1 files changed, 61 insertions, 41 deletions

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 5351e1f3950d..c5ff6bfe2825 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -208,13 +208,13 @@ static inline int is_ra_save_ins(union mips_instruction *ip, int *poff)
          *
          * microMIPS is way more fun...
          */
-        if (mm_insn_16bit(ip->halfword[1])) {
+        if (mm_insn_16bit(ip->word >> 16)) {
                 switch (ip->mm16_r5_format.opcode) {
                 case mm_swsp16_op:
                         if (ip->mm16_r5_format.rt != 31)
                                 return 0;
 
-                        *poff = ip->mm16_r5_format.simmediate;
+                        *poff = ip->mm16_r5_format.imm;
                         *poff = (*poff << 2) / sizeof(ulong);
                         return 1;
 
@@ -287,7 +287,7 @@ static inline int is_jump_ins(union mips_instruction *ip)
          *
          * microMIPS is kind of more fun...
          */
-        if (mm_insn_16bit(ip->halfword[1])) {
+        if (mm_insn_16bit(ip->word >> 16)) {
                 if ((ip->mm16_r5_format.opcode == mm_pool16c_op &&
                     (ip->mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op))
                         return 1;
@@ -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
@@ -324,21 +326,40 @@ static inline int is_sp_move_ins(union mips_instruction *ip)
          *
          * microMIPS is not more fun...
          */
-        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);
+        if (mm_insn_16bit(ip->word >> 16)) {
+                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;
 }
@@ -348,7 +369,9 @@ static int get_frame_info(struct mips_frame_info *info)
         bool is_mmips = IS_ENABLED(CONFIG_CPU_MICROMIPS);
         union mips_instruction insn, *ip, *ip_end;
         const unsigned int max_insns = 128;
+        unsigned int last_insn_size = 0;
         unsigned int i;
+        bool saw_jump = false;
 
         info->pc_offset = -1;
         info->frame_size = 0;
@@ -359,47 +382,44 @@ static int get_frame_info(struct mips_frame_info *info)
 
         ip_end = (void *)ip + info->func_size;
 
-        for (i = 0; i < max_insns && ip < ip_end; i++, ip++) {
+        for (i = 0; i < max_insns && ip < ip_end; i++) {
+                ip = (void *)ip + last_insn_size;
                 if (is_mmips && mm_insn_16bit(ip->halfword[0])) {
-                        insn.halfword[0] = 0;
-                        insn.halfword[1] = ip->halfword[0];
+                        insn.word = ip->halfword[0] << 16;
+                        last_insn_size = 2;
                 } else if (is_mmips) {
-                        insn.halfword[0] = ip->halfword[1];
-                        insn.halfword[1] = ip->halfword[0];
+                        insn.word = ip->halfword[0] << 16 | ip->halfword[1];
+                        last_insn_size = 4;
                 } else {
                         insn.word = ip->word;
+                        last_insn_size = 4;
                 }
 
-                if (is_jump_ins(&insn))
-                        break;
-
                 if (!info->frame_size) {
-                        if (is_sp_move_ins(&insn))
-                        {
-#ifdef CONFIG_CPU_MICROMIPS
-                                if (mm_insn_16bit(ip->halfword[0]))
-                                {
-                                        unsigned short tmp;
-
-                                        if (ip->halfword[0] & mm_addiusp_func)
-                                        {
-                                                tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2);
-                                                info->frame_size = -(signed short)(tmp | ((tmp & 0x100) ? 0xfe00 : 0));
-                                        } else {
-                                                tmp = (ip->halfword[0] >> 1);
-                                                info->frame_size = -(signed short)(tmp & 0xf);
-                                        }
-                                        ip = (void *) &ip->halfword[1];
-                                        ip--;
-                                } 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)) {
+                        /*
+                         * If we see a jump instruction, we are finished
+                         * with the frame save.
+                         *
+                         * Some functions can have a shortcut return at
+                         * the beginning of the function, so don't start
+                         * looking for jump instruction until we see the
+                         * frame setup.
+                         *
+                         * The RA save instruction can get put into the
+                         * delay slot of the jump instruction, so look
+                         * at the next instruction, too.
+                         */
+                        saw_jump = true;
                         continue;
                 }
                 if (info->pc_offset == -1 &&
                     is_ra_save_ins(&insn, &info->pc_offset))
                         break;
+                if (saw_jump)
+                        break;
         }
         if (info->frame_size && info->pc_offset >= 0) /* nested */
                 return 0;