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x86 get_unmapped_area: Access mmap_legacy_base through mm_struct member 

This is the updated version of df54d6fa54 ("x86 get_unmapped_area():
use proper mmap base for bottom-up direction") that only randomizes the
mmap base address once.

Signed-off-by: Radu Caragea <sinaelgl@gmail.com>
Reported-and-tested-by: Jeff Shorey <shoreyjeff@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michel Lespinasse <walken@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Adrian Sendroiu <molecula2788@gmail.com>
Cc: Greg KH <greg@kroah.com>
Cc: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Radu Caragea 2013-08-21 20:55:59 +03:00 committed by Linus Torvalds
parent 5ea80f76a5
commit 41aacc1eea
3 changed files with 6 additions and 3 deletions
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2
arch/x86/kernel/sys_x86_64.c
View File

@ -101,7 +101,7 @@ static void find_start_end(unsigned long flags, unsigned long *begin,
*begin = new_begin;
}
} else {
*begin = TASK_UNMAPPED_BASE;
*begin = current->mm->mmap_legacy_base;
*end = TASK_SIZE;
}
}

6
arch/x86/mm/mmap.c
View File

@ -112,11 +112,13 @@ static unsigned long mmap_legacy_base(void)
*/
void arch_pick_mmap_layout(struct mm_struct *mm)
{
mm->mmap_legacy_base = mmap_legacy_base();
mm->mmap_base = mmap_base();
if (mmap_is_legacy()) {
mm->mmap_base = mmap_legacy_base();
mm->mmap_base = mm->mmap_legacy_base;
mm->get_unmapped_area = arch_get_unmapped_area;
} else {
mm->mmap_base = mmap_base();
mm->get_unmapped_area = arch_get_unmapped_area_topdown;
}
}

1
include/linux/mm_types.h
View File

@ -332,6 +332,7 @@ struct mm_struct {
unsigned long pgoff, unsigned long flags);
#endif
unsigned long mmap_base; /* base of mmap area */
unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */
unsigned long task_size; /* size of task vm space */
unsigned long highest_vm_end; /* highest vma end address */
pgd_t * pgd;