parisc: add flexible mmap memory layout support

Add support for the flexible mmap memory layout (as described in
http://lwn.net/Articles/91829). This is especially very interesting on
parisc since we currently only support 32bit userspace (even with a
64bit Linux kernel).

Signed-off-by: Helge Deller <deller@gmx.de>
This commit is contained in:
Helge Deller 2014-01-31 22:19:52 +01:00
Родитель f5a408d53e
Коммит 9dabf60dc4
6 изменённых файлов: 243 добавлений и 53 удалений

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@ -348,4 +348,8 @@ struct pt_regs; /* forward declaration... */
#define ELF_HWCAP 0
struct mm_struct;
extern unsigned long arch_randomize_brk(struct mm_struct *);
#define arch_randomize_brk arch_randomize_brk
#endif

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@ -511,6 +511,7 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr,
/* We provide our own get_unmapped_area to provide cache coherency */
#define HAVE_ARCH_UNMAPPED_AREA
#define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
#define __HAVE_ARCH_PTEP_GET_AND_CLEAR

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@ -30,6 +30,8 @@
#endif
#define current_text_addr() ({ void *pc; current_ia(pc); pc; })
#define HAVE_ARCH_PICK_MMAP_LAYOUT
#define TASK_SIZE_OF(tsk) ((tsk)->thread.task_size)
#define TASK_SIZE TASK_SIZE_OF(current)
#define TASK_UNMAPPED_BASE (current->thread.map_base)

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@ -76,6 +76,16 @@ struct thread_info {
#define _TIF_SYSCALL_TRACE_MASK (_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP | \
_TIF_BLOCKSTEP | _TIF_SYSCALL_AUDIT)
#ifdef CONFIG_64BIT
# ifdef CONFIG_COMPAT
# define is_32bit_task() (test_thread_flag(TIF_32BIT))
# else
# define is_32bit_task() (0)
# endif
#else
# define is_32bit_task() (1)
#endif
#endif /* __KERNEL__ */
#endif /* _ASM_PARISC_THREAD_INFO_H */

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@ -13,7 +13,7 @@
* Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org>
* Copyright (C) 2001 Alan Modra <amodra at parisc-linux.org>
* Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org>
* Copyright (C) 2001-2007 Helge Deller <deller at parisc-linux.org>
* Copyright (C) 2001-2014 Helge Deller <deller@gmx.de>
* Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
*
*
@ -49,6 +49,7 @@
#include <linux/kallsyms.h>
#include <linux/uaccess.h>
#include <linux/rcupdate.h>
#include <linux/random.h>
#include <asm/io.h>
#include <asm/asm-offsets.h>
@ -286,3 +287,21 @@ void *dereference_function_descriptor(void *ptr)
return ptr;
}
#endif
static inline unsigned long brk_rnd(void)
{
/* 8MB for 32bit, 1GB for 64bit */
if (is_32bit_task())
return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
else
return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT;
}
unsigned long arch_randomize_brk(struct mm_struct *mm)
{
unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
if (ret < mm->brk)
return mm->brk;
return ret;
}

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@ -5,6 +5,7 @@
* 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
@ -23,6 +24,7 @@
*/
#include <asm/uaccess.h>
#include <asm/elf.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/linkage.h>
@ -32,78 +34,230 @@
#include <linux/syscalls.h>
#include <linux/utsname.h>
#include <linux/personality.h>
#include <linux/random.h>
static unsigned long get_unshared_area(unsigned long addr, unsigned long len)
/* 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)
{
struct vm_unmapped_area_info info;
return (last_mmap & (SHMLBA-1)) >> PAGE_SHIFT;
}
info.flags = 0;
info.length = len;
info.low_limit = PAGE_ALIGN(addr);
info.high_limit = TASK_SIZE;
info.align_mask = 0;
info.align_offset = 0;
return vm_unmapped_area(&info);
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+SHMLBA-1) & ~(SHMLBA-1);
unsigned long off = (SHMLBA-1) &
(shared_align_offset(last_mmap, pgoff) << PAGE_SHIFT);
return base + off;
}
/*
* We need to know the offset to use. Old scheme was to look for
* existing mapping and use the same offset. New scheme is to use the
* address of the kernel data structure as the seed for the offset.
* We'll see how that works...
*
* The mapping is cacheline aligned, so there's no information in the bottom
* few bits of the address. We're looking for 10 bits (4MB / 4k), so let's
* drop the bottom 8 bits and use bits 8-17.
* Top of mmap area (just below the process stack).
*/
static int get_offset(struct address_space *mapping)
static unsigned long mmap_upper_limit(void)
{
return (unsigned long) mapping >> 8;
unsigned long stack_base;
/* Limit stack size to 1GB - see setup_arg_pages() in fs/exec.c */
stack_base = rlimit_max(RLIMIT_STACK);
if (stack_base > (1 << 30))
stack_base = 1 << 30;
return PAGE_ALIGN(STACK_TOP - stack_base);
}
static unsigned long shared_align_offset(struct file *filp, unsigned long pgoff)
{
struct address_space *mapping = filp ? filp->f_mapping : NULL;
return (get_offset(mapping) + pgoff) << PAGE_SHIFT;
}
static unsigned long get_shared_area(struct file *filp, unsigned long addr,
unsigned long len, unsigned long pgoff)
{
struct vm_unmapped_area_info info;
info.flags = 0;
info.length = len;
info.low_limit = PAGE_ALIGN(addr);
info.high_limit = TASK_SIZE;
info.align_mask = PAGE_MASK & (SHMLBA - 1);
info.align_offset = shared_align_offset(filp, pgoff);
return vm_unmapped_area(&info);
}
unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
unsigned long len, unsigned long pgoff, unsigned long flags)
{
if (len > TASK_SIZE)
return -ENOMEM;
if (flags & MAP_FIXED) {
if ((flags & MAP_SHARED) &&
(addr - shared_align_offset(filp, pgoff)) & (SHMLBA - 1))
return -EINVAL;
return addr;
}
if (!addr)
addr = TASK_UNMAPPED_BASE;
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
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))
addr = get_shared_area(filp, addr, len, pgoff);
else
addr = get_unshared_area(addr, len);
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))
& (SHMLBA - 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(mm, addr);
if (task_size - len >= addr &&
(!vma || addr + len <= vma->vm_start))
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 & (SHMLBA - 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;
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))
& (SHMLBA - 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(mm, addr);
if (TASK_SIZE - len >= addr &&
(!vma || addr + len <= vma->vm_start))
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 & (SHMLBA - 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;
/*
* 8 bits of randomness in 32bit mmaps, 20 address space bits
* 28 bits of randomness in 64bit mmaps, 40 address space bits
*/
if (current->flags & PF_RANDOMIZE) {
if (is_32bit_task())
rnd = get_random_int() % (1<<8);
else
rnd = get_random_int() % (1<<28);
}
return rnd << 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)