MN10300: Handle misaligned postinc-with-imm addressing mode correctly

Correctly handle misalignment in MOV instructions with postinc-with-immediate
addressing mode operands.  In these, the immediate value is the increment to
be applied the address register, not the displacement to the address.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/mn10300/mm/misalignment.c b/arch/mn10300/mm/misalignment.c
index d5b45bb7d108493b69f8ebc1e2904c77da6a31ea..61e65ec47db83ec739c8ec69d2ca9b9b3a6376d9 100644 (file)
--- a/arch/mn10300/mm/misalignment.c
+++ b/arch/mn10300/mm/misalignment.c
@@ -44,7 +44,8 @@
 
 static int misalignment_addr(unsigned long *registers, unsigned params,
                             unsigned opcode, unsigned long disp,
-                            void **_address, unsigned long **_postinc);
+                            void **_address, unsigned long **_postinc,
+                            unsigned long *_inc);
 
 static int misalignment_reg(unsigned long *registers, unsigned params,
                            unsigned opcode, unsigned long disp,
@@ -150,7 +151,7 @@ enum value_id {
 };
 
 struct mn10300_opcode {
-       const char      *name;
+       const char      name[8];
        u_int32_t       opcode;
        u_int32_t       opmask;
        unsigned        exclusion;
@@ -310,7 +311,7 @@ static const struct mn10300_opcode mn10300_opcodes[] = {
 { "mov_lne",   0xf7e00009,  0xffff000f,  0x22, FMT_D10, AM33,   {MEMINC2 (RN4,SIMM4_2), RM6}},
 { "mov_lra",   0xf7e0000a,  0xffff000f,  0x22, FMT_D10, AM33,   {MEMINC2 (RN4,SIMM4_2), RM6}},
 
-{ 0, 0, 0, 0, 0, 0, {0}},
+{ "", 0, 0, 0, 0, 0, {0}},
 };
 
 /*
@@ -321,11 +322,11 @@ asmlinkage void misalignment(struct pt_regs *regs, enum exception_code code)
        const struct exception_table_entry *fixup;
        const struct mn10300_opcode *pop;
        unsigned long *registers = (unsigned long *) regs;
-       unsigned long data, *store, *postinc, disp;
+       unsigned long data, *store, *postinc, disp, inc;
        mm_segment_t seg;
        siginfo_t info;
        uint32_t opcode, noc, xo, xm;
-       uint8_t *pc, byte;
+       uint8_t *pc, byte, datasz;
        void *address;
        unsigned tmp, npop, dispsz, loop;
 
@@ -347,7 +348,7 @@ asmlinkage void misalignment(struct pt_regs *regs, enum exception_code code)
        opcode = byte;
        noc = 8;
 
-       for (pop = mn10300_opcodes; pop->name; pop++) {
+       for (pop = mn10300_opcodes; pop->name[0]; pop++) {
                npop = ilog2(pop->opcode | pop->opmask);
                if (npop <= 0 || npop > 31)
                        continue;
@@ -484,32 +485,31 @@ found_opcode:
                goto failed;
        }
 
+       /* determine the data transfer size of the move */
+       if (pop->name[3] == 0 || /* "mov" */
+           pop->name[4] == 'l') /* mov_lcc */
+               inc = datasz = 4;
+       else if (pop->name[3] == 'h') /* movhu */
+               inc = datasz = 2;
+       else
+               goto unsupported_instruction;
+
        if (pop->params[0] & 0x80000000) {
                /* move memory to register */
                if (!misalignment_addr(registers, pop->params[0], opcode, disp,
-                                      &address, &postinc))
+                                      &address, &postinc, &inc))
                        goto bad_addr_mode;
 
                if (!misalignment_reg(registers, pop->params[1], opcode, disp,
                                      &store))
                        goto bad_reg_mode;
 
-               if (strcmp(pop->name, "mov") == 0 ||
-                   memcmp(pop->name, "mov_l", 5) == 0) {
-                       kdebug("mov (%p),DARn", address);
-                       if (copy_from_user(&data, (void *) address, 4) != 0)
-                               goto transfer_failed;
-                       if (pop->params[0] & 0x1000000)
-                               *postinc += 4;
-               } else if (strcmp(pop->name, "movhu") == 0) {
-                       kdebug("movhu (%p),DARn", address);
-                       data = 0;
-                       if (copy_from_user(&data, (void *) address, 2) != 0)
-                               goto transfer_failed;
-                       if (pop->params[0] & 0x1000000)
-                               *postinc += 2;
-               } else {
-                       goto unsupported_instruction;
+               kdebug("mov%u (%p),DARn", datasz, address);
+               if (copy_from_user(&data, (void *) address, datasz) != 0)
+                       goto transfer_failed;
+               if (pop->params[0] & 0x1000000) {
+                       kdebug("inc=%lx", inc);
+                       *postinc += inc;
                }
 
                *store = data;
@@ -521,26 +521,16 @@ found_opcode:
                        goto bad_reg_mode;
 
                if (!misalignment_addr(registers, pop->params[1], opcode, disp,
-                                      &address, &postinc))
+                                      &address, &postinc, &inc))
                        goto bad_addr_mode;
 
                data = *store;
 
-               if (strcmp(pop->name, "mov") == 0) {
-                       kdebug("mov %lx,(%p)", data, address);
-                       if (copy_to_user((void *) address, &data, 4) != 0)
-                               goto transfer_failed;
-                       if (pop->params[1] & 0x1000000)
-                               *postinc += 4;
-               } else if (strcmp(pop->name, "movhu") == 0) {
-                       kdebug("movhu %hx,(%p)", (uint16_t) data, address);
-                       if (copy_to_user((void *) address, &data, 2) != 0)
-                               goto transfer_failed;
-                       if (pop->params[1] & 0x1000000)
-                               *postinc += 2;
-               } else {
-                       goto unsupported_instruction;
-               }
+               kdebug("mov%u %lx,(%p)", datasz, data, address);
+               if (copy_to_user((void *) address, &data, datasz) != 0)
+                       goto transfer_failed;
+               if (pop->params[1] & 0x1000000)
+                       *postinc += inc;
        }
 
        tmp = format_tbl[pop->format].opsz + format_tbl[pop->format].dispsz;
@@ -560,10 +550,17 @@ found_opcode:
  */
 static int misalignment_addr(unsigned long *registers, unsigned params,
                             unsigned opcode, unsigned long disp,
-                            void **_address, unsigned long **_postinc)
+                            void **_address, unsigned long **_postinc,
+                            unsigned long *_inc)
 {
        unsigned long *postinc = NULL, address = 0, tmp;
 
+       if (!(params & 0x1000000)) {
+               kdebug("noinc");
+               *_inc = 0;
+               _inc = NULL;
+       }
+
        params &= 0x00ffffff;
 
        do {
@@ -624,32 +621,40 @@ static int misalignment_addr(unsigned long *registers, unsigned params,
                        address += registers[REG_SP >> 2];
                        break;
 
+                       /* displacements are either to be added to the address
+                        * before use, or, in the case of post-inc addressing,
+                        * to be added into the base register after use */
                case SD8:
                case SIMM8:
-                       address += (int32_t) (int8_t) (disp & 0xff);
-                       break;
+                       disp = (long) (int8_t) (disp & 0xff);
+                       goto displace_or_inc;
                case SD16:
-                       address += (int32_t) (int16_t) (disp & 0xffff);
-                       break;
+                       disp = (long) (int16_t) (disp & 0xffff);
+                       goto displace_or_inc;
                case SD24:
                        tmp = disp << 8;
                        asm("asr 8,%0" : "=r"(tmp) : "0"(tmp));
-                       address += tmp;
-                       break;
+                       disp = (long) tmp;
+                       goto displace_or_inc;
                case SIMM4_2:
                        tmp = opcode >> 4 & 0x0f;
                        tmp <<= 28;
                        asm("asr 28,%0" : "=r"(tmp) : "0"(tmp));
-                       address += tmp;
-                       break;
+                       disp = (long) tmp;
+                       goto displace_or_inc;
                case IMM24:
-                       address += disp & 0x00ffffff;
-                       break;
+                       disp &= 0x00ffffff;
+                       goto displace_or_inc;
                case IMM32:
                case IMM32_MEM:
                case IMM32_HIGH8:
                case IMM32_HIGH8_MEM:
-                       address += disp;
+               displace_or_inc:
+                       kdebug("%s %lx", _inc ? "incr" : "disp", disp);
+                       if (!_inc)
+                               address += disp;
+                       else
+                               *_inc = disp;
                        break;
                default:
                        BUG();