sh: Handle unaligned 16-bit instructions on SH-2A.

This adds some sanity checking in the unaligned instruction handler to
verify the instruction size, which enables basic support for 16-bit
fixups on SH-2A parts.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 8 insertions, 3 deletions

diff --git a/arch/sh/kernel/traps_32.c b/arch/sh/kernel/traps_32.c
index 6aba9af79eaf..f9760c5c234a 100644
--- a/arch/sh/kernel/traps_32.c
+++ b/arch/sh/kernel/traps_32.c
@@ -452,6 +452,12 @@ int handle_unaligned_access(insn_size_t instruction, struct pt_regs *regs,
         u_int rm;
         int ret, index;
 
+        /*
+         * XXX: We can't handle mixed 16/32-bit instructions yet
+         */
+        if (instruction_size(instruction) != 2)
+                return -EINVAL;
+
         index = (instruction>>8)&15;    /* 0x0F00 */
         rm = regs->regs[index];
 
@@ -619,9 +625,9 @@ asmlinkage void do_address_error(struct pt_regs *regs,
 
                 se_user += 1;
 
-#ifndef CONFIG_CPU_SH2A
                 set_fs(USER_DS);
-                if (copy_from_user(&instruction, (u16 *)(regs->pc & ~1), 2)) {
+                if (copy_from_user(&instruction, (insn_size_t *)(regs->pc & ~1),
+                                   sizeof(instruction))) {
                         set_fs(oldfs);
                         goto uspace_segv;
                 }
@@ -633,7 +639,6 @@ asmlinkage void do_address_error(struct pt_regs *regs,
                                "in \"%s\" pid=%d pc=0x%p ins=0x%04hx\n",
                                current->comm, current->pid, (void *)regs->pc,
                                instruction);
-#endif
 
                 if (se_usermode & 2)
                         goto fixup;