linux-user: add pseudo /proc/cpuinfo for sparc

SPARC libc6 debian package wants to check the cpu level to be
installed or not:

  WARNING: This machine has a SPARC V8 or earlier class processor.
  Debian lenny and later does not support such old hardware
  any longer.

To avoid this, it only needs to know if the machine type is sun4u or sun4v,
for that it reads the information from /proc/cpuinfo.

Fixes: 9a93c152fcdb4ab2cd85094487b33578fd693915
       ("linux-user: fix UNAME_MACHINE for sparc/sparc64")
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190517133149.19593-2-laurent@vivier.eu>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index efa3ec2..68484a8 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -6786,12 +6786,15 @@
     return 0;
 }
 
-#if defined(HOST_WORDS_BIGENDIAN) != defined(TARGET_WORDS_BIGENDIAN)
+#if defined(HOST_WORDS_BIGENDIAN) != defined(TARGET_WORDS_BIGENDIAN) || \
+    defined(TARGET_SPARC)
 static int is_proc(const char *filename, const char *entry)
 {
     return strcmp(filename, entry) == 0;
 }
+#endif
 
+#if defined(HOST_WORDS_BIGENDIAN) != defined(TARGET_WORDS_BIGENDIAN)
 static int open_net_route(void *cpu_env, int fd)
 {
     FILE *fp;
@@ -6836,6 +6839,14 @@
 }
 #endif
 
+#if defined(TARGET_SPARC)
+static int open_cpuinfo(void *cpu_env, int fd)
+{
+    dprintf(fd, "type\t\t: sun4u\n");
+    return 0;
+}
+#endif
+
 static int do_openat(void *cpu_env, int dirfd, const char *pathname, int flags, mode_t mode)
 {
     struct fake_open {
@@ -6852,6 +6863,9 @@
 #if defined(HOST_WORDS_BIGENDIAN) != defined(TARGET_WORDS_BIGENDIAN)
         { "/proc/net/route", open_net_route, is_proc },
 #endif
+#if defined(TARGET_SPARC)
+        { "/proc/cpuinfo", open_cpuinfo, is_proc },
+#endif
         { NULL, NULL, NULL }
     };