Commit 50886234 authored by Jinyang He's avatar Jinyang He Committed by Thomas Bogendoerfer
Browse files

MIPS: Add is_jr_ra_ins() to end the loop early 



For those leaf functions, they are likely to have no stack operations.
Add is_jr_ra_ins() to determine whether jr ra has been touched before
the frame_size is found. Without this patch, the get frame_size operation
may be out of range and get the frame_size from the next nested function.

There is no POOL32A format in uapi/asm/inst.h, so some bits here use the
format of r_format instead.
e.g.
---------------------------------------------------------------------
|    format      |  31:26  | 25:21 | 20:16 |    15:6    |    5:0    |
-----------------+---------+-------+-------+------------+------------
| pool32a_format | pool32a |  rt   |  rs   |   jalrc    | pool32axf |
-----------------+---------+-------+-------+------------+------------
|    r_format    |  opcode |  rs   |  rt   | rd:5, re:5 |    func   |
---------------------------------------------------------------------

Signed-off-by: default avatarJinyang He <hejinyang@loongson.cn>
Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
parent 2d62f64b

arch/mips/kernel/process.c

+33 −1
Original line number Diff line number Diff line
@@ -188,6 +188,36 @@ struct mips_frame_info { 
#define J_TARGET(pc,target)	\

		(((unsigned long)(pc) & 0xf0000000) | ((target) << 2))



static inline int is_jr_ra_ins(union mips_instruction *ip)

{

#ifdef CONFIG_CPU_MICROMIPS

	/*

	 * jr16 ra

	 * jr ra

	 */

	if (mm_insn_16bit(ip->word >> 16)) {

		if (ip->mm16_r5_format.opcode == mm_pool16c_op &&

		    ip->mm16_r5_format.rt == mm_jr16_op &&

		    ip->mm16_r5_format.imm == 31)

			return 1;

		return 0;

	}



	if (ip->r_format.opcode == mm_pool32a_op &&

	    ip->r_format.func == mm_pool32axf_op &&

	    ((ip->u_format.uimmediate >> 6) & GENMASK(9, 0)) == mm_jalr_op &&

	    ip->r_format.rt == 31)

		return 1;

	return 0;

#else

	if (ip->r_format.opcode == spec_op &&

	    ip->r_format.func == jr_op &&

	    ip->r_format.rs == 31)

		return 1;

	return 0;

#endif

}



static inline int is_ra_save_ins(union mips_instruction *ip, int *poff)

{

#ifdef CONFIG_CPU_MICROMIPS
@@ -400,7 +430,9 @@ static int get_frame_info(struct mips_frame_info *info) 
			last_insn_size = 4;

		}



		if (!info->frame_size) {

		if (is_jr_ra_ins(ip)) {

			break;

		} else if (!info->frame_size) {

			is_sp_move_ins(&insn, &info->frame_size);

			continue;

		} else if (!saw_jump && is_jump_ins(ip)) {