diff options
Diffstat (limited to 'drivers/mxc/security/rng/shw_memory_mapper.c')
| -rw-r--r-- | drivers/mxc/security/rng/shw_memory_mapper.c | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/drivers/mxc/security/rng/shw_memory_mapper.c b/drivers/mxc/security/rng/shw_memory_mapper.c new file mode 100644 index 000000000000..d7b82576a6cd --- /dev/null +++ b/drivers/mxc/security/rng/shw_memory_mapper.c @@ -0,0 +1,213 @@ +/* + * Copyright (C) 2005-2010 Freescale Semiconductor, Inc. All Rights Reserved. + */ + +/* + * The code contained herein is licensed under the GNU General Public + * License. You may obtain a copy of the GNU General Public License + * Version 2 or later at the following locations: + * + * http://www.opensource.org/licenses/gpl-license.html + * http://www.gnu.org/copyleft/gpl.html + */ + + + +/** + * Memory management functions, from Sahara Crypto API + * + * This is a subset of the memory management functions from the Sahara Crypto + * API, and is intended to support user secure partitions. + */ + +#include "portable_os.h" +#include "fsl_shw.h" + +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/pagemap.h> + +#ifdef SHW_DEBUG +#include <diagnostic.h> +#endif + +/* Page context structure. Used by wire_user_memory and unwire_user_memory */ +typedef struct page_ctx_t { + uint32_t count; + struct page **local_pages; +} page_ctx_t; + +/** +******************************************************************************* +* Map and wire down a region of user memory. +* +* +* @param address Userspace address of the memory to wire +* @param length Length of the memory region to wire +* @param page_ctx Page context, to be passed to unwire_user_memory +* +* @return (if successful) Kernel virtual address of the wired pages +*/ +void* wire_user_memory(void* address, uint32_t length, void **page_ctx) +{ + void* kernel_black_addr = NULL; + int result = -1; + int page_index = 0; + page_ctx_t *page_context; + int nr_pages = 0; + unsigned long start_page; + fsl_shw_return_t status; + + /* Determine the number of pages being used for this link */ + nr_pages = (((unsigned long)(address) & ~PAGE_MASK) + + length + ~PAGE_MASK) >> PAGE_SHIFT; + + start_page = (unsigned long)(address) & PAGE_MASK; + + /* Allocate some memory to keep track of the wired user pages, so that + * they can be deallocated later. The block of memory will contain both + * the structure and the array of pages. + */ + page_context = kmalloc(sizeof(page_ctx_t) + + nr_pages * sizeof(struct page *), GFP_KERNEL); + + if (page_context == NULL) { + status = FSL_RETURN_NO_RESOURCE_S; /* no memory! */ +#ifdef DIAG_DRV_IF + LOG_KDIAG("kmalloc() failed."); +#endif + return NULL; + } + + /* Set the page pointer to point to the allocated region of memory */ + page_context->local_pages = (void*)page_context + sizeof(page_ctx_t); + +#ifdef DIAG_DRV_IF + LOG_KDIAG_ARGS("page_context at: %p, local_pages at: %p", + (void *)page_context, + (void *)(page_context->local_pages)); +#endif + + /* Wire down the pages from user space */ + down_read(¤t->mm->mmap_sem); + result = get_user_pages(current, current->mm, + start_page, nr_pages, + WRITE, 0 /* noforce */, + (page_context->local_pages), NULL); + up_read(¤t->mm->mmap_sem); + + if (result < nr_pages) { +#ifdef DIAG_DRV_IF + LOG_KDIAG("get_user_pages() failed."); +#endif + if (result > 0) { + for (page_index = 0; page_index < result; page_index++) + page_cache_release((page_context->local_pages[page_index])); + + kfree(page_context); + } + return NULL; + } + + kernel_black_addr = page_address(page_context->local_pages[0]) + + ((unsigned long)address & ~PAGE_MASK); + + page_context->count = nr_pages; + *page_ctx = page_context; + + return kernel_black_addr; +} + + +/** +******************************************************************************* +* Release and unmap a region of user memory. +* +* @param page_ctx Page context from wire_user_memory +*/ +void unwire_user_memory(void** page_ctx) +{ + int page_index = 0; + struct page_ctx_t *page_context = *page_ctx; + +#ifdef DIAG_DRV_IF + LOG_KDIAG_ARGS("page_context at: %p, first page at:%p, count: %i", + (void *)page_context, + (void *)(page_context->local_pages), + page_context->count); +#endif + + if ((page_context != NULL) && (page_context->local_pages != NULL)) { + for (page_index = 0; page_index < page_context->count; page_index++) + page_cache_release(page_context->local_pages[page_index]); + + kfree(page_context); + *page_ctx = NULL; + } +} + + +/** +******************************************************************************* +* Map some physical memory into a users memory space +* +* @param vma Memory structure to map to +* @param physical_addr Physical address of the memory to be mapped in +* @param size Size of the memory to map (bytes) +* +* @return +*/ +os_error_code +map_user_memory(struct vm_area_struct *vma, uint32_t physical_addr, uint32_t size) +{ + os_error_code retval; + + /* Map the acquired partition into the user's memory space */ + vma->vm_end = vma->vm_start + size; + + /* set cache policy to uncached so that each write of the UMID and + * permissions get directly to the SCC2 in order to engage it + * properly. Once the permissions have been written, it may be + * useful to provide a service for the user to request a different + * cache policy + */ + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + + /* Make sure that the user cannot fork() a child which will inherit + * this mapping, as it creates a security hole. Likewise, do not + * allow the user to 'expand' his mapping beyond this partition. + */ + vma->vm_flags |= VM_IO | VM_RESERVED | VM_DONTCOPY | VM_DONTEXPAND; + + retval = remap_pfn_range(vma, + vma->vm_start, + __phys_to_pfn(physical_addr), + size, + vma->vm_page_prot); + + return retval; +} + + +/** +******************************************************************************* +* Remove some memory from a user's memory space +* +* @param user_addr Userspace address of the memory to be unmapped +* @param size Size of the memory to map (bytes) +* +* @return +*/ +os_error_code +unmap_user_memory(uint32_t user_addr, uint32_t size) +{ + os_error_code retval; + struct mm_struct *mm = current->mm; + + /* Unmap the memory region (see sys_munmap in mmap.c) */ + down_write(&mm->mmap_sem); + retval = do_munmap(mm, (unsigned long)user_addr, size); + up_write(&mm->mmap_sem); + + return retval; +} |