MIPS: Tracing: Cleanup of instructions used
This patch adds some cleanups of the instructions:
o use macros instead of magic numbers
o use macros instead of variables to reduce some overhead
o add new macro for the jal instruction
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips <linux-mips@linux-mips.org>
Cc: David Daney <david.s.daney@gmail.com>
Patchwork: http://patchwork.linux-mips.org/patch/1229/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c
index 37aa767..b1b8fec 100644
--- a/arch/mips/kernel/ftrace.c
+++ b/arch/mips/kernel/ftrace.c
@@ -23,7 +23,10 @@
#define jump_insn_encode(op_code, addr) \
((unsigned int)((op_code) | (((addr) >> 2) & ADDR_MASK)))
-static unsigned int ftrace_nop = 0x00000000;
+#define INSN_B_1F_4 0x10000004 /* b 1f; offset = 4 */
+#define INSN_B_1F_5 0x10000005 /* b 1f; offset = 5 */
+#define INSN_NOP 0x00000000 /* nop */
+#define INSN_JAL(addr) jump_insn_encode(JAL, addr)
static int ftrace_modify_code(unsigned long ip, unsigned int new_code)
{
@@ -71,7 +74,7 @@
* sub sp, sp, 8
* 1: offset = 5 instructions
*/
- new = 0x10000005;
+ new = INSN_B_1F_5;
#else
/* lui v1, hi_16bit_of_mcount --> b 1f (0x10000004)
* addiu v1, v1, low_16bit_of_mcount
@@ -80,7 +83,7 @@
* nop | move $12, ra_address | sub sp, sp, 8
* 1: offset = 4 instructions
*/
- new = 0x10000004;
+ new = INSN_B_1F_4;
#endif
} else {
/* record/calculate it for ftrace_make_call */
@@ -88,13 +91,13 @@
/* We can record it directly like this:
* jal_mcount = *(unsigned int *)ip;
* Herein, jump over the first two nop instructions */
- jal_mcount = jump_insn_encode(JAL, (MCOUNT_ADDR + 8));
+ jal_mcount = INSN_JAL(MCOUNT_ADDR + 8);
}
/* move at, ra
* jalr v1 --> nop
*/
- new = ftrace_nop;
+ new = INSN_NOP;
}
return ftrace_modify_code(ip, new);
}
@@ -109,7 +112,7 @@
/* We just need to remove the "b ftrace_stub" at the fist time! */
if (modified == 0) {
modified = 1;
- ftrace_modify_code(addr, ftrace_nop);
+ ftrace_modify_code(addr, INSN_NOP);
}
/* ip, module: 0xc0000000, kernel: 0x80000000 */
new = (ip & 0x40000000) ? lui_v1 : jal_mcount;
@@ -123,7 +126,7 @@
{
unsigned int new;
- new = jump_insn_encode(JAL, (unsigned long)func);
+ new = INSN_JAL((unsigned long)func);
return ftrace_modify_code(FTRACE_CALL_IP, new);
}
@@ -155,7 +158,7 @@
int ftrace_disable_ftrace_graph_caller(void)
{
- return ftrace_modify_code(FTRACE_GRAPH_CALL_IP, ftrace_nop);
+ return ftrace_modify_code(FTRACE_GRAPH_CALL_IP, INSN_NOP);
}
#endif /* !CONFIG_DYNAMIC_FTRACE */