diff options
| -rw-r--r-- | arch/x86/mm/Makefile_32 | 2 | ||||
| -rw-r--r-- | arch/x86/mm/Makefile_64 | 3 | ||||
| -rw-r--r-- | arch/x86/mm/mmap.c (renamed from arch/x86/mm/mmap_64.c) | 95 | ||||
| -rw-r--r-- | arch/x86/mm/mmap_32.c | 81 |
4 files changed, 53 insertions, 128 deletions
diff --git a/arch/x86/mm/Makefile_32 b/arch/x86/mm/Makefile_32 index 362b4ad082d..a01aca79dc6 100644 --- a/arch/x86/mm/Makefile_32 +++ b/arch/x86/mm/Makefile_32 @@ -2,7 +2,7 @@ # Makefile for the linux i386-specific parts of the memory manager. # -obj-y := init_32.o pgtable_32.o fault_32.o ioremap_32.o extable_32.o pageattr_32.o mmap_32.o +obj-y := init_32.o pgtable_32.o fault_32.o ioremap_32.o extable_32.o pageattr_32.o mmap.o obj-$(CONFIG_NUMA) += discontig_32.o obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o diff --git a/arch/x86/mm/Makefile_64 b/arch/x86/mm/Makefile_64 index d18baed54fc..b5a74486c3a 100644 --- a/arch/x86/mm/Makefile_64 +++ b/arch/x86/mm/Makefile_64 @@ -2,9 +2,8 @@ # Makefile for the linux x86_64-specific parts of the memory manager. # -obj-y := init_64.o fault_64.o ioremap_64.o extable_64.o pageattr_64.o mmap_64.o +obj-y := init_64.o fault_64.o ioremap_64.o extable_64.o pageattr_64.o mmap.o obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o obj-$(CONFIG_NUMA) += numa_64.o obj-$(CONFIG_K8_NUMA) += k8topology_64.o obj-$(CONFIG_ACPI_NUMA) += srat_64.o -obj-$(CONFIG_IA32_EMULATION) += mmap_32.o diff --git a/arch/x86/mm/mmap_64.c b/arch/x86/mm/mmap.c index 119bf34ec52..56fe7124fbe 100644 --- a/arch/x86/mm/mmap_64.c +++ b/arch/x86/mm/mmap.c @@ -1,7 +1,5 @@ /* - * linux/arch/x86-64/mm/mmap.c - * - * flexible mmap layout support + * Flexible mmap layout support * * Based on code by Ingo Molnar and Andi Kleen, copyrighted * as follows: @@ -24,7 +22,6 @@ * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA - * */ #include <linux/personality.h> @@ -32,7 +29,6 @@ #include <linux/random.h> #include <linux/limits.h> #include <linux/sched.h> -#include <asm/ia32.h> /* * Top of mmap area (just below the process stack). @@ -42,20 +38,14 @@ #define MIN_GAP (128*1024*1024) #define MAX_GAP (TASK_SIZE/6*5) -static unsigned long mmap_base(void) -{ - unsigned long gap = current->signal->rlim[RLIMIT_STACK].rlim_cur; - - if (gap < MIN_GAP) - gap = MIN_GAP; - else if (gap > MAX_GAP) - gap = MAX_GAP; - - return TASK_SIZE - (gap & PAGE_MASK); -} - -static int mmap_is_32(void) +/* + * True on X86_32 or when emulating IA32 on X86_64 + */ +static int mmap_is_ia32(void) { +#ifdef CONFIG_X86_32 + return 1; +#endif #ifdef CONFIG_IA32_EMULATION if (test_thread_flag(TIF_IA32)) return 1; @@ -74,43 +64,60 @@ static int mmap_is_legacy(void) 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 (mmap_is_ia32()) + rnd = (long)get_random_int() % (1<<8); + else + rnd = (long)(get_random_int() % (1<<28)); + } + return rnd << PAGE_SHIFT; +} + +static unsigned long mmap_base(void) +{ + unsigned long gap = current->signal->rlim[RLIMIT_STACK].rlim_cur; + + if (gap < MIN_GAP) + gap = MIN_GAP; + else if (gap > MAX_GAP) + gap = MAX_GAP; + + return PAGE_ALIGN(TASK_SIZE - gap - mmap_rnd()); +} + +/* + * Bottom-up (legacy) layout on X86_32 did not support randomization, X86_64 + * does, but not when emulating X86_32 + */ +static unsigned long mmap_legacy_base(void) +{ + if (mmap_is_ia32()) + return TASK_UNMAPPED_BASE; + else + 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) { - int rnd = 0; - if (current->flags & PF_RANDOMIZE) { - /* - * Add 28bit randomness which is about 40bits of address space - * because mmap base has to be page aligned. - * or ~1/128 of the total user VM - * (total user address space is 47bits) - */ - rnd = get_random_int() & 0xfffffff; - } - - /* - * Fall back to the standard layout if the personality - * bit is set, or if the expected stack growth is unlimited: - */ - if (mmap_is_32()) { -#ifdef CONFIG_IA32_EMULATION - /* ia32_pick_mmap_layout has its own. */ - return ia32_pick_mmap_layout(mm); -#endif - } else if (mmap_is_legacy()) { - mm->mmap_base = TASK_UNMAPPED_BASE; + if (mmap_is_legacy()) { + mm->mmap_base = mmap_legacy_base(); mm->get_unmapped_area = arch_get_unmapped_area; mm->unmap_area = arch_unmap_area; } else { mm->mmap_base = mmap_base(); mm->get_unmapped_area = arch_get_unmapped_area_topdown; mm->unmap_area = arch_unmap_area_topdown; - if (current->flags & PF_RANDOMIZE) - rnd = -rnd; } - if (current->flags & PF_RANDOMIZE) - mm->mmap_base += ((long)rnd) << PAGE_SHIFT; } diff --git a/arch/x86/mm/mmap_32.c b/arch/x86/mm/mmap_32.c deleted file mode 100644 index d490662e4af..00000000000 --- a/arch/x86/mm/mmap_32.c +++ /dev/null @@ -1,81 +0,0 @@ -/* - * linux/arch/i386/mm/mmap.c - * - * flexible mmap layout support - * - * Copyright 2003-2004 Red Hat Inc., Durham, North Carolina. - * All Rights Reserved. - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA - * - * - * Started by Ingo Molnar <mingo@elte.hu> - */ - -#include <linux/personality.h> -#include <linux/mm.h> -#include <linux/random.h> -#include <linux/sched.h> - -/* - * Top of mmap area (just below the process stack). - * - * Leave an at least ~128 MB hole. - */ -#define MIN_GAP (128*1024*1024) -#define MAX_GAP (TASK_SIZE/6*5) - -static inline unsigned long mmap_base(struct mm_struct *mm) -{ - unsigned long gap = current->signal->rlim[RLIMIT_STACK].rlim_cur; - unsigned long random_factor = 0; - - if (current->flags & PF_RANDOMIZE) - random_factor = get_random_int() % (1024*1024); - - if (gap < MIN_GAP) - gap = MIN_GAP; - else if (gap > MAX_GAP) - gap = MAX_GAP; - - return PAGE_ALIGN(TASK_SIZE - gap - random_factor); -} - -/* - * This function, called very early during the creation of a new - * process VM image, sets up which VM layout function to use: - */ -#ifdef CONFIG_X86_32 -void arch_pick_mmap_layout(struct mm_struct *mm) -#else -void ia32_pick_mmap_layout(struct mm_struct *mm) -#endif -{ - /* - * Fall back to the standard layout if the personality - * bit is set, or if the expected stack growth is unlimited: - */ - if (sysctl_legacy_va_layout || - (current->personality & ADDR_COMPAT_LAYOUT) || - current->signal->rlim[RLIMIT_STACK].rlim_cur == RLIM_INFINITY) { - mm->mmap_base = TASK_UNMAPPED_BASE; - mm->get_unmapped_area = arch_get_unmapped_area; - mm->unmap_area = arch_unmap_area; - } else { - mm->mmap_base = mmap_base(mm); - mm->get_unmapped_area = arch_get_unmapped_area_topdown; - mm->unmap_area = arch_unmap_area_topdown; - } -} |