microblaze: Simplify syscall rutine

Syscall can be called only from userspace that's why
we don't need to check which space kernel come from.

Kernel syscall calling is not check and shouldn't come
throught this part of code.

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

1 files changed, 7 insertions, 39 deletions

diff --git a/arch/microblaze/kernel/entry.S b/arch/microblaze/kernel/entry.S
index 6c117ceaabea..bf6b2b122485 100644
--- a/arch/microblaze/kernel/entry.S
+++ b/arch/microblaze/kernel/entry.S
@@ -318,42 +318,23 @@
  * are masked. This is nice, means we don't have to CLI before state save
  */
 C_ENTRY(_user_exception):
-        swi     r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) /* save stack */
         addi    r14, r14, 4     /* return address is 4 byte after call */
+        swi     r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) /* save stack */
 
-        mfs     r1, rmsr
-        nop
-        andi    r1, r1, MSR_UMS
-        bnei    r1, 1f
-
-/* Kernel-mode state save - kernel execve */
-        lwi     r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* Reload kernel stack-ptr*/
-        tophys(r1,r1);
-
-        addik   r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack. */
-        SAVE_REGS
-
-        swi     r1, r1, PTO + PT_MODE; /* pt_regs -> kernel mode */
-        brid    2f;
-        nop;                            /* Fill delay slot */
-
-/* User-mode state save.  */
-1:
         lwi     r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */
         tophys(r1,r1);
         lwi     r1, r1, TS_THREAD_INFO; /* get stack from task_struct */
-/* calculate kernel stack pointer from task struct 8k */
-        addik   r1, r1, THREAD_SIZE;
-        tophys(r1,r1);
-
-        addik   r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack.  */
+        /* MS these three instructions can be added to one */
+        /* addik        r1, r1, THREAD_SIZE; */
+        /* tophys(r1,r1); */
+        /* addik        r1, r1, -STATE_SAVE_SIZE; */
+        addik r1, r1, THREAD_SIZE + CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - STATE_SAVE_SIZE;
         SAVE_REGS
 
-        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.  */
         clear_ums;
-2:      lwi     CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
+        lwi     CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
         /* Save away the syscall number.  */
         swi     r12, r1, PTO+PT_R0;
         tovirt(r1,r1)
@@ -423,9 +404,6 @@ C_ENTRY(ret_from_trap):
         swi     r3, r1, PTO + PT_R3
         swi     r4, r1, PTO + PT_R4
 
-        lwi     r11, r1, PTO + PT_MODE;
-/* See if returning to kernel mode, if so, skip resched &c.  */
-        bnei    r11, 2f;
         /* We're returning to user mode, so check for various conditions that
          * trigger rescheduling. */
         /* FIXME: Restructure all these flag checks. */
@@ -468,16 +446,6 @@ C_ENTRY(ret_from_trap):
         RESTORE_REGS;
         addik   r1, r1, STATE_SAVE_SIZE         /* Clean up stack space.  */
         lwi     r1, r1, PT_R1 - PT_SIZE;/* Restore user stack pointer. */
-        bri     6f;
-
-/* Return to kernel state.  */
-2:      set_bip;                        /*  Ints masked for state restore */
-        VM_OFF;
-        tophys(r1,r1);
-        RESTORE_REGS;
-        addik   r1, r1, STATE_SAVE_SIZE         /* Clean up stack space.  */
-        tovirt(r1,r1);
-6:
 TRAP_return:            /* Make global symbol for debugging */
         rtbd    r14, 0; /* Instructions to return from an IRQ */
         nop;