From: Wu Zhangjin <wuzhangjin@xxxxxxxxx>
For 32bit kernel, the -mmcount-ra-address option of gcc 4.5 has
introduced one more instruction before calling to _mcount, so we need to
use a different "b 1f" for it.
Signed-off-by: Wu Zhangjin <wuzhangjin@xxxxxxxxx>
---
arch/mips/kernel/ftrace.c | 16 ++++++++++++++--
1 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c
index e9e64e0..37aa767 100644
--- a/arch/mips/kernel/ftrace.c
+++ b/arch/mips/kernel/ftrace.c
@@ -62,14 +62,26 @@ int ftrace_make_nop(struct module *mod,
return -EFAULT;
}
+#if defined(KBUILD_MCOUNT_RA_ADDRESS) && defined(CONFIG_32BIT)
+ /* lui v1, hi_16bit_of_mcount --> b 1f (0x10000005)
+ * addiu v1, v1, low_16bit_of_mcount
+ * move at, ra
+ * move $12, ra_address
+ * jalr v1
+ * sub sp, sp, 8
+ * 1: offset = 5 instructions
+ */
+ new = 0x10000005;
+#else
/* lui v1, hi_16bit_of_mcount --> b 1f (0x10000004)
* addiu v1, v1, low_16bit_of_mcount
* move at, ra
* jalr v1
- * nop
- * 1f: (ip + 12)
+ * nop | move $12, ra_address | sub sp, sp, 8
+ * 1: offset = 4 instructions
*/
new = 0x10000004;
+#endif
} else {
/* record/calculate it for ftrace_make_call */
if (jal_mcount == 0) {
--
1.7.0.4
