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authorRadu Caragea <sinaelgl@gmail.com>2013-08-21 20:55:59 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2013-08-22 10:19:35 -0700
commit41aacc1eea645c99edbe8fbcf78a97dc9b862adc (patch)
tree2f1a4a363b738d374c58ca2a0d520f2b0981bf67
parent5ea80f76a56605a190a7ea16846c82aa63dbd0aa (diff)
x86 get_unmapped_area: Access mmap_legacy_base through mm_struct member
This is the updated version of df54d6fa5427 ("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>
-rw-r--r--arch/x86/kernel/sys_x86_64.c2
-rw-r--r--arch/x86/mm/mmap.c6
-rw-r--r--include/linux/mm_types.h1
3 files changed, 6 insertions, 3 deletions
diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index dbded5aedb81..30277e27431a 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -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;
}
}
diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c
index 62c29a5bfe26..25e7e1372bb2 100644
--- a/arch/x86/mm/mmap.c
+++ b/arch/x86/mm/mmap.c
@@ -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;
}
}
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index fb425aa16c01..faf4b7c1ad12 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -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;