powerpc64, tracing: add function graph tracer with dynamic tracing
This is the port of the function graph tracer to PowerPC with
dynamic tracing.
Geoff Lavand tested on PS3.
Tested-by: Geoff Levand <geoffrey.levand@am.sony.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index e122d24..b298fb0 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -111,7 +111,7 @@
select HAVE_FTRACE_MCOUNT_RECORD
select HAVE_DYNAMIC_FTRACE
select HAVE_FUNCTION_TRACER
- select HAVE_FUNCTION_GRAPH_TRACER if !DYNAMIC_FTRACE && PPC64
+ select HAVE_FUNCTION_GRAPH_TRACER if PPC64
select ARCH_WANT_OPTIONAL_GPIOLIB
select HAVE_IDE
select HAVE_IOREMAP_PROT
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index a32699e..9f61fd6 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -908,6 +908,12 @@
ftrace_call:
bl ftrace_stub
nop
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+.globl ftrace_graph_call
+ftrace_graph_call:
+ b ftrace_graph_stub
+_GLOBAL(ftrace_graph_stub)
+#endif
ld r0, 128(r1)
mtlr r0
addi r1, r1, 112
@@ -946,7 +952,7 @@
#endif /* CONFIG_DYNAMIC_FTRACE */
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-ftrace_graph_caller:
+_GLOBAL(ftrace_graph_caller)
/* load r4 with local address */
ld r4, 128(r1)
subi r4, r4, MCOUNT_INSN_SIZE
diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index c9b1547..7538b94 100644
--- a/arch/powerpc/kernel/ftrace.c
+++ b/arch/powerpc/kernel/ftrace.c
@@ -43,7 +43,8 @@
return (char *)&ftrace_nop;
}
-static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
+static unsigned char *
+ftrace_call_replace(unsigned long ip, unsigned long addr, int link)
{
static unsigned int op;
@@ -55,8 +56,9 @@
*/
addr = GET_ADDR(addr);
- /* Set to "bl addr" */
- op = 0x48000001 | (ftrace_calc_offset(ip, addr) & 0x03fffffc);
+ /* if (link) set op to 'bl' else 'b' */
+ op = 0x48000000 | (link ? 1 : 0);
+ op |= (ftrace_calc_offset(ip, addr) & 0x03fffffc);
/*
* No locking needed, this must be called via kstop_machine
@@ -344,7 +346,7 @@
*/
if (test_24bit_addr(ip, addr)) {
/* within range */
- old = ftrace_call_replace(ip, addr);
+ old = ftrace_call_replace(ip, addr, 1);
new = ftrace_nop_replace();
return ftrace_modify_code(ip, old, new);
}
@@ -484,7 +486,7 @@
if (test_24bit_addr(ip, addr)) {
/* within range */
old = ftrace_nop_replace();
- new = ftrace_call_replace(ip, addr);
+ new = ftrace_call_replace(ip, addr, 1);
return ftrace_modify_code(ip, old, new);
}
@@ -513,7 +515,7 @@
int ret;
memcpy(old, &ftrace_call, MCOUNT_INSN_SIZE);
- new = ftrace_call_replace(ip, (unsigned long)func);
+ new = ftrace_call_replace(ip, (unsigned long)func, 1);
ret = ftrace_modify_code(ip, old, new);
return ret;
@@ -532,6 +534,39 @@
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+#ifdef CONFIG_DYNAMIC_FTRACE
+extern void ftrace_graph_call(void);
+extern void ftrace_graph_stub(void);
+
+int ftrace_enable_ftrace_graph_caller(void)
+{
+ unsigned long ip = (unsigned long)(&ftrace_graph_call);
+ unsigned long addr = (unsigned long)(&ftrace_graph_caller);
+ unsigned long stub = (unsigned long)(&ftrace_graph_stub);
+ unsigned char old[MCOUNT_INSN_SIZE], *new;
+
+ new = ftrace_call_replace(ip, stub, 0);
+ memcpy(old, new, MCOUNT_INSN_SIZE);
+ new = ftrace_call_replace(ip, addr, 0);
+
+ return ftrace_modify_code(ip, old, new);
+}
+
+int ftrace_disable_ftrace_graph_caller(void)
+{
+ unsigned long ip = (unsigned long)(&ftrace_graph_call);
+ unsigned long addr = (unsigned long)(&ftrace_graph_caller);
+ unsigned long stub = (unsigned long)(&ftrace_graph_stub);
+ unsigned char old[MCOUNT_INSN_SIZE], *new;
+
+ new = ftrace_call_replace(ip, addr, 0);
+ memcpy(old, new, MCOUNT_INSN_SIZE);
+ new = ftrace_call_replace(ip, stub, 0);
+
+ return ftrace_modify_code(ip, old, new);
+}
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
/*
* Hook the return address and push it in the stack of return addrs
* in current thread info.