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authorMatt Redfearn <matt.redfearn@imgtec.com>2017-08-08 13:22:35 +0100
committerRalf Baechle <ralf@linux-mips.org>2017-09-06 13:21:44 +0200
commit56dfb7001a396ef6c7928adcb890043ff55e9977 (patch)
treeb7923c132b608758722c140a8538bd254baad778 /arch/mips/kernel
parent41885b02127c7ae169dc94542de4a8eed175495a (diff)
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 <macro@imgtec.com> Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com> Cc: Marcin Nowakowski <marcin.nowakowski@imgtec.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Paul Burton <paul.burton@imgtec.com> 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 <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/kernel')
-rw-r--r--arch/mips/kernel/process.c61
1 files changed, 30 insertions, 31 deletions
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)) {
/*