From c1771216ab48bb077cee30e6d197a5a55f707101 Mon Sep 17 00:00:00 2001
From: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Date: Thu, 12 Dec 2013 16:15:15 +0000
Subject: [PATCH] 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>
---
arch/mips/kernel/unaligned.c | 86 +++++++++++++++++++++++++++++++++++-
1 file changed, 85 insertions(+), 1 deletion(-)
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;
--
2.20.1