powerpc: Merge enough to start building in arch/powerpc.

This creates the directory structure under arch/powerpc and a bunch
of Kconfig files.  It does a first-cut merge of arch/powerpc/mm,
arch/powerpc/lib and arch/powerpc/platforms/powermac.  This is enough
to build a 32-bit powermac kernel with ARCH=powerpc.

For now we are getting some unmerged files from arch/ppc/kernel and
arch/ppc/syslib, or arch/ppc64/kernel.  This makes some minor changes
to files in those directories and files outside arch/powerpc.

The boot directory is still not merged.  That's going to be interesting.

Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
new file mode 100644
index 0000000..345db08
--- /dev/null
+++ b/arch/powerpc/mm/mem.c
@@ -0,0 +1,299 @@
+/*
+ *  PowerPC version
+ *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ *
+ *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
+ *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
+ *    Copyright (C) 1996 Paul Mackerras
+ *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
+ *  PPC44x/36-bit changes by Matt Porter (mporter@mvista.com)
+ *
+ *  Derived from "arch/i386/mm/init.c"
+ *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version
+ *  2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/stddef.h>
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/highmem.h>
+#include <linux/initrd.h>
+#include <linux/pagemap.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/smp.h>
+#include <asm/machdep.h>
+#include <asm/btext.h>
+#include <asm/tlb.h>
+#include <asm/bootinfo.h>
+#include <asm/prom.h>
+
+#include "mem_pieces.h"
+#include "mmu_decl.h"
+
+#ifndef CPU_FTR_COHERENT_ICACHE
+#define CPU_FTR_COHERENT_ICACHE	0	/* XXX for now */
+#define CPU_FTR_NOEXECUTE	0
+#endif
+
+/*
+ * This is called by /dev/mem to know if a given address has to
+ * be mapped non-cacheable or not
+ */
+int page_is_ram(unsigned long pfn)
+{
+	unsigned long paddr = (pfn << PAGE_SHIFT);
+
+#ifndef CONFIG_PPC64	/* XXX for now */
+	return paddr < __pa(high_memory);
+#else
+	int i;
+	for (i=0; i < lmb.memory.cnt; i++) {
+		unsigned long base;
+
+		base = lmb.memory.region[i].base;
+
+		if ((paddr >= base) &&
+			(paddr < (base + lmb.memory.region[i].size))) {
+			return 1;
+		}
+	}
+
+	return 0;
+#endif
+}
+EXPORT_SYMBOL(page_is_ram);
+
+pgprot_t phys_mem_access_prot(struct file *file, unsigned long addr,
+			      unsigned long size, pgprot_t vma_prot)
+{
+	if (ppc_md.phys_mem_access_prot)
+		return ppc_md.phys_mem_access_prot(file, addr, size, vma_prot);
+
+	if (!page_is_ram(addr >> PAGE_SHIFT))
+		vma_prot = __pgprot(pgprot_val(vma_prot)
+				    | _PAGE_GUARDED | _PAGE_NO_CACHE);
+	return vma_prot;
+}
+EXPORT_SYMBOL(phys_mem_access_prot);
+
+void show_mem(void)
+{
+	unsigned long total = 0, reserved = 0;
+	unsigned long shared = 0, cached = 0;
+	unsigned long highmem = 0;
+	struct page *page;
+	pg_data_t *pgdat;
+	unsigned long i;
+
+	printk("Mem-info:\n");
+	show_free_areas();
+	printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
+	for_each_pgdat(pgdat) {
+		for (i = 0; i < pgdat->node_spanned_pages; i++) {
+			page = pgdat_page_nr(pgdat, i);
+			total++;
+			if (PageHighMem(page))
+				highmem++;
+			if (PageReserved(page))
+				reserved++;
+			else if (PageSwapCache(page))
+				cached++;
+			else if (page_count(page))
+				shared += page_count(page) - 1;
+		}
+	}
+	printk("%ld pages of RAM\n", total);
+#ifdef CONFIG_HIGHMEM
+	printk("%ld pages of HIGHMEM\n", highmem);
+#endif
+	printk("%ld reserved pages\n", reserved);
+	printk("%ld pages shared\n", shared);
+	printk("%ld pages swap cached\n", cached);
+}
+
+/*
+ * This is called when a page has been modified by the kernel.
+ * It just marks the page as not i-cache clean.  We do the i-cache
+ * flush later when the page is given to a user process, if necessary.
+ */
+void flush_dcache_page(struct page *page)
+{
+	if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
+		return;
+	/* avoid an atomic op if possible */
+	if (test_bit(PG_arch_1, &page->flags))
+		clear_bit(PG_arch_1, &page->flags);
+}
+EXPORT_SYMBOL(flush_dcache_page);
+
+void flush_dcache_icache_page(struct page *page)
+{
+#ifdef CONFIG_BOOKE
+	void *start = kmap_atomic(page, KM_PPC_SYNC_ICACHE);
+	__flush_dcache_icache(start);
+	kunmap_atomic(start, KM_PPC_SYNC_ICACHE);
+#elif defined(CONFIG_8xx)
+	/* On 8xx there is no need to kmap since highmem is not supported */
+	__flush_dcache_icache(page_address(page)); 
+#else
+	__flush_dcache_icache_phys(page_to_pfn(page) << PAGE_SHIFT);
+#endif
+
+}
+void clear_user_page(void *page, unsigned long vaddr, struct page *pg)
+{
+	clear_page(page);
+
+	if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
+		return;
+	/*
+	 * We shouldnt have to do this, but some versions of glibc
+	 * require it (ld.so assumes zero filled pages are icache clean)
+	 * - Anton
+	 */
+
+	/* avoid an atomic op if possible */
+	if (test_bit(PG_arch_1, &pg->flags))
+		clear_bit(PG_arch_1, &pg->flags);
+}
+EXPORT_SYMBOL(clear_user_page);
+
+void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
+		    struct page *pg)
+{
+	copy_page(vto, vfrom);
+
+	/*
+	 * We should be able to use the following optimisation, however
+	 * there are two problems.
+	 * Firstly a bug in some versions of binutils meant PLT sections
+	 * were not marked executable.
+	 * Secondly the first word in the GOT section is blrl, used
+	 * to establish the GOT address. Until recently the GOT was
+	 * not marked executable.
+	 * - Anton
+	 */
+#if 0
+	if (!vma->vm_file && ((vma->vm_flags & VM_EXEC) == 0))
+		return;
+#endif
+
+	if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
+		return;
+
+	/* avoid an atomic op if possible */
+	if (test_bit(PG_arch_1, &pg->flags))
+		clear_bit(PG_arch_1, &pg->flags);
+}
+
+void flush_icache_user_range(struct vm_area_struct *vma, struct page *page,
+			     unsigned long addr, int len)
+{
+	unsigned long maddr;
+
+	maddr = (unsigned long) kmap(page) + (addr & ~PAGE_MASK);
+	flush_icache_range(maddr, maddr + len);
+	kunmap(page);
+}
+EXPORT_SYMBOL(flush_icache_user_range);
+
+/*
+ * This is called at the end of handling a user page fault, when the
+ * fault has been handled by updating a PTE in the linux page tables.
+ * We use it to preload an HPTE into the hash table corresponding to
+ * the updated linux PTE.
+ * 
+ * This must always be called with the mm->page_table_lock held
+ */
+void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
+		      pte_t pte)
+{
+	/* handle i-cache coherency */
+	unsigned long pfn = pte_pfn(pte);
+#ifdef CONFIG_PPC32
+	pmd_t *pmd;
+#else
+	unsigned long vsid;
+	void *pgdir;
+	pte_t *ptep;
+	int local = 0;
+	cpumask_t tmp;
+	unsigned long flags;
+#endif
+
+	/* handle i-cache coherency */
+	if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE) &&
+	    !cpu_has_feature(CPU_FTR_NOEXECUTE) &&
+	    pfn_valid(pfn)) {
+		struct page *page = pfn_to_page(pfn);
+		if (!PageReserved(page)
+		    && !test_bit(PG_arch_1, &page->flags)) {
+			if (vma->vm_mm == current->active_mm) {
+#ifdef CONFIG_8xx
+			/* On 8xx, cache control instructions (particularly 
+		 	 * "dcbst" from flush_dcache_icache) fault as write 
+			 * operation if there is an unpopulated TLB entry 
+			 * for the address in question. To workaround that, 
+			 * we invalidate the TLB here, thus avoiding dcbst 
+			 * misbehaviour.
+			 */
+				_tlbie(address);
+#endif
+				__flush_dcache_icache((void *) address);
+			} else
+				flush_dcache_icache_page(page);
+			set_bit(PG_arch_1, &page->flags);
+		}
+	}
+
+#ifdef CONFIG_PPC_STD_MMU
+	/* We only want HPTEs for linux PTEs that have _PAGE_ACCESSED set */
+	if (!pte_young(pte) || address >= TASK_SIZE)
+		return;
+#ifdef CONFIG_PPC32
+	if (Hash == 0)
+		return;
+	pmd = pmd_offset(pgd_offset(vma->vm_mm, address), address);
+	if (!pmd_none(*pmd))
+		add_hash_page(vma->vm_mm->context, address, pmd_val(*pmd));
+#else
+	pgdir = vma->vm_mm->pgd;
+	if (pgdir == NULL)
+		return;
+
+	ptep = find_linux_pte(pgdir, ea);
+	if (!ptep)
+		return;
+
+	vsid = get_vsid(vma->vm_mm->context.id, ea);
+
+	local_irq_save(flags);
+	tmp = cpumask_of_cpu(smp_processor_id());
+	if (cpus_equal(vma->vm_mm->cpu_vm_mask, tmp))
+		local = 1;
+
+	__hash_page(ea, pte_val(pte) & (_PAGE_USER|_PAGE_RW), vsid, ptep,
+		    0x300, local);
+	local_irq_restore(flags);
+#endif
+#endif
+}