[POWERPC] Revise PPC44x MMU code for arch/powerpc

This patch takes the definitions for the PPC44x MMU (a software loaded
TLB) from asm-ppc/mmu.h, cleans them up of things no longer necessary
in arch/powerpc and puts them in a new asm-powerpc/mmu_44x.h file.  It
also substantially simplifies arch/powerpc/mm/44x_mmu.c and makes a
couple of small fixes necessary for the 44x MMU code to build and work
properly in arch/powerpc.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

3 files changed, 23 insertions, 66 deletions

diff --git a/arch/powerpc/kernel/head_44x.S b/arch/powerpc/kernel/head_44x.S
index a15d4b8cce48..9ee6773cf026 100644
--- a/arch/powerpc/kernel/head_44x.S
+++ b/arch/powerpc/kernel/head_44x.S
@@ -120,8 +120,8 @@ skpinv:	addi	r4,r4,1				/* Increment */
  * Configure and load pinned entry into TLB slot 63.
  */
 
-        lis     r3,KERNELBASE@h         /* Load the kernel virtual address */
-        ori     r3,r3,KERNELBASE@l
+        lis     r3,PAGE_OFFSET@h
+        ori     r3,r3,PAGE_OFFSET@l
 
         /* Kernel is at the base of RAM */
         li r4, 0                        /* Load the kernel physical address */
diff --git a/arch/powerpc/mm/44x_mmu.c b/arch/powerpc/mm/44x_mmu.c
index 0a0a0487b334..ca4dcb07a939 100644
--- a/arch/powerpc/mm/44x_mmu.c
+++ b/arch/powerpc/mm/44x_mmu.c
@@ -24,73 +24,38 @@
  *
  */
 
-#include <linux/signal.h>
-#include <linux/sched.h>
-#include <linux/kernel.h>
-#include <linux/errno.h>
-#include <linux/string.h>
-#include <linux/types.h>
-#include <linux/ptrace.h>
-#include <linux/mman.h>
-#include <linux/mm.h>
-#include <linux/swap.h>
-#include <linux/stddef.h>
-#include <linux/vmalloc.h>
 #include <linux/init.h>
-#include <linux/delay.h>
-#include <linux/highmem.h>
-
-#include <asm/pgalloc.h>
-#include <asm/prom.h>
-#include <asm/io.h>
-#include <asm/mmu_context.h>
-#include <asm/pgtable.h>
 #include <asm/mmu.h>
-#include <asm/uaccess.h>
-#include <asm/smp.h>
-#include <asm/bootx.h>
-#include <asm/machdep.h>
-#include <asm/setup.h>
+#include <asm/system.h>
+#include <asm/page.h>
 
 #include "mmu_decl.h"
 
-extern char etext[], _stext[];
-
 /* Used by the 44x TLB replacement exception handler.
  * Just needed it declared someplace.
  */
-unsigned int tlb_44x_index = 0;
-unsigned int tlb_44x_hwater = 62;
+unsigned int tlb_44x_index; /* = 0 */
+unsigned int tlb_44x_hwater = PPC44x_TLB_SIZE - 1 - PPC44x_EARLY_TLBS;
 
 /*
  * "Pins" a 256MB TLB entry in AS0 for kernel lowmem
  */
-static void __init
-ppc44x_pin_tlb(int slot, unsigned int virt, unsigned int phys)
+static void __init ppc44x_pin_tlb(unsigned int virt, unsigned int phys)
 {
-        unsigned long attrib = 0;
-
-        __asm__ __volatile__("\
-        clrrwi  %2,%2,10\n\
-        ori     %2,%2,%4\n\
-        clrrwi  %1,%1,10\n\
-        li      %0,0\n\
-        ori     %0,%0,%5\n\
-        tlbwe   %2,%3,%6\n\
-        tlbwe   %1,%3,%7\n\
-        tlbwe   %0,%3,%8"
+        __asm__ __volatile__(
+                "tlbwe  %2,%3,%4\n"
+                "tlbwe  %1,%3,%5\n"
+                "tlbwe  %0,%3,%6\n"
         :
-        : "r" (attrib), "r" (phys), "r" (virt), "r" (slot),
-          "i" (PPC44x_TLB_VALID | PPC44x_TLB_256M),
-          "i" (PPC44x_TLB_SW | PPC44x_TLB_SR | PPC44x_TLB_SX | PPC44x_TLB_G),
+        : "r" (PPC44x_TLB_SW | PPC44x_TLB_SR | PPC44x_TLB_SX | PPC44x_TLB_G),
+          "r" (phys),
+          "r" (virt | PPC44x_TLB_VALID | PPC44x_TLB_256M),
+          "r" (tlb_44x_hwater--), /* slot for this TLB entry */
           "i" (PPC44x_TLB_PAGEID),
           "i" (PPC44x_TLB_XLAT),
           "i" (PPC44x_TLB_ATTRIB));
 }
 
-/*
- * MMU_init_hw does the chip-specific initialization of the MMU hardware.
- */
 void __init MMU_init_hw(void)
 {
         flush_instruction_cache();
@@ -98,22 +63,13 @@ void __init MMU_init_hw(void)
 
 unsigned long __init mmu_mapin_ram(void)
 {
-        unsigned int pinned_tlbs = 1;
-        int i;
-
-        /* Determine number of entries necessary to cover lowmem */
-        pinned_tlbs = (unsigned int)
-                (_ALIGN(total_lowmem, PPC_PIN_SIZE) >> PPC44x_PIN_SHIFT);
-
-        /* Write upper watermark to save location */
-        tlb_44x_hwater = PPC44x_LOW_SLOT - pinned_tlbs;
+        unsigned long addr;
 
-        /* If necessary, set additional pinned TLBs */
-        if (pinned_tlbs > 1)
-                for (i = (PPC44x_LOW_SLOT-(pinned_tlbs-1)); i < PPC44x_LOW_SLOT; i++) {
-                        unsigned int phys_addr = (PPC44x_LOW_SLOT-i) * PPC_PIN_SIZE;
-                        ppc44x_pin_tlb(i, phys_addr+PAGE_OFFSET, phys_addr);
-                }
+        /* Pin in enough TLBs to cover any lowmem not covered by the
+         * initial 256M mapping established in head_44x.S */
+        for (addr = PPC_PIN_SIZE; addr < total_lowmem;
+             addr += PPC_PIN_SIZE)
+                ppc44x_pin_tlb(addr + PAGE_OFFSET, addr);
 
         return total_lowmem;
 }
diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h
index 9c4538bb04b0..2558c34eedaa 100644
--- a/arch/powerpc/mm/mmu_decl.h
+++ b/arch/powerpc/mm/mmu_decl.h
@@ -40,7 +40,8 @@ extern int __map_without_bats;
 extern unsigned long ioremap_base;
 extern unsigned int rtas_data, rtas_size;
 
-extern PTE *Hash, *Hash_end;
+struct _PTE;
+extern struct _PTE *Hash, *Hash_end;
 extern unsigned long Hash_size, Hash_mask;
 
 extern unsigned int num_tlbcam_entries;