qemu_sh4_r2d: update to kernel 3.1 and update readme

diff --git a/arch/sh/include/asm/syscalls_32.h b/arch/sh/include/asm/syscalls_32.h

index be201fd..454538a 100644

--- a/arch/sh/include/asm/syscalls_32.h

+++ b/arch/sh/include/asm/syscalls_32.h

@@ -19,8 +19,10 @@ asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,

 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,

 			 unsigned long r6, unsigned long r7,

 			 struct pt_regs __regs);

-asmlinkage int sys_execve(const char __user *ufilename, char __user * __user *uargv,

-			  char __user * __user *uenvp, unsigned long r7,

+asmlinkage int sys_execve(const char __user *ufilename,

+			  const char __user *const __user *uargv,

+			  const char __user *const __user *uenvp,

+			  unsigned long r7,

 			  struct pt_regs __regs);

 asmlinkage int sys_sigsuspend(old_sigset_t mask, unsigned long r5,

 			      unsigned long r6, unsigned long r7,

diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig

index 33990fa..06645b6 100644

--- a/arch/sh/Kconfig

+++ b/arch/sh/Kconfig

@@ -45,7 +45,7 @@ config SUPERH32

 	select HAVE_ARCH_KGDB

 	select HAVE_HW_BREAKPOINT

 	select HAVE_MIXED_BREAKPOINTS_REGS

-	select PERF_EVENTS if HAVE_HW_BREAKPOINT

+	select PERF_EVENTS

 	select ARCH_HIBERNATION_POSSIBLE if MMU

 config SUPERH64

This little documentation explains how to build a kernel and a rootfs

for qemu with sh4 architecture.

Run the emulation with:

1) Select qemu sh4 configuration and compile it :

  qemu-system-sh4 -M r2d -kernel output/images/zImage -drive file=output/images/rootfs.ext2,if=ide -append "root=/dev/sda noiotrap"

make sh4_defconfig

make all

2) Run qemu-system-sh4 with the kernel and rootfs previously generated

It's recommended to use a git release for qemu (the current stable

version has framebuffer display issues). If you want to avoid building

all target, you can use this option on qemu configure :

--target-list=sh4-softmmu

The command is :

qemu-system-sh4 -M r2d -kernel output/images/zImage -drive file=output/images/rootfs.ext2,if=ide,format=raw -append root=/dev/sda console=ttySC1,115200 noiotrap

The login prompt will appear in the graphical window.

BR2_sh=y

BR2_sh4=y

# system

BR2_TARGET_GENERIC_GETTY=y

BR2_TARGET_GENERIC_GETTY_PORT="tty1"

# filesystem

BR2_TARGET_ROOTFS_EXT2=y

# BR2_TARGET_ROOTFS_TAR is not set

# Linux kernel

BR2_LINUX_KERNEL=y

BR2_LINUX_KERNEL_CUSTOM_VERSION=y

BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="2.6.36"

BR2_LINUX_KERNEL_PATCH="board/qemu/sh4-r2d/kernel-patches/"

BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="3.1"

BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y

BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/qemu/sh4-r2d/linux-2.6.36.config"

BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/qemu/sh4-r2d/linux-3.1.config"

BR2_LINUX_KERNEL_ZIMAGE=y