/*
 * Copyright (C) 2013 Altera Corporation
 * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
 * Copyright (C) 2009 Wind River Systems Inc
 *   Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
 * Copyright (C) 2004 Microtronix Datacom Ltd
 *
 * based on arch/m68k/mm/init.c
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License. See the file "COPYING" in the main directory of this archive
 * for more details.
 */

#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/init.h>
#include <linux/pagemap.h>
#include <linux/memblock.h>
#include <linux/slab.h>
#include <linux/binfmts.h>
#include <linux/execmem.h>

#include <asm/setup.h>
#include <asm/page.h>
#include <asm/sections.h>
#include <asm/tlb.h>
#include <asm/mmu_context.h>
#include <asm/cpuinfo.h>
#include <asm/processor.h>

pgd_t *pgd_current;

void __init arch_zone_limits_init(unsigned long *max_zone_pfns)
{
        max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
}

/*
 * paging_init() continues the virtual memory environment setup which
 * was begun by the code in arch/head.S.
 * The parameters are pointers to where to stick the starting and ending
 * addresses of available kernel virtual memory.
 */
void __init paging_init(void)
{
        pagetable_init();
        pgd_current = swapper_pg_dir;

        flush_dcache_range((unsigned long)empty_zero_page,
                        (unsigned long)empty_zero_page + PAGE_SIZE);
}

void __init mmu_init(void)
{
        flush_tlb_all();
}

pgd_t swapper_pg_dir[PTRS_PER_PGD] __aligned(PAGE_SIZE);
pte_t invalid_pte_table[PTRS_PER_PTE] __aligned(PAGE_SIZE);
static struct page *kuser_page[1];
static struct vm_special_mapping vdso_mapping = {
        .name = "[vdso]",
        .pages = kuser_page,
};

static int alloc_kuser_page(void)
{
        extern char __kuser_helper_start[], __kuser_helper_end[];
        int kuser_sz = __kuser_helper_end - __kuser_helper_start;
        unsigned long vpage;

        vpage = get_zeroed_page(GFP_ATOMIC);
        if (!vpage)
                return -ENOMEM;

        /* Copy kuser helpers */
        memcpy((void *)vpage, __kuser_helper_start, kuser_sz);

        flush_icache_range(vpage, vpage + KUSER_SIZE);
        kuser_page[0] = virt_to_page(vpage);

        return 0;
}
arch_initcall(alloc_kuser_page);

int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
        struct mm_struct *mm = current->mm;
        struct vm_area_struct *vma;

        mmap_write_lock(mm);

        /* Map kuser helpers to user space address */
        vma = _install_special_mapping(mm, KUSER_BASE, KUSER_SIZE,
                                      VM_READ | VM_EXEC | VM_MAYREAD |
                                      VM_MAYEXEC, &vdso_mapping);

        mmap_write_unlock(mm);

        return IS_ERR(vma) ? PTR_ERR(vma) : 0;
}

const char *arch_vma_name(struct vm_area_struct *vma)
{
        return (vma->vm_start == KUSER_BASE) ? "[kuser]" : NULL;
}

static const pgprot_t protection_map[16] = {
        [VM_NONE]                                       = MKP(0, 0, 0),
        [VM_READ]                                       = MKP(0, 0, 1),
        [VM_WRITE]                                      = MKP(0, 0, 0),
        [VM_WRITE | VM_READ]                            = MKP(0, 0, 1),
        [VM_EXEC]                                       = MKP(1, 0, 0),
        [VM_EXEC | VM_READ]                             = MKP(1, 0, 1),
        [VM_EXEC | VM_WRITE]                            = MKP(1, 0, 0),
        [VM_EXEC | VM_WRITE | VM_READ]                  = MKP(1, 0, 1),
        [VM_SHARED]                                     = MKP(0, 0, 0),
        [VM_SHARED | VM_READ]                           = MKP(0, 0, 1),
        [VM_SHARED | VM_WRITE]                          = MKP(0, 1, 0),
        [VM_SHARED | VM_WRITE | VM_READ]                = MKP(0, 1, 1),
        [VM_SHARED | VM_EXEC]                           = MKP(1, 0, 0),
        [VM_SHARED | VM_EXEC | VM_READ]                 = MKP(1, 0, 1),
        [VM_SHARED | VM_EXEC | VM_WRITE]                = MKP(1, 1, 0),
        [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]      = MKP(1, 1, 1)
};
DECLARE_VM_GET_PAGE_PROT

#ifdef CONFIG_EXECMEM
static struct execmem_info execmem_info __ro_after_init;

struct execmem_info __init *execmem_arch_setup(void)
{
        execmem_info = (struct execmem_info){
                .ranges = {
                        [EXECMEM_DEFAULT] = {
                                .start  = MODULES_VADDR,
                                .end    = MODULES_END,
                                .pgprot = PAGE_KERNEL_EXEC,
                                .alignment = 1,
                        },
                },
        };

        return &execmem_info;
}
#endif /* CONFIG_EXECMEM */