From 50886234e846bbf2cbf14a86c727e5fc309fdf25 Mon Sep 17 00:00:00 2001 From: Jinyang He Date: Thu, 21 Jan 2021 13:31:38 +0800 Subject: [PATCH] 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: Jinyang He Signed-off-by: Thomas Bogendoerfer --- arch/mips/kernel/process.c | 34 +++++++++++++++++++++++++++++++++- 1 file changed, 33 insertions(+), 1 deletion(-) diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c index 9bf993f..f94f291 100644 --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -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)) { -- 2.7.4