm architecture.
The output below mimics output as seen on debian porterboxes.

aarch64 output example:

processor       : 0
BogoMIPS        : 100.00
Features        : fp asimd evtstrm cpuid
CPU implementer : 0x50
CPU architecture: 8
CPU variant     : 0x0
CPU part        : 0x0
CPU revision    : 1

arm output example:

processor       : 0
model name      : ARMv7 Processor rev 2 (v7l)
BogoMIPS        : 50.00
Features        : half thumb fastmult vfp edsp thumbee vfpv3 tls idiva idivt vfpd32 lpae
CPU implementer : 0x56
CPU architecture: 7
CPU variant     : 0x2
CPU part        : 0x584
CPU revision    : 2

Signed-off-by: Helge Deller <deller@gmx.de>

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index dc8266c073..917c388073 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -8287,7 +8287,8 @@ void target_exception_dump(CPUArchState *env, const char *fmt, int code)

 #if HOST_BIG_ENDIAN != TARGET_BIG_ENDIAN || \
     defined(TARGET_SPARC) || defined(TARGET_M68K) || defined(TARGET_HPPA) || \
-    defined(TARGET_RISCV) || defined(TARGET_S390X)
+    defined(TARGET_RISCV) || defined(TARGET_S390X) || defined(TARGET_ARM) || \
+    defined(TARGET_AARCH64)
 static int is_proc(const char *filename, const char *entry)
 {
     return strcmp(filename, entry) == 0;
@@ -8503,6 +8504,33 @@ static int open_hardware(CPUArchState *cpu_env, int fd)
 }
 #endif

+#if defined(TARGET_AARCH64) || defined(TARGET_ARM)
+static int open_cpuinfo(CPUArchState *cpu_env, int fd)
+{
+    int i, num_cpus;
+    const int is64 = TARGET_ABI_BITS == 64;
+
+    num_cpus = sysconf(_SC_NPROCESSORS_ONLN);
+    for (i = 0; i < num_cpus; i++) {
+        dprintf(fd, "processor\t: %d\n", i);
+        if (!is64) {
+            dprintf(fd, "model name\t: ARMv7 Processor rev 2 (v7l)\n");
+        }
+        dprintf(fd, "BogoMIPS\t: %d.00\n", is64 ? 100 : 50);
+        dprintf(fd, "Features\t: %s\n",
+                is64 ? "fp asimd evtstrm cpuid"
+                     : "half thumb fastmult vfp edsp thumbee vfpv3 " \
+                       "tls idiva idivt vfpd32 lpae");
+        dprintf(fd, "CPU implementer\t: 0x%d\n", is64 ? 50 : 56);
+        dprintf(fd, "CPU architecture: %d\n",    is64 ? 8 : 7);
+        dprintf(fd, "CPU variant\t: 0x%d\n",     is64 ? 0 : 2);
+        dprintf(fd, "CPU part\t: 0x%d\n",        is64 ? 0 : 584);
+        dprintf(fd, "CPU revision\t: %d\n\n",    is64 ? 1 : 2);
+    }
+    return 0;
+}
+#endif
+
 int do_guest_openat(CPUArchState *cpu_env, int dirfd, const char *pathname,
                     int flags, mode_t mode, bool safe)
 {
@@ -8522,7 +8550,8 @@ int do_guest_openat(CPUArchState *cpu_env, int dirfd, const char *pathname,
         { "/proc/net/route", open_net_route, is_proc },
 #endif
 #if defined(TARGET_SPARC) || defined(TARGET_HPPA) || \
-    defined(TARGET_RISCV) || defined(TARGET_S390X)
+    defined(TARGET_RISCV) || defined(TARGET_S390X) || \
+    defined(TARGET_ARM)   || defined(TARGET_AARCH64)
         { "/proc/cpuinfo", open_cpuinfo, is_proc },
 #endif
 #if defined(TARGET_M68K)