Commit 41aacc1e authored by Radu Caragea's avatar Radu Caragea Committed by Linus Torvalds

x86 get_unmapped_area: Access mmap_legacy_base through mm_struct member

This is the updated version of df54d6fa ("x86 get_unmapped_area():
use proper mmap base for bottom-up direction") that only randomizes the
mmap base address once.
Signed-off-by: default avatarRadu Caragea <sinaelgl@gmail.com>
Reported-and-tested-by: default avatarJeff 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: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5ea80f76
...@@ -101,7 +101,7 @@ static void find_start_end(unsigned long flags, unsigned long *begin, ...@@ -101,7 +101,7 @@ static void find_start_end(unsigned long flags, unsigned long *begin,
*begin = new_begin; *begin = new_begin;
} }
} else { } else {
*begin = TASK_UNMAPPED_BASE; *begin = current->mm->mmap_legacy_base;
*end = TASK_SIZE; *end = TASK_SIZE;
} }
} }
......
...@@ -112,11 +112,13 @@ static unsigned long mmap_legacy_base(void) ...@@ -112,11 +112,13 @@ static unsigned long mmap_legacy_base(void)
*/ */
void arch_pick_mmap_layout(struct mm_struct *mm) 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()) { 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; mm->get_unmapped_area = arch_get_unmapped_area;
} else { } else {
mm->mmap_base = mmap_base();
mm->get_unmapped_area = arch_get_unmapped_area_topdown; mm->get_unmapped_area = arch_get_unmapped_area_topdown;
} }
} }
...@@ -332,6 +332,7 @@ struct mm_struct { ...@@ -332,6 +332,7 @@ struct mm_struct {
unsigned long pgoff, unsigned long flags); unsigned long pgoff, unsigned long flags);
#endif #endif
unsigned long mmap_base; /* base of mmap area */ 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 task_size; /* size of task vm space */
unsigned long highest_vm_end; /* highest vma end address */ unsigned long highest_vm_end; /* highest vma end address */
pgd_t * pgd; pgd_t * pgd;
......
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