[PATCH] x86_64: Flexmap for 32bit and randomized mappings for 64bit (8817210d) · Commits · 戴 / test

arch/x86_64/ia32/Makefile

+2 −1

Original line number	Diff line number	Diff line
		@@ -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)

arch/x86_64/ia32/mmap32.c

0 → 100644

+78 −0

Original line number	Diff line number	Diff line
		/*
		* 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 <mingo@elte.hu>
		*/

		#include <linux/personality.h>
		#include <linux/mm.h>
		#include <linux/random.h>

		/*
		* Top of mmap area (just below the process stack).
		*
		* Leave an at least ~128 MB hole.
		*/
		#define MIN_GAP (12810241024)
		#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;
		}
		}

arch/x86_64/mm/Makefile

+1 −1

Original line number	Diff line number	Diff line
		@@ -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

arch/x86_64/mm/mmap.c

0 → 100644

+30 −0

Original line number	Diff line number	Diff line
		/* Copyright 2005 Andi Kleen, SuSE Labs.
		* Licensed under GPL, v.2
		*/
		#include <linux/config.h>
		#include <linux/mm.h>
		#include <linux/sched.h>
		#include <linux/random.h>
		#include <asm/ia32.h>

		/* 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;
		}

include/asm-x86_64/ia32.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -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

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