1 files changed, 47 insertions, 23 deletions

diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 3ef743fa5d7c..1f1a04b5c2a4 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -71,9 +71,6 @@ _ENTRY(_start);
  * in the first level table, but that would require many changes to the
  * Linux page directory/table functions that I don't want to do right now.
  *
- * I used to use SPRG2 for a temporary register in the TLB handler, but it
- * has since been put to other uses.  I now use a hack to save a register
- * and the CCR at memory location 0.....Someday I'll fix this.....
  *      -- Dan
  */
         .globl  __start
@@ -302,8 +299,13 @@ InstructionTLBMiss:
         DO_8xx_CPU6(0x3f80, r3)
         mtspr   SPRN_M_TW, r10  /* Save a couple of working registers */
         mfcr    r10
+#ifdef CONFIG_8xx_CPU6
         stw     r10, 0(r0)
         stw     r11, 4(r0)
+#else
+        mtspr   SPRN_DAR, r10
+        mtspr   SPRN_SPRG2, r11
+#endif
         mfspr   r10, SPRN_SRR0  /* Get effective address of fault */
 #ifdef CONFIG_8xx_CPU15
         addi    r11, r10, 0x1000
@@ -318,12 +320,16 @@ InstructionTLBMiss:
         /* If we are faulting a kernel address, we have to use the
          * kernel page tables.
          */
+#ifdef CONFIG_MODULES
+        /* Only modules will cause ITLB Misses as we always
+         * pin the first 8MB of kernel memory */
         andi.   r11, r10, 0x0800        /* Address >= 0x80000000 */
         beq     3f
         lis     r11, swapper_pg_dir@h
         ori     r11, r11, swapper_pg_dir@l
         rlwimi  r10, r11, 0, 2, 19
 3:
+#endif
         lwz     r11, 0(r10)     /* Get the level 1 entry */
         rlwinm. r10, r11,0,0,19 /* Extract page descriptor page address */
         beq     2f              /* If zero, don't try to find a pte */
@@ -339,31 +345,35 @@ InstructionTLBMiss:
         mfspr   r11, SPRN_MD_TWC        /* ....and get the pte address */
         lwz     r10, 0(r11)     /* Get the pte */
 
+#ifdef CONFIG_SWAP
         andi.   r11, r10, _PAGE_ACCESSED | _PAGE_PRESENT
         cmpwi   cr0, r11, _PAGE_ACCESSED | _PAGE_PRESENT
         bne-    cr0, 2f
-
-        /* Clear PP lsb, 0x400 */
-        rlwinm  r10, r10, 0, 22, 20
-
+#endif
         /* The Linux PTE won't go exactly into the MMU TLB.
-         * Software indicator bits 22 and 28 must be clear.
+         * Software indicator bits 21 and 28 must be clear.
          * Software indicator bits 24, 25, 26, and 27 must be
          * set.  All other Linux PTE bits control the behavior
          * of the MMU.
          */
         li      r11, 0x00f0
-        rlwimi  r10, r11, 0, 24, 28     /* Set 24-27, clear 28 */
+        rlwimi  r10, r11, 0, 0x07f8     /* Set 24-27, clear 21-23,28 */
         DO_8xx_CPU6(0x2d80, r3)
         mtspr   SPRN_MI_RPN, r10        /* Update TLB entry */
 
-        mfspr   r10, SPRN_M_TW  /* Restore registers */
+        /* Restore registers */
+#ifndef CONFIG_8xx_CPU6
+        mfspr   r10, SPRN_DAR
+        mtcr    r10
+        mtspr   SPRN_DAR, r11   /* Tag DAR */
+        mfspr   r11, SPRN_SPRG2
+#else
         lwz     r11, 0(r0)
         mtcr    r11
         lwz     r11, 4(r0)
-#ifdef CONFIG_8xx_CPU6
         lwz     r3, 8(r0)
 #endif
+        mfspr   r10, SPRN_M_TW
         rfi
 2:
         mfspr   r11, SPRN_SRR1
@@ -373,13 +383,20 @@ InstructionTLBMiss:
         rlwinm  r11, r11, 0, 0xffff
         mtspr   SPRN_SRR1, r11
 
-        mfspr   r10, SPRN_M_TW  /* Restore registers */
+        /* Restore registers */
+#ifndef CONFIG_8xx_CPU6
+        mfspr   r10, SPRN_DAR
+        mtcr    r10
+        li      r11, 0x00f0
+        mtspr   SPRN_DAR, r11   /* Tag DAR */
+        mfspr   r11, SPRN_SPRG2
+#else
         lwz     r11, 0(r0)
         mtcr    r11
         lwz     r11, 4(r0)
-#ifdef CONFIG_8xx_CPU6
         lwz     r3, 8(r0)
 #endif
+        mfspr   r10, SPRN_M_TW
         b       InstructionAccess
 
         . = 0x1200
@@ -390,8 +407,13 @@ DataStoreTLBMiss:
         DO_8xx_CPU6(0x3f80, r3)
         mtspr   SPRN_M_TW, r10  /* Save a couple of working registers */
         mfcr    r10
+#ifdef CONFIG_8xx_CPU6
         stw     r10, 0(r0)
         stw     r11, 4(r0)
+#else
+        mtspr   SPRN_DAR, r10
+        mtspr   SPRN_SPRG2, r11
+#endif
         mfspr   r10, SPRN_M_TWB /* Get level 1 table entry address */
 
         /* If we are faulting a kernel address, we have to use the
@@ -438,15 +460,14 @@ DataStoreTLBMiss:
          * r11 = ((r10 & PRESENT) & ((r10 & ACCESSED) >> 5));
          * r10 = (r10 & ~PRESENT) | r11;
          */
+#ifdef CONFIG_SWAP
         rlwinm  r11, r10, 32-5, _PAGE_PRESENT
         and     r11, r11, r10
         rlwimi  r10, r11, 0, _PAGE_PRESENT
-
+#endif
         /* Honour kernel RO, User NA */
         /* 0x200 == Extended encoding, bit 22 */
-        /* r11 =  (r10 & _PAGE_USER) >> 2 */
-        rlwinm  r11, r10, 32-2, 0x200
-        or      r10, r11, r10
+        rlwimi  r10, r10, 32-2, 0x200 /* Copy USER to bit 22, 0x200 */
         /* r11 =  (r10 & _PAGE_RW) >> 1 */
         rlwinm  r11, r10, 32-1, 0x200
         or      r10, r11, r10
@@ -460,18 +481,24 @@ DataStoreTLBMiss:
          * of the MMU.
          */
 2:      li      r11, 0x00f0
-        mtspr   SPRN_DAR,r11    /* Tag DAR */
         rlwimi  r10, r11, 0, 24, 28     /* Set 24-27, clear 28 */
         DO_8xx_CPU6(0x3d80, r3)
         mtspr   SPRN_MD_RPN, r10        /* Update TLB entry */
 
-        mfspr   r10, SPRN_M_TW  /* Restore registers */
+        /* Restore registers */
+#ifndef CONFIG_8xx_CPU6
+        mfspr   r10, SPRN_DAR
+        mtcr    r10
+        mtspr   SPRN_DAR, r11   /* Tag DAR */
+        mfspr   r11, SPRN_SPRG2
+#else
+        mtspr   SPRN_DAR, r11   /* Tag DAR */
         lwz     r11, 0(r0)
         mtcr    r11
         lwz     r11, 4(r0)
-#ifdef CONFIG_8xx_CPU6
         lwz     r3, 8(r0)
 #endif
+        mfspr   r10, SPRN_M_TW
         rfi
 
 /* This is an instruction TLB error on the MPC8xx.  This could be due
@@ -683,9 +710,6 @@ start_here:
         tophys(r4,r2)
         addi    r4,r4,THREAD    /* init task's THREAD */
         mtspr   SPRN_SPRG_THREAD,r4
-        li      r3,0
-        /* XXX What is that for ? SPRG2 appears otherwise unused on 8xx */
-        mtspr   SPRN_SPRG2,r3   /* 0 => r1 has kernel sp */
 
         /* stack */
         lis     r1,init_thread_union@ha