diff options
Diffstat (limited to 'arch/arm/mm/mmap.c')
| -rw-r--r-- | arch/arm/mm/mmap.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c index f5abc51c5a07..b0a98305055c 100644 --- a/arch/arm/mm/mmap.c +++ b/arch/arm/mm/mmap.c @@ -7,6 +7,7 @@ #include <linux/shm.h> #include <linux/sched.h> #include <linux/io.h> +#include <linux/random.h> #include <asm/cputype.h> #include <asm/system.h> @@ -80,6 +81,9 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, start_addr = addr = TASK_UNMAPPED_BASE; mm->cached_hole_size = 0; } + /* 8 bits of randomness in 20 address space bits */ + if (current->flags & PF_RANDOMIZE) + addr += (get_random_int() % (1 << 8)) << PAGE_SHIFT; full_search: if (do_align) @@ -140,3 +144,25 @@ int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) { return !(pfn + (size >> PAGE_SHIFT) > 0x00100000); } + +#ifdef CONFIG_STRICT_DEVMEM + +#include <linux/ioport.h> + +/* + * devmem_is_allowed() checks to see if /dev/mem access to a certain + * address is valid. The argument is a physical page number. + * We mimic x86 here by disallowing access to system RAM as well as + * device-exclusive MMIO regions. This effectively disable read()/write() + * on /dev/mem. + */ +int devmem_is_allowed(unsigned long pfn) +{ + if (iomem_is_exclusive(pfn << PAGE_SHIFT)) + return 0; + if (!page_is_ram(pfn)) + return 1; + return 0; +} + +#endif |