x86: introduce initmem_init for 64 bit

[mirror_ubuntu-hirsute-kernel.git] / arch / x86 / mm / init_32.c

/*
 *
 *  Copyright (C) 1995  Linus Torvalds
 *
 *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
 */

#include <linux/module.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/pfn.h>
#include <linux/poison.h>
#include <linux/bootmem.h>
#include <linux/slab.h>
#include <linux/proc_fs.h>
#include <linux/memory_hotplug.h>
#include <linux/initrd.h>
#include <linux/cpumask.h>

#include <asm/asm.h>
#include <asm/processor.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/dma.h>
#include <asm/fixmap.h>
#include <asm/e820.h>
#include <asm/apic.h>
#include <asm/bugs.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/pgalloc.h>
#include <asm/sections.h>
#include <asm/paravirt.h>
#include <asm/setup.h>
#include <asm/cacheflush.h>

unsigned int __VMALLOC_RESERVE = 128 << 20;

unsigned long max_pfn_mapped;

DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
unsigned long highstart_pfn, highend_pfn;

static noinline int do_test_wp_bit(void);

/*
 * Creates a middle page table and puts a pointer to it in the
 * given global directory entry. This only returns the gd entry
 * in non-PAE compilation mode, since the middle layer is folded.
 */
static pmd_t * __init one_md_table_init(pgd_t *pgd)
{
        pud_t *pud;
        pmd_t *pmd_table;

#ifdef CONFIG_X86_PAE
        if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
                pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);

                paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
                set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
                pud = pud_offset(pgd, 0);
                BUG_ON(pmd_table != pmd_offset(pud, 0));
        }
#endif
        pud = pud_offset(pgd, 0);
        pmd_table = pmd_offset(pud, 0);

        return pmd_table;
}

/*
 * Create a page table and place a pointer to it in a middle page
 * directory entry:
 */
static pte_t * __init one_page_table_init(pmd_t *pmd)
{
        if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
                pte_t *page_table = NULL;

#ifdef CONFIG_DEBUG_PAGEALLOC
                page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
#endif
                if (!page_table) {
                        page_table =
                                (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
                }

                paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT);
                set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
                BUG_ON(page_table != pte_offset_kernel(pmd, 0));
        }

        return pte_offset_kernel(pmd, 0);
}

/*
 * This function initializes a certain range of kernel virtual memory
 * with new bootmem page tables, everywhere page tables are missing in
 * the given range.
 *
 * NOTE: The pagetables are allocated contiguous on the physical space
 * so we can cache the place of the first one and move around without
 * checking the pgd every time.
 */
static void __init
page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
{
        int pgd_idx, pmd_idx;
        unsigned long vaddr;
        pgd_t *pgd;
        pmd_t *pmd;

        vaddr = start;
        pgd_idx = pgd_index(vaddr);
        pmd_idx = pmd_index(vaddr);
        pgd = pgd_base + pgd_idx;

        for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
                pmd = one_md_table_init(pgd);
                pmd = pmd + pmd_index(vaddr);
                for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
                                                        pmd++, pmd_idx++) {
                        one_page_table_init(pmd);

                        vaddr += PMD_SIZE;
                }
                pmd_idx = 0;
        }
}

static inline int is_kernel_text(unsigned long addr)
{
        if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
                return 1;
        return 0;
}

/*
 * This maps the physical memory to kernel virtual address space, a total
 * of max_low_pfn pages, by creating page tables starting from address
 * PAGE_OFFSET:
 */
static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
{
        int pgd_idx, pmd_idx, pte_ofs;
        unsigned long pfn;
        pgd_t *pgd;
        pmd_t *pmd;
        pte_t *pte;
        unsigned pages_2m = 0, pages_4k = 0;

        pgd_idx = pgd_index(PAGE_OFFSET);
        pgd = pgd_base + pgd_idx;
        pfn = 0;

        for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
                pmd = one_md_table_init(pgd);
                if (pfn >= max_low_pfn)
                        continue;

                for (pmd_idx = 0;
                     pmd_idx < PTRS_PER_PMD && pfn < max_low_pfn;
                     pmd++, pmd_idx++) {
                        unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;

                        /*
                         * Map with big pages if possible, otherwise
                         * create normal page tables:
                         *
                         * Don't use a large page for the first 2/4MB of memory
                         * because there are often fixed size MTRRs in there
                         * and overlapping MTRRs into large pages can cause
                         * slowdowns.
                         */
                        if (cpu_has_pse && !(pgd_idx == 0 && pmd_idx == 0)) {
                                unsigned int addr2;
                                pgprot_t prot = PAGE_KERNEL_LARGE;

                                addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
                                        PAGE_OFFSET + PAGE_SIZE-1;

                                if (is_kernel_text(addr) ||
                                    is_kernel_text(addr2))
                                        prot = PAGE_KERNEL_LARGE_EXEC;

                                pages_2m++;
                                set_pmd(pmd, pfn_pmd(pfn, prot));

                                pfn += PTRS_PER_PTE;
                                max_pfn_mapped = pfn;
                                continue;
                        }
                        pte = one_page_table_init(pmd);

                        for (pte_ofs = 0;
                             pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn;
                             pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
                                pgprot_t prot = PAGE_KERNEL;

                                if (is_kernel_text(addr))
                                        prot = PAGE_KERNEL_EXEC;

                                pages_4k++;
                                set_pte(pte, pfn_pte(pfn, prot));
                        }
                        max_pfn_mapped = pfn;
                }
        }
        update_page_count(PG_LEVEL_2M, pages_2m);
        update_page_count(PG_LEVEL_4K, pages_4k);
}

/*
 * devmem_is_allowed() checks to see if /dev/mem access to a certain address
 * is valid. The argument is a physical page number.
 *
 *
 * On x86, access has to be given to the first megabyte of ram because that area
 * contains bios code and data regions used by X and dosemu and similar apps.
 * 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 pagenr)
{
        if (pagenr <= 256)
                return 1;
        if (!page_is_ram(pagenr))
                return 1;
        return 0;
}

#ifdef CONFIG_HIGHMEM
pte_t *kmap_pte;
pgprot_t kmap_prot;

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

static void __init kmap_init(void)
{
        unsigned long kmap_vstart;

        /*
         * Cache the first kmap pte:
         */
        kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
        kmap_pte = kmap_get_fixmap_pte(kmap_vstart);

        kmap_prot = PAGE_KERNEL;
}

static void __init permanent_kmaps_init(pgd_t *pgd_base)
{
        unsigned long vaddr;
        pgd_t *pgd;
        pud_t *pud;
        pmd_t *pmd;
        pte_t *pte;

        vaddr = PKMAP_BASE;
        page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);

        pgd = swapper_pg_dir + pgd_index(vaddr);
        pud = pud_offset(pgd, vaddr);
        pmd = pmd_offset(pud, vaddr);
        pte = pte_offset_kernel(pmd, vaddr);
        pkmap_page_table = pte;
}

static void __init add_one_highpage_init(struct page *page, int pfn)
{
        ClearPageReserved(page);
        init_page_count(page);
        __free_page(page);
        totalhigh_pages++;
}

struct add_highpages_data {
        unsigned long start_pfn;
        unsigned long end_pfn;
};

static int __init add_highpages_work_fn(unsigned long start_pfn,
                                         unsigned long end_pfn, void *datax)
{
        int node_pfn;
        struct page *page;
        unsigned long final_start_pfn, final_end_pfn;
        struct add_highpages_data *data;

        data = (struct add_highpages_data *)datax;

        final_start_pfn = max(start_pfn, data->start_pfn);
        final_end_pfn = min(end_pfn, data->end_pfn);
        if (final_start_pfn >= final_end_pfn)
                return 0;

        for (node_pfn = final_start_pfn; node_pfn < final_end_pfn;
             node_pfn++) {
                if (!pfn_valid(node_pfn))
                        continue;
                page = pfn_to_page(node_pfn);
                add_one_highpage_init(page, node_pfn);
        }

        return 0;

}

void __init add_highpages_with_active_regions(int nid, unsigned long start_pfn,
                                              unsigned long end_pfn)
{
        struct add_highpages_data data;

        data.start_pfn = start_pfn;
        data.end_pfn = end_pfn;

        work_with_active_regions(nid, add_highpages_work_fn, &data);
}

#ifndef CONFIG_NUMA
static void __init set_highmem_pages_init(void)
{
        add_highpages_with_active_regions(0, highstart_pfn, highend_pfn);

        totalram_pages += totalhigh_pages;
}
#endif /* !CONFIG_NUMA */

#else
# define kmap_init()                            do { } while (0)
# define permanent_kmaps_init(pgd_base)         do { } while (0)
# define set_highmem_pages_init()       do { } while (0)
#endif /* CONFIG_HIGHMEM */

pteval_t __PAGE_KERNEL = _PAGE_KERNEL;
EXPORT_SYMBOL(__PAGE_KERNEL);

pteval_t __PAGE_KERNEL_EXEC = _PAGE_KERNEL_EXEC;

void __init native_pagetable_setup_start(pgd_t *base)
{
        unsigned long pfn, va;
        pgd_t *pgd;
        pud_t *pud;
        pmd_t *pmd;
        pte_t *pte;

        /*
         * Remove any mappings which extend past the end of physical
         * memory from the boot time page table:
         */
        for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
                va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
                pgd = base + pgd_index(va);
                if (!pgd_present(*pgd))
                        break;

                pud = pud_offset(pgd, va);
                pmd = pmd_offset(pud, va);
                if (!pmd_present(*pmd))
                        break;

                pte = pte_offset_kernel(pmd, va);
                if (!pte_present(*pte))
                        break;

                pte_clear(NULL, va, pte);
        }
        paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);
}

void __init native_pagetable_setup_done(pgd_t *base)
{
}

/*
 * Build a proper pagetable for the kernel mappings.  Up until this
 * point, we've been running on some set of pagetables constructed by
 * the boot process.
 *
 * If we're booting on native hardware, this will be a pagetable
 * constructed in arch/x86/kernel/head_32.S.  The root of the
 * pagetable will be swapper_pg_dir.
 *
 * If we're booting paravirtualized under a hypervisor, then there are
 * more options: we may already be running PAE, and the pagetable may
 * or may not be based in swapper_pg_dir.  In any case,
 * paravirt_pagetable_setup_start() will set up swapper_pg_dir
 * appropriately for the rest of the initialization to work.
 *
 * In general, pagetable_init() assumes that the pagetable may already
 * be partially populated, and so it avoids stomping on any existing
 * mappings.
 */
static void __init pagetable_init(void)
{
        pgd_t *pgd_base = swapper_pg_dir;
        unsigned long vaddr, end;

        paravirt_pagetable_setup_start(pgd_base);

        /* Enable PSE if available */
        if (cpu_has_pse)
                set_in_cr4(X86_CR4_PSE);

        /* Enable PGE if available */
        if (cpu_has_pge) {
                set_in_cr4(X86_CR4_PGE);
                __PAGE_KERNEL |= _PAGE_GLOBAL;
                __PAGE_KERNEL_EXEC |= _PAGE_GLOBAL;
        }

        kernel_physical_mapping_init(pgd_base);
        remap_numa_kva();

        /*
         * Fixed mappings, only the page table structure has to be
         * created - mappings will be set by set_fixmap():
         */
        early_ioremap_clear();
        vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
        end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
        page_table_range_init(vaddr, end, pgd_base);
        early_ioremap_reset();

        permanent_kmaps_init(pgd_base);

        paravirt_pagetable_setup_done(pgd_base);
}

#ifdef CONFIG_ACPI_SLEEP
/*
 * ACPI suspend needs this for resume, because things like the intel-agp
 * driver might have split up a kernel 4MB mapping.
 */
char swsusp_pg_dir[PAGE_SIZE]
        __attribute__ ((aligned(PAGE_SIZE)));

static inline void save_pg_dir(void)
{
        memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
}
#else /* !CONFIG_ACPI_SLEEP */
static inline void save_pg_dir(void)
{
}
#endif /* !CONFIG_ACPI_SLEEP */

void zap_low_mappings(void)
{
        int i;

        /*
         * Zap initial low-memory mappings.
         *
         * Note that "pgd_clear()" doesn't do it for
         * us, because pgd_clear() is a no-op on i386.
         */
        for (i = 0; i < KERNEL_PGD_BOUNDARY; i++) {
#ifdef CONFIG_X86_PAE
                set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
#else
                set_pgd(swapper_pg_dir+i, __pgd(0));
#endif
        }
        flush_tlb_all();
}

int nx_enabled;

pteval_t __supported_pte_mask __read_mostly = ~_PAGE_NX;
EXPORT_SYMBOL_GPL(__supported_pte_mask);

#ifdef CONFIG_X86_PAE

static int disable_nx __initdata;

/*
 * noexec = on|off
 *
 * Control non executable mappings.
 *
 * on      Enable
 * off     Disable
 */
static int __init noexec_setup(char *str)
{
        if (!str || !strcmp(str, "on")) {
                if (cpu_has_nx) {
                        __supported_pte_mask |= _PAGE_NX;
                        disable_nx = 0;
                }
        } else {
                if (!strcmp(str, "off")) {
                        disable_nx = 1;
                        __supported_pte_mask &= ~_PAGE_NX;
                } else {
                        return -EINVAL;
                }
        }

        return 0;
}
early_param("noexec", noexec_setup);

static void __init set_nx(void)
{
        unsigned int v[4], l, h;

        if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
                cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);

                if ((v[3] & (1 << 20)) && !disable_nx) {
                        rdmsr(MSR_EFER, l, h);
                        l |= EFER_NX;
                        wrmsr(MSR_EFER, l, h);
                        nx_enabled = 1;
                        __supported_pte_mask |= _PAGE_NX;
                }
        }
}
#endif

/*
 * paging_init() sets up the page tables - note that the first 8MB are
 * already mapped by head.S.
 *
 * This routines also unmaps the page at virtual kernel address 0, so
 * that we can trap those pesky NULL-reference errors in the kernel.
 */
void __init paging_init(void)
{
#ifdef CONFIG_X86_PAE
        set_nx();
        if (nx_enabled)
                printk(KERN_INFO "NX (Execute Disable) protection: active\n");
#endif
        pagetable_init();

        load_cr3(swapper_pg_dir);

        __flush_tlb_all();

        kmap_init();
}

/*
 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
 * and also on some strange 486's. All 586+'s are OK. This used to involve
 * black magic jumps to work around some nasty CPU bugs, but fortunately the
 * switch to using exceptions got rid of all that.
 */
static void __init test_wp_bit(void)
{
        printk(KERN_INFO
  "Checking if this processor honours the WP bit even in supervisor mode...");

        /* Any page-aligned address will do, the test is non-destructive */
        __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
        boot_cpu_data.wp_works_ok = do_test_wp_bit();
        clear_fixmap(FIX_WP_TEST);

        if (!boot_cpu_data.wp_works_ok) {
                printk(KERN_CONT "No.\n");
#ifdef CONFIG_X86_WP_WORKS_OK
                panic(
  "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
#endif
        } else {
                printk(KERN_CONT "Ok.\n");
        }
}

static struct kcore_list kcore_mem, kcore_vmalloc;

void __init mem_init(void)
{
        int codesize, reservedpages, datasize, initsize;
        int tmp;

#ifdef CONFIG_FLATMEM
        BUG_ON(!mem_map);
#endif
        /* this will put all low memory onto the freelists */
        totalram_pages += free_all_bootmem();

        reservedpages = 0;
        for (tmp = 0; tmp < max_low_pfn; tmp++)
                /*
                 * Only count reserved RAM pages:
                 */
                if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
                        reservedpages++;

        set_highmem_pages_init();

        codesize =  (unsigned long) &_etext - (unsigned long) &_text;
        datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
        initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;

        kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
        kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
                   VMALLOC_END-VMALLOC_START);

        printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
                        "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
                (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
                num_physpages << (PAGE_SHIFT-10),
                codesize >> 10,
                reservedpages << (PAGE_SHIFT-10),
                datasize >> 10,
                initsize >> 10,
                (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
               );

        printk(KERN_INFO "virtual kernel memory layout:\n"
                "    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
#ifdef CONFIG_HIGHMEM
                "    pkmap   : 0x%08lx - 0x%08lx   (%4ld kB)\n"
#endif
                "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
                "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
                "      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"
                "      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"
                "      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",
                FIXADDR_START, FIXADDR_TOP,
                (FIXADDR_TOP - FIXADDR_START) >> 10,

#ifdef CONFIG_HIGHMEM
                PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
                (LAST_PKMAP*PAGE_SIZE) >> 10,
#endif

                VMALLOC_START, VMALLOC_END,
                (VMALLOC_END - VMALLOC_START) >> 20,

                (unsigned long)__va(0), (unsigned long)high_memory,
                ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,

                (unsigned long)&__init_begin, (unsigned long)&__init_end,
                ((unsigned long)&__init_end -
                 (unsigned long)&__init_begin) >> 10,

                (unsigned long)&_etext, (unsigned long)&_edata,
                ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,

                (unsigned long)&_text, (unsigned long)&_etext,
                ((unsigned long)&_etext - (unsigned long)&_text) >> 10);

#ifdef CONFIG_HIGHMEM
        BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE        > FIXADDR_START);
        BUG_ON(VMALLOC_END                              > PKMAP_BASE);
#endif
        BUG_ON(VMALLOC_START                            > VMALLOC_END);
        BUG_ON((unsigned long)high_memory               > VMALLOC_START);

        if (boot_cpu_data.wp_works_ok < 0)
                test_wp_bit();

        cpa_init();
        save_pg_dir();
        zap_low_mappings();
}

#ifdef CONFIG_MEMORY_HOTPLUG
int arch_add_memory(int nid, u64 start, u64 size)
{
        struct pglist_data *pgdata = NODE_DATA(nid);
        struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
        unsigned long start_pfn = start >> PAGE_SHIFT;
        unsigned long nr_pages = size >> PAGE_SHIFT;

        return __add_pages(zone, start_pfn, nr_pages);
}
#endif

/*
 * This function cannot be __init, since exceptions don't work in that
 * section.  Put this after the callers, so that it cannot be inlined.
 */
static noinline int do_test_wp_bit(void)
{
        char tmp_reg;
        int flag;

        __asm__ __volatile__(
                "       movb %0, %1     \n"
                "1:     movb %1, %0     \n"
                "       xorl %2, %2     \n"
                "2:                     \n"
                _ASM_EXTABLE(1b,2b)
                :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
                 "=q" (tmp_reg),
                 "=r" (flag)
                :"2" (1)
                :"memory");

        return flag;
}

#ifdef CONFIG_DEBUG_RODATA
const int rodata_test_data = 0xC3;
EXPORT_SYMBOL_GPL(rodata_test_data);

void mark_rodata_ro(void)
{
        unsigned long start = PFN_ALIGN(_text);
        unsigned long size = PFN_ALIGN(_etext) - start;

        set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
        printk(KERN_INFO "Write protecting the kernel text: %luk\n",
                size >> 10);

#ifdef CONFIG_CPA_DEBUG
        printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
                start, start+size);
        set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);

        printk(KERN_INFO "Testing CPA: write protecting again\n");
        set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
#endif
        start += size;
        size = (unsigned long)__end_rodata - start;
        set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
        printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
                size >> 10);
        rodata_test();

#ifdef CONFIG_CPA_DEBUG
        printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
        set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);

        printk(KERN_INFO "Testing CPA: write protecting again\n");
        set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
#endif
}
#endif

void free_init_pages(char *what, unsigned long begin, unsigned long end)
{
#ifdef CONFIG_DEBUG_PAGEALLOC
        /*
         * If debugging page accesses then do not free this memory but
         * mark them not present - any buggy init-section access will
         * create a kernel page fault:
         */
        printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
                begin, PAGE_ALIGN(end));
        set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
#else
        unsigned long addr;

        /*
         * We just marked the kernel text read only above, now that
         * we are going to free part of that, we need to make that
         * writeable first.
         */
        set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);

        for (addr = begin; addr < end; addr += PAGE_SIZE) {
                ClearPageReserved(virt_to_page(addr));
                init_page_count(virt_to_page(addr));
                memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
                free_page(addr);
                totalram_pages++;
        }
        printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
#endif
}

void free_initmem(void)
{
        free_init_pages("unused kernel memory",
                        (unsigned long)(&__init_begin),
                        (unsigned long)(&__init_end));
}

#ifdef CONFIG_BLK_DEV_INITRD
void free_initrd_mem(unsigned long start, unsigned long end)
{
        free_init_pages("initrd memory", start, end);
}
#endif

int __init reserve_bootmem_generic(unsigned long phys, unsigned long len,
                                   int flags)
{
        return reserve_bootmem(phys, len, flags);
}