MN10300: Handle misaligned SP-based operands

Support misalignment handling for instructions that have kernel SP-based
address operands, including fixing those that include IMM8 or IMM16
displacements.

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

1 files changed, 24 insertions, 9 deletions

diff --git a/arch/mn10300/mm/misalignment.c b/arch/mn10300/mm/misalignment.c
index a59836804bc6..e247a6e1b8de 100644
--- a/arch/mn10300/mm/misalignment.c
+++ b/arch/mn10300/mm/misalignment.c
@@ -42,8 +42,9 @@
 #define kdebug(FMT, ...) do {} while (0)
 #endif
 
-static int misalignment_addr(unsigned long *registers, unsigned params,
-                             unsigned opcode, unsigned long disp,
+static int misalignment_addr(unsigned long *registers, unsigned long sp,
+                             unsigned params, unsigned opcode,
+                             unsigned long disp,
                              void **_address, unsigned long **_postinc,
                              unsigned long *_inc);
 
@@ -322,7 +323,7 @@ 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, inc;
+        unsigned long data, *store, *postinc, disp, inc, sp;
         mm_segment_t seg;
         siginfo_t info;
         uint32_t opcode, noc, xo, xm;
@@ -330,7 +331,12 @@ asmlinkage void misalignment(struct pt_regs *regs, enum exception_code code)
         void *address;
         unsigned tmp, npop, dispsz, loop;
 
-        kdebug("==>misalignment({pc=%lx})", regs->pc);
+        if (user_mode(regs))
+                sp = regs->sp;
+        else
+                sp = (unsigned long) regs + sizeof(*regs);
+
+        kdebug("==>misalignment({pc=%lx,sp=%lx})", regs->pc, sp);
 
         if (regs->epsw & EPSW_IE)
                 asm volatile("or %0,epsw" : : "i"(EPSW_IE));
@@ -496,7 +502,8 @@ found_opcode:
 
         if (pop->params[0] & 0x80000000) {
                 /* move memory to register */
-                if (!misalignment_addr(registers, pop->params[0], opcode, disp,
+                if (!misalignment_addr(registers, sp,
+                                       pop->params[0], opcode, disp,
                                        &address, &postinc, &inc))
                         goto bad_addr_mode;
 
@@ -520,7 +527,8 @@ found_opcode:
                                       &store))
                         goto bad_reg_mode;
 
-                if (!misalignment_addr(registers, pop->params[1], opcode, disp,
+                if (!misalignment_addr(registers, sp,
+                                       pop->params[1], opcode, disp,
                                        &address, &postinc, &inc))
                         goto bad_addr_mode;
 
@@ -548,8 +556,9 @@ found_opcode:
 /*
  * determine the address that was being accessed
  */
-static int misalignment_addr(unsigned long *registers, unsigned params,
-                             unsigned opcode, unsigned long disp,
+static int misalignment_addr(unsigned long *registers, unsigned long sp,
+                             unsigned params, unsigned opcode,
+                             unsigned long disp,
                              void **_address, unsigned long **_postinc,
                              unsigned long *_inc)
 {
@@ -618,7 +627,7 @@ static int misalignment_addr(unsigned long *registers, unsigned params,
                         address += *postinc;
                         break;
                 case SP:
-                        address += registers[REG_SP >> 2];
+                        address += sp;
                         break;
 
                         /* displacements are either to be added to the address
@@ -642,6 +651,12 @@ static int misalignment_addr(unsigned long *registers, unsigned params,
                         asm("asr 28,%0" : "=r"(tmp) : "0"(tmp));
                         disp = (long) tmp;
                         goto displace_or_inc;
+                case IMM8:
+                        disp &= 0x000000ff;
+                        goto displace_or_inc;
+                case IMM16:
+                        disp &= 0x0000ffff;
+                        goto displace_or_inc;
                 case IMM24:
                         disp &= 0x00ffffff;
                         goto displace_or_inc;