[PATCH 2/7] ftrace, ppc: convert to new dynamic ftrace arch API

Steven Rostedt
2008-11-16T21:25:29Z

[-- Attachment #1: 0002-ftrace-ppc-convert-to-new-dynamic-ftrace-arch-API.patch --]
[-- Type: text/plain, Size: 3508 bytes --]

Impact: change PPC to use new ftrace arch API

This patch converts PPC to use the new dynamic ftrace arch API.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
---
arch/powerpc/include/asm/ftrace.h | 14 ++++++++-
arch/powerpc/kernel/ftrace.c | 60 +++++++++++++++++++++++++++++++++---
2 files changed, 68 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h
index b298f7a..17efecc 100644
--- a/arch/powerpc/include/asm/ftrace.h
+++ b/arch/powerpc/include/asm/ftrace.h
@@ -7,7 +7,19 @@

#ifndef __ASSEMBLY__
extern void _mcount(void);
-#endif
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+static inline unsigned long ftrace_call_adjust(unsigned long addr)
+{
+ /* reloction of mcount call site is the same as the address */
+ return addr;
+}
+
+struct dyn_arch_ftrace {
+ /* nothing yet */
+};
+#endif /* CONFIG_DYNAMIC_FTRACE */
+#endif /* __ASSEMBLY__ */

#endif

diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index f4b006e..aa5d0b2 100644
--- a/arch/powerpc/kernel/ftrace.c
+++ b/arch/powerpc/kernel/ftrace.c
@@ -33,12 +33,12 @@ static unsigned int ftrace_calc_offset(long ip, long addr)
return (int)(addr - ip);
}

-unsigned char *ftrace_nop_replace(void)
+static unsigned char *ftrace_nop_replace(void)
{
return (char *)&ftrace_nop;
}

-unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
+static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
{
static unsigned int op;

@@ -68,7 +68,7 @@ unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
# define _ASM_PTR " .long "
#endif

-int
+static int
ftrace_modify_code(unsigned long ip, unsigned char *old_code,
unsigned char *new_code)
{
@@ -113,6 +113,55 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code,
return faulted;
}

+static int test_24bit_addr(unsigned long ip, unsigned long addr)
+{
+ unsigned long diff;
+
+ /* can we get to addr from ip in 24 bits? */
+ diff = ip > addr ? ip - addr : addr - ip;
+
+ return !(diff & ((unsigned long)-1 << 24));
+}
+
+int ftrace_make_nop(struct module *mod,
+ struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned char *old, *new;
+
+ /*
+ * If the calling address is more that 24 bits away,
+ * then we had to use a trampoline to make the call.
+ * Otherwise just update the call site.
+ */
+ if (test_24bit_addr(rec->ip, addr)) {
+ /* within range */
+ old = ftrace_call_replace(rec->ip, addr);
+ new = ftrace_nop_replace();
+ return ftrace_modify_code(rec->ip, old, new);
+ }
+
+ return 0;
+}
+
+int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned char *old, *new;
+
+ /*
+ * If the calling address is more that 24 bits away,
+ * then we had to use a trampoline to make the call.
+ * Otherwise just update the call site.
+ */
+ if (test_24bit_addr(rec->ip, addr)) {
+ /* within range */
+ old = ftrace_nop_replace();
+ new = ftrace_call_replace(rec->ip, addr);
+ return ftrace_modify_code(rec->ip, old, new);
+ }
+
+ return 0;
+}
+
int ftrace_update_ftrace_func(ftrace_func_t func)
{
unsigned long ip = (unsigned long)(&ftrace_call);
@@ -128,9 +177,10 @@ int ftrace_update_ftrace_func(ftrace_func_t func)

int __init ftrace_dyn_arch_init(void *data)
{
- /* This is running in kstop_machine */
+ /* caller expects data to be zero */
+ unsigned long *p = data;

- ftrace_mcount_set(data);
+ *p = 0;

return 0;
}
--
1.5.6.5

--