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authorMike Frysinger <vapier@gentoo.org>2010-07-21 09:13:02 -0400
committerMike Frysinger <vapier@gentoo.org>2010-08-06 12:55:54 -0400
commitf5074429621ceb0ec42f8116bd51d02c031faf82 (patch)
treea5d22f85446c63be25961e2ea04321e197c615db /arch/blackfin/kernel
parent67df6cc665dc3441bf5eb2ad7018e969463a2588 (diff)
downloadlinux-2.6.38-lt-ux500-f5074429621ceb0ec42f8116bd51d02c031faf82.tar.gz
Blackfin: add support for dynamic ftrace
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Diffstat (limited to 'arch/blackfin/kernel')
-rw-r--r--arch/blackfin/kernel/Makefile1
-rw-r--r--arch/blackfin/kernel/ftrace-entry.S85
-rw-r--r--arch/blackfin/kernel/ftrace.c86
3 files changed, 163 insertions, 9 deletions
diff --git a/arch/blackfin/kernel/Makefile b/arch/blackfin/kernel/Makefile
index 30d0d1f01dc..ca5ccc77777 100644
--- a/arch/blackfin/kernel/Makefile
+++ b/arch/blackfin/kernel/Makefile
@@ -16,6 +16,7 @@ else
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
diff --git a/arch/blackfin/kernel/ftrace-entry.S b/arch/blackfin/kernel/ftrace-entry.S
index d66446b572c..7eed00bbd26 100644
--- a/arch/blackfin/kernel/ftrace-entry.S
+++ b/arch/blackfin/kernel/ftrace-entry.S
@@ -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 @@ ENTRY(__mcount)
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 @@ ENTRY(__mcount)
r3 = [p0];
cc = r2 == r3;
if ! cc jump _ftrace_graph_caller;
-#endif
+# endif
r2 = [sp++];
rts;
@@ -103,6 +165,8 @@ _ftrace_stub:
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 @@ ENDPROC(__mcount)
* 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 @@ ENTRY(_ftrace_graph_caller)
/* 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 @@ ENTRY(_return_to_handler)
[--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;
diff --git a/arch/blackfin/kernel/ftrace.c b/arch/blackfin/kernel/ftrace.c
index a61d948ea92..48808a12b42 100644
--- a/arch/blackfin/kernel/ftrace.c
+++ b/arch/blackfin/kernel/ftrace.c
@@ -1,17 +1,101 @@
/*
* 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
* in current thread info.