MIPS: kernel: unaligned: Handle unaligned accesses for EVA

Handle unaligned accesses when we access userspace memory
EVA mode.

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

1 files changed, 85 insertions, 1 deletions

diff --git a/arch/mips/kernel/unaligned.c b/arch/mips/kernel/unaligned.c
index 5ec8f00b51b5..2b3517214d6d 100644
--- a/arch/mips/kernel/unaligned.c
+++ b/arch/mips/kernel/unaligned.c
@@ -431,7 +431,9 @@ static void emulate_load_store_insn(struct pt_regs *regs,
         unsigned long origpc;
         unsigned long orig31;
         void __user *fault_addr = NULL;
-
+#ifdef  CONFIG_EVA
+        mm_segment_t seg;
+#endif
         origpc = (unsigned long)pc;
         orig31 = regs->regs[31];
 
@@ -476,6 +478,88 @@ static void emulate_load_store_insn(struct pt_regs *regs,
                  * The remaining opcodes are the ones that are really of
                  * interest.
                  */
+#ifdef CONFIG_EVA
+        case spec3_op:
+                /*
+                 * we can land here only from kernel accessing user memory,
+                 * so we need to "switch" the address limit to user space, so
+                 * address check can work properly.
+                 */
+                seg = get_fs();
+                set_fs(USER_DS);
+                switch (insn.spec3_format.func) {
+                case lhe_op:
+                        if (!access_ok(VERIFY_READ, addr, 2)) {
+                                set_fs(seg);
+                                goto sigbus;
+                        }
+                        LoadHW(addr, value, res);
+                        if (res) {
+                                set_fs(seg);
+                                goto fault;
+                        }
+                        compute_return_epc(regs);
+                        regs->regs[insn.spec3_format.rt] = value;
+                        break;
+                case lwe_op:
+                        if (!access_ok(VERIFY_READ, addr, 4)) {
+                                set_fs(seg);
+                                goto sigbus;
+                        }
+                                LoadW(addr, value, res);
+                        if (res) {
+                                set_fs(seg);
+                                goto fault;
+                        }
+                        compute_return_epc(regs);
+                        regs->regs[insn.spec3_format.rt] = value;
+                        break;
+                case lhue_op:
+                        if (!access_ok(VERIFY_READ, addr, 2)) {
+                                set_fs(seg);
+                                goto sigbus;
+                        }
+                        LoadHWU(addr, value, res);
+                        if (res) {
+                                set_fs(seg);
+                                goto fault;
+                        }
+                        compute_return_epc(regs);
+                        regs->regs[insn.spec3_format.rt] = value;
+                        break;
+                case she_op:
+                        if (!access_ok(VERIFY_WRITE, addr, 2)) {
+                                set_fs(seg);
+                                goto sigbus;
+                        }
+                        compute_return_epc(regs);
+                        value = regs->regs[insn.spec3_format.rt];
+                        StoreHW(addr, value, res);
+                        if (res) {
+                                set_fs(seg);
+                                goto fault;
+                        }
+                        break;
+                case swe_op:
+                        if (!access_ok(VERIFY_WRITE, addr, 4)) {
+                                set_fs(seg);
+                                goto sigbus;
+                        }
+                        compute_return_epc(regs);
+                        value = regs->regs[insn.spec3_format.rt];
+                        StoreW(addr, value, res);
+                        if (res) {
+                                set_fs(seg);
+                                goto fault;
+                        }
+                        break;
+                default:
+                        set_fs(seg);
+                        goto sigill;
+                }
+                set_fs(seg);
+                break;
+#endif
         case lh_op:
                 if (!access_ok(VERIFY_READ, addr, 2))
                         goto sigbus;