mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 10:49:33 +00:00
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:
parent
f5a408d53e
commit
9dabf60dc4
6 changed files with 243 additions and 53 deletions
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@ -348,4 +348,8 @@ struct pt_regs; /* forward declaration... */
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#define ELF_HWCAP 0
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struct mm_struct;
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extern unsigned long arch_randomize_brk(struct mm_struct *);
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#define arch_randomize_brk arch_randomize_brk
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#endif
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@ -511,6 +511,7 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr,
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/* We provide our own get_unmapped_area to provide cache coherency */
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#define HAVE_ARCH_UNMAPPED_AREA
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#define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
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#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
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#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
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@ -30,6 +30,8 @@
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#endif
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#define current_text_addr() ({ void *pc; current_ia(pc); pc; })
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#define HAVE_ARCH_PICK_MMAP_LAYOUT
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#define TASK_SIZE_OF(tsk) ((tsk)->thread.task_size)
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#define TASK_SIZE TASK_SIZE_OF(current)
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#define TASK_UNMAPPED_BASE (current->thread.map_base)
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@ -76,6 +76,16 @@ struct thread_info {
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#define _TIF_SYSCALL_TRACE_MASK (_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP | \
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_TIF_BLOCKSTEP | _TIF_SYSCALL_AUDIT)
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#ifdef CONFIG_64BIT
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# ifdef CONFIG_COMPAT
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# define is_32bit_task() (test_thread_flag(TIF_32BIT))
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# else
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# define is_32bit_task() (0)
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# endif
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#else
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# define is_32bit_task() (1)
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#endif
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#endif /* __KERNEL__ */
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#endif /* _ASM_PARISC_THREAD_INFO_H */
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@ -13,7 +13,7 @@
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* Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org>
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* Copyright (C) 2001 Alan Modra <amodra at parisc-linux.org>
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* Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org>
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* Copyright (C) 2001-2007 Helge Deller <deller at parisc-linux.org>
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* Copyright (C) 2001-2014 Helge Deller <deller@gmx.de>
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* Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
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*
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*
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@ -49,6 +49,7 @@
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#include <linux/kallsyms.h>
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#include <linux/uaccess.h>
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#include <linux/rcupdate.h>
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#include <linux/random.h>
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#include <asm/io.h>
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#include <asm/asm-offsets.h>
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@ -286,3 +287,21 @@ void *dereference_function_descriptor(void *ptr)
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return ptr;
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}
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#endif
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static inline unsigned long brk_rnd(void)
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{
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/* 8MB for 32bit, 1GB for 64bit */
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if (is_32bit_task())
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return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
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else
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return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT;
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}
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unsigned long arch_randomize_brk(struct mm_struct *mm)
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{
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unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
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if (ret < mm->brk)
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return mm->brk;
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return ret;
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}
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@ -5,6 +5,7 @@
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* Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org>
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* Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org>
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* Copyright (C) 2001 Thomas Bogendoerfer <tsbogend at parisc-linux.org>
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* Copyright (C) 1999-2014 Helge Deller <deller@gmx.de>
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*
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*
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* This program is free software; you can redistribute it and/or modify
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@ -23,6 +24,7 @@
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*/
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#include <asm/uaccess.h>
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#include <asm/elf.h>
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#include <linux/file.h>
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#include <linux/fs.h>
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#include <linux/linkage.h>
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@ -32,78 +34,230 @@
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#include <linux/syscalls.h>
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#include <linux/utsname.h>
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#include <linux/personality.h>
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#include <linux/random.h>
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static unsigned long get_unshared_area(unsigned long addr, unsigned long len)
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/* we construct an artificial offset for the mapping based on the physical
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* address of the kernel mapping variable */
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#define GET_LAST_MMAP(filp) \
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(filp ? ((unsigned long) filp->f_mapping) >> 8 : 0UL)
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#define SET_LAST_MMAP(filp, val) \
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{ /* nothing */ }
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static int get_offset(unsigned int last_mmap)
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{
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struct vm_unmapped_area_info info;
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return (last_mmap & (SHMLBA-1)) >> PAGE_SHIFT;
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}
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info.flags = 0;
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info.length = len;
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info.low_limit = PAGE_ALIGN(addr);
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info.high_limit = TASK_SIZE;
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info.align_mask = 0;
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info.align_offset = 0;
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return vm_unmapped_area(&info);
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static unsigned long shared_align_offset(unsigned int last_mmap,
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unsigned long pgoff)
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{
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return (get_offset(last_mmap) + pgoff) << PAGE_SHIFT;
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}
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static inline unsigned long COLOR_ALIGN(unsigned long addr,
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unsigned int last_mmap, unsigned long pgoff)
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{
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unsigned long base = (addr+SHMLBA-1) & ~(SHMLBA-1);
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unsigned long off = (SHMLBA-1) &
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(shared_align_offset(last_mmap, pgoff) << PAGE_SHIFT);
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return base + off;
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}
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/*
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* We need to know the offset to use. Old scheme was to look for
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* existing mapping and use the same offset. New scheme is to use the
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* address of the kernel data structure as the seed for the offset.
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* We'll see how that works...
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*
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* The mapping is cacheline aligned, so there's no information in the bottom
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* few bits of the address. We're looking for 10 bits (4MB / 4k), so let's
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* drop the bottom 8 bits and use bits 8-17.
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* Top of mmap area (just below the process stack).
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*/
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static int get_offset(struct address_space *mapping)
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static unsigned long mmap_upper_limit(void)
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{
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return (unsigned long) mapping >> 8;
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unsigned long stack_base;
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/* Limit stack size to 1GB - see setup_arg_pages() in fs/exec.c */
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stack_base = rlimit_max(RLIMIT_STACK);
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if (stack_base > (1 << 30))
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stack_base = 1 << 30;
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return PAGE_ALIGN(STACK_TOP - stack_base);
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}
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static unsigned long shared_align_offset(struct file *filp, unsigned long pgoff)
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{
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struct address_space *mapping = filp ? filp->f_mapping : NULL;
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return (get_offset(mapping) + pgoff) << PAGE_SHIFT;
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}
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static unsigned long get_shared_area(struct file *filp, unsigned long addr,
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unsigned long len, unsigned long pgoff)
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{
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struct vm_unmapped_area_info info;
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info.flags = 0;
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info.length = len;
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info.low_limit = PAGE_ALIGN(addr);
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info.high_limit = TASK_SIZE;
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info.align_mask = PAGE_MASK & (SHMLBA - 1);
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info.align_offset = shared_align_offset(filp, pgoff);
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return vm_unmapped_area(&info);
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}
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unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
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unsigned long len, unsigned long pgoff, unsigned long flags)
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{
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struct mm_struct *mm = current->mm;
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struct vm_area_struct *vma;
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unsigned long task_size = TASK_SIZE;
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int do_color_align, last_mmap;
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struct vm_unmapped_area_info info;
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if (len > task_size)
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return -ENOMEM;
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do_color_align = 0;
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if (filp || (flags & MAP_SHARED))
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do_color_align = 1;
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last_mmap = GET_LAST_MMAP(filp);
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if (flags & MAP_FIXED) {
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if ((flags & MAP_SHARED) && last_mmap &&
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(addr - shared_align_offset(last_mmap, pgoff))
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& (SHMLBA - 1))
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return -EINVAL;
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goto found_addr;
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}
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if (addr) {
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if (do_color_align && last_mmap)
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addr = COLOR_ALIGN(addr, last_mmap, pgoff);
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else
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addr = PAGE_ALIGN(addr);
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vma = find_vma(mm, addr);
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if (task_size - len >= addr &&
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(!vma || addr + len <= vma->vm_start))
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goto found_addr;
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}
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info.flags = 0;
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info.length = len;
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info.low_limit = mm->mmap_legacy_base;
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info.high_limit = mmap_upper_limit();
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info.align_mask = last_mmap ? (PAGE_MASK & (SHMLBA - 1)) : 0;
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info.align_offset = shared_align_offset(last_mmap, pgoff);
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addr = vm_unmapped_area(&info);
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found_addr:
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if (do_color_align && !last_mmap && !(addr & ~PAGE_MASK))
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SET_LAST_MMAP(filp, addr - (pgoff << PAGE_SHIFT));
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return addr;
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}
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unsigned long
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arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
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const unsigned long len, const unsigned long pgoff,
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const unsigned long flags)
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{
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struct vm_area_struct *vma;
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struct mm_struct *mm = current->mm;
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unsigned long addr = addr0;
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int do_color_align, last_mmap;
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struct vm_unmapped_area_info info;
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#ifdef CONFIG_64BIT
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/* This should only ever run for 32-bit processes. */
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BUG_ON(!test_thread_flag(TIF_32BIT));
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#endif
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/* requested length too big for entire address space */
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if (len > TASK_SIZE)
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return -ENOMEM;
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if (flags & MAP_FIXED) {
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if ((flags & MAP_SHARED) &&
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(addr - shared_align_offset(filp, pgoff)) & (SHMLBA - 1))
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return -EINVAL;
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return addr;
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}
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if (!addr)
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addr = TASK_UNMAPPED_BASE;
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do_color_align = 0;
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if (filp || (flags & MAP_SHARED))
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addr = get_shared_area(filp, addr, len, pgoff);
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do_color_align = 1;
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last_mmap = GET_LAST_MMAP(filp);
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if (flags & MAP_FIXED) {
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if ((flags & MAP_SHARED) && last_mmap &&
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(addr - shared_align_offset(last_mmap, pgoff))
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& (SHMLBA - 1))
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return -EINVAL;
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goto found_addr;
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}
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/* requesting a specific address */
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if (addr) {
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if (do_color_align && last_mmap)
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addr = COLOR_ALIGN(addr, last_mmap, pgoff);
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else
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addr = get_unshared_area(addr, len);
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addr = PAGE_ALIGN(addr);
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vma = find_vma(mm, addr);
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if (TASK_SIZE - len >= addr &&
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(!vma || addr + len <= vma->vm_start))
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goto found_addr;
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}
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info.flags = VM_UNMAPPED_AREA_TOPDOWN;
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info.length = len;
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info.low_limit = PAGE_SIZE;
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info.high_limit = mm->mmap_base;
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info.align_mask = last_mmap ? (PAGE_MASK & (SHMLBA - 1)) : 0;
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info.align_offset = shared_align_offset(last_mmap, pgoff);
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addr = vm_unmapped_area(&info);
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if (!(addr & ~PAGE_MASK))
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goto found_addr;
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VM_BUG_ON(addr != -ENOMEM);
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/*
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* A failed mmap() very likely causes application failure,
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* so fall back to the bottom-up function here. This scenario
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* can happen with large stack limits and large mmap()
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* allocations.
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*/
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return arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
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found_addr:
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if (do_color_align && !last_mmap && !(addr & ~PAGE_MASK))
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SET_LAST_MMAP(filp, addr - (pgoff << PAGE_SHIFT));
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return addr;
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}
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static int mmap_is_legacy(void)
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{
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if (current->personality & ADDR_COMPAT_LAYOUT)
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return 1;
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/* parisc stack always grows up - so a unlimited stack should
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* not be an indicator to use the legacy memory layout.
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* if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
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* return 1;
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*/
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return sysctl_legacy_va_layout;
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}
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static unsigned long mmap_rnd(void)
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{
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unsigned long rnd = 0;
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/*
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* 8 bits of randomness in 32bit mmaps, 20 address space bits
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* 28 bits of randomness in 64bit mmaps, 40 address space bits
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*/
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if (current->flags & PF_RANDOMIZE) {
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if (is_32bit_task())
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rnd = get_random_int() % (1<<8);
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else
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rnd = get_random_int() % (1<<28);
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}
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return rnd << PAGE_SHIFT;
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}
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static unsigned long mmap_legacy_base(void)
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{
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return TASK_UNMAPPED_BASE + mmap_rnd();
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}
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/*
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* This function, called very early during the creation of a new
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* process VM image, sets up which VM layout function to use:
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*/
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void arch_pick_mmap_layout(struct mm_struct *mm)
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{
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mm->mmap_legacy_base = mmap_legacy_base();
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mm->mmap_base = mmap_upper_limit();
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if (mmap_is_legacy()) {
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mm->mmap_base = mm->mmap_legacy_base;
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mm->get_unmapped_area = arch_get_unmapped_area;
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} else {
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mm->get_unmapped_area = arch_get_unmapped_area_topdown;
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}
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}
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asmlinkage unsigned long sys_mmap2(unsigned long addr, unsigned long len,
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unsigned long prot, unsigned long flags, unsigned long fd,
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unsigned long pgoff)
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