microblaze: Implement clear_ums macro and fix SAVE_STATE macro

VMS is always setup because VM mode was before
exception/syscall/interrupt. Kernel continues in kernel mode
that's why we have to clear UMS bit if kernel comes from
user space.

Signed-off-by: Michal Simek <monstr@monstr.eu>

1 files changed, 15 insertions, 0 deletions

diff --git a/arch/microblaze/kernel/entry.S b/arch/microblaze/kernel/entry.S
index 5318ad375fec..5529f64e97e8 100644
--- a/arch/microblaze/kernel/entry.S
+++ b/arch/microblaze/kernel/entry.S
@@ -91,6 +91,11 @@
         nop
         .endm
 
+        .macro  clear_ums
+        msrclr  r11, MSR_UMS
+        nop
+        .endm
+
         .macro  clear_vms_ums
         msrclr  r11, MSR_VMS | MSR_UMS
         nop
@@ -162,6 +167,14 @@
         nop
         .endm
 
+        .macro  clear_ums
+        mfs     r11, rmsr
+        nop
+        andni   r11, r11, MSR_UMS
+        mts     rmsr,r11
+        nop
+        .endm
+
         .macro  clear_vms_ums
         mfs     r11, rmsr
         nop
@@ -526,6 +539,8 @@ C_ENTRY(sys_rt_sigreturn_wrapper):
         swi     r0, r1, PTO + PT_MODE; /* Was in user-mode.  */         \
         lwi     r11, r0, TOPHYS(PER_CPU(ENTRY_SP));                     \
         swi     r11, r1, PTO+PT_R1; /* Store user SP.  */               \
+        /* MS: I am clearing UMS even in case when I come from kernel space */ \
+        clear_ums;                                                      \
 2:      lwi     CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
 
 C_ENTRY(full_exception_trap):