linux-user: adapt uname machine to emulated CPU

This patch for linux-user adapts the output of the emulated uname()
syscall to match the configured CPU.  Tested with x86, x86-64 and arm
emulation.

Signed-off-by: Riku Voipio <riku.voipio@iki.fi>
Signed-off-by: Loïc Minier <lool@dooz.org>

Makefile.target

@@ -95,7 +95,7 @@ $(call set-vpath, $(SRC_PATH)/linux-user:$(SRC_PATH)/linux-user/$(TARGET_ABI_DIR
 
 QEMU_CFLAGS+=-I$(SRC_PATH)/linux-user -I$(SRC_PATH)/linux-user/$(TARGET_ABI_DIR)
 obj-y = main.o syscall.o strace.o mmap.o signal.o thunk.o \
-      elfload.o linuxload.o uaccess.o gdbstub.o
+      elfload.o linuxload.o uaccess.o gdbstub.o cpu-uname.o
 
 obj-$(TARGET_HAS_BFLT) += flatload.o
 obj-$(TARGET_HAS_ELFLOAD32) += elfload32.o

linux-user/cpu-uname.c

@@ -0,0 +1,72 @@
+/*
+ *  cpu to uname machine name map
+ *
+ *  Copyright (c) 2009 Loïc Minier
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdio.h>
+
+#include "qemu.h"
+//#include "qemu-common.h"
+#include "cpu-uname.h"
+
+/* return highest utsname machine name for emulated instruction set
+ *
+ * NB: the default emulated CPU ("any") might not match any existing CPU, e.g.
+ * on ARM it has all features turned on, so there is no perfect arch string to
+ * return here */
+const char *cpu_to_uname_machine(void *cpu_env)
+{
+#ifdef TARGET_ARM
+    /* utsname machine name on linux arm is CPU arch name + endianness, e.g.
+     * armv7l; to get a list of CPU arch names from the linux source, use:
+     *     grep arch_name: -A1 linux/arch/arm/mm/proc-*.S
+     * see arch/arm/kernel/setup.c: setup_processor()
+     *
+     * to test by CPU id, compare cpu_env->cp15.c0_cpuid to ARM_CPUID_*
+     * defines and to test by CPU feature, use arm_feature(cpu_env,
+     * ARM_FEATURE_*) */
+
+    /* in theory, endianness is configurable on some ARM CPUs, but this isn't
+     * used in user mode emulation */
+#ifdef TARGET_WORDS_BIGENDIAN
+#define utsname_suffix "b"
+#else
+#define utsname_suffix "l"
+#endif
+    if (arm_feature(cpu_env, ARM_FEATURE_V7))
+        return "armv7" utsname_suffix;
+    if (arm_feature(cpu_env, ARM_FEATURE_V6))
+        return "armv6" utsname_suffix;
+    /* earliest emulated CPU is ARMv5TE; qemu can emulate the 1026, but not its
+     * Jazelle support */
+    return "armv5te" utsname_suffix;
+#elif defined(TARGET_X86_64)
+    return "x86-64";
+#elif defined(TARGET_I386)
+    /* see arch/x86/kernel/cpu/bugs.c: check_bugs(), 386, 486, 586, 686 */
+    uint32_t cpuid_version = ((CPUX86State *)cpu_env)->cpuid_version;
+    int family = ((cpuid_version >> 8) & 0x0f) + ((cpuid_version >> 20) & 0xff);
+    if (family == 4)
+        return "i486";
+    if (family == 5)
+        return "i586";
+    return "i686";
+#else
+    /* default is #define-d in each arch/ subdir */
+    return UNAME_MACHINE;
+#endif
+}

linux-user/cpu-uname.h

@@ -0,0 +1 @@
+const char *cpu_to_uname_machine(void *cpu_env);

linux-user/syscall.c

@@ -82,6 +82,7 @@
 #include <linux/fb.h>
 #include <linux/vt.h>
 #include "linux_loop.h"
+#include "cpu-uname.h"
 
 #include "qemu.h"
 #include "qemu-common.h"
@@ -5739,7 +5740,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
             if (!is_error(ret)) {
                 /* Overrite the native machine name with whatever is being
                    emulated. */
-                strcpy (buf->machine, UNAME_MACHINE);
+                strcpy (buf->machine, cpu_to_uname_machine(cpu_env));
                 /* Allow the user to override the reported release.  */
                 if (qemu_uname_release && *qemu_uname_release)
                   strcpy (buf->release, qemu_uname_release);