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 <hejinyang@xxxxxxxxxxx>
---
v2:
- microMIPS: ip->r_format.rs -> ip->r_format.rt
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 adf29f7..592f02e 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -186,6 +186,36 @@ 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
@@ -398,7 +428,9 @@ 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)) {
--
2.1.0
