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author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2011-01-12 03:55:27 -0500 |
---|---|---|
committer | Martin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com> | 2011-01-12 03:55:25 -0500 |
commit | df1ca53cba34b1d40a4ed47907d71397e4ee72c2 (patch) | |
tree | cbfc440a178eaadbfea7af7dbf0b2d69dec48a1b /arch/s390/mm/mmap.c | |
parent | 1060f62ea47e609b0c1672e8d1ac216e57f11a8e (diff) |
[S390] Randomize mmap start address
Randomize mmap start address with 8MB.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/mm/mmap.c')
-rw-r--r-- | arch/s390/mm/mmap.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c index 74d663f367e2..c9a9f7f18188 100644 --- a/arch/s390/mm/mmap.c +++ b/arch/s390/mm/mmap.c | |||
@@ -27,6 +27,7 @@ | |||
27 | #include <linux/personality.h> | 27 | #include <linux/personality.h> |
28 | #include <linux/mm.h> | 28 | #include <linux/mm.h> |
29 | #include <linux/module.h> | 29 | #include <linux/module.h> |
30 | #include <linux/random.h> | ||
30 | #include <asm/pgalloc.h> | 31 | #include <asm/pgalloc.h> |
31 | #include <asm/compat.h> | 32 | #include <asm/compat.h> |
32 | 33 | ||
@@ -56,6 +57,14 @@ static inline int mmap_is_legacy(void) | |||
56 | return sysctl_legacy_va_layout; | 57 | return sysctl_legacy_va_layout; |
57 | } | 58 | } |
58 | 59 | ||
60 | static unsigned long mmap_rnd(void) | ||
61 | { | ||
62 | if (!(current->flags & PF_RANDOMIZE)) | ||
63 | return 0; | ||
64 | /* 8MB randomization for mmap_base */ | ||
65 | return (get_random_int() & 0x7ffUL) << PAGE_SHIFT; | ||
66 | } | ||
67 | |||
59 | static inline unsigned long mmap_base(void) | 68 | static inline unsigned long mmap_base(void) |
60 | { | 69 | { |
61 | unsigned long gap = rlimit(RLIMIT_STACK); | 70 | unsigned long gap = rlimit(RLIMIT_STACK); |
@@ -64,8 +73,8 @@ static inline unsigned long mmap_base(void) | |||
64 | gap = MIN_GAP; | 73 | gap = MIN_GAP; |
65 | else if (gap > MAX_GAP) | 74 | else if (gap > MAX_GAP) |
66 | gap = MAX_GAP; | 75 | gap = MAX_GAP; |
67 | 76 | gap &= PAGE_MASK; | |
68 | return STACK_TOP - stack_maxrandom_size() - (gap & PAGE_MASK); | 77 | return STACK_TOP - stack_maxrandom_size() - mmap_rnd() - gap; |
69 | } | 78 | } |
70 | 79 | ||
71 | #ifndef CONFIG_64BIT | 80 | #ifndef CONFIG_64BIT |