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>
diff --git a/arch/microblaze/kernel/entry.S b/arch/microblaze/kernel/entry.S
index 5318ad3..5529f64 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 @@
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):