From 56dfb7001a396ef6c7928adcb890043ff55e9977 Mon Sep 17 00:00:00 2001 From: Matt Redfearn Date: Tue, 8 Aug 2017 13:22:35 +0100 Subject: MIPS: Refactor handling of stack pointer in get_frame_info Commit 34c2f668d0f6 ("MIPS: microMIPS: Add unaligned access support.") added handling of microMIPS instructions to manipulate the stack pointer. The code that was added violates code style rules with long lines caused by lots of nested conditionals. The added code interprets (inline) any known stack pointer manipulation instruction to find the stack frame size. Handling the microMIPS cases added quite a bit of complication to this function. Refactor is_sp_move_ins to perform the interpretation of the immediate as the instruction manipulating the stack pointer is found. This reduces the amount of indentation required in get_frame_info, and more closely matches the operation of is_ra_save_ins. Suggested-by: Maciej W. Rozycki Signed-off-by: Matt Redfearn Cc: Marcin Nowakowski Cc: Ingo Molnar Cc: Paul Burton Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/16958/ Signed-off-by: Ralf Baechle --- arch/mips/kernel/process.c | 61 +++++++++++++++++++++++----------------------- 1 file changed, 30 insertions(+), 31 deletions(-) (limited to 'arch') diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c index 86139ac3bbad..c5ff6bfe2825 100644 --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -313,9 +313,11 @@ static inline int is_jump_ins(union mips_instruction *ip) #endif } -static inline int is_sp_move_ins(union mips_instruction *ip) +static inline int is_sp_move_ins(union mips_instruction *ip, int *frame_size) { #ifdef CONFIG_CPU_MICROMIPS + unsigned short tmp; + /* * addiusp -imm * addius5 sp,-imm @@ -325,20 +327,39 @@ static inline int is_sp_move_ins(union mips_instruction *ip) * microMIPS is not more fun... */ if (mm_insn_16bit(ip->word >> 16)) { - return (ip->mm16_r3_format.opcode == mm_pool16d_op && - ip->mm16_r3_format.simmediate & mm_addiusp_func) || - (ip->mm16_r5_format.opcode == mm_pool16d_op && - ip->mm16_r5_format.rt == 29); + if (ip->mm16_r3_format.opcode == mm_pool16d_op && + ip->mm16_r3_format.simmediate & mm_addiusp_func) { + tmp = ip->mm_b0_format.simmediate >> 1; + tmp = ((tmp & 0x1ff) ^ 0x100) - 0x100; + if ((tmp + 2) < 4) /* 0x0,0x1,0x1fe,0x1ff are special */ + tmp ^= 0x100; + *frame_size = -(signed short)(tmp << 2); + return 1; + } + if (ip->mm16_r5_format.opcode == mm_pool16d_op && + ip->mm16_r5_format.rt == 29) { + tmp = ip->mm16_r5_format.imm >> 1; + *frame_size = -(signed short)(tmp & 0xf); + return 1; + } + return 0; } - return ip->mm_i_format.opcode == mm_addiu32_op && - ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29; + if (ip->mm_i_format.opcode == mm_addiu32_op && + ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29) { + *frame_size = -ip->i_format.simmediate; + return 1; + } #else /* addiu/daddiu sp,sp,-imm */ if (ip->i_format.rs != 29 || ip->i_format.rt != 29) return 0; - if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op) + + if (ip->i_format.opcode == addiu_op || + ip->i_format.opcode == daddiu_op) { + *frame_size = -ip->i_format.simmediate; return 1; + } #endif return 0; } @@ -375,29 +396,7 @@ static int get_frame_info(struct mips_frame_info *info) } if (!info->frame_size) { - if (is_sp_move_ins(&insn)) - { -#ifdef CONFIG_CPU_MICROMIPS - if (mm_insn_16bit(insn.word >> 16)) - { - unsigned short tmp; - - if (ip->mm16_r3_format.simmediate & mm_addiusp_func) - { - tmp = ip->mm_b0_format.simmediate >> 1; - tmp = ((tmp & 0x1ff) ^ 0x100) - 0x100; - /* 0x0,0x1,0x1fe,0x1ff are special */ - if ((tmp + 2) < 4) - tmp ^= 0x100; - info->frame_size = -(signed short)(tmp << 2); - } else { - tmp = (ip->mm16_r5_format.imm >> 1); - info->frame_size = -(signed short)(tmp & 0xf); - } - } else -#endif - info->frame_size = - ip->i_format.simmediate; - } + is_sp_move_ins(&insn, &info->frame_size); continue; } else if (!saw_jump && is_jump_ins(ip)) { /* -- cgit v1.2.3