MIPS: Provide arch_syscall_addr.

The generic version is wrong for MIPS.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/syscall.h

+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2012 Ralf Baechle <ralf@linux-mips.org>
+ */
+
+#ifndef __ASM_MIPS_SYSCALL_H
+#define __ASM_MIPS_SYSCALL_H
+
+extern const unsigned long sys_call_table[];
+extern const unsigned long sys32_call_table[];
+extern const unsigned long sysn32_call_table[];
+
+#endif	/* __ASM_MIPS_SYSCALL_H */

arch/mips/kernel/Makefile

@@ -35,6 +35,7 @@ obj-$(CONFIG_STACKTRACE)	+= stacktrace.o
 obj-$(CONFIG_MODULES)		+= mips_ksyms.o module.o
 obj-$(CONFIG_MODULES_USE_ELF_RELA) += module-rela.o
 
+obj-$(CONFIG_FTRACE_SYSCALLS)	+= ftrace.o
 obj-$(CONFIG_FUNCTION_TRACER)	+= mcount.o ftrace.o
 
 obj-$(CONFIG_CPU_R4K_FPU)	+= r4k_fpu.o r4k_switch.o

arch/mips/kernel/ftrace.c

@@ -11,11 +11,14 @@
 #include <linux/uaccess.h>
 #include <linux/init.h>
 #include <linux/ftrace.h>
+#include <linux/syscalls.h>
 
 #include <asm/asm.h>
 #include <asm/asm-offsets.h>
 #include <asm/cacheflush.h>
+#include <asm/syscall.h>
 #include <asm/uasm.h>
+#include <asm/unistd.h>
 
 #include <asm-generic/sections.h>
 
@@ -364,3 +367,33 @@ void prepare_ftrace_return(unsigned long *parent_ra_addr, unsigned long self_ra,
 	WARN_ON(1);
 }
 #endif	/* CONFIG_FUNCTION_GRAPH_TRACER */
+
+#ifdef CONFIG_FTRACE_SYSCALLS
+
+#ifdef CONFIG_32BIT
+unsigned long __init arch_syscall_addr(int nr)
+{
+	return (unsigned long)sys_call_table[nr - __NR_O32_Linux];
+}
+#endif
+
+#ifdef CONFIG_64BIT
+
+unsigned long __init arch_syscall_addr(int nr)
+{
+#ifdef CONFIG_MIPS32_N32
+	if (nr >= __NR_N32_Linux && nr <= __NR_N32_Linux + __NR_N32_Linux_syscalls)
+		return (unsigned long)sysn32_call_table[(nr - __NR_N32_Linux) * 2];
+#endif
+	if (nr >= __NR_64_Linux  && nr <= __NR_64_Linux + __NR_64_Linux_syscalls)
+		return (unsigned long)sys_call_table[nr - __NR_64_Linux];
+#ifdef CONFIG_MIPS32_O32
+	if (nr >= __NR_O32_Linux && nr <= __NR_O32_Linux + __NR_O32_Linux_syscalls)
+		return (unsigned long)sys32_call_table[nr - __NR_O32_Linux];
+#endif
+
+	return (unsigned long) &sys_ni_syscall;
+}
+#endif
+
+#endif /* CONFIG_FTRACE_SYSCALLS */