diff options
| author | Helge Deller <deller@gmx.de> | 2014-01-31 22:19:52 +0100 |
|---|---|---|
| committer | Helge Deller <deller@gmx.de> | 2014-02-02 21:00:13 +0100 |
| commit | 9dabf60dc4abe6e06bebcc2ee46b4d76ec8741f2 (patch) | |
| tree | 93b98d806b1941b91ac3de04b7bd730103d3fab8 /arch/parisc/kernel/process.c | |
| parent | f5a408d53edef3af07ac7697b8bc54a755628450 (diff) | |
parisc: add flexible mmap memory layout support
Add support for the flexible mmap memory layout (as described in
http://lwn.net/Articles/91829). This is especially very interesting on
parisc since we currently only support 32bit userspace (even with a
64bit Linux kernel).
Signed-off-by: Helge Deller <deller@gmx.de>
Diffstat (limited to 'arch/parisc/kernel/process.c')
| -rw-r--r-- | arch/parisc/kernel/process.c | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c index 55f92b614182..0bbbf0d3f608 100644 --- a/arch/parisc/kernel/process.c +++ b/arch/parisc/kernel/process.c @@ -13,7 +13,7 @@ * Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org> * Copyright (C) 2001 Alan Modra <amodra at parisc-linux.org> * Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org> - * Copyright (C) 2001-2007 Helge Deller <deller at parisc-linux.org> + * Copyright (C) 2001-2014 Helge Deller <deller@gmx.de> * Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org> * * @@ -49,6 +49,7 @@ #include <linux/kallsyms.h> #include <linux/uaccess.h> #include <linux/rcupdate.h> +#include <linux/random.h> #include <asm/io.h> #include <asm/asm-offsets.h> @@ -286,3 +287,21 @@ void *dereference_function_descriptor(void *ptr) return ptr; } #endif + +static inline unsigned long brk_rnd(void) +{ + /* 8MB for 32bit, 1GB for 64bit */ + if (is_32bit_task()) + return (get_random_int() & 0x7ffUL) << PAGE_SHIFT; + else + return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT; +} + +unsigned long arch_randomize_brk(struct mm_struct *mm) +{ + unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd()); + + if (ret < mm->brk) + return mm->brk; + return ret; +} |