path: root/arch/parisc/kernel/sys_parisc.c

/*
 *    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