linux/arch/x86/kernel/sys_x86_64.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/compat.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/sched/mm.h>
#include <linux/syscalls.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/smp.h>
#include <linux/sem.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/stat.h>
#include <linux/mman.h>
#include <linux/file.h>
#include <linux/utsname.h>
#include <linux/personality.h>
#include <linux/random.h>
#include <linux/uaccess.h>
#include <linux/elf.h>

#include <asm/elf.h>
#include <asm/ia32.h>

/*
 * Align a virtual address to avoid aliasing in the I$ on AMD F15h.
 */
static unsigned long get_align_mask(void)
{ … }

/*
 * To avoid aliasing in the I$ on AMD F15h, the bits defined by the
 * va_align.bits, [12:upper_bit), are set to a random value instead of
 * zeroing them. This random value is computed once per boot. This form
 * of ASLR is known as "per-boot ASLR".
 *
 * To achieve this, the random value is added to the info.align_offset
 * value before calling vm_unmapped_area() or ORed directly to the
 * address.
 */
static unsigned long get_align_bits(void)
{ … }

static int __init control_va_addr_alignment(char *str)
{ … }
__setup(…);

SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
		unsigned long, prot, unsigned long, flags,
		unsigned long, fd, unsigned long, off)
{ … }

static void find_start_end(unsigned long addr, unsigned long flags,
		unsigned long *begin, unsigned long *end)
{ … }

static inline unsigned long stack_guard_placement(vm_flags_t vm_flags)
{ … }

unsigned long
arch_get_unmapped_area_vmflags(struct file *filp, unsigned long addr, unsigned long len,
		       unsigned long pgoff, unsigned long flags, vm_flags_t vm_flags)
{ … }

unsigned long
arch_get_unmapped_area_topdown_vmflags(struct file *filp, unsigned long addr0,
			  unsigned long len, unsigned long pgoff,
			  unsigned long flags, vm_flags_t vm_flags)
{ … }

unsigned long
arch_get_unmapped_area(struct file *filp, unsigned long addr,
		unsigned long len, unsigned long pgoff, unsigned long flags)
{ … }

unsigned long
arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr,
			  const unsigned long len, const unsigned long pgoff,
			  const unsigned long flags)
{ … }