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>

diff --git a/arch/sh/kernel/traps_32.c b/arch/sh/kernel/traps_32.c
index 6aba9af79eaf023a818434a01166dac1cd557c24..f9760c5c234ad306c16a31d64fb15bdc3744ef3c 100644 (file)
--- 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;