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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>
This commit is contained in:
Wu Zhangjin 2010-05-14 19:08:31 +08:00 committed by Ralf Baechle
parent 3a2af2dc1b
commit 4d6829f92a
1 changed files with 11 additions and 8 deletions
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19
arch/mips/kernel/ftrace.c
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@ -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 @@ int ftrace_make_nop(struct module *mod,
* 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 @@ int ftrace_make_nop(struct module *mod,
* 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 @@ int ftrace_make_nop(struct module *mod,
/* 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 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
/* 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 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
{
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_enable_ftrace_graph_caller(void)
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 */