11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * linux/arch/arm/mm/mmap.c 31da177e4SLinus Torvalds */ 41da177e4SLinus Torvalds #include <linux/fs.h> 51da177e4SLinus Torvalds #include <linux/mm.h> 61da177e4SLinus Torvalds #include <linux/mman.h> 71da177e4SLinus Torvalds #include <linux/shm.h> 8e8edc6e0SAlexey Dobriyan #include <linux/sched.h> 909d9bae0SRussell King #include <linux/io.h> 10df5419a9SNicolas Pitre #include <linux/personality.h> 11cc92c28bSNicolas Pitre #include <linux/random.h> 1241dfaa93SRob Herring #include <asm/cachetype.h> 131da177e4SLinus Torvalds 141da177e4SLinus Torvalds #define COLOUR_ALIGN(addr,pgoff) \ 151da177e4SLinus Torvalds ((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \ 161da177e4SLinus Torvalds (((pgoff)<<PAGE_SHIFT) & (SHMLBA-1))) 171da177e4SLinus Torvalds 181da177e4SLinus Torvalds /* 191da177e4SLinus Torvalds * We need to ensure that shared mappings are correctly aligned to 201da177e4SLinus Torvalds * avoid aliasing issues with VIPT caches. We need to ensure that 211da177e4SLinus Torvalds * a specific page of an object is always mapped at a multiple of 221da177e4SLinus Torvalds * SHMLBA bytes. 231da177e4SLinus Torvalds * 241da177e4SLinus Torvalds * We unconditionally provide this function for all cases, however 251da177e4SLinus Torvalds * in the VIVT case, we optimise out the alignment rules. 261da177e4SLinus Torvalds */ 271da177e4SLinus Torvalds unsigned long 281da177e4SLinus Torvalds arch_get_unmapped_area(struct file *filp, unsigned long addr, 291da177e4SLinus Torvalds unsigned long len, unsigned long pgoff, unsigned long flags) 301da177e4SLinus Torvalds { 311da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 321da177e4SLinus Torvalds struct vm_area_struct *vma; 331da177e4SLinus Torvalds unsigned long start_addr; 3441dfaa93SRob Herring int do_align = 0; 3541dfaa93SRob Herring int aliasing = cache_is_vipt_aliasing(); 361da177e4SLinus Torvalds 371da177e4SLinus Torvalds /* 381da177e4SLinus Torvalds * We only need to do colour alignment if either the I or D 3941dfaa93SRob Herring * caches alias. 401da177e4SLinus Torvalds */ 411da177e4SLinus Torvalds if (aliasing) 4241dfaa93SRob Herring do_align = filp || (flags & MAP_SHARED); 431da177e4SLinus Torvalds 441da177e4SLinus Torvalds /* 45acec0ac0SBenjamin Herrenschmidt * We enforce the MAP_FIXED case. 461da177e4SLinus Torvalds */ 471da177e4SLinus Torvalds if (flags & MAP_FIXED) { 48e77414e0SAl Viro if (aliasing && flags & MAP_SHARED && 49e77414e0SAl Viro (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1)) 501da177e4SLinus Torvalds return -EINVAL; 511da177e4SLinus Torvalds return addr; 521da177e4SLinus Torvalds } 531da177e4SLinus Torvalds 541da177e4SLinus Torvalds if (len > TASK_SIZE) 551da177e4SLinus Torvalds return -ENOMEM; 561da177e4SLinus Torvalds 571da177e4SLinus Torvalds if (addr) { 581da177e4SLinus Torvalds if (do_align) 591da177e4SLinus Torvalds addr = COLOUR_ALIGN(addr, pgoff); 601da177e4SLinus Torvalds else 611da177e4SLinus Torvalds addr = PAGE_ALIGN(addr); 621da177e4SLinus Torvalds 631da177e4SLinus Torvalds vma = find_vma(mm, addr); 641da177e4SLinus Torvalds if (TASK_SIZE - len >= addr && 651da177e4SLinus Torvalds (!vma || addr + len <= vma->vm_start)) 661da177e4SLinus Torvalds return addr; 671da177e4SLinus Torvalds } 681363c3cdSWolfgang Wander if (len > mm->cached_hole_size) { 691da177e4SLinus Torvalds start_addr = addr = mm->free_area_cache; 701363c3cdSWolfgang Wander } else { 711363c3cdSWolfgang Wander start_addr = addr = TASK_UNMAPPED_BASE; 721363c3cdSWolfgang Wander mm->cached_hole_size = 0; 731363c3cdSWolfgang Wander } 74cc92c28bSNicolas Pitre /* 8 bits of randomness in 20 address space bits */ 75df5419a9SNicolas Pitre if ((current->flags & PF_RANDOMIZE) && 76df5419a9SNicolas Pitre !(current->personality & ADDR_NO_RANDOMIZE)) 77cc92c28bSNicolas Pitre addr += (get_random_int() % (1 << 8)) << PAGE_SHIFT; 781da177e4SLinus Torvalds 791da177e4SLinus Torvalds full_search: 801da177e4SLinus Torvalds if (do_align) 811da177e4SLinus Torvalds addr = COLOUR_ALIGN(addr, pgoff); 821da177e4SLinus Torvalds else 831da177e4SLinus Torvalds addr = PAGE_ALIGN(addr); 841da177e4SLinus Torvalds 851da177e4SLinus Torvalds for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { 861da177e4SLinus Torvalds /* At this point: (!vma || addr < vma->vm_end). */ 871da177e4SLinus Torvalds if (TASK_SIZE - len < addr) { 881da177e4SLinus Torvalds /* 891da177e4SLinus Torvalds * Start a new search - just in case we missed 901da177e4SLinus Torvalds * some holes. 911da177e4SLinus Torvalds */ 921da177e4SLinus Torvalds if (start_addr != TASK_UNMAPPED_BASE) { 931da177e4SLinus Torvalds start_addr = addr = TASK_UNMAPPED_BASE; 941363c3cdSWolfgang Wander mm->cached_hole_size = 0; 951da177e4SLinus Torvalds goto full_search; 961da177e4SLinus Torvalds } 971da177e4SLinus Torvalds return -ENOMEM; 981da177e4SLinus Torvalds } 991da177e4SLinus Torvalds if (!vma || addr + len <= vma->vm_start) { 1001da177e4SLinus Torvalds /* 1011da177e4SLinus Torvalds * Remember the place where we stopped the search: 1021da177e4SLinus Torvalds */ 1031da177e4SLinus Torvalds mm->free_area_cache = addr + len; 1041da177e4SLinus Torvalds return addr; 1051da177e4SLinus Torvalds } 1061363c3cdSWolfgang Wander if (addr + mm->cached_hole_size < vma->vm_start) 1071363c3cdSWolfgang Wander mm->cached_hole_size = vma->vm_start - addr; 1081da177e4SLinus Torvalds addr = vma->vm_end; 1091da177e4SLinus Torvalds if (do_align) 1101da177e4SLinus Torvalds addr = COLOUR_ALIGN(addr, pgoff); 1111da177e4SLinus Torvalds } 1121da177e4SLinus Torvalds } 1131da177e4SLinus Torvalds 11451635ad2SLennert Buytenhek 11551635ad2SLennert Buytenhek /* 11651635ad2SLennert Buytenhek * You really shouldn't be using read() or write() on /dev/mem. This 11751635ad2SLennert Buytenhek * might go away in the future. 11851635ad2SLennert Buytenhek */ 11951635ad2SLennert Buytenhek int valid_phys_addr_range(unsigned long addr, size_t size) 12051635ad2SLennert Buytenhek { 1219ae3ae0bSAlexandre Rusev if (addr < PHYS_OFFSET) 1229ae3ae0bSAlexandre Rusev return 0; 1236806bfe1SGreg Ungerer if (addr + size > __pa(high_memory - 1) + 1) 12451635ad2SLennert Buytenhek return 0; 12551635ad2SLennert Buytenhek 12651635ad2SLennert Buytenhek return 1; 12751635ad2SLennert Buytenhek } 12851635ad2SLennert Buytenhek 12951635ad2SLennert Buytenhek /* 13051635ad2SLennert Buytenhek * We don't use supersection mappings for mmap() on /dev/mem, which 13151635ad2SLennert Buytenhek * means that we can't map the memory area above the 4G barrier into 13251635ad2SLennert Buytenhek * userspace. 13351635ad2SLennert Buytenhek */ 13451635ad2SLennert Buytenhek int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) 13551635ad2SLennert Buytenhek { 13651635ad2SLennert Buytenhek return !(pfn + (size >> PAGE_SHIFT) > 0x00100000); 13751635ad2SLennert Buytenhek } 138087aaffcSNicolas Pitre 139087aaffcSNicolas Pitre #ifdef CONFIG_STRICT_DEVMEM 140087aaffcSNicolas Pitre 141087aaffcSNicolas Pitre #include <linux/ioport.h> 142087aaffcSNicolas Pitre 143087aaffcSNicolas Pitre /* 144087aaffcSNicolas Pitre * devmem_is_allowed() checks to see if /dev/mem access to a certain 145087aaffcSNicolas Pitre * address is valid. The argument is a physical page number. 146087aaffcSNicolas Pitre * We mimic x86 here by disallowing access to system RAM as well as 147087aaffcSNicolas Pitre * device-exclusive MMIO regions. This effectively disable read()/write() 148087aaffcSNicolas Pitre * on /dev/mem. 149087aaffcSNicolas Pitre */ 150087aaffcSNicolas Pitre int devmem_is_allowed(unsigned long pfn) 151087aaffcSNicolas Pitre { 152087aaffcSNicolas Pitre if (iomem_is_exclusive(pfn << PAGE_SHIFT)) 153087aaffcSNicolas Pitre return 0; 154087aaffcSNicolas Pitre if (!page_is_ram(pfn)) 155087aaffcSNicolas Pitre return 1; 156087aaffcSNicolas Pitre return 0; 157087aaffcSNicolas Pitre } 158087aaffcSNicolas Pitre 159087aaffcSNicolas Pitre #endif 160