/*
 *    PARISC specific syscalls
 *
 *    Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org>
 *    Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org>
 *    Copyright (C) 2001 Thomas Bogendoerfer <tsbogend at parisc-linux.org>
 *    Copyright (C) 1999-2014 Helge Deller <deller@gmx.de>
 *
 *
 *    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.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/uaccess.h>
#include <asm/elf.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/linkage.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/sched/signal.h>
#include <linux/sched/mm.h>
#include <linux/shm.h>
#include <linux/syscalls.h>
#include <linux/utsname.h>
#include <linux/personality.h>
#include <linux/random.h>

/* we construct an artificial offset for the mapping based on the physical
 * address of the kernel mapping variable */
#define GET_LAST_MMAP(filp)             \
        (filp ? ((unsigned long) filp->f_mapping) >> 8 : 0UL)
#define SET_LAST_MMAP(filp, val)        \
         { /* nothing */ }

static int get_offset(unsigned int last_mmap)
{
        return (last_mmap & (SHM_COLOUR-1)) >> PAGE_SHIFT;
}

static unsigned long shared_align_offset(unsigned int last_mmap,
                                         unsigned long pgoff)
{
        return (get_offset(last_mmap) + pgoff) << PAGE_SHIFT;
}

static inline unsigned long COLOR_ALIGN(unsigned long addr,
                         unsigned int last_mmap, unsigned long pgoff)
{
        unsigned long base = (addr+SHM_COLOUR-1) & ~(SHM_COLOUR-1);
        unsigned long off  = (SHM_COLOUR-1) &
                (shared_align_offset(last_mmap, pgoff) << PAGE_SHIFT);

        return base + off;
}

/*
 * Top of mmap area (just below the process stack).
 */

static unsigned long mmap_upper_limit(void)
{
        unsigned long stack_base;

        /* Limit stack size - see setup_arg_pages() in fs/exec.c */
        stack_base = rlimit_max(RLIMIT_STACK);
        if (stack_base > STACK_SIZE_MAX)
                stack_base = STACK_SIZE_MAX;

        /* Add space for stack randomization. */
        stack_base += (STACK_RND_MASK << PAGE_SHIFT);

        return PAGE_ALIGN(STACK_TOP - stack_base);
}


unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
                unsigned long len, unsigned long pgoff, unsigned long flags)
{
        struct mm_struct *mm = current->mm;
        struct vm_area_struct *vma, *prev;
        unsigned long task_size = TASK_SIZE;
        int do_color_align, last_mmap;
        struct vm_unmapped_area_info info;

        if (len > task_size)
                return -ENOMEM;

        do_color_align = 0;
        if (filp || (flags & MAP_SHARED))
                do_color_align = 1;
        last_mmap = GET_LAST_MMAP(filp);

        if (flags & MAP_FIXED) {
                if ((flags & MAP_SHARED) && last_mmap &&
                    (addr - shared_align_offset(last_mmap, pgoff))
                                & (SHM_COLOUR - 1))
                        return -EINVAL;
                goto found_addr;
        }

        if (addr) {
                if (do_color_align && last_mmap)
                        addr = COLOR_ALIGN(addr, last_mmap, pgoff);
                else
                        addr = PAGE_ALIGN(addr);

                vma = find_vma_prev(mm, addr, &prev);
                if (task_size - len >= addr &&
                    (!vma || addr + len <= vm_start_gap(vma)) &&
                    (!prev || addr >= vm_end_gap(prev)))
                        goto found_addr;
        }

        info.flags = 0;
        info.length = len;
        info.low_limit = mm->mmap_legacy_base;
        info.high_limit = mmap_upper_limit();
        info.align_mask = last_mmap ? (PAGE_MASK & (SHM_COLOUR - 1)) : 0;
        info.align_offset = shared_align_offset(last_mmap, pgoff);
        addr = vm_unmapped_area(&info);

found_addr:
        if (do_color_align && !last_mmap && !(addr & ~PAGE_MASK))
                SET_LAST_MMAP(filp, addr - (pgoff << PAGE_SHIFT));

        return addr;
}

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)
{
        struct vm_area_struct *vma, *prev;
        struct mm_struct *mm = current->mm;
        unsigned long addr = addr0;
        int do_color_align, last_mmap;
        struct vm_unmapped_area_info info;

#ifdef CONFIG_64BIT
        /* This should only ever run for 32-bit processes.  */
        BUG_ON(!test_thread_flag(TIF_32BIT));
#endif

        /* requested length too big for entire address space */
        if (len > TASK_SIZE)
                return -ENOMEM;

        do_color_align = 0;
        if (filp || (flags & MAP_SHARED))
                do_color_align = 1;
        last_mmap = GET_LAST_MMAP(filp);

        if (flags & MAP_FIXED) {
                if ((flags & MAP_SHARED) && last_mmap &&
                    (addr - shared_align_offset(last_mmap, pgoff))
                        & (SHM_COLOUR - 1))
                        return -EINVAL;
                goto found_addr;
        }

        /* requesting a specific address */
        if (addr) {
                if (do_color_align && last_mmap)
                        addr = COLOR_ALIGN(addr, last_mmap, pgoff);
                else
                        addr = PAGE_ALIGN(addr);

                vma = find_vma_prev(mm, addr, &prev);
                if (TASK_SIZE - len >= addr &&
                    (!vma || addr + len <= vm_start_gap(vma)) &&
                    (!prev || addr >= vm_end_gap(prev)))
                        goto found_addr;
        }

        info.flags = VM_UNMAPPED_AREA_TOPDOWN;
        info.length = len;
        info.low_limit = PAGE_SIZE;
        info.high_limit = mm->mmap_base;
        info.align_mask = last_mmap ? (PAGE_MASK & (SHM_COLOUR - 1)) : 0;
        info.align_offset = shared_align_offset(last_mmap, pgoff);
        addr = vm_unmapped_area(&info);
        if (!(addr & ~PAGE_MASK))
                goto found_addr;
        VM_BUG_ON(addr != -ENOMEM);

        /*
         * 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.
         */
        return arch_get_unmapped_area(filp, addr0, len, pgoff, flags);

found_addr:
        if (do_color_align && !last_mmap && !(addr & ~PAGE_MASK))
                SET_LAST_MMAP(filp, addr - (pgoff << PAGE_SHIFT));

        return addr;
}

static int mmap_is_legacy(void)
{
        if (current->personality & ADDR_COMPAT_LAYOUT)
                return 1;

        /* parisc stack always grows up - so a unlimited stack should
         * not be an indicator to use the legacy memory layout.
         * if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
         *      return 1;
         */

        return sysctl_legacy_va_layout;
}

static unsigned long mmap_rnd(void)
{
        unsigned long rnd = 0;

        if (current->flags & PF_RANDOMIZE)
                rnd = get_random_int() & MMAP_RND_MASK;

        return rnd << PAGE_SHIFT;
}

unsigned long arch_mmap_rnd(void)
{
        return (get_random_int() & MMAP_RND_MASK) << PAGE_SHIFT;
}

static unsigned long mmap_legacy_base(void)
{
        return TASK_UNMAPPED_BASE + mmap_rnd();
}

/*
 * This function, called very early during the creation of a new
 * process VM image, sets up which VM layout function to use:
 */
void arch_pick_mmap_layout(struct mm_struct *mm)
{
        mm->mmap_legacy_base = mmap_legacy_base();
        mm->mmap_base = mmap_upper_limit();

        if (mmap_is_legacy()) {
                mm->mmap_base = mm->mmap_legacy_base;
                mm->get_unmapped_area = arch_get_unmapped_area;
        } else {
                mm->get_unmapped_area = arch_get_unmapped_area_topdown;
        }
}


asmlinkage unsigned long sys_mmap2(unsigned long addr, unsigned long len,
        unsigned long prot, unsigned long flags, unsigned long fd,
        unsigned long pgoff)
{
        /* Make sure the shift for mmap2 is constant (12), no matter what PAGE_SIZE
           we have. */
        return sys_mmap_pgoff(addr, len, prot, flags, fd,
                              pgoff >> (PAGE_SHIFT - 12));
}

asmlinkage unsigned long sys_mmap(unsigned long addr, unsigned long len,
                unsigned long prot, unsigned long flags, unsigned long fd,
                unsigned long offset)
{
        if (!(offset & ~PAGE_MASK)) {
                return sys_mmap_pgoff(addr, len, prot, flags, fd,
                                        offset >> PAGE_SHIFT);
        } else {
                return -EINVAL;
        }
}

/* Fucking broken ABI */

#ifdef CONFIG_64BIT
asmlinkage long parisc_truncate64(const char __user * path,
                                        unsigned int high, unsigned int low)
{
        return sys_truncate(path, (long)high << 32 | low);
}

asmlinkage long parisc_ftruncate64(unsigned int fd,
                                        unsigned int high, unsigned int low)
{
        return sys_ftruncate(fd, (long)high << 32 | low);
}

/* stubs for the benefit of the syscall_table since truncate64 and truncate 
 * are identical on LP64 */
asmlinkage long sys_truncate64(const char __user * path, unsigned long length)
{
        return sys_truncate(path, length);
}
asmlinkage long sys_ftruncate64(unsigned int fd, unsigned long length)
{
        return sys_ftruncate(fd, length);
}
asmlinkage long sys_fcntl64(unsigned int fd, unsigned int cmd, unsigned long arg)
{
        return sys_fcntl(fd, cmd, arg);
}
#else

asmlinkage long parisc_truncate64(const char __user * path,
                                        unsigned int high, unsigned int low)
{
        return sys_truncate64(path, (loff_t)high << 32 | low);
}

asmlinkage long parisc_ftruncate64(unsigned int fd,
                                        unsigned int high, unsigned int low)
{
        return sys_ftruncate64(fd, (loff_t)high << 32 | low);
}
#endif

asmlinkage ssize_t parisc_pread64(unsigned int fd, char __user *buf, size_t count,
                                        unsigned int high, unsigned int low)
{
        return sys_pread64(fd, buf, count, (loff_t)high << 32 | low);
}

asmlinkage ssize_t parisc_pwrite64(unsigned int fd, const char __user *buf,
                        size_t count, unsigned int high, unsigned int low)
{
        return sys_pwrite64(fd, buf, count, (loff_t)high << 32 | low);
}

asmlinkage ssize_t parisc_readahead(int fd, unsigned int high, unsigned int low,
                                    size_t count)
{
        return sys_readahead(fd, (loff_t)high << 32 | low, count);
}

asmlinkage long parisc_fadvise64_64(int fd,
                        unsigned int high_off, unsigned int low_off,
                        unsigned int high_len, unsigned int low_len, int advice)
{
        return sys_fadvise64_64(fd, (loff_t)high_off << 32 | low_off,
                        (loff_t)high_len << 32 | low_len, advice);
}

asmlinkage long parisc_sync_file_range(int fd,
                        u32 hi_off, u32 lo_off, u32 hi_nbytes, u32 lo_nbytes,
                        unsigned int flags)
{
        return sys_sync_file_range(fd, (loff_t)hi_off << 32 | lo_off,
                        (loff_t)hi_nbytes << 32 | lo_nbytes, flags);
}

asmlinkage long parisc_fallocate(int fd, int mode, u32 offhi, u32 offlo,
                                u32 lenhi, u32 lenlo)
{
        return sys_fallocate(fd, mode, ((u64)offhi << 32) | offlo,
                             ((u64)lenhi << 32) | lenlo);
}

long parisc_personality(unsigned long personality)
{
        long err;

        if (personality(current->personality) == PER_LINUX32
            && personality(personality) == PER_LINUX)
                personality = (personality & ~PER_MASK) | PER_LINUX32;

        err = sys_personality(personality);
        if (personality(err) == PER_LINUX32)
                err = (err & ~PER_MASK) | PER_LINUX;

        return err;
}