unicore32 core architecture: mm related: fault handling

This patch implements fault handling of memory management.

Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 533 insertions, 0 deletions

diff --git a/arch/unicore32/mm/mmu.c b/arch/unicore32/mm/mmu.c
new file mode 100644
index 000000000000..7bf3d588631f
--- /dev/null
+++ b/arch/unicore32/mm/mmu.c
@@ -0,0 +1,533 @@
+/*
+ * linux/arch/unicore32/mm/mmu.c
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * 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/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/mman.h>
+#include <linux/nodemask.h>
+#include <linux/memblock.h>
+#include <linux/fs.h>
+#include <linux/bootmem.h>
+#include <linux/io.h>
+
+#include <asm/cputype.h>
+#include <asm/sections.h>
+#include <asm/setup.h>
+#include <asm/sizes.h>
+#include <asm/tlb.h>
+
+#include <mach/map.h>
+
+#include "mm.h"
+
+DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
+
+/*
+ * empty_zero_page is a special page that is used for
+ * zero-initialized data and COW.
+ */
+struct page *empty_zero_page;
+EXPORT_SYMBOL(empty_zero_page);
+
+/*
+ * The pmd table for the upper-most set of pages.
+ */
+pmd_t *top_pmd;
+
+pgprot_t pgprot_user;
+EXPORT_SYMBOL(pgprot_user);
+
+pgprot_t pgprot_kernel;
+EXPORT_SYMBOL(pgprot_kernel);
+
+static int __init noalign_setup(char *__unused)
+{
+	cr_alignment &= ~CR_A;
+	cr_no_alignment &= ~CR_A;
+	set_cr(cr_alignment);
+	return 1;
+}
+__setup("noalign", noalign_setup);
+
+void adjust_cr(unsigned long mask, unsigned long set)
+{
+	unsigned long flags;
+
+	mask &= ~CR_A;
+
+	set &= mask;
+
+	local_irq_save(flags);
+
+	cr_no_alignment = (cr_no_alignment & ~mask) | set;
+	cr_alignment = (cr_alignment & ~mask) | set;
+
+	set_cr((get_cr() & ~mask) | set);
+
+	local_irq_restore(flags);
+}
+
+struct map_desc {
+	unsigned long virtual;
+	unsigned long pfn;
+	unsigned long length;
+	unsigned int type;
+};
+
+#define PROT_PTE_DEVICE		(PTE_PRESENT | PTE_YOUNG |	\
+				PTE_DIRTY | PTE_READ | PTE_WRITE)
+#define PROT_SECT_DEVICE	(PMD_TYPE_SECT | PMD_PRESENT |	\
+				PMD_SECT_READ | PMD_SECT_WRITE)
+
+static struct mem_type mem_types[] = {
+	[MT_DEVICE] = {		  /* Strongly ordered */
+		.prot_pte	= PROT_PTE_DEVICE,
+		.prot_l1	= PMD_TYPE_TABLE | PMD_PRESENT,
+		.prot_sect	= PROT_SECT_DEVICE,
+	},
+	/*
+	 * MT_KUSER: pte for vecpage -- cacheable,
+	 *       and sect for unigfx mmap -- noncacheable
+	 */
+	[MT_KUSER] = {
+		.prot_pte  = PTE_PRESENT | PTE_YOUNG | PTE_DIRTY |
+				PTE_CACHEABLE | PTE_READ | PTE_EXEC,
+		.prot_l1   = PMD_TYPE_TABLE | PMD_PRESENT,
+		.prot_sect = PROT_SECT_DEVICE,
+	},
+	[MT_HIGH_VECTORS] = {
+		.prot_pte  = PTE_PRESENT | PTE_YOUNG | PTE_DIRTY |
+				PTE_CACHEABLE | PTE_READ | PTE_WRITE |
+				PTE_EXEC,
+		.prot_l1   = PMD_TYPE_TABLE | PMD_PRESENT,
+	},
+	[MT_MEMORY] = {
+		.prot_pte  = PTE_PRESENT | PTE_YOUNG | PTE_DIRTY |
+				PTE_WRITE | PTE_EXEC,
+		.prot_l1   = PMD_TYPE_TABLE | PMD_PRESENT,
+		.prot_sect = PMD_TYPE_SECT | PMD_PRESENT | PMD_SECT_CACHEABLE |
+				PMD_SECT_READ | PMD_SECT_WRITE | PMD_SECT_EXEC,
+	},
+	[MT_ROM] = {
+		.prot_sect = PMD_TYPE_SECT | PMD_PRESENT | PMD_SECT_CACHEABLE |
+				PMD_SECT_READ,
+	},
+};
+
+const struct mem_type *get_mem_type(unsigned int type)
+{
+	return type < ARRAY_SIZE(mem_types) ? &mem_types[type] : NULL;
+}
+EXPORT_SYMBOL(get_mem_type);
+
+/*
+ * Adjust the PMD section entries according to the CPU in use.
+ */
+static void __init build_mem_type_table(void)
+{
+	pgprot_user   = __pgprot(PTE_PRESENT | PTE_YOUNG | PTE_CACHEABLE);
+	pgprot_kernel = __pgprot(PTE_PRESENT | PTE_YOUNG |
+				 PTE_DIRTY | PTE_READ | PTE_WRITE |
+				 PTE_EXEC | PTE_CACHEABLE);
+}
+
+#define vectors_base()	(vectors_high() ? 0xffff0000 : 0)
+
+static void __init *early_alloc(unsigned long sz)
+{
+	void *ptr = __va(memblock_alloc(sz, sz));
+	memset(ptr, 0, sz);
+	return ptr;
+}
+
+static pte_t * __init early_pte_alloc(pmd_t *pmd, unsigned long addr,
+		unsigned long prot)
+{
+	if (pmd_none(*pmd)) {
+		pte_t *pte = early_alloc(PTRS_PER_PTE * sizeof(pte_t));
+		__pmd_populate(pmd, __pa(pte) | prot);
+	}
+	BUG_ON(pmd_bad(*pmd));
+	return pte_offset_kernel(pmd, addr);
+}
+
+static void __init alloc_init_pte(pmd_t *pmd, unsigned long addr,
+				  unsigned long end, unsigned long pfn,
+				  const struct mem_type *type)
+{
+	pte_t *pte = early_pte_alloc(pmd, addr, type->prot_l1);
+	do {
+		set_pte(pte, pfn_pte(pfn, __pgprot(type->prot_pte)));
+		pfn++;
+	} while (pte++, addr += PAGE_SIZE, addr != end);
+}
+
+static void __init alloc_init_section(pgd_t *pgd, unsigned long addr,
+				      unsigned long end, unsigned long phys,
+				      const struct mem_type *type)
+{
+	pmd_t *pmd = pmd_offset((pud_t *)pgd, addr);
+
+	/*
+	 * Try a section mapping - end, addr and phys must all be aligned
+	 * to a section boundary.
+	 */
+	if (((addr | end | phys) & ~SECTION_MASK) == 0) {
+		pmd_t *p = pmd;
+
+		do {
+			set_pmd(pmd, __pmd(phys | type->prot_sect));
+			phys += SECTION_SIZE;
+		} while (pmd++, addr += SECTION_SIZE, addr != end);
+
+		flush_pmd_entry(p);
+	} else {
+		/*
+		 * No need to loop; pte's aren't interested in the
+		 * individual L1 entries.
+		 */
+		alloc_init_pte(pmd, addr, end, __phys_to_pfn(phys), type);
+	}
+}
+
+/*
+ * Create the page directory entries and any necessary
+ * page tables for the mapping specified by `md'.  We
+ * are able to cope here with varying sizes and address
+ * offsets, and we take full advantage of sections.
+ */
+static void __init create_mapping(struct map_desc *md)
+{
+	unsigned long phys, addr, length, end;
+	const struct mem_type *type;
+	pgd_t *pgd;
+
+	if (md->virtual != vectors_base() && md->virtual < TASK_SIZE) {
+		printk(KERN_WARNING "BUG: not creating mapping for "
+		       "0x%08llx at 0x%08lx in user region\n",
+		       __pfn_to_phys((u64)md->pfn), md->virtual);
+		return;
+	}
+
+	if ((md->type == MT_DEVICE || md->type == MT_ROM) &&
+	    md->virtual >= PAGE_OFFSET && md->virtual < VMALLOC_END) {
+		printk(KERN_WARNING "BUG: mapping for 0x%08llx at 0x%08lx "
+		       "overlaps vmalloc space\n",
+		       __pfn_to_phys((u64)md->pfn), md->virtual);
+	}
+
+	type = &mem_types[md->type];
+
+	addr = md->virtual & PAGE_MASK;
+	phys = (unsigned long)__pfn_to_phys(md->pfn);
+	length = PAGE_ALIGN(md->length + (md->virtual & ~PAGE_MASK));
+
+	if (type->prot_l1 == 0 && ((addr | phys | length) & ~SECTION_MASK)) {
+		printk(KERN_WARNING "BUG: map for 0x%08lx at 0x%08lx can not "
+		       "be mapped using pages, ignoring.\n",
+		       __pfn_to_phys(md->pfn), addr);
+		return;
+	}
+
+	pgd = pgd_offset_k(addr);
+	end = addr + length;
+	do {
+		unsigned long next = pgd_addr_end(addr, end);
+
+		alloc_init_section(pgd, addr, next, phys, type);
+
+		phys += next - addr;
+		addr = next;
+	} while (pgd++, addr != end);
+}
+
+static void * __initdata vmalloc_min = (void *)(VMALLOC_END - SZ_128M);
+
+/*
+ * vmalloc=size forces the vmalloc area to be exactly 'size'
+ * bytes. This can be used to increase (or decrease) the vmalloc
+ * area - the default is 128m.
+ */
+static int __init early_vmalloc(char *arg)
+{
+	unsigned long vmalloc_reserve = memparse(arg, NULL);
+
+	if (vmalloc_reserve < SZ_16M) {
+		vmalloc_reserve = SZ_16M;
+		printk(KERN_WARNING
+			"vmalloc area too small, limiting to %luMB\n",
+			vmalloc_reserve >> 20);
+	}
+
+	if (vmalloc_reserve > VMALLOC_END - (PAGE_OFFSET + SZ_32M)) {
+		vmalloc_reserve = VMALLOC_END - (PAGE_OFFSET + SZ_32M);
+		printk(KERN_WARNING
+			"vmalloc area is too big, limiting to %luMB\n",
+			vmalloc_reserve >> 20);
+	}
+
+	vmalloc_min = (void *)(VMALLOC_END - vmalloc_reserve);
+	return 0;
+}
+early_param("vmalloc", early_vmalloc);
+
+static phys_addr_t lowmem_limit __initdata = SZ_1G;
+
+static void __init sanity_check_meminfo(void)
+{
+	int i, j;
+
+	lowmem_limit = __pa(vmalloc_min - 1) + 1;
+	memblock_set_current_limit(lowmem_limit);
+
+	for (i = 0, j = 0; i < meminfo.nr_banks; i++) {
+		struct membank *bank = &meminfo.bank[j];
+		*bank = meminfo.bank[i];
+		j++;
+	}
+	meminfo.nr_banks = j;
+}
+
+static inline void prepare_page_table(void)
+{
+	unsigned long addr;
+	phys_addr_t end;
+
+	/*
+	 * Clear out all the mappings below the kernel image.
+	 */
+	for (addr = 0; addr < MODULES_VADDR; addr += PGDIR_SIZE)
+		pmd_clear(pmd_off_k(addr));
+
+	for ( ; addr < PAGE_OFFSET; addr += PGDIR_SIZE)
+		pmd_clear(pmd_off_k(addr));
+
+	/*
+	 * Find the end of the first block of lowmem.
+	 */
+	end = memblock.memory.regions[0].base + memblock.memory.regions[0].size;
+	if (end >= lowmem_limit)
+		end = lowmem_limit;
+
+	/*
+	 * 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(end);
+	     addr < VMALLOC_END; addr += PGDIR_SIZE)
+		pmd_clear(pmd_off_k(addr));
+}
+
+/*
+ * Reserve the special regions of memory
+ */
+void __init uc32_mm_memblock_reserve(void)
+{
+	/*
+	 * Reserve the page tables.  These are already in use,
+	 * and can only be in node 0.
+	 */
+	memblock_reserve(__pa(swapper_pg_dir), PTRS_PER_PGD * sizeof(pgd_t));
+
+#ifdef CONFIG_PUV3_UNIGFX
+	/*
+	 * These should likewise go elsewhere.  They pre-reserve the
+	 * screen/video memory region at the 48M~64M of main system memory.
+	 */
+	memblock_reserve(PKUNITY_UNIGFX_MMAP_BASE, PKUNITY_UNIGFX_MMAP_SIZE);
+	memblock_reserve(PKUNITY_UVC_MMAP_BASE, PKUNITY_UVC_MMAP_SIZE);
+#endif
+}
+
+/*
+ * 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(void)
+{
+	struct map_desc map;
+	unsigned long addr;
+	void *vectors;
+
+	/*
+	 * Allocate the vector page early.
+	 */
+	vectors = early_alloc(PAGE_SIZE);
+
+	for (addr = VMALLOC_END; addr; addr += PGDIR_SIZE)
+		pmd_clear(pmd_off_k(addr));
+
+	/*
+	 * Create a mapping for UniGFX VRAM
+	 */
+#ifdef CONFIG_PUV3_UNIGFX
+	map.pfn = __phys_to_pfn(PKUNITY_UNIGFX_MMAP_BASE);
+	map.virtual = KUSER_UNIGFX_BASE;
+	map.length = PKUNITY_UNIGFX_MMAP_SIZE;
+	map.type = MT_KUSER;
+	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 = VECTORS_BASE;
+	map.length = PAGE_SIZE;
+	map.type = MT_HIGH_VECTORS;
+	create_mapping(&map);
+
+	/*
+	 * Create a mapping for the kuser page at the special
+	 * location (0xbfff0000) to the same vectors location.
+	 */
+	map.pfn = __phys_to_pfn(virt_to_phys(vectors));
+	map.virtual = KUSER_VECPAGE_BASE;
+	map.length = PAGE_SIZE;
+	map.type = MT_KUSER;
+	create_mapping(&map);
+
+	/*
+	 * 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();
+}
+
+static void __init map_lowmem(void)
+{
+	struct memblock_region *reg;
+
+	/* Map all the lowmem memory banks. */
+	for_each_memblock(memory, reg) {
+		phys_addr_t start = reg->base;
+		phys_addr_t end = start + reg->size;
+		struct map_desc map;
+
+		if (end > lowmem_limit)
+			end = lowmem_limit;
+		if (start >= end)
+			break;
+
+		map.pfn = __phys_to_pfn(start);
+		map.virtual = __phys_to_virt(start);
+		map.length = end - start;
+		map.type = MT_MEMORY;
+
+		create_mapping(&map);
+	}
+}
+
+/*
+ * 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(void)
+{
+	void *zero_page;
+
+	build_mem_type_table();
+	sanity_check_meminfo();
+	prepare_page_table();
+	map_lowmem();
+	devicemaps_init();
+
+	top_pmd = pmd_off_k(0xffff0000);
+
+	/* allocate the zero page. */
+	zero_page = early_alloc(PAGE_SIZE);
+
+	bootmem_init();
+
+	empty_zero_page = virt_to_page(zero_page);
+	__flush_dcache_page(NULL, empty_zero_page);
+}
+
+/*
+ * In order to soft-boot, we need to insert a 1:1 mapping in place of
+ * the user-mode pages.  This will then ensure that we have predictable
+ * results when turning the mmu off
+ */
+void setup_mm_for_reboot(char mode)
+{
+	unsigned long base_pmdval;
+	pgd_t *pgd;
+	int i;
+
+	/*
+	 * We need to access to user-mode page tables here. For kernel threads
+	 * we don't have any user-mode mappings so we use the context that we
+	 * "borrowed".
+	 */
+	pgd = current->active_mm->pgd;
+
+	base_pmdval = PMD_SECT_WRITE | PMD_SECT_READ | PMD_TYPE_SECT;
+
+	for (i = 0; i < FIRST_USER_PGD_NR + USER_PTRS_PER_PGD; i++, pgd++) {
+		unsigned long pmdval = (i << PGDIR_SHIFT) | base_pmdval;
+		pmd_t *pmd;
+
+		pmd = pmd_off(pgd, i << PGDIR_SHIFT);
+		set_pmd(pmd, __pmd(pmdval));
+		flush_pmd_entry(pmd);
+	}
+
+	local_flush_tlb_all();
+}
+
+/*
+ * Take care of architecture specific things when placing a new PTE into
+ * a page table, or changing an existing PTE.  Basically, there are two
+ * things that we need to take care of:
+ *
+ *  1. If PG_dcache_clean is not set for the page, we need to ensure
+ *     that any cache entries for the kernels virtual memory
+ *     range are written back to the page.
+ *  2. If we have multiple shared mappings of the same space in
+ *     an object, we need to deal with the cache aliasing issues.
+ *
+ * Note that the pte lock will be held.
+ */
+void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr,
+	pte_t *ptep)
+{
+	unsigned long pfn = pte_pfn(*ptep);
+	struct address_space *mapping;
+	struct page *page;
+
+	if (!pfn_valid(pfn))
+		return;
+
+	/*
+	 * The zero page is never written to, so never has any dirty
+	 * cache lines, and therefore never needs to be flushed.
+	 */
+	page = pfn_to_page(pfn);
+	if (page == ZERO_PAGE(0))
+		return;
+
+	mapping = page_mapping(page);
+	if (!test_and_set_bit(PG_dcache_clean, &page->flags))
+		__flush_dcache_page(mapping, page);
+	if (mapping)
+		if (vma->vm_flags & VM_EXEC)
+			__flush_icache_all();
+}