sparc64: add ftrace support.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

5 files changed, 156 insertions, 5 deletions

diff --git a/arch/sparc64/Kconfig b/arch/sparc64/Kconfig
index eb36f3b746b8..a480df6e6012 100644
--- a/arch/sparc64/Kconfig
+++ b/arch/sparc64/Kconfig
@@ -11,6 +11,7 @@ config SPARC
 config SPARC64
 	bool
 	default y
+	select HAVE_FTRACE
 	select HAVE_IDE
 	select HAVE_LMB
 	select HAVE_ARCH_KGDB
diff --git a/arch/sparc64/Kconfig.debug b/arch/sparc64/Kconfig.debug
index 6a4d28a4076d..d6d32d178fc8 100644
--- a/arch/sparc64/Kconfig.debug
+++ b/arch/sparc64/Kconfig.debug
@@ -33,7 +33,7 @@ config DEBUG_PAGEALLOC
 
 config MCOUNT
 	bool
-	depends on STACK_DEBUG
+	depends on STACK_DEBUG || FTRACE
 	default y
 
 config FRAME_POINTER
diff --git a/arch/sparc64/kernel/Makefile b/arch/sparc64/kernel/Makefile
index ec4f5ebb1ca6..418b5782096e 100644
--- a/arch/sparc64/kernel/Makefile
+++ b/arch/sparc64/kernel/Makefile
@@ -14,6 +14,7 @@ obj-y		:= process.o setup.o cpu.o idprom.o \
 		   power.o sbus.o sparc64_ksyms.o chmc.o \
 		   visemul.o prom.o of_device.o hvapi.o sstate.o mdesc.o
 
+obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o
 obj-$(CONFIG_STACKTRACE) += stacktrace.o
 obj-$(CONFIG_PCI)	 += ebus.o pci_common.o \
 			    pci_psycho.o pci_sabre.o pci_schizo.o \
diff --git a/arch/sparc64/kernel/ftrace.c b/arch/sparc64/kernel/ftrace.c
new file mode 100644
index 000000000000..f449e6df6c4a
--- /dev/null
+++ b/arch/sparc64/kernel/ftrace.c
@@ -0,0 +1,99 @@
+#include <linux/spinlock.h>
+#include <linux/hardirq.h>
+#include <linux/ftrace.h>
+#include <linux/percpu.h>
+#include <linux/init.h>
+#include <linux/list.h>
+
+static const u32 ftrace_nop = 0x01000000;
+
+notrace int ftrace_ip_converted(unsigned long ip)
+{
+	u32 insn = *(u32 *) ip;
+
+	return (insn == ftrace_nop);
+}
+
+notrace unsigned char *ftrace_nop_replace(void)
+{
+	return (char *)&ftrace_nop;
+}
+
+notrace unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
+{
+	static u32 call;
+	s32 off;
+
+	off = ((s32)addr - (s32)ip);
+	call = 0x40000000 | ((u32)off >> 2);
+
+	return (unsigned char *) &call;
+}
+
+notrace int
+ftrace_modify_code(unsigned long ip, unsigned char *old_code,
+		   unsigned char *new_code)
+{
+	u32 old = *(u32 *)old_code;
+	u32 new = *(u32 *)new_code;
+	u32 replaced;
+	int faulted;
+
+	__asm__ __volatile__(
+	"1:	cas	[%[ip]], %[old], %[new]\n"
+	"	flush	%[ip]\n"
+	"	mov	0, %[faulted]\n"
+	"2:\n"
+	"	.section .fixup,#alloc,#execinstr\n"
+	"	.align	4\n"
+	"3:	sethi	%%hi(2b), %[faulted]\n"
+	"	jmpl	%[faulted] + %%lo(2b), %%g0\n"
+	"	 mov	1, %[faulted]\n"
+	"	.previous\n"
+	"	.section __ex_table,\"a\"\n"
+	"	.align	4\n"
+	"	.word	1b, 3b\n"
+	"	.previous\n"
+	: "=r" (replaced), [faulted] "=r" (faulted)
+	: [new] "0" (new), [old] "r" (old), [ip] "r" (ip)
+	: "memory");
+
+	if (replaced != old && replaced != new)
+		faulted = 2;
+
+	return faulted;
+}
+
+notrace int ftrace_update_ftrace_func(ftrace_func_t func)
+{
+	unsigned long ip = (unsigned long)(&ftrace_call);
+	unsigned char old[4], *new;
+
+	memcpy(old, &ftrace_call, 4);
+	new = ftrace_call_replace(ip, (unsigned long)func);
+	return ftrace_modify_code(ip, old, new);
+}
+
+notrace int ftrace_mcount_set(unsigned long *data)
+{
+	unsigned long ip = (long)(&mcount_call);
+	unsigned long *addr = data;
+	unsigned char old[4], *new;
+
+	/*
+	 * Replace the mcount stub with a pointer to the
+	 * ip recorder function.
+	 */
+	memcpy(old, &mcount_call, 4);
+	new = ftrace_call_replace(ip, *addr);
+	*addr = ftrace_modify_code(ip, old, new);
+
+	return 0;
+}
+
+
+int __init ftrace_dyn_arch_init(void *data)
+{
+	ftrace_mcount_set(data);
+	return 0;
+}
diff --git a/arch/sparc64/lib/mcount.S b/arch/sparc64/lib/mcount.S
index 9e4534b485c7..7735a7a60533 100644
--- a/arch/sparc64/lib/mcount.S
+++ b/arch/sparc64/lib/mcount.S
@@ -28,10 +28,13 @@ ovstack:
 	.skip		OVSTACKSIZE
 #endif
 	.text
-	.align 32
-	.globl mcount, _mcount
-mcount:
+	.align		32
+	.globl		_mcount
+	.type		_mcount,#function
+	.globl		mcount
+	.type		mcount,#function
 _mcount:
+mcount:
 #ifdef CONFIG_STACK_DEBUG
 	/*
 	 * Check whether %sp is dangerously low.
@@ -55,6 +58,53 @@ _mcount:
 	 or		%g3, %lo(panicstring), %o0
 	call		prom_halt
 	 nop
+1:
+#endif
+#ifdef CONFIG_FTRACE
+#ifdef CONFIG_DYNAMIC_FTRACE
+	mov		%o7, %o0
+	.globl		mcount_call
+mcount_call:
+	call		ftrace_stub
+	 mov		%o0, %o7
+#else
+	sethi		%hi(ftrace_trace_function), %g1
+	sethi		%hi(ftrace_stub), %g2
+	ldx		[%g1 + %lo(ftrace_trace_function)], %g1
+	or		%g2, %lo(ftrace_stub), %g2
+	cmp		%g1, %g2
+	be,pn		%icc, 1f
+	 mov		%i7, %o1
+	jmpl		%g1, %g0
+	 mov		%o7, %o0
+	/* not reached */
+1:
 #endif
-1:	retl
+#endif
+	retl
 	 nop
+	.size		_mcount,.-_mcount
+	.size		mcount,.-mcount
+
+#ifdef CONFIG_FTRACE
+	.globl		ftrace_stub
+	.type		ftrace_stub,#function
+ftrace_stub:
+	retl
+	 nop
+	.size		ftrace_stub,.-ftrace_stub
+#ifdef CONFIG_DYNAMIC_FTRACE
+	.globl		ftrace_caller
+	.type		ftrace_caller,#function
+ftrace_caller:
+	mov		%i7, %o1
+	mov		%o7, %o0
+	.globl		ftrace_call
+ftrace_call:
+	call		ftrace_stub
+	 mov		%o0, %o7
+	retl
+	 nop
+	.size		ftrace_caller,.-ftrace_caller
+#endif
+#endif