Release 4.11 arch/x86/kernel/sys_x86_64.c

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

/*
 * Align a virtual address to avoid aliasing in the I$ on AMD F15h.
 */


static unsigned long get_align_mask(void)
{
	/* handle 32- and 64-bit case with a single conditional */
	if (va_align.flags < 0 || !(va_align.flags & (2 - mmap_is_ia32())))
		return 0;

	if (!(current->flags & PF_RANDOMIZE))
		return 0;

	return va_align.mask;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Borislav Petkov
45
83.33%
1
50.00%
Michel Lespinasse
9
16.67%
1
50.00%
Total
54
100.00%
2
100.00%

/*
 * 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)
{
	return va_align.bits & get_align_mask();
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Hector Marco-Gisbert
17
100.00%
1
100.00%
Total
17
100.00%
1
100.00%



unsigned long align_vdso_addr(unsigned long addr)
{
	unsigned long align_mask = get_align_mask();
	addr = (addr + align_mask) & ~align_mask;
	return addr | get_align_bits();
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Michel Lespinasse
20
58.82%
1
33.33%
Hector Marco-Gisbert
8
23.53%
1
33.33%
Borislav Petkov
6
17.65%
1
33.33%
Total
34
100.00%
3
100.00%



static int __init control_va_addr_alignment(char *str)
{
	/* guard against enabling this on other CPU families */
	if (va_align.flags < 0)
		return 1;

	if (*str == 0)
		return 1;

	if (*str == '=')
		str++;

	if (!strcmp(str, "32"))
		va_align.flags = ALIGN_VA_32;
	else if (!strcmp(str, "64"))
		va_align.flags = ALIGN_VA_64;
	else if (!strcmp(str, "off"))
		va_align.flags = 0;
	else if (!strcmp(str, "on"))
		va_align.flags = ALIGN_VA_32 | ALIGN_VA_64;
	else
		return 0;

	return 1;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Borislav Petkov
119
100.00%
1
100.00%
Total
119
100.00%
1
100.00%

__setup("align_va_addr", control_va_addr_alignment);


SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
		unsigned long, prot, unsigned long, flags,
		unsigned long, fd, unsigned long, off)
{
	long error;
	error = -EINVAL;
	if (off & ~PAGE_MASK)
		goto out;

	error = sys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
out:
	return error;
}



static void find_start_end(unsigned long flags, unsigned long *begin,
			   unsigned long *end)
{
	if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT)) {
		/* This is usually used needed to map code in small
                   model, so it needs to be in the first 31bit. Limit
                   it to that.  This means we need to move the
                   unmapped base down for this case. This can give
                   conflicts with the heap, but we assume that glibc
                   malloc knows how to fall back to mmap. Give it 1GB
                   of playground for now. -AK */
		*begin = 0x40000000;
		*end = 0x80000000;
		if (current->flags & PF_RANDOMIZE) {
			*begin = randomize_page(*begin, 0x02000000);
		}
	} else {
		*begin = current->mm->mmap_legacy_base;
		*end = TASK_SIZE;
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Andi Kleen
54
63.53%
4
44.44%
Jiri Kosina
18
21.18%
1
11.11%
Radu Caragea
5
5.88%
1
11.11%
Suresh B. Siddha
4
4.71%
1
11.11%
Jason Cooper
3
3.53%
1
11.11%
H. Peter Anvin
1
1.18%
1
11.11%
Total
85
100.00%
9
100.00%


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;
	struct vm_unmapped_area_info info;
	unsigned long begin, end;

	if (flags & MAP_FIXED)
		return addr;

	find_start_end(flags, &begin, &end);

	if (len > end)
		return -ENOMEM;

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

	info.flags = 0;
	info.length = len;
	info.low_limit = begin;
	info.high_limit = end;
	info.align_mask = 0;
	info.align_offset = pgoff << PAGE_SHIFT;
	if (filp) {
		info.align_mask = get_align_mask();
		info.align_offset += get_align_bits();
	}
	return vm_unmapped_area(&info);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Andi Kleen
124
64.58%
3
33.33%
Michel Lespinasse
29
15.10%
2
22.22%
Hector Marco-Gisbert
20
10.42%
1
11.11%
Benjamin Herrenschmidt
9
4.69%
1
11.11%
Wolfgang Wander
6
3.12%
1
11.11%
Borislav Petkov
4
2.08%
1
11.11%
Total
192
100.00%
9
100.00%


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;
	struct mm_struct *mm = current->mm;
	unsigned long addr = addr0;
	struct vm_unmapped_area_info info;

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

	if (flags & MAP_FIXED)
		return addr;

	/* for MAP_32BIT mappings we force the legacy mmap base */
	if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT))
		goto bottomup;

	/* requesting a specific address */
	if (addr) {
		addr = PAGE_ALIGN(addr);
		vma = find_vma(mm, addr);
		if (TASK_SIZE - len >= addr &&
				(!vma || addr + len <= vma->vm_start))
			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 = 0;
	info.align_offset = pgoff << PAGE_SHIFT;
	if (filp) {
		info.align_mask = get_align_mask();
		info.align_offset += get_align_bits();
	}
	addr = vm_unmapped_area(&info);
	if (!(addr & ~PAGE_MASK))
		return addr;
	VM_BUG_ON(addr != -ENOMEM);

bottomup:
	/*
         * 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);
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Jiri Kosina
171
69.51%
1
12.50%
Michel Lespinasse
48
19.51%
2
25.00%
Hector Marco-Gisbert
20
8.13%
1
12.50%
Xiao Guangrong
3
1.22%
1
12.50%
Borislav Petkov
2
0.81%
1
12.50%
H. Peter Anvin
1
0.41%
1
12.50%
Yuanhan Liu
1
0.41%
1
12.50%
Total
246
100.00%
8
100.00%

Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
Andi Kleen
260
29.28%
5
19.23%
Jiri Kosina
192
21.62%
1
3.85%
Borislav Petkov
183
20.61%
1
3.85%
Michel Lespinasse
107
12.05%
2
7.69%
Hector Marco-Gisbert
66
7.43%
1
3.85%
Jason Baron
28
3.15%
1
3.85%
Benjamin Herrenschmidt
9
1.01%
1
3.85%
Wolfgang Wander
6
0.68%
1
3.85%
Radu Caragea
5
0.56%
1
3.85%
Suresh B. Siddha
4
0.45%
1
3.85%
Xiao Guangrong
3
0.34%
1
3.85%
Jason Cooper
3
0.34%
1
3.85%
Jaswinder Singh Rajput
3
0.34%
1
3.85%
Al Viro
3
0.34%
1
3.85%
Andrew Morton
3
0.34%
1
3.85%
Alexey Dobriyan
3
0.34%
1
3.85%
Stephen Rothwell
3
0.34%
1
3.85%
Ingo Molnar
3
0.34%
1
3.85%
H. Peter Anvin
2
0.23%
1
3.85%
Gustavo Fernando Padovan
1
0.11%
1
3.85%
Yuanhan Liu
1
0.11%
1
3.85%
Total
888
100.00%
26
100.00%
Directory: arch/x86/kernel

Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.