* 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
*/
#include <asm/uaccess.h>
+#include <asm/elf.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/linkage.h>
#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;
}
-/*
- * 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.
- */
-static int get_offset(struct address_space *mapping)
+static inline unsigned long COLOR_ALIGN(unsigned long addr,
+ unsigned int last_mmap, unsigned long pgoff)
{
- return (unsigned long) mapping >> 8;
+ unsigned long base = (addr+SHMLBA-1) & ~(SHMLBA-1);
+ unsigned long off = (SHMLBA-1) &
+ (shared_align_offset(last_mmap, pgoff) << PAGE_SHIFT);
+
+ return base + off;
}
-static unsigned long shared_align_offset(struct file *filp, unsigned long pgoff)
+/*
+ * Top of mmap area (just below the process stack).
+ */
+
+static unsigned long mmap_upper_limit(void)
{
- struct address_space *mapping = filp ? filp->f_mapping : NULL;
+ unsigned long stack_base;
- return (get_offset(mapping) + pgoff) << PAGE_SHIFT;
+ /* 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 get_shared_area(struct file *filp, unsigned long addr,
- unsigned long len, unsigned long pgoff)
+
+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;
+ 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))
+ 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 = 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);
+ 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(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 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) &&
- (addr - shared_align_offset(filp, pgoff)) & (SHMLBA - 1))
+ if ((flags & MAP_SHARED) && last_mmap &&
+ (addr - shared_align_offset(last_mmap, pgoff))
+ & (SHMLBA - 1))
return -EINVAL;
- return addr;
+ goto found_addr;
}
- if (!addr)
- addr = TASK_UNMAPPED_BASE;
- if (filp || (flags & MAP_SHARED))
- addr = get_shared_area(filp, addr, len, pgoff);
- else
- addr = get_unshared_area(addr, len);
+ /* 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)
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff