/*
 * arch/sh/mm/mmap.c
 *
 * Copyright (C) 2008 - 2009  Paul Mundt
 *
 * 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/io.h>
#include <linux/mm.h>
#include <linux/sched/mm.h>
#include <linux/mman.h>
#include <linux/module.h>
#include <asm/page.h>
#include <asm/processor.h>

unsigned long shm_align_mask = PAGE_SIZE - 1;   /* Sane caches */
EXPORT_SYMBOL(shm_align_mask);

#ifdef CONFIG_MMU
static const pgprot_t protection_map[16] = {
        [VM_NONE]                                       = PAGE_NONE,
        [VM_READ]                                       = PAGE_READONLY,
        [VM_WRITE]                                      = PAGE_COPY,
        [VM_WRITE | VM_READ]                            = PAGE_COPY,
        [VM_EXEC]                                       = PAGE_EXECREAD,
        [VM_EXEC | VM_READ]                             = PAGE_EXECREAD,
        [VM_EXEC | VM_WRITE]                            = PAGE_COPY,
        [VM_EXEC | VM_WRITE | VM_READ]                  = PAGE_COPY,
        [VM_SHARED]                                     = PAGE_NONE,
        [VM_SHARED | VM_READ]                           = PAGE_READONLY,
        [VM_SHARED | VM_WRITE]                          = PAGE_WRITEONLY,
        [VM_SHARED | VM_WRITE | VM_READ]                = PAGE_SHARED,
        [VM_SHARED | VM_EXEC]                           = PAGE_EXECREAD,
        [VM_SHARED | VM_EXEC | VM_READ]                 = PAGE_EXECREAD,
        [VM_SHARED | VM_EXEC | VM_WRITE]                = PAGE_RWX,
        [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]      = PAGE_RWX
};
DECLARE_VM_GET_PAGE_PROT

/*
 * To avoid cache aliases, we map the shared page with same color.
 */
static inline unsigned long COLOUR_ALIGN(unsigned long addr,
                                         unsigned long pgoff)
{
        unsigned long base = (addr + shm_align_mask) & ~shm_align_mask;
        unsigned long off = (pgoff << PAGE_SHIFT) & shm_align_mask;

        return base + off;
}

unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
        unsigned long len, unsigned long pgoff, unsigned long flags,
        vm_flags_t vm_flags)
{
        struct mm_struct *mm = current->mm;
        struct vm_area_struct *vma;
        int do_colour_align;
        struct vm_unmapped_area_info info = {};

        if (flags & MAP_FIXED) {
                /* We do not accept a shared mapping if it would violate
                 * cache aliasing constraints.
                 */
                if ((flags & MAP_SHARED) &&
                    ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
                        return -EINVAL;
                return addr;
        }

        if (unlikely(len > TASK_SIZE))
                return -ENOMEM;

        do_colour_align = 0;
        if (filp || (flags & MAP_SHARED))
                do_colour_align = 1;

        if (addr) {
                if (do_colour_align)
                        addr = COLOUR_ALIGN(addr, pgoff);
                else
                        addr = PAGE_ALIGN(addr);

                vma = find_vma(mm, addr);
                if (TASK_SIZE - len >= addr &&
                    (!vma || addr + len <= vm_start_gap(vma)))
                        return addr;
        }

        info.length = len;
        info.low_limit = TASK_UNMAPPED_BASE;
        info.high_limit = TASK_SIZE;
        info.align_mask = do_colour_align ? (PAGE_MASK & shm_align_mask) : 0;
        info.align_offset = pgoff << PAGE_SHIFT;
        return vm_unmapped_area(&info);
}

unsigned long
arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
                          const unsigned long len, const unsigned long pgoff,
                          const unsigned long flags, vm_flags_t vm_flags)
{
        struct vm_area_struct *vma;
        struct mm_struct *mm = current->mm;
        unsigned long addr = addr0;
        int do_colour_align;
        struct vm_unmapped_area_info info = {};

        if (flags & MAP_FIXED) {
                /* We do not accept a shared mapping if it would violate
                 * cache aliasing constraints.
                 */
                if ((flags & MAP_SHARED) &&
                    ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
                        return -EINVAL;
                return addr;
        }

        if (unlikely(len > TASK_SIZE))
                return -ENOMEM;

        do_colour_align = 0;
        if (filp || (flags & MAP_SHARED))
                do_colour_align = 1;

        /* requesting a specific address */
        if (addr) {
                if (do_colour_align)
                        addr = COLOUR_ALIGN(addr, pgoff);
                else
                        addr = PAGE_ALIGN(addr);

                vma = find_vma(mm, addr);
                if (TASK_SIZE - len >= addr &&
                    (!vma || addr + len <= vm_start_gap(vma)))
                        return addr;
        }

        info.flags = VM_UNMAPPED_AREA_TOPDOWN;
        info.length = len;
        info.low_limit = PAGE_SIZE;
        info.high_limit = mm->mmap_base;
        info.align_mask = do_colour_align ? (PAGE_MASK & shm_align_mask) : 0;
        info.align_offset = pgoff << PAGE_SHIFT;
        addr = vm_unmapped_area(&info);

        /*
         * A failed mmap() very likely causes application failure,
         * so fall back to the bottom-up function here. This scenario
         * can happen with large stack limits and large mmap()
         * allocations.
         */
        if (addr & ~PAGE_MASK) {
                VM_BUG_ON(addr != -ENOMEM);
                info.flags = 0;
                info.low_limit = TASK_UNMAPPED_BASE;
                info.high_limit = TASK_SIZE;
                addr = vm_unmapped_area(&info);
        }

        return addr;
}
#endif /* CONFIG_MMU */

/*
 * You really shouldn't be using read() or write() on /dev/mem.  This
 * might go away in the future.
 */
int valid_phys_addr_range(phys_addr_t addr, size_t count)
{
        if (addr < __MEMORY_START)
                return 0;
        if (addr + count > __pa(high_memory))
                return 0;

        return 1;
}

int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
{
        return 1;
}