MIPS: unaligned: Fix regular load/store instruction emulation for EVA

When emulating a regular lh/lw/lhu/sh/sw we need to use the appropriate
instruction if we are in EVA mode. This is necessary for userspace
applications which trigger alignment exceptions. In such case, the
userspace load/store instruction needs to be emulated with the correct
eva/non-eva instruction by the kernel emulator.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Fixes: c1771216ab48 ("MIPS: kernel: unaligned: Handle unaligned accesses for EVA")
Cc: <stable@vger.kernel.org> # v3.15+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9503/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/kernel/unaligned.c b/arch/mips/kernel/unaligned.c
index ab47590..7659da2 100644 (file)
--- a/arch/mips/kernel/unaligned.c
+++ b/arch/mips/kernel/unaligned.c
@@ -1023,7 +1023,15 @@ static void emulate_load_store_insn(struct pt_regs *regs,
                if (!access_ok(VERIFY_READ, addr, 2))
                        goto sigbus;
 
-               LoadHW(addr, value, res);
+               if (config_enabled(CONFIG_EVA)) {
+                       if (segment_eq(get_fs(), get_ds()))
+                               LoadHW(addr, value, res);
+                       else
+                               LoadHWE(addr, value, res);
+               } else {
+                       LoadHW(addr, value, res);
+               }
+
                if (res)
                        goto fault;
                compute_return_epc(regs);
@@ -1034,7 +1042,15 @@ static void emulate_load_store_insn(struct pt_regs *regs,
                if (!access_ok(VERIFY_READ, addr, 4))
                        goto sigbus;
 
-               LoadW(addr, value, res);
+               if (config_enabled(CONFIG_EVA)) {
+                       if (segment_eq(get_fs(), get_ds()))
+                               LoadW(addr, value, res);
+                       else
+                               LoadWE(addr, value, res);
+               } else {
+                       LoadW(addr, value, res);
+               }
+
                if (res)
                        goto fault;
                compute_return_epc(regs);
@@ -1045,7 +1061,15 @@ static void emulate_load_store_insn(struct pt_regs *regs,
                if (!access_ok(VERIFY_READ, addr, 2))
                        goto sigbus;
 
-               LoadHWU(addr, value, res);
+               if (config_enabled(CONFIG_EVA)) {
+                       if (segment_eq(get_fs(), get_ds()))
+                               LoadHWU(addr, value, res);
+                       else
+                               LoadHWUE(addr, value, res);
+               } else {
+                       LoadHWU(addr, value, res);
+               }
+
                if (res)
                        goto fault;
                compute_return_epc(regs);
@@ -1104,7 +1128,16 @@ static void emulate_load_store_insn(struct pt_regs *regs,
 
                compute_return_epc(regs);
                value = regs->regs[insn.i_format.rt];
-               StoreHW(addr, value, res);
+
+               if (config_enabled(CONFIG_EVA)) {
+                       if (segment_eq(get_fs(), get_ds()))
+                               StoreHW(addr, value, res);
+                       else
+                               StoreHWE(addr, value, res);
+               } else {
+                       StoreHW(addr, value, res);
+               }
+
                if (res)
                        goto fault;
                break;
@@ -1115,7 +1148,16 @@ static void emulate_load_store_insn(struct pt_regs *regs,
 
                compute_return_epc(regs);
                value = regs->regs[insn.i_format.rt];
-               StoreW(addr, value, res);
+
+               if (config_enabled(CONFIG_EVA)) {
+                       if (segment_eq(get_fs(), get_ds()))
+                               StoreW(addr, value, res);
+                       else
+                               StoreWE(addr, value, res);
+               } else {
+                       StoreW(addr, value, res);
+               }
+
                if (res)
                        goto fault;
                break;