path: root/arch/sparc/kernel/sys_sparc_64.c

/* linux/arch/sparc64/kernel/sys_sparc.c
 *
 * This file contains various random system calls that
 * have a non-standard calling sequence on the Linux/sparc
 * platform.
 */

#include <linux/errno.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/sem.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/stat.h>
#include <linux/mman.h>
#include <linux/utsname.h>
#include <linux/smp.h>
#include <linux/slab.h>
#include <linux/syscalls.h>
#include <linux/ipc.h>
#include <linux/personality.h>
#include <linux/random.h>
#include <linux/module.h>

#include <asm/uaccess.h>
#include <asm/utrap.h>
#include <asm/perfctr.h>
#include <asm/unistd.h>

#include "entry.h"
#include "systbls.h"

/* #define DEBUG_UNIMP_SYSCALL */

asmlinkage unsigned long sys_getpagesize(void)
{
	return PAGE_SIZE;
}

#define VA_EXCLUDE_START (0x0000080000000000UL - (1UL << 32UL))
#define VA_EXCLUDE_END   (0xfffff80000000000UL + (1UL << 32UL))

/* Does addr --> addr+len fall within 4GB of the VA-space hole or
 * overflow past the end of the 64-bit address space?
 */
static inline int invalid_64bit_range(unsigned long addr, unsigned long len)
{
	unsigned long va_exclude_start, va_exclude_end;

	va_exclude_start = VA_EXCLUDE_START;
	va_exclude_end   = VA_EXCLUDE_END;

	if (unlikely(len >= va_exclude_start))
		return 1;

	if (unlikely((addr + len) < addr))
		return 1;

	if (unlikely((addr >= va_exclude_start && addr < va_exclude_end) ||
		     ((addr + len) >= va_exclude_start &&
		      (addr + len) < va_exclude_end)))
		return 1;

	return 0;
}

/* Does start,end straddle the VA-space hole?  */
static inline int straddles_64bit_va_hole(unsigned long start, unsigned long end)
{
	unsigned long va_exclude_start, va_exclude_end;

	va_exclude_start = VA_EXCLUDE_START;
	va_exclude_end   = VA_EXCLUDE_END;

	if (likely(start < va_exclude_start && end < va_exclude_start))
		return 0;

	if (likely(start >= va_exclude_end && end >= va_exclude_end))
		return 0;

	return 1;
}

/* These functions differ from the default implementations in
 * mm/mmap.c in two ways:
 *
 * 1) For file backed MAP_SHARED mmap()'s we D-cache color align,
 *    for fixed such mappings we just validate what the user gave us.
 * 2) For 64-bit tasks we avoid mapping anything within 4GB of
 *    the spitfire/niagara VA-hole.
 */

static inline unsigned long COLOUR_ALIGN(unsigned long addr,
					 unsigned long pgoff)
{
	unsigned long base = (addr+SHMLBA-1)&~(SHMLBA-1);
	unsigned long off = (pgoff<<PAGE_SHIFT) & (SHMLBA-1);

	return base + off;
}

static inline unsigned long COLOUR_ALIGN_DOWN(unsigned long addr,
					      unsigned long pgoff)
{
	unsigned long base = addr & ~(SHMLBA-1);
	unsigned long off = (pgoff<<PAGE_SHIFT) & (SHMLBA-1);

	if (base + off <= addr)
		return base + off;
	return base - off;
}

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;
	unsigned long task_size = TASK_SIZE;
	unsigned long start_addr;
	int do_color_align;

	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)) & (SHMLBA - 1)))
			return -EINVAL;
		return addr;
	}

	if (test_thread_flag(TIF_32BIT))
		task_size = STACK_TOP32;
	if (unlikely(len > task_size || len >= VA_EXCLUDE_START))
		return -ENOMEM;

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

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

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

	if (len > mm->cached_hole_size) {
	        start_addr = addr = mm->free_area_cache;
	} else {
	        start_addr = addr = TASK_UNMAPPED_BASE;
	        mm->cached_hole_size = 0;
	}

	task_size -= len;

full_search:
	if (do_color_align)
		addr = COLOUR_ALIGN(addr, pgoff);