Changeset 2bd4fdf in mainline for arch/mips/src/start.S

Timestamp:

2005-09-06T23:10:17Z (20 years ago)

Author:

Ondrej Palkovsky <ondrap@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

0b512a8

Parents:

2c9de7e

Message:

MIPS bug fixes.
Added usermode to MIPS, unfortunately impossible to test until
MM is ready.

File:

• arch/mips/src/start.S (modified) (5 diffs)

arch/mips/src/start.S

@@ -44 +44 @@
 .global cache_error_entry
 .global exception_entry
-
+.global userspace_asm
+
+# Save registers to space defined by \r
+# We will change $at on the way
 .macro REGISTERS_STORE r
         sw $at,EOFFSET_AT(\r)
@@ -63 +66 @@
         sw $t8,EOFFSET_T8(\r)
         sw $t9,EOFFSET_T9(\r)
+
+        mflo $at
+        sw $at, EOFFSET_LO(\r)
+        mfhi $at
+        sw $at, EOFFSET_HI(\r)
+        
         sw $s0,EOFFSET_S0(\r)
         sw $s1,EOFFSET_S1(\r)
@@ -74 +83 @@
         sw $gp,EOFFSET_GP(\r)
         sw $ra,EOFFSET_RA(\r)
-        mflo $k0
-        mfhi $k1
-        sw $k0,EOFFSET_LO(\r)
-        sw $k1,EOFFSET_HI(\r)
+        sw $sp,EOFFSET_SP(\r)
+
+        mfc0 $at, $status
+        sw $at,EOFFSET_STATUS(\r)
 .endm
 
 .macro REGISTERS_LOAD r
-        lw $at,EOFFSET_AT(\r)
         lw $v0,EOFFSET_V0(\r)
         lw $v1,EOFFSET_V1(\r)
@@ -110 +118 @@
         lw $ra,EOFFSET_RA(\r)
         
-        lw $k0,EOFFSET_LO(\r)
-        lw $k1,EOFFSET_HI(\r)
-        mtlo $k0
-        mthi $k1
+        lw $at,EOFFSET_LO(\r)
+        mtlo $at
+        lw $at,EOFFSET_HI(\r)
+        mthi $at
+
+        lw $at,EOFFSET_STATUS(\r)
+        mtc0 $at, $status
+        
+        lw $at,EOFFSET_AT(\r)
+        lw $sp,EOFFSET_SP(\r)
 .endm
 
-        
+# Move kernel stack pointer address to register K0
+# - if we are in user mode, load the appropriate stack
+# address
+.macro KERNEL_STACK_TO_K0
+        # If we are in user mode
+        mfc0 $k0, $status
+        andi $k0, 0x10
+        
+        beq $k0, $0, 1f
+        add $k0, $sp, 0
+        
+        # Move $k0 pointer to kernel stack
+        lui $k0, %hi(supervisor_sp)
+        ori $k0, %lo(supervisor_sp)
+        # Move $k0 (superveisor_sp)
+        lw $k0, 0($k0)
+1:              
+.endm
+                
 .org 0x0
 tlb_refill_entry:
@@ -128 +160 @@
 
 .org 0x180
+norm_exception: 
+        j exception_handler
+        nop     
+
+.org 0x200
+iv_exception:   
+        j exception_handler
+        nop     
+
+.org KA2PA(KERNEL_STARTUP_ADDRESS)
+kernel_image_start:
+        /* Load temporary stack */
+        lui $sp, %hi(end_stack)
+        ori $sp, $0, %lo(end_stack)
+
+        /* Not sure about this, but might be needed for PIC code???? */
+        lui $gp, 0x8000
+        
+        jal main_bsp
+        nop
+
+
+        .space TEMP_STACK_SIZE
+end_stack:      
+        
+exception_handler:
 exception_entry:
-exception_handler:
+        KERNEL_STACK_TO_K0
+        sub $k0, REGISTER_SPACE
+        REGISTERS_STORE $k0
+        add $sp, $k0, 0
+
+        jal exception
+        nop
+
+        REGISTERS_LOAD $sp
+        # The $sp is automatically restored to former value
+        eret
+        nop
+        
+tlb_refill_handler:
+        KERNEL_STACK_TO_K0
+        sub $k0, REGISTER_SPACE
+        REGISTERS_STORE $k0
+        add $sp, $k0, 0
+
+        jal tlb_refill
+        nop
+
+        REGISTERS_LOAD $sp
+
+        eret
+        nop
+
+cache_error_handler:
+        KERNEL_STACK_TO_K0
         sub $sp, REGISTER_SPACE
         REGISTERS_STORE $sp
-
-        jal exception
+        add $sp, $k0, 0
+
+        jal cache_error
         nop
 
         REGISTERS_LOAD $sp
-        add $sp, REGISTER_SPACE
-
-        eret
-        nop
-
-.org KA2PA(0x80000300)
-kernel_image_start:
-        /* Load temporary stack */
-        lui $sp, (TEMP_STACK_START + TEMP_STACK_SIZE) >> 16
-        ori $sp, (TEMP_STACK_START + TEMP_STACK_SIZE) & 0xffff
-
-        /* Not sure about this, but might be needed for PIC code???? */
-        lui $gp, 0x8000
-        
-        jal main_bsp
-        nop
-
-.org KA2PA(TEMP_STACK_START)
-        .space TEMP_STACK_SIZE
-        
-tlb_refill_handler:
-        sub $sp, REGISTER_SPACE
-        REGISTERS_STORE $sp
-
-        jal tlb_refill
-        nop
-
-        REGISTERS_LOAD $sp
-        add $sp, REGISTER_SPACE
-
-        eret
-        nop
-
-cache_error_handler:
-        sub $sp, REGISTER_SPACE
-        REGISTERS_STORE $sp
-
-        jal cache_error
-        nop
-
-        REGISTERS_LOAD $sp
-        add $sp, REGISTER_SPACE
-
-        eret
-        nop
+
+        eret
+        nop
+
+userspace_asm:
+        .word 0x29
+        add $sp, $a0, 0
+        eret
+        nop
+