MIPS: Prevent unaligned accesses during stack unwinding
am: ce449cbdcf
Change-Id: I7e6e790cb8db07930f08cfc1e61a19b516163ae2
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index c0aa99b..941a881 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -198,8 +198,6 @@
static inline int is_ra_save_ins(union mips_instruction *ip)
{
#ifdef CONFIG_CPU_MICROMIPS
- union mips_instruction mmi;
-
/*
* swsp ra,offset
* swm16 reglist,offset(sp)
@@ -209,23 +207,20 @@
*
* microMIPS is way more fun...
*/
- if (mm_insn_16bit(ip->halfword[0])) {
- mmi.word = (ip->halfword[0] << 16);
- return (mmi.mm16_r5_format.opcode == mm_swsp16_op &&
- mmi.mm16_r5_format.rt == 31) ||
- (mmi.mm16_m_format.opcode == mm_pool16c_op &&
- mmi.mm16_m_format.func == mm_swm16_op);
+ if (mm_insn_16bit(ip->halfword[1])) {
+ return (ip->mm16_r5_format.opcode == mm_swsp16_op &&
+ ip->mm16_r5_format.rt == 31) ||
+ (ip->mm16_m_format.opcode == mm_pool16c_op &&
+ ip->mm16_m_format.func == mm_swm16_op);
}
else {
- mmi.halfword[0] = ip->halfword[1];
- mmi.halfword[1] = ip->halfword[0];
- return (mmi.mm_m_format.opcode == mm_pool32b_op &&
- mmi.mm_m_format.rd > 9 &&
- mmi.mm_m_format.base == 29 &&
- mmi.mm_m_format.func == mm_swm32_func) ||
- (mmi.i_format.opcode == mm_sw32_op &&
- mmi.i_format.rs == 29 &&
- mmi.i_format.rt == 31);
+ return (ip->mm_m_format.opcode == mm_pool32b_op &&
+ ip->mm_m_format.rd > 9 &&
+ ip->mm_m_format.base == 29 &&
+ ip->mm_m_format.func == mm_swm32_func) ||
+ (ip->i_format.opcode == mm_sw32_op &&
+ ip->i_format.rs == 29 &&
+ ip->i_format.rt == 31);
}
#else
/* sw / sd $ra, offset($sp) */
@@ -246,12 +241,8 @@
*
* microMIPS is kind of more fun...
*/
- union mips_instruction mmi;
-
- mmi.word = (ip->halfword[0] << 16);
-
- if ((mmi.mm16_r5_format.opcode == mm_pool16c_op &&
- (mmi.mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op) ||
+ if ((ip->mm16_r5_format.opcode == mm_pool16c_op &&
+ (ip->mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op) ||
ip->j_format.opcode == mm_jal32_op)
return 1;
if (ip->r_format.opcode != mm_pool32a_op ||
@@ -280,15 +271,13 @@
*
* microMIPS is not more fun...
*/
- if (mm_insn_16bit(ip->halfword[0])) {
- union mips_instruction mmi;
-
- mmi.word = (ip->halfword[0] << 16);
- return (mmi.mm16_r3_format.opcode == mm_pool16d_op &&
- mmi.mm16_r3_format.simmediate && mm_addiusp_func) ||
- (mmi.mm16_r5_format.opcode == mm_pool16d_op &&
- mmi.mm16_r5_format.rt == 29);
+ if (mm_insn_16bit(ip->halfword[1])) {
+ 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);
}
+
return ip->mm_i_format.opcode == mm_addiu32_op &&
ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29;
#else
@@ -303,7 +292,8 @@
static int get_frame_info(struct mips_frame_info *info)
{
- union mips_instruction *ip;
+ bool is_mmips = IS_ENABLED(CONFIG_CPU_MICROMIPS);
+ union mips_instruction insn, *ip;
unsigned max_insns = info->func_size / sizeof(union mips_instruction);
unsigned i;
@@ -319,11 +309,21 @@
max_insns = min(128U, max_insns);
for (i = 0; i < max_insns; i++, ip++) {
+ if (is_mmips && mm_insn_16bit(ip->halfword[0])) {
+ insn.halfword[0] = 0;
+ insn.halfword[1] = ip->halfword[0];
+ } else if (is_mmips) {
+ insn.halfword[0] = ip->halfword[1];
+ insn.halfword[1] = ip->halfword[0];
+ } else {
+ insn.word = ip->word;
+ }
- if (is_jump_ins(ip))
+ if (is_jump_ins(&insn))
break;
+
if (!info->frame_size) {
- if (is_sp_move_ins(ip))
+ if (is_sp_move_ins(&insn))
{
#ifdef CONFIG_CPU_MICROMIPS
if (mm_insn_16bit(ip->halfword[0]))
@@ -346,7 +346,7 @@
}
continue;
}
- if (info->pc_offset == -1 && is_ra_save_ins(ip)) {
+ if (info->pc_offset == -1 && is_ra_save_ins(&insn)) {
info->pc_offset =
ip->i_format.simmediate / sizeof(long);
break;