[ARM] Split ARM MM initialisation for !mmu

Move the MMU specific code from init.c into mmu.c, and add nommu
fixups to nommu.c

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 229 insertions, 0 deletions

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
new file mode 100644
index 000000000000..9648e6800ffe
--- /dev/null
+++ b/arch/arm/mm/mmu.c
@@ -0,0 +1,229 @@
+/*
+ *  linux/arch/arm/mm/mmu.c
+ *
+ *  Copyright (C) 1995-2005 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/mman.h>
+#include <linux/nodemask.h>
+
+#include <asm/mach-types.h>
+#include <asm/setup.h>
+#include <asm/sizes.h>
+#include <asm/tlb.h>
+
+#include <asm/mach/arch.h>
+#include <asm/mach/map.h>
+
+#include "mm.h"
+
+DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
+
+extern void _stext, __data_start, _end;
+extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
+
+/*
+ * empty_zero_page is a special page that is used for
+ * zero-initialized data and COW.
+ */
+struct page *empty_zero_page;
+
+/*
+ * The pmd table for the upper-most set of pages.
+ */
+pmd_t *top_pmd;
+
+static inline void prepare_page_table(struct meminfo *mi)
+{
+        unsigned long addr;
+
+        /*
+         * Clear out all the mappings below the kernel image.
+         */
+        for (addr = 0; addr < MODULE_START; addr += PGDIR_SIZE)
+                pmd_clear(pmd_off_k(addr));
+
+#ifdef CONFIG_XIP_KERNEL
+        /* The XIP kernel is mapped in the module area -- skip over it */
+        addr = ((unsigned long)&_etext + PGDIR_SIZE - 1) & PGDIR_MASK;
+#endif
+        for ( ; addr < PAGE_OFFSET; addr += PGDIR_SIZE)
+                pmd_clear(pmd_off_k(addr));
+
+        /*
+         * Clear out all the kernel space mappings, except for the first
+         * memory bank, up to the end of the vmalloc region.
+         */
+        for (addr = __phys_to_virt(mi->bank[0].start + mi->bank[0].size);
+             addr < VMALLOC_END; addr += PGDIR_SIZE)
+                pmd_clear(pmd_off_k(addr));
+}
+
+/*
+ * Reserve the various regions of node 0
+ */
+void __init reserve_node_zero(pg_data_t *pgdat)
+{
+        unsigned long res_size = 0;
+
+        /*
+         * Register the kernel text and data with bootmem.
+         * Note that this can only be in node 0.
+         */
+#ifdef CONFIG_XIP_KERNEL
+        reserve_bootmem_node(pgdat, __pa(&__data_start), &_end - &__data_start);
+#else
+        reserve_bootmem_node(pgdat, __pa(&_stext), &_end - &_stext);
+#endif
+
+        /*
+         * Reserve the page tables.  These are already in use,
+         * and can only be in node 0.
+         */
+        reserve_bootmem_node(pgdat, __pa(swapper_pg_dir),
+                             PTRS_PER_PGD * sizeof(pgd_t));
+
+        /*
+         * Hmm... This should go elsewhere, but we really really need to
+         * stop things allocating the low memory; ideally we need a better
+         * implementation of GFP_DMA which does not assume that DMA-able
+         * memory starts at zero.
+         */
+        if (machine_is_integrator() || machine_is_cintegrator())
+                res_size = __pa(swapper_pg_dir) - PHYS_OFFSET;
+
+        /*
+         * These should likewise go elsewhere.  They pre-reserve the
+         * screen memory region at the start of main system memory.
+         */
+        if (machine_is_edb7211())
+                res_size = 0x00020000;
+        if (machine_is_p720t())
+                res_size = 0x00014000;
+
+#ifdef CONFIG_SA1111
+        /*
+         * Because of the SA1111 DMA bug, we want to preserve our
+         * precious DMA-able memory...
+         */
+        res_size = __pa(swapper_pg_dir) - PHYS_OFFSET;
+#endif
+        if (res_size)
+                reserve_bootmem_node(pgdat, PHYS_OFFSET, res_size);
+}
+
+/*
+ * Set up device the mappings.  Since we clear out the page tables for all
+ * mappings above VMALLOC_END, we will remove any debug device mappings.
+ * This means you have to be careful how you debug this function, or any
+ * called function.  This means you can't use any function or debugging
+ * method which may touch any device, otherwise the kernel _will_ crash.
+ */
+static void __init devicemaps_init(struct machine_desc *mdesc)
+{
+        struct map_desc map;
+        unsigned long addr;
+        void *vectors;
+
+        /*
+         * Allocate the vector page early.
+         */
+        vectors = alloc_bootmem_low_pages(PAGE_SIZE);
+        BUG_ON(!vectors);
+
+        for (addr = VMALLOC_END; addr; addr += PGDIR_SIZE)
+                pmd_clear(pmd_off_k(addr));
+
+        /*
+         * Map the kernel if it is XIP.
+         * It is always first in the modulearea.
+         */
+#ifdef CONFIG_XIP_KERNEL
+        map.pfn = __phys_to_pfn(CONFIG_XIP_PHYS_ADDR & SECTION_MASK);
+        map.virtual = MODULE_START;
+        map.length = ((unsigned long)&_etext - map.virtual + ~SECTION_MASK) & SECTION_MASK;
+        map.type = MT_ROM;
+        create_mapping(&map);
+#endif
+
+        /*
+         * Map the cache flushing regions.
+         */
+#ifdef FLUSH_BASE
+        map.pfn = __phys_to_pfn(FLUSH_BASE_PHYS);
+        map.virtual = FLUSH_BASE;
+        map.length = SZ_1M;
+        map.type = MT_CACHECLEAN;
+        create_mapping(&map);
+#endif
+#ifdef FLUSH_BASE_MINICACHE
+        map.pfn = __phys_to_pfn(FLUSH_BASE_PHYS + SZ_1M);
+        map.virtual = FLUSH_BASE_MINICACHE;
+        map.length = SZ_1M;
+        map.type = MT_MINICLEAN;
+        create_mapping(&map);
+#endif
+
+        /*
+         * Create a mapping for the machine vectors at the high-vectors
+         * location (0xffff0000).  If we aren't using high-vectors, also
+         * create a mapping at the low-vectors virtual address.
+         */
+        map.pfn = __phys_to_pfn(virt_to_phys(vectors));
+        map.virtual = 0xffff0000;
+        map.length = PAGE_SIZE;
+        map.type = MT_HIGH_VECTORS;
+        create_mapping(&map);
+
+        if (!vectors_high()) {
+                map.virtual = 0;
+                map.type = MT_LOW_VECTORS;
+                create_mapping(&map);
+        }
+
+        /*
+         * Ask the machine support to map in the statically mapped devices.
+         */
+        if (mdesc->map_io)
+                mdesc->map_io();
+
+        /*
+         * Finally flush the caches and tlb to ensure that we're in a
+         * consistent state wrt the writebuffer.  This also ensures that
+         * any write-allocated cache lines in the vector page are written
+         * back.  After this point, we can start to touch devices again.
+         */
+        local_flush_tlb_all();
+        flush_cache_all();
+}
+
+/*
+ * paging_init() sets up the page tables, initialises the zone memory
+ * maps, and sets up the zero page, bad page and bad page tables.
+ */
+void __init paging_init(struct meminfo *mi, struct machine_desc *mdesc)
+{
+        void *zero_page;
+
+        build_mem_type_table();
+        prepare_page_table(mi);
+        bootmem_init(mi);
+        devicemaps_init(mdesc);
+
+        top_pmd = pmd_off_k(0xffff0000);
+
+        /*
+         * allocate the zero page.  Note that we count on this going ok.
+         */
+        zero_page = alloc_bootmem_low_pages(PAGE_SIZE);
+        memzero(zero_page, PAGE_SIZE);
+        empty_zero_page = virt_to_page(zero_page);
+        flush_dcache_page(empty_zero_page);
+}