Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 4d6829f9 authored by Wu Zhangjin's avatar Wu Zhangjin Committed by Ralf Baechle
Browse files

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: default avatarWu 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: default avatarRalf Baechle <ralf@linux-mips.org>
parent 3a2af2dc

arch/mips/kernel/ftrace.c

+11 −8
Original line number Diff line number Diff line
@@ -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 */