From 8817210d4d968e58f7d93db2eecd17b20dd03d40 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Tue, 17 Jan 2006 07:03:38 +0100 Subject: [PATCH] [PATCH] x86_64: Flexmap for 32bit and randomized mappings for 64bit Another try at this. For 32bit follow the 32bit implementation from Ingo - mappings are growing down from the end of stack now and vary randomly by 1GB. Randomized mappings for 64bit just vary the normal mmap break by 1TB. I didn't bother implementing full flex mmap for 64bit because it shouldn't be needed there. Cc: mingo@elte.hu Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- arch/x86_64/ia32/Makefile | 3 +- arch/x86_64/ia32/mmap32.c | 78 ++++++++++++++++++++++++++++++++++ arch/x86_64/mm/Makefile | 2 +- arch/x86_64/mm/mmap.c | 30 +++++++++++++ include/asm-x86_64/ia32.h | 2 + include/asm-x86_64/processor.h | 2 + 6 files changed, 115 insertions(+), 2 deletions(-) create mode 100644 arch/x86_64/ia32/mmap32.c create mode 100644 arch/x86_64/mm/mmap.c diff --git a/arch/x86_64/ia32/Makefile b/arch/x86_64/ia32/Makefile index 051608d55920..929e6b0771f8 100644 --- a/arch/x86_64/ia32/Makefile +++ b/arch/x86_64/ia32/Makefile @@ -3,7 +3,8 @@ # obj-$(CONFIG_IA32_EMULATION) := ia32entry.o sys_ia32.o ia32_signal.o tls32.o \ - ia32_binfmt.o fpu32.o ptrace32.o syscall32.o syscall32_syscall.o + ia32_binfmt.o fpu32.o ptrace32.o syscall32.o syscall32_syscall.o \ + mmap32.o sysv-$(CONFIG_SYSVIPC) := ipc32.o obj-$(CONFIG_IA32_EMULATION) += $(sysv-y) diff --git a/arch/x86_64/ia32/mmap32.c b/arch/x86_64/ia32/mmap32.c new file mode 100644 index 000000000000..079f4132575c --- /dev/null +++ b/arch/x86_64/ia32/mmap32.c @@ -0,0 +1,78 @@ +/* + * linux/arch/x86_64/ia32/mm/mmap.c + * + * flexible mmap layout support + * + * Based on the i386 version which was + * + * 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 + */ + +#include +#include +#include + +/* + * 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: + */ +void ia32_pick_mmap_layout(struct mm_struct *mm) +{ + /* + * 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; + } +} diff --git a/arch/x86_64/mm/Makefile b/arch/x86_64/mm/Makefile index 1d232a87f113..d25ac86fe27a 100644 --- a/arch/x86_64/mm/Makefile +++ b/arch/x86_64/mm/Makefile @@ -2,7 +2,7 @@ # Makefile for the linux x86_64-specific parts of the memory manager. # -obj-y := init.o fault.o ioremap.o extable.o pageattr.o +obj-y := init.o fault.o ioremap.o extable.o pageattr.o mmap.o obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o obj-$(CONFIG_NUMA) += numa.o obj-$(CONFIG_K8_NUMA) += k8topology.o diff --git a/arch/x86_64/mm/mmap.c b/arch/x86_64/mm/mmap.c new file mode 100644 index 000000000000..43e9b99bdf25 --- /dev/null +++ b/arch/x86_64/mm/mmap.c @@ -0,0 +1,30 @@ +/* Copyright 2005 Andi Kleen, SuSE Labs. + * Licensed under GPL, v.2 + */ +#include +#include +#include +#include +#include + +/* Notebook: move the mmap code from sys_x86_64.c over here. */ + +void arch_pick_mmap_layout(struct mm_struct *mm) +{ +#ifdef CONFIG_IA32_EMULATION + if (current_thread_info()->flags & _TIF_IA32) + return ia32_pick_mmap_layout(mm); +#endif + mm->mmap_base = TASK_UNMAPPED_BASE; + 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) */ + unsigned rnd = get_random_int() & 0xfffffff; + mm->mmap_base += ((unsigned long)rnd) << PAGE_SHIFT; + } + mm->get_unmapped_area = arch_get_unmapped_area; + mm->unmap_area = arch_unmap_area; +} + diff --git a/include/asm-x86_64/ia32.h b/include/asm-x86_64/ia32.h index c7bc9c0525ba..e6b7f2234e43 100644 --- a/include/asm-x86_64/ia32.h +++ b/include/asm-x86_64/ia32.h @@ -169,6 +169,8 @@ int ia32_child_tls(struct task_struct *p, struct pt_regs *childregs); struct linux_binprm; extern int ia32_setup_arg_pages(struct linux_binprm *bprm, unsigned long stack_top, int exec_stack); +struct mm_struct; +extern void ia32_pick_mmap_layout(struct mm_struct *mm); #endif diff --git a/include/asm-x86_64/processor.h b/include/asm-x86_64/processor.h index a1ba7c97465a..8c8d88c036ed 100644 --- a/include/asm-x86_64/processor.h +++ b/include/asm-x86_64/processor.h @@ -477,4 +477,6 @@ extern unsigned long boot_option_idle_override; /* Boot loader type from the setup header */ extern int bootloader_type; +#define HAVE_ARCH_PICK_MMAP_LAYOUT 1 + #endif /* __ASM_X86_64_PROCESSOR_H */ -- 2.20.1