Re: [Qemu-devel] [PATCH] linux-user: adapt uname machine to emulated CPU

[Riku Voipio <riku.voipio@iki.fi>]

Hi,

Works great, thanks.

Acked-By: Riku Voipio <riku.voipio@iki.fi>

On Tue, Dec 29, 2009 at 10:39:21PM +0100, Loïc Minier wrote:
>         Hey there
> 
>  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.
> 
>    Thanks,
> 
> 
> ---
>  Makefile.target        |    2 +-
>  linux-user/cpu-uname.c |   72 ++++++++++++++++++++++++++++++++++++++++++++++++
>  linux-user/cpu-uname.h |    1 +
>  linux-user/syscall.c   |    3 +-
>  4 files changed, 76 insertions(+), 2 deletions(-)
>  create mode 100644 linux-user/cpu-uname.c
>  create mode 100644 linux-user/cpu-uname.h
> 
> diff --git a/Makefile.target b/Makefile.target
> index 7c1f30c..6414472 100644
> --- a/Makefile.target
> +++ b/Makefile.target
> @@ -90,7 +90,7 @@ ifdef CONFIG_LINUX_USER
>  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
> diff --git a/linux-user/cpu-uname.c b/linux-user/cpu-uname.c
> new file mode 100644
> index 0000000..ddc37be
> --- /dev/null
> +++ b/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
> +}
> diff --git a/linux-user/cpu-uname.h b/linux-user/cpu-uname.h
> new file mode 100644
> index 0000000..32492de
> --- /dev/null
> +++ b/linux-user/cpu-uname.h
> @@ -0,0 +1 @@
> +const char *cpu_to_uname_machine(void *cpu_env);
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 1acf1f5..9e2e89a 100644
> --- a/linux-user/syscall.c
> +++ b/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);
> -- 
> 1.6.5
> 
> 
> -- 
> Loïc Minier
>