mem.c

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/*
 *  PowerPC version
 *    Copyright (C) 1995-1996 Gary Thomas ([email protected])
 *
 *  Modifications by Paul Mackerras (PowerMac) ([email protected])
 *  and Cort Dougan (PReP) ([email protected])
 *    Copyright (C) 1996 Paul Mackerras
 *  PPC44x/36-bit changes by Matt Porter ([email protected])
 *
 *  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/export.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/gfp.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 <linux/suspend.h>
#include <linux/memblock.h>
#include <linux/hugetlb.h>
#include <linux/slab.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/sections.h>
#include <asm/sparsemem.h>
#include <asm/vdso.h>
#include <asm/fixmap.h>
#include <asm/swiotlb.h>
#include <asm/rtas.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

int init_bootmem_done;
int mem_init_done;
unsigned long long memory_limit;

#ifdef CONFIG_HIGHMEM
pte_t *kmap_pte;
pgprot_t kmap_prot;

EXPORT_SYMBOL(kmap_prot);
EXPORT_SYMBOL(kmap_pte);

static inline pte_t *virt_to_kpte(unsigned long vaddr)
{
    return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
            vaddr), vaddr), vaddr);
}
#endif

int page_is_ram(unsigned long pfn)
{
#ifndef CONFIG_PPC64    /* XXX for now */
    return pfn < max_pfn;
#else
    unsigned long paddr = (pfn << PAGE_SHIFT);
    struct memblock_region *reg;

    for_each_memblock(memory, reg)
        if (paddr >= reg->base && paddr < (reg->base + reg->size))
            return 1;
    return 0;
#endif
}

pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
                  unsigned long size, pgprot_t vma_prot)
{
    if (ppc_md.phys_mem_access_prot)
        return ppc_md.phys_mem_access_prot(file, pfn, size, vma_prot);

    if (!page_is_ram(pfn))
        vma_prot = pgprot_noncached(vma_prot);

    return vma_prot;
}
EXPORT_SYMBOL(phys_mem_access_prot);

#ifdef CONFIG_MEMORY_HOTPLUG

#ifdef CONFIG_NUMA
int memory_add_physaddr_to_nid(u64 start)
{
    return hot_add_scn_to_nid(start);
}
#endif

int arch_add_memory(int nid, u64 start, u64 size)
{
    struct pglist_data *pgdata;
    struct zone *zone;
    unsigned long start_pfn = start >> PAGE_SHIFT;
    unsigned long nr_pages = size >> PAGE_SHIFT;

    pgdata = NODE_DATA(nid);

    start = (unsigned long)__va(start);
    if (create_section_mapping(start, start + size))
        return -EINVAL;

    /* this should work for most non-highmem platforms */
    zone = pgdata->node_zones;

    return __add_pages(nid, zone, start_pfn, nr_pages);
}
#endif /* CONFIG_MEMORY_HOTPLUG */

/*
 * walk_memory_resource() needs to make sure there is no holes in a given
 * memory range.  PPC64 does not maintain the memory layout in /proc/iomem.
 * Instead it maintains it in memblock.memory structures.  Walk through the
 * memory regions, find holes and callback for contiguous regions.
 */
int
walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
        void *arg, int (*func)(unsigned long, unsigned long, void *))
{
    struct memblock_region *reg;
    unsigned long end_pfn = start_pfn + nr_pages;
    unsigned long tstart, tend;
    int ret = -1;

    for_each_memblock(memory, reg) {
        tstart = max(start_pfn, memblock_region_memory_base_pfn(reg));
        tend = min(end_pfn, memblock_region_memory_end_pfn(reg));
        if (tstart >= tend)
            continue;
        ret = (*func)(tstart, tend - tstart, arg);
        if (ret)
            break;
    }
    return ret;
}
EXPORT_SYMBOL_GPL(walk_system_ram_range);

/*
 * Initialize the bootmem system and give it all the memory we
 * have available.  If we are using highmem, we only put the
 * lowmem into the bootmem system.
 */
#ifndef CONFIG_NEED_MULTIPLE_NODES
void __init do_init_bootmem(void)
{
    unsigned long start, bootmap_pages;
    unsigned long total_pages;
    struct memblock_region *reg;
    int boot_mapsize;

    max_low_pfn = max_pfn = memblock_end_of_DRAM() >> PAGE_SHIFT;
    total_pages = (memblock_end_of_DRAM() - memstart_addr) >> PAGE_SHIFT;
#ifdef CONFIG_HIGHMEM
    total_pages = total_lowmem >> PAGE_SHIFT;
    max_low_pfn = lowmem_end_addr >> PAGE_SHIFT;
#endif

    /*
     * Find an area to use for the bootmem bitmap.  Calculate the size of
     * bitmap required as (Total Memory) / PAGE_SIZE / BITS_PER_BYTE.
     * Add 1 additional page in case the address isn't page-aligned.
     */
    bootmap_pages = bootmem_bootmap_pages(total_pages);

    start = memblock_alloc(bootmap_pages << PAGE_SHIFT, PAGE_SIZE);

    min_low_pfn = MEMORY_START >> PAGE_SHIFT;
    boot_mapsize = init_bootmem_node(NODE_DATA(0), start >> PAGE_SHIFT, min_low_pfn, max_low_pfn);

    /* Add active regions with valid PFNs */
    for_each_memblock(memory, reg) {
        unsigned long start_pfn, end_pfn;
        start_pfn = memblock_region_memory_base_pfn(reg);
        end_pfn = memblock_region_memory_end_pfn(reg);
        memblock_set_node(0, (phys_addr_t)ULLONG_MAX, 0);
    }

    /* Add all physical memory to the bootmem map, mark each area
     * present.
     */
#ifdef CONFIG_HIGHMEM
    free_bootmem_with_active_regions(0, lowmem_end_addr >> PAGE_SHIFT);

    /* reserve the sections we're already using */
    for_each_memblock(reserved, reg) {
        unsigned long top = reg->base + reg->size - 1;
        if (top < lowmem_end_addr)
            reserve_bootmem(reg->base, reg->size, BOOTMEM_DEFAULT);
        else if (reg->base < lowmem_end_addr) {
            unsigned long trunc_size = lowmem_end_addr - reg->base;
            reserve_bootmem(reg->base, trunc_size, BOOTMEM_DEFAULT);
        }
    }
#else
    free_bootmem_with_active_regions(0, max_pfn);

    /* reserve the sections we're already using */
    for_each_memblock(reserved, reg)
        reserve_bootmem(reg->base, reg->size, BOOTMEM_DEFAULT);
#endif
    /* XXX need to clip this if using highmem? */
    sparse_memory_present_with_active_regions(0);

    init_bootmem_done = 1;
}

/* mark pages that don't exist as nosave */
static int __init mark_nonram_nosave(void)
{
    struct memblock_region *reg, *prev = NULL;

    for_each_memblock(memory, reg) {
        if (prev &&
            memblock_region_memory_end_pfn(prev) < memblock_region_memory_base_pfn(reg))
            register_nosave_region(memblock_region_memory_end_pfn(prev),
                           memblock_region_memory_base_pfn(reg));
        prev = reg;
    }
    return 0;
}

/*
 * paging_init() sets up the page tables - in fact we've already done this.
 */
void __init paging_init(void)
{
    unsigned long long total_ram = memblock_phys_mem_size();
    phys_addr_t top_of_ram = memblock_end_of_DRAM();
    unsigned long max_zone_pfns[MAX_NR_ZONES];

#ifdef CONFIG_PPC32
    unsigned long v = __fix_to_virt(__end_of_fixed_addresses - 1);
    unsigned long end = __fix_to_virt(FIX_HOLE);

    for (; v < end; v += PAGE_SIZE)
        map_page(v, 0, 0); /* XXX gross */
#endif

#ifdef CONFIG_HIGHMEM
    map_page(PKMAP_BASE, 0, 0); /* XXX gross */
    pkmap_page_table = virt_to_kpte(PKMAP_BASE);

    kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
    kmap_prot = PAGE_KERNEL;
#endif /* CONFIG_HIGHMEM */

    printk(KERN_DEBUG "Top of RAM: 0x%llx, Total RAM: 0x%llx\n",
           (unsigned long long)top_of_ram, total_ram);
    printk(KERN_DEBUG "Memory hole size: %ldMB\n",
           (long int)((top_of_ram - total_ram) >> 20));
    memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
#ifdef CONFIG_HIGHMEM
    max_zone_pfns[ZONE_DMA] = lowmem_end_addr >> PAGE_SHIFT;
    max_zone_pfns[ZONE_HIGHMEM] = top_of_ram >> PAGE_SHIFT;
#else
    max_zone_pfns[ZONE_DMA] = top_of_ram >> PAGE_SHIFT;
#endif
    free_area_init_nodes(max_zone_pfns);

    mark_nonram_nosave();
}
#endif /* ! CONFIG_NEED_MULTIPLE_NODES */

void __init mem_init(void)
{
#ifdef CONFIG_NEED_MULTIPLE_NODES
    int nid;
#endif
    pg_data_t *pgdat;
    unsigned long i;
    struct page *page;
    unsigned long reservedpages = 0, codesize, initsize, datasize, bsssize;

#ifdef CONFIG_SWIOTLB
    swiotlb_init(0);
#endif

    num_physpages = memblock_phys_mem_size() >> PAGE_SHIFT;
    high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);

#ifdef CONFIG_NEED_MULTIPLE_NODES
        for_each_online_node(nid) {
        if (NODE_DATA(nid)->node_spanned_pages != 0) {
            printk("freeing bootmem node %d\n", nid);
            totalram_pages +=
                free_all_bootmem_node(NODE_DATA(nid));
        }
    }
#else
    max_mapnr = max_pfn;
    totalram_pages += free_all_bootmem();
#endif
    for_each_online_pgdat(pgdat) {
        for (i = 0; i < pgdat->node_spanned_pages; i++) {
            if (!pfn_valid(pgdat->node_start_pfn + i))
                continue;
            page = pgdat_page_nr(pgdat, i);
            if (PageReserved(page))
                reservedpages++;
        }
    }

    codesize = (unsigned long)&_sdata - (unsigned long)&_stext;
    datasize = (unsigned long)&_edata - (unsigned long)&_sdata;
    initsize = (unsigned long)&__init_end - (unsigned long)&__init_begin;
    bsssize = (unsigned long)&__bss_stop - (unsigned long)&__bss_start;

#ifdef CONFIG_HIGHMEM
    {
        unsigned long pfn, highmem_mapnr;

        highmem_mapnr = lowmem_end_addr >> PAGE_SHIFT;
        for (pfn = highmem_mapnr; pfn < max_mapnr; ++pfn) {
            phys_addr_t paddr = (phys_addr_t)pfn << PAGE_SHIFT;
            struct page *page = pfn_to_page(pfn);
            if (memblock_is_reserved(paddr))
                continue;
            ClearPageReserved(page);
            init_page_count(page);
            __free_page(page);
            totalhigh_pages++;
            reservedpages--;
        }
        totalram_pages += totalhigh_pages;
        printk(KERN_DEBUG "High memory: %luk\n",
               totalhigh_pages << (PAGE_SHIFT-10));
    }
#endif /* CONFIG_HIGHMEM */

#if defined(CONFIG_PPC_FSL_BOOK3E) && !defined(CONFIG_SMP)
    /*
     * If smp is enabled, next_tlbcam_idx is initialized in the cpu up
     * functions.... do it here for the non-smp case.
     */
    per_cpu(next_tlbcam_idx, smp_processor_id()) =
        (mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY) - 1;
#endif

    printk(KERN_INFO "Memory: %luk/%luk available (%luk kernel code, "
           "%luk reserved, %luk data, %luk bss, %luk init)\n",
        nr_free_pages() << (PAGE_SHIFT-10),
        num_physpages << (PAGE_SHIFT-10),
        codesize >> 10,
        reservedpages << (PAGE_SHIFT-10),
        datasize >> 10,
        bsssize >> 10,
        initsize >> 10);

#ifdef CONFIG_PPC32
    pr_info("Kernel virtual memory layout:\n");
    pr_info("  * 0x%08lx..0x%08lx  : fixmap\n", FIXADDR_START, FIXADDR_TOP);
#ifdef CONFIG_HIGHMEM
    pr_info("  * 0x%08lx..0x%08lx  : highmem PTEs\n",
        PKMAP_BASE, PKMAP_ADDR(LAST_PKMAP));
#endif /* CONFIG_HIGHMEM */
#ifdef CONFIG_NOT_COHERENT_CACHE
    pr_info("  * 0x%08lx..0x%08lx  : consistent mem\n",
        IOREMAP_TOP, IOREMAP_TOP + CONFIG_CONSISTENT_SIZE);
#endif /* CONFIG_NOT_COHERENT_CACHE */
    pr_info("  * 0x%08lx..0x%08lx  : early ioremap\n",
        ioremap_bot, IOREMAP_TOP);
    pr_info("  * 0x%08lx..0x%08lx  : vmalloc & ioremap\n",
        VMALLOC_START, VMALLOC_END);
#endif /* CONFIG_PPC32 */

    mem_init_done = 1;
}

void free_initmem(void)
{
    unsigned long addr;

    ppc_md.progress = ppc_printk_progress;

    addr = (unsigned long)__init_begin;
    for (; addr < (unsigned long)__init_end; addr += PAGE_SIZE) {
        memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
        ClearPageReserved(virt_to_page(addr));
        init_page_count(virt_to_page(addr));
        free_page(addr);
        totalram_pages++;
    }
    pr_info("Freeing unused kernel memory: %luk freed\n",
        ((unsigned long)__init_end -
        (unsigned long)__init_begin) >> 10);
}

#ifdef CONFIG_BLK_DEV_INITRD
void __init free_initrd_mem(unsigned long start, unsigned long end)
{
    if (start >= end)
        return;

    start = _ALIGN_DOWN(start, PAGE_SIZE);
    end = _ALIGN_UP(end, PAGE_SIZE);
    pr_info("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);

    for (; start < end; start += PAGE_SIZE) {
        ClearPageReserved(virt_to_page(start));
        init_page_count(virt_to_page(start));
        free_page(start);
        totalram_pages++;
    }
}
#endif

/*
 * 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_HUGETLB_PAGE
    if (PageCompound(page)) {
        flush_dcache_icache_hugepage(page);
        return;
    }
#endif
#ifdef CONFIG_BOOKE
    {
        void *start = kmap_atomic(page);
        __flush_dcache_icache(start);
        kunmap_atomic(start);
    }
#elif defined(CONFIG_8xx) || defined(CONFIG_PPC64)
    /* 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
}
EXPORT_SYMBOL(flush_dcache_icache_page);

void clear_user_page(void *page, unsigned long vaddr, struct page *pg)
{
    clear_page(page);

    /*
     * We shouldn't have to do this, but some versions of glibc
     * require it (ld.so assumes zero filled pages are icache clean)
     * - Anton
     */
    flush_dcache_page(pg);
}
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

    flush_dcache_page(pg);
}

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 pte lock held.
 */
void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
              pte_t *ptep)
{
#ifdef CONFIG_PPC_STD_MMU
    unsigned long access = 0, trap;

    /* We only want HPTEs for linux PTEs that have _PAGE_ACCESSED set */
    if (!pte_young(*ptep) || address >= TASK_SIZE)
        return;

    /* We try to figure out if we are coming from an instruction
     * access fault and pass that down to __hash_page so we avoid
     * double-faulting on execution of fresh text. We have to test
     * for regs NULL since init will get here first thing at boot
     *
     * We also avoid filling the hash if not coming from a fault
     */
    if (current->thread.regs == NULL)
        return;
    trap = TRAP(current->thread.regs);
    if (trap == 0x400)
        access |= _PAGE_EXEC;
    else if (trap != 0x300)
        return;
    hash_preload(vma->vm_mm, address, access, trap);
#endif /* CONFIG_PPC_STD_MMU */
#if (defined(CONFIG_PPC_BOOK3E_64) || defined(CONFIG_PPC_FSL_BOOK3E)) \
    && defined(CONFIG_HUGETLB_PAGE)
    if (is_vm_hugetlb_page(vma))
        book3e_hugetlb_preload(vma, address, *ptep);
#endif
}

/*
 * System memory should not be in /proc/iomem but various tools expect it
 * (eg kdump).
 */
static int add_system_ram_resources(void)
{
    struct memblock_region *reg;

    for_each_memblock(memory, reg) {
        struct resource *res;
        unsigned long base = reg->base;
        unsigned long size = reg->size;

        res = kzalloc(sizeof(struct resource), GFP_KERNEL);
        WARN_ON(!res);

        if (res) {
            res->name = "System RAM";
            res->start = base;
            res->end = base + size - 1;
            res->flags = IORESOURCE_MEM;
            WARN_ON(request_resource(&iomem_resource, res) < 0);
        }
    }

    return 0;
}
subsys_initcall(add_system_ram_resources);

#ifdef CONFIG_STRICT_DEVMEM
/*
 * devmem_is_allowed(): check to see if /dev/mem access to a certain address
 * is valid. The argument is a physical page number.
 *
 * Access has to be given to non-kernel-ram areas as well, these contain the
 * PCI mmio resources as well as potential bios/acpi data regions.
 */
int devmem_is_allowed(unsigned long pfn)
{
    if (iomem_is_exclusive(pfn << PAGE_SHIFT))
        return 0;
    if (!page_is_ram(pfn))
        return 1;
    if (page_is_rtas_user_buf(pfn))
        return 1;
    return 0;
}
#endif /* CONFIG_STRICT_DEVMEM */