[POWERPC] Remove and replace uses of PPC_MEMSTART with memstart_addr

A number of users of PPC_MEMSTART (40x, ppc_mmu_32) can just always
use 0 as we don't support booting these kernels at non-zero physical
addresses since their exception vectors must be at 0 (or 0xfffx_xxxx).

For the sub-arches that support relocatable interrupt vectors
(book-e), it's reasonable to have memory start at a non-zero physical
address.  For those cases use the variable memstart_addr instead of
the #define PPC_MEMSTART since the only uses of PPC_MEMSTART are for
initialization and in the future we can set memstart_addr at runtime
to have a relocatable kernel.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/mm/40x_mmu.c

@@ -97,7 +97,7 @@ unsigned long __init mmu_mapin_ram(void)
 	phys_addr_t p;
 
 	v = KERNELBASE;
-	p = PPC_MEMSTART;
+	p = 0;
 	s = total_lowmem;
 
 	if (__map_without_ltlbs)

arch/powerpc/mm/fsl_booke_mmu.c

@@ -53,13 +53,12 @@
 #include <asm/machdep.h>
 #include <asm/setup.h>
 
+#include "mmu_decl.h"
+
 extern void loadcam_entry(unsigned int index);
 unsigned int tlbcam_index;
 unsigned int num_tlbcam_entries;
 static unsigned long __cam0, __cam1, __cam2;
-extern unsigned long total_lowmem;
-extern unsigned long __max_low_memory;
-extern unsigned long __initial_memory_limit;
 #define MAX_LOW_MEM	CONFIG_LOWMEM_SIZE
 
 #define NUM_TLBCAMS	(16)
@@ -165,15 +164,15 @@ void invalidate_tlbcam_entry(int index)
 void __init cam_mapin_ram(unsigned long cam0, unsigned long cam1,
 		unsigned long cam2)
 {
-	settlbcam(0, PAGE_OFFSET, PPC_MEMSTART, cam0, _PAGE_KERNEL, 0);
+	settlbcam(0, PAGE_OFFSET, memstart_addr, cam0, _PAGE_KERNEL, 0);
 	tlbcam_index++;
 	if (cam1) {
 		tlbcam_index++;
-		settlbcam(1, PAGE_OFFSET+cam0, PPC_MEMSTART+cam0, cam1, _PAGE_KERNEL, 0);
+		settlbcam(1, PAGE_OFFSET+cam0, memstart_addr+cam0, cam1, _PAGE_KERNEL, 0);
 	}
 	if (cam2) {
 		tlbcam_index++;
-		settlbcam(2, PAGE_OFFSET+cam0+cam1, PPC_MEMSTART+cam0+cam1, cam2, _PAGE_KERNEL, 0);
+		settlbcam(2, PAGE_OFFSET+cam0+cam1, memstart_addr+cam0+cam1, cam2, _PAGE_KERNEL, 0);
 	}
 }
 

arch/powerpc/mm/init_32.c

@@ -59,8 +59,8 @@ DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
 unsigned long total_memory;
 unsigned long total_lowmem;
 
-unsigned long ppc_memstart;
-unsigned long ppc_memoffset = PAGE_OFFSET;
+phys_addr_t memstart_addr;
+phys_addr_t lowmem_end_addr;
 
 int boot_mapsize;
 #ifdef CONFIG_PPC_PMAC
@@ -145,8 +145,7 @@ void __init MMU_init(void)
 		printk(KERN_WARNING "Only using first contiguous memory region");
 	}
 
-	total_memory = lmb_end_of_DRAM();
-	total_lowmem = total_memory;
+	total_lowmem = total_memory = lmb_end_of_DRAM() - memstart_addr;
 
 #ifdef CONFIG_FSL_BOOKE
 	/* Freescale Book-E parts expect lowmem to be mapped by fixed TLB

arch/powerpc/mm/mmu_decl.h

@@ -51,6 +51,7 @@ extern unsigned long __max_low_memory;
 extern unsigned long __initial_memory_limit;
 extern unsigned long total_memory;
 extern unsigned long total_lowmem;
+extern phys_addr_t memstart_addr;
 
 /* ...and now those things that may be slightly different between processor
  * architectures.  -- Dan

arch/powerpc/mm/pgtable_32.c

@@ -281,12 +281,13 @@ int map_page(unsigned long va, phys_addr_t pa, int flags)
  */
 void __init mapin_ram(void)
 {
-	unsigned long v, p, s, f;
+	unsigned long v, s, f;
+	phys_addr_t p;
 	int ktext;
 
 	s = mmu_mapin_ram();
 	v = KERNELBASE + s;
-	p = PPC_MEMSTART + s;
+	p = memstart_addr + s;
 	for (; s < total_lowmem; s += PAGE_SIZE) {
 		ktext = ((char *) v >= _stext && (char *) v < etext);
 		f = ktext ?_PAGE_RAM_TEXT : _PAGE_RAM;

arch/powerpc/mm/ppc_mmu_32.c

@@ -82,7 +82,6 @@ unsigned long __init mmu_mapin_ram(void)
 #else
 	unsigned long tot, bl, done;
 	unsigned long max_size = (256<<20);
-	unsigned long align;
 
 	if (__map_without_bats) {
 		printk(KERN_DEBUG "RAM mapped without BATs\n");
@@ -93,27 +92,21 @@ unsigned long __init mmu_mapin_ram(void)
 
 	/* Make sure we don't map a block larger than the
 	   smallest alignment of the physical address. */
-	/* alignment of PPC_MEMSTART */
-	align = ~(PPC_MEMSTART-1) & PPC_MEMSTART;
-	/* set BAT block size to MIN(max_size, align) */
-	if (align && align < max_size)
-		max_size = align;
-
 	tot = total_lowmem;
 	for (bl = 128<<10; bl < max_size; bl <<= 1) {
 		if (bl * 2 > tot)
 			break;
 	}
 
-	setbat(2, KERNELBASE, PPC_MEMSTART, bl, _PAGE_RAM);
+	setbat(2, KERNELBASE, 0, bl, _PAGE_RAM);
 	done = (unsigned long)bat_addrs[2].limit - KERNELBASE + 1;
 	if ((done < tot) && !bat_addrs[3].limit) {
 		/* use BAT3 to cover a bit more */
 		tot -= done;
 		for (bl = 128<<10; bl < max_size; bl <<= 1)
 			if (bl * 2 > tot)
 				break;
-		setbat(3, KERNELBASE+done, PPC_MEMSTART+done, bl, _PAGE_RAM);
+		setbat(3, KERNELBASE+done, done, bl, _PAGE_RAM);
 		done = (unsigned long)bat_addrs[3].limit - KERNELBASE + 1;
 	}
 

include/asm-powerpc/page_32.h

@@ -3,8 +3,6 @@
 
 #define VM_DATA_DEFAULT_FLAGS	VM_DATA_DEFAULT_FLAGS32
 
-#define PPC_MEMSTART	0
-
 #ifdef CONFIG_NOT_COHERENT_CACHE
 #define ARCH_KMALLOC_MINALIGN	L1_CACHE_BYTES
 #endif