Blackfin: add support for dynamic ftrace

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

Blackfin: add support for dynamic ftrace
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Mike Frysinger
1 parent 67df6cc665
Showing 5 changed files with 181 additions and 9 deletions Side-by-side Diff
arch/blackfin/Kconfig
arch/blackfin/include/asm/ftrace.h
arch/blackfin/kernel/Makefile
arch/blackfin/kernel/ftrace-entry.S
arch/blackfin/kernel/ftrace.c
@@ -25,6 +25,8 @@
 	def_bool y
 	select HAVE_ARCH_KGDB
 	select HAVE_ARCH_TRACEHOOK
+	select HAVE_DYNAMIC_FTRACE
+	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FUNCTION_TRACER
 	select HAVE_FUNCTION_TRACE_MCOUNT_TEST
@@ -12,6 +12,22 @@
  
 #ifndef __ASSEMBLY__
  
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+extern void _mcount(void);
+#define MCOUNT_ADDR ((unsigned long)_mcount)
+
+static inline unsigned long ftrace_call_adjust(unsigned long addr)
+{
+	return addr;
+}
+
+struct dyn_arch_ftrace {
+	/* No extra data needed for Blackfin */
+};
+
+#endif
+
 #ifdef CONFIG_FRAME_POINTER
 #include <linux/mm.h>
  
@@ -16,6 +16,7 @@
     obj-y += time.o
 endif
  
+obj-$(CONFIG_DYNAMIC_FTRACE)         += ftrace.o
 obj-$(CONFIG_FUNCTION_TRACER)        += ftrace-entry.o
 obj-$(CONFIG_FUNCTION_GRAPH_TRACER)  += ftrace.o
 CFLAGS_REMOVE_ftrace.o = -pg
@@ -10,6 +10,18 @@
  
 .text
  
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+/* Simple stub so we can boot the kernel until runtime patching has
+ * disabled all calls to this.  Then it'll be unused.
+ */
+ENTRY(__mcount)
+# if ANOMALY_05000371
+	nop; nop; nop; nop;
+# endif
+	rts;
+ENDPROC(__mcount)
+
 /* GCC will have called us before setting up the function prologue, so we
  * can clobber the normal scratch registers, but we need to make sure to
  * save/restore the registers used for argument passing (R0-R2) in case
  
  
@@ -20,15 +32,65 @@
  * function.  And since GCC pushed the previous RETS for us, the previous
  * function will be waiting there.  mmmm pie.
  */
+ENTRY(_ftrace_caller)
+# ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
+	/* optional micro optimization: return if stopped */
+	p1.l = _function_trace_stop;
+	p1.h = _function_trace_stop;
+	r3 = [p1];
+	cc = r3 == 0;
+	if ! cc jump _ftrace_stub (bp);
+# endif
+
+	/* save first/second/third function arg and the return register */
+	[--sp] = r2;
+	[--sp] = r0;
+	[--sp] = r1;
+	[--sp] = rets;
+
+	/* function_trace_call(unsigned long ip, unsigned long parent_ip):
+	 *  ip: this point was called by ...
+	 *  parent_ip: ... this function
+	 * the ip itself will need adjusting for the mcount call
+	 */
+	r0 = rets;
+	r1 = [sp + 16];	/* skip the 4 local regs on stack */
+	r0 += -MCOUNT_INSN_SIZE;
+
+.globl _ftrace_call
+_ftrace_call:
+	call _ftrace_stub
+
+# ifdef CONFIG_FUNCTION_GRAPH_TRACER
+.globl _ftrace_graph_call
+_ftrace_graph_call:
+	nop;	/* jump _ftrace_graph_caller; */
+# endif
+
+	/* restore state and get out of dodge */
+.Lfinish_trace:
+	rets = [sp++];
+	r1 = [sp++];
+	r0 = [sp++];
+	r2 = [sp++];
+
+.globl _ftrace_stub
+_ftrace_stub:
+	rts;
+ENDPROC(_ftrace_caller)
+
+#else
+
+/* See documentation for _ftrace_caller */
 ENTRY(__mcount)
-#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
+# ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 	/* optional micro optimization: return if stopped */
 	p1.l = _function_trace_stop;
 	p1.h = _function_trace_stop;
 	r3 = [p1];
 	cc = r3 == 0;
 	if ! cc jump _ftrace_stub (bp);
-#endif
+# endif
  
 	/* save third function arg early so we can do testing below */
 	[--sp] = r2;
@@ -44,7 +106,7 @@
 	cc = r2 == r3;
 	if ! cc jump .Ldo_trace;
  
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+# ifdef CONFIG_FUNCTION_GRAPH_TRACER
 	/* if the ftrace_graph_return function pointer is not set to
 	 * the ftrace_stub entry, call prepare_ftrace_return().
 	 */
@@ -64,7 +126,7 @@
 	r3 = [p0];
 	cc = r2 == r3;
 	if ! cc jump _ftrace_graph_caller;
-#endif
+# endif
  
 	r2 = [sp++];
 	rts;
@@ -103,6 +165,8 @@
 	rts;
 ENDPROC(__mcount)
  
+#endif
+
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 /* The prepare_ftrace_return() function is similar to the trace function
  * except it takes a pointer to the location of the frompc.  This is so
@@ -110,6 +174,7 @@
  * purposes.
  */
 ENTRY(_ftrace_graph_caller)
+# ifndef CONFIG_DYNAMIC_FTRACE
 	/* save first/second function arg and the return register */
 	[--sp] = r0;
 	[--sp] = r1;
  
@@ -118,9 +183,13 @@
 	/* prepare_ftrace_return(parent, self_addr, frame_pointer) */
 	r0 = sp;	/* unsigned long *parent */
 	r1 = rets;	/* unsigned long self_addr */
-#ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
+# else
+	r0 = sp;	/* unsigned long *parent */
+	r1 = [sp];	/* unsigned long self_addr */
+# endif
+# ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
 	r2 = fp;	/* unsigned long frame_pointer */
-#endif
+# endif
 	r0 += 16;	/* skip the 4 local regs on stack */
 	r1 += -MCOUNT_INSN_SIZE;
 	call _prepare_ftrace_return;
  
@@ -139,9 +208,9 @@
 	[--sp] = r1;
  
 	/* get original return address */
-#ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
+# ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
 	r0 = fp;	/* Blackfin is sane, so omit this */
-#endif
+# endif
 	call _ftrace_return_to_handler;
 	rets = r0;
  
 /*
  * ftrace graph code
  *
- * Copyright (C) 2009 Analog Devices Inc.
+ * Copyright (C) 2009-2010 Analog Devices Inc.
  * Licensed under the GPL-2 or later.
  */
  
 #include <linux/ftrace.h>
 #include <linux/kernel.h>
 #include <linux/sched.h>
+#include <linux/uaccess.h>
 #include <asm/atomic.h>
+#include <asm/cacheflush.h>
  
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+static const unsigned char mnop[] = {
+	0x03, 0xc0, 0x00, 0x18, /* MNOP; */
+	0x03, 0xc0, 0x00, 0x18, /* MNOP; */
+};
+
+static void bfin_make_pcrel24(unsigned char *insn, unsigned long src,
+                              unsigned long dst)
+{
+	uint32_t pcrel = (dst - src) >> 1;
+	insn[0] = pcrel >> 16;
+	insn[1] = 0xe3;
+	insn[2] = pcrel;
+	insn[3] = pcrel >> 8;
+}
+#define bfin_make_pcrel24(insn, src, dst) bfin_make_pcrel24(insn, src, (unsigned long)(dst))
+
+static int ftrace_modify_code(unsigned long ip, const unsigned char *code,
+                              unsigned long len)
+{
+	int ret = probe_kernel_write((void *)ip, (void *)code, len);
+	flush_icache_range(ip, ip + len);
+	return ret;
+}
+
+int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
+                    unsigned long addr)
+{
+	/* Turn the mcount call site into two MNOPs as those are 32bit insns */
+	return ftrace_modify_code(rec->ip, mnop, sizeof(mnop));
+}
+
+int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+	/* Restore the mcount call site */
+	unsigned char call[8];
+	call[0] = 0x67; /* [--SP] = RETS; */
+	call[1] = 0x01;
+	bfin_make_pcrel24(&call[2], rec->ip + 2, addr);
+	call[6] = 0x27; /* RETS = [SP++]; */
+	call[7] = 0x01;
+	return ftrace_modify_code(rec->ip, call, sizeof(call));
+}
+
+int ftrace_update_ftrace_func(ftrace_func_t func)
+{
+	unsigned char call[4];
+	unsigned long ip = (unsigned long)&ftrace_call;
+	bfin_make_pcrel24(call, ip, func);
+	return ftrace_modify_code(ip, call, sizeof(call));
+}
+
+int __init ftrace_dyn_arch_init(void *data)
+{
+	/* return value is done indirectly via data */
+	*(unsigned long *)data = 0;
+
+	return 0;
+}
+
+#endif
+
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+# ifdef CONFIG_DYNAMIC_FTRACE
+
+extern void ftrace_graph_call(void);
+
+int ftrace_enable_ftrace_graph_caller(void)
+{
+	unsigned long ip = (unsigned long)&ftrace_graph_call;
+	uint16_t jump_pcrel12 = ((unsigned long)&ftrace_graph_caller - ip) >> 1;
+	jump_pcrel12 |= 0x2000;
+	return ftrace_modify_code(ip, (void *)&jump_pcrel12, sizeof(jump_pcrel12));
+}
+
+int ftrace_disable_ftrace_graph_caller(void)
+{
+	return ftrace_modify_code((unsigned long)&ftrace_graph_call, empty_zero_page, 2);
+}
+
+# endif
  
 /*
  * Hook the return address and push it in the stack of return addrs
...	...	@@ -25,6 +25,8 @@
25	25	def_bool y
26	26	select HAVE_ARCH_KGDB
27	27	select HAVE_ARCH_TRACEHOOK
	28	+ select HAVE_DYNAMIC_FTRACE
	29	+ select HAVE_FTRACE_MCOUNT_RECORD
28	30	select HAVE_FUNCTION_GRAPH_TRACER
29	31	select HAVE_FUNCTION_TRACER
30	32	select HAVE_FUNCTION_TRACE_MCOUNT_TEST
...	...	@@ -12,6 +12,22 @@
12	12
13	13	#ifndef __ASSEMBLY__
14	14
	15	+#ifdef CONFIG_DYNAMIC_FTRACE
	16	+
	17	+extern void _mcount(void);
	18	+#define MCOUNT_ADDR ((unsigned long)_mcount)
	19	+
	20	+static inline unsigned long ftrace_call_adjust(unsigned long addr)
	21	+{
	22	+ return addr;
	23	+}
	24	+
	25	+struct dyn_arch_ftrace {
	26	+ /* No extra data needed for Blackfin */
	27	+};
	28	+
	29	+#endif
	30	+
15	31	#ifdef CONFIG_FRAME_POINTER
16	32	#include <linux/mm.h>
17	33
...	...	@@ -16,6 +16,7 @@
16	16	obj-y += time.o
17	17	endif
18	18
	19	+obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o
19	20	obj-$(CONFIG_FUNCTION_TRACER) += ftrace-entry.o
20	21	obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o
21	22	CFLAGS_REMOVE_ftrace.o = -pg
...	...	@@ -10,6 +10,18 @@
10	10
11	11	.text
12	12
	13	+#ifdef CONFIG_DYNAMIC_FTRACE
	14	+
	15	+/* Simple stub so we can boot the kernel until runtime patching has
	16	+ * disabled all calls to this. Then it'll be unused.
	17	+ */
	18	+ENTRY(__mcount)
	19	+# if ANOMALY_05000371
	20	+ nop; nop; nop; nop;
	21	+# endif
	22	+ rts;
	23	+ENDPROC(__mcount)
	24	+
13	25	/* GCC will have called us before setting up the function prologue, so we
14	26	* can clobber the normal scratch registers, but we need to make sure to
15	27	* save/restore the registers used for argument passing (R0-R2) in case
16	28
17	29
...	...	@@ -20,15 +32,65 @@
20	32	* function. And since GCC pushed the previous RETS for us, the previous
21	33	* function will be waiting there. mmmm pie.
22	34	*/
	35	+ENTRY(_ftrace_caller)
	36	+# ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
	37	+ /* optional micro optimization: return if stopped */
	38	+ p1.l = _function_trace_stop;
	39	+ p1.h = _function_trace_stop;
	40	+ r3 = [p1];
	41	+ cc = r3 == 0;
	42	+ if ! cc jump _ftrace_stub (bp);
	43	+# endif
	44	+
	45	+ /* save first/second/third function arg and the return register */
	46	+ [--sp] = r2;
	47	+ [--sp] = r0;
	48	+ [--sp] = r1;
	49	+ [--sp] = rets;
	50	+
	51	+ /* function_trace_call(unsigned long ip, unsigned long parent_ip):
	52	+ * ip: this point was called by ...
	53	+ * parent_ip: ... this function
	54	+ * the ip itself will need adjusting for the mcount call
	55	+ */
	56	+ r0 = rets;
	57	+ r1 = [sp + 16]; /* skip the 4 local regs on stack */
	58	+ r0 += -MCOUNT_INSN_SIZE;
	59	+
	60	+.globl _ftrace_call
	61	+_ftrace_call:
	62	+ call _ftrace_stub
	63	+
	64	+# ifdef CONFIG_FUNCTION_GRAPH_TRACER
	65	+.globl _ftrace_graph_call
	66	+_ftrace_graph_call:
	67	+ nop; /* jump _ftrace_graph_caller; */
	68	+# endif
	69	+
	70	+ /* restore state and get out of dodge */
	71	+.Lfinish_trace:
	72	+ rets = [sp++];
	73	+ r1 = [sp++];
	74	+ r0 = [sp++];
	75	+ r2 = [sp++];
	76	+
	77	+.globl _ftrace_stub
	78	+_ftrace_stub:
	79	+ rts;
	80	+ENDPROC(_ftrace_caller)
	81	+
	82	+#else
	83	+
	84	+/* See documentation for _ftrace_caller */
23	85	ENTRY(__mcount)
24		-#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
	86	+# ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
25	87	/* optional micro optimization: return if stopped */
26	88	p1.l = _function_trace_stop;
27	89	p1.h = _function_trace_stop;
28	90	r3 = [p1];
29	91	cc = r3 == 0;
30	92	if ! cc jump _ftrace_stub (bp);
31		-#endif
	93	+# endif
32	94
33	95	/* save third function arg early so we can do testing below */
34	96	[--sp] = r2;
...	...	@@ -44,7 +106,7 @@
44	106	cc = r2 == r3;
45	107	if ! cc jump .Ldo_trace;
46	108
47		-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
	109	+# ifdef CONFIG_FUNCTION_GRAPH_TRACER
48	110	/* if the ftrace_graph_return function pointer is not set to
49	111	* the ftrace_stub entry, call prepare_ftrace_return().
50	112	*/
...	...	@@ -64,7 +126,7 @@
64	126	r3 = [p0];
65	127	cc = r2 == r3;
66	128	if ! cc jump _ftrace_graph_caller;
67		-#endif
	129	+# endif
68	130
69	131	r2 = [sp++];
70	132	rts;
...	...	@@ -103,6 +165,8 @@
103	165	rts;
104	166	ENDPROC(__mcount)
105	167
	168	+#endif
	169	+
106	170	#ifdef CONFIG_FUNCTION_GRAPH_TRACER
107	171	/* The prepare_ftrace_return() function is similar to the trace function
108	172	* except it takes a pointer to the location of the frompc. This is so
...	...	@@ -110,6 +174,7 @@
110	174	* purposes.
111	175	*/
112	176	ENTRY(_ftrace_graph_caller)
	177	+# ifndef CONFIG_DYNAMIC_FTRACE
113	178	/* save first/second function arg and the return register */
114	179	[--sp] = r0;
115	180	[--sp] = r1;
116	181
...	...	@@ -118,9 +183,13 @@
118	183	/* prepare_ftrace_return(parent, self_addr, frame_pointer) */
119	184	r0 = sp; /* unsigned long parent /
120	185	r1 = rets; /* unsigned long self_addr */
121		-#ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
	186	+# else
	187	+ r0 = sp; /* unsigned long parent /
	188	+ r1 = [sp]; /* unsigned long self_addr */
	189	+# endif
	190	+# ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
122	191	r2 = fp; /* unsigned long frame_pointer */
123		-#endif
	192	+# endif
124	193	r0 += 16; /* skip the 4 local regs on stack */
125	194	r1 += -MCOUNT_INSN_SIZE;
126	195	call _prepare_ftrace_return;
127	196
...	...	@@ -139,9 +208,9 @@
139	208	[--sp] = r1;
140	209
141	210	/* get original return address */
142		-#ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
	211	+# ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
143	212	r0 = fp; /* Blackfin is sane, so omit this */
144		-#endif
	213	+# endif
145	214	call _ftrace_return_to_handler;
146	215	rets = r0;
147	216
1	1	/*
2	2	* ftrace graph code
3	3	*
4		- * Copyright (C) 2009 Analog Devices Inc.
	4	+ * Copyright (C) 2009-2010 Analog Devices Inc.
5	5	* Licensed under the GPL-2 or later.
6	6	*/
7	7
8	8	#include <linux/ftrace.h>
9	9	#include <linux/kernel.h>
10	10	#include <linux/sched.h>
	11	+#include <linux/uaccess.h>
11	12	#include <asm/atomic.h>
	13	+#include <asm/cacheflush.h>
12	14
	15	+#ifdef CONFIG_DYNAMIC_FTRACE
	16	+
	17	+static const unsigned char mnop[] = {
	18	+ 0x03, 0xc0, 0x00, 0x18, /* MNOP; */
	19	+ 0x03, 0xc0, 0x00, 0x18, /* MNOP; */
	20	+};
	21	+
	22	+static void bfin_make_pcrel24(unsigned char *insn, unsigned long src,
	23	+ unsigned long dst)
	24	+{
	25	+ uint32_t pcrel = (dst - src) >> 1;
	26	+ insn[0] = pcrel >> 16;
	27	+ insn[1] = 0xe3;
	28	+ insn[2] = pcrel;
	29	+ insn[3] = pcrel >> 8;
	30	+}
	31	+#define bfin_make_pcrel24(insn, src, dst) bfin_make_pcrel24(insn, src, (unsigned long)(dst))
	32	+
	33	+static int ftrace_modify_code(unsigned long ip, const unsigned char *code,
	34	+ unsigned long len)
	35	+{
	36	+ int ret = probe_kernel_write((void )ip, (void )code, len);
	37	+ flush_icache_range(ip, ip + len);
	38	+ return ret;
	39	+}
	40	+
	41	+int ftrace_make_nop(struct module mod, struct dyn_ftrace rec,
	42	+ unsigned long addr)
	43	+{
	44	+ /* Turn the mcount call site into two MNOPs as those are 32bit insns */
	45	+ return ftrace_modify_code(rec->ip, mnop, sizeof(mnop));
	46	+}
	47	+
	48	+int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
	49	+{
	50	+ /* Restore the mcount call site */
	51	+ unsigned char call[8];
	52	+ call[0] = 0x67; /* [--SP] = RETS; */
	53	+ call[1] = 0x01;
	54	+ bfin_make_pcrel24(&call[2], rec->ip + 2, addr);
	55	+ call[6] = 0x27; /* RETS = [SP++]; */
	56	+ call[7] = 0x01;
	57	+ return ftrace_modify_code(rec->ip, call, sizeof(call));
	58	+}
	59	+
	60	+int ftrace_update_ftrace_func(ftrace_func_t func)
	61	+{
	62	+ unsigned char call[4];
	63	+ unsigned long ip = (unsigned long)&ftrace_call;
	64	+ bfin_make_pcrel24(call, ip, func);
	65	+ return ftrace_modify_code(ip, call, sizeof(call));
	66	+}
	67	+
	68	+int __init ftrace_dyn_arch_init(void *data)
	69	+{
	70	+ /* return value is done indirectly via data */
	71	+ (unsigned long )data = 0;
	72	+
	73	+ return 0;
	74	+}
	75	+
	76	+#endif
	77	+
13	78	#ifdef CONFIG_FUNCTION_GRAPH_TRACER
	79	+
	80	+# ifdef CONFIG_DYNAMIC_FTRACE
	81	+
	82	+extern void ftrace_graph_call(void);
	83	+
	84	+int ftrace_enable_ftrace_graph_caller(void)
	85	+{
	86	+ unsigned long ip = (unsigned long)&ftrace_graph_call;
	87	+ uint16_t jump_pcrel12 = ((unsigned long)&ftrace_graph_caller - ip) >> 1;
	88	+ jump_pcrel12 \|= 0x2000;
	89	+ return ftrace_modify_code(ip, (void *)&jump_pcrel12, sizeof(jump_pcrel12));
	90	+}
	91	+
	92	+int ftrace_disable_ftrace_graph_caller(void)
	93	+{
	94	+ return ftrace_modify_code((unsigned long)&ftrace_graph_call, empty_zero_page, 2);
	95	+}
	96	+
	97	+# endif
14	98
15	99	/*
16	100	* Hook the return address and push it in the stack of return addrs