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    Subject[PATCH] x86_64: Implement personality ADDR_LIMIT_32BIT
    Date
    Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: H. Peter Anvin <hpa@zytor.com>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    ---
    arch/x86/kernel/sys_x86_64.c | 15 +++++++++++----
    include/asm-x86/elf.h | 4 +++-
    include/asm-x86/processor.h | 6 ++++--
    3 files changed, 18 insertions(+), 7 deletions(-)

    diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
    index 3b360ef..d6ac928 100644
    --- a/arch/x86/kernel/sys_x86_64.c
    +++ b/arch/x86/kernel/sys_x86_64.c
    @@ -48,7 +48,9 @@ out:
    static void find_start_end(unsigned long flags, unsigned long *begin,
    unsigned long *end)
    {
    - if (!test_thread_flag(TIF_IA32) && (flags & MAP_32BIT)) {
    + if (!test_thread_flag(TIF_IA32) &&
    + ((flags & MAP_32BIT) ||
    + (current->personality & ADDR_LIMIT_32BIT))) {
    unsigned long new_begin;
    /* This is usually used needed to map code in small
    model, so it needs to be in the first 31bit. Limit
    @@ -94,7 +96,8 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
    (!vma || addr + len <= vma->vm_start))
    return addr;
    }
    - if (((flags & MAP_32BIT) || test_thread_flag(TIF_IA32))
    + if (((flags & MAP_32BIT) || test_thread_flag(TIF_IA32) ||
    + (current->personality & ADDR_LIMIT_32BIT))
    && len <= mm->cached_hole_size) {
    mm->cached_hole_size = 0;
    mm->free_area_cache = begin;
    @@ -150,8 +153,12 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
    if (flags & MAP_FIXED)
    return addr;

    - /* for MAP_32BIT mappings we force the legact mmap base */
    - if (!test_thread_flag(TIF_IA32) && (flags & MAP_32BIT))
    + /* for MAP_32BIT mappings and ADDR_LIMIT_32BIT personality we force the
    + * legact mmap base
    + */
    + if (!test_thread_flag(TIF_IA32) &&
    + ((flags & MAP_32BIT) ||
    + (current->personality & ADDR_LIMIT_32BIT)))
    goto bottomup;

    /* requesting a specific address */
    diff --git a/include/asm-x86/elf.h b/include/asm-x86/elf.h
    index 7be4733..fa39e10 100644
    --- a/include/asm-x86/elf.h
    +++ b/include/asm-x86/elf.h
    @@ -298,7 +298,9 @@ do { \
    #define VDSO_HIGH_BASE 0xffffe000U /* CONFIG_COMPAT_VDSO address */

    /* 1GB for 64bit, 8MB for 32bit */
    -#define STACK_RND_MASK (test_thread_flag(TIF_IA32) ? 0x7ff : 0x3fffff)
    +#define STACK_RND_MASK ((test_thread_flag(TIF_IA32) || \
    + current->personality & ADDR_LIMIT_32BIT ) ? \
    + 0x7ff : 0x3fffff)

    #define ARCH_DLINFO \
    do { \
    diff --git a/include/asm-x86/processor.h b/include/asm-x86/processor.h
    index 4df3e2f..6d7f2f9 100644
    --- a/include/asm-x86/processor.h
    +++ b/include/asm-x86/processor.h
    @@ -904,7 +904,8 @@ extern unsigned long thread_saved_pc(struct task_struct *tsk);
    #define TASK_SIZE_OF(child) ((test_tsk_thread_flag(child, TIF_IA32)) ? \
    IA32_PAGE_OFFSET : TASK_SIZE64)

    -#define STACK_TOP TASK_SIZE
    +#define STACK_TOP (current->personality & ADDR_LIMIT_32BIT ? \
    + 0x80000000 : TASK_SIZE)
    #define STACK_TOP_MAX TASK_SIZE64

    #define INIT_THREAD { \
    @@ -932,7 +933,8 @@ extern void start_thread(struct pt_regs *regs, unsigned long new_ip,
    * This decides where the kernel will search for a free chunk of vm
    * space during mmap's.
    */
    -#define TASK_UNMAPPED_BASE (PAGE_ALIGN(TASK_SIZE / 3))
    +#define TASK_UNMAPPED_BASE (current->personality & ADDR_LIMIT_32BIT ? \
    + 0x40000000 : PAGE_ALIGN(TASK_SIZE / 3))

    #define KSTK_EIP(task) (task_pt_regs(task)->ip)

    --
    1.5.6.5.GIT


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