sh: ftrace support.

This adds support for ftrace to SH. This only includes CONFIG_FTRACE,
and does not handle dynamic ftrace presently.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/Kconfig

@@ -24,6 +24,7 @@ config SUPERH32
 	select HAVE_KPROBES
 	select HAVE_KRETPROBES
 	select HAVE_ARCH_TRACEHOOK if !SH_FPU
+	select HAVE_FTRACE
 
 config SUPERH64
 	def_bool y if CPU_SH5

arch/sh/boot/compressed/Makefile_32

@@ -23,6 +23,11 @@ IMAGE_OFFSET	:= $(shell /bin/bash -c 'printf "0x%08x" \
 
 LIBGCC	:= $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
 
+ifeq ($(CONFIG_FTRACE),y)
+ORIG_CFLAGS := $(KBUILD_CFLAGS)
+KBUILD_CFLAGS = $(subst -pg, , $(ORIG_CFLAGS))
+endif
+
 LDFLAGS_vmlinux := -Ttext $(IMAGE_OFFSET) -e startup -T $(obj)/../../kernel/vmlinux.lds
 
 $(obj)/vmlinux: $(OBJECTS) $(obj)/piggy.o $(LIBGCC) FORCE

arch/sh/kernel/entry-common.S

@@ -371,3 +371,47 @@ syscall_exit:
 #endif
 7:	.long	do_syscall_trace_enter
 8:	.long	do_syscall_trace_leave
+
+#ifdef CONFIG_FTRACE
+	.align 2
+	.globl	_mcount
+	.type	_mcount,@function
+	.globl	mcount
+	.type	mcount,@function
+_mcount:
+mcount:
+	mov.l	r4, @-r15
+	mov.l	r5, @-r15
+	mov.l	r6, @-r15
+	mov.l	r7, @-r15
+	sts.l	pr, @-r15
+
+	mov.l	@(20,r15),r4
+	sts	pr, r5
+
+	mov.l	1f, r6
+	mov.l	ftrace_stub, r7	
+	cmp/eq	r6, r7
+	bt	skip_trace
+
+	mov.l	@r6, r6
+	jsr	@r6
+	 nop
+
+skip_trace:
+
+	lds.l	@r15+, pr
+	mov.l	@r15+, r7
+	mov.l	@r15+, r6
+	mov.l	@r15+, r5
+	rts
+	 mov.l	@r15+, r4
+
+	.align 2
+1:	.long	ftrace_trace_function
+
+	.globl	ftrace_stub
+ftrace_stub:
+	rts
+	 nop
+#endif /* CONFIG_FTRACE */

arch/sh/kernel/sh_ksyms_32.c

@@ -16,6 +16,7 @@
 #include <asm/delay.h>
 #include <asm/tlbflush.h>
 #include <asm/cacheflush.h>
+#include <asm/ftrace.h>
 
 extern int dump_fpu(struct pt_regs *, elf_fpregset_t *);
 extern struct hw_interrupt_type no_irq_type;
@@ -133,6 +134,9 @@ EXPORT_SYMBOL(__flush_purge_region);
 EXPORT_SYMBOL(clear_user_page);
 #endif
 
+#ifdef CONFIG_FTRACE
+EXPORT_SYMBOL(mcount);
+#endif
 EXPORT_SYMBOL(csum_partial);
 EXPORT_SYMBOL(csum_partial_copy_generic);
 #ifdef CONFIG_IPV6