From: Volodymyr Babchuk vlad.babchuk@gmail.com
These functions will be used to pass information about shared buffers to OP-TEE. ABI between Linux and OP-TEE is defined in optee_msg.h and optee_smc.h.
optee_msg.h defines OPTEE_MSG_ATTR_NONCONTIG attribute for shared memory references and describes how such references should be passed. Note that it uses 64-bit page addresses even on 32 bit systems. This is done to support LPAE and to unify interface.
Signed-off-by: Volodymyr Babchuk vlad.babchuk@gmail.com --- drivers/tee/optee/call.c | 91 +++++++++++++++++++++++++++++++++++++++ drivers/tee/optee/optee_private.h | 5 +++ 2 files changed, 96 insertions(+)
diff --git a/drivers/tee/optee/call.c b/drivers/tee/optee/call.c index f7b7b40..4db52fe 100644 --- a/drivers/tee/optee/call.c +++ b/drivers/tee/optee/call.c @@ -11,6 +11,7 @@ * GNU General Public License for more details. * */ +#include <asm/pgtable.h> #include <linux/arm-smccc.h> #include <linux/device.h> #include <linux/err.h> @@ -442,3 +443,93 @@ void optee_disable_shm_cache(struct optee *optee) } optee_cq_wait_final(&optee->call_queue, &w); } + +#define PAGELIST_ENTRIES_PER_PAGE \ + ((OPTEE_MSG_NONCONTIG_PAGE_SIZE / sizeof(u64)) - 1) + +/** + * optee_fill_pages_list() - write list of user pages to given shared + * buffer. + * + * @dst: page-aligned buffer where list of pages will be stored + * @pages: array of pages that represents shared buffer + * @num_pages: number of entries in @pages + * @page_offset: offset of user buffer from page start + * + * @dst should be big enough to hold list of user page addresses and + * links to the next pages of buffer + */ +void optee_fill_pages_list(u64 *dst, struct page **pages, int num_pages, + size_t page_offset) +{ + int n = 0; + phys_addr_t optee_page; + /* + * Refer to OPTEE_MSG_ATTR_NONCONTIG description in optee_msg.h + * for details. + */ + struct { + uint64_t pages_list[PAGELIST_ENTRIES_PER_PAGE]; + uint64_t next_page_data; + } *pages_data; + + /* + * Currently OP-TEE uses 4k page size and it does not looks + * like this will change in the future. On other hand, there are + * no know ARM architectures with page size < 4k. + * Thus the next built assert looks redundant. But the following + * code heavily relies on this assumption, so it is better be + * safe than sorry. + */ + BUILD_BUG_ON(PAGE_SIZE < OPTEE_MSG_NONCONTIG_PAGE_SIZE); + + pages_data = (void *)dst; + /* + * If linux page is bigger than 4k, and user buffer offset is + * larger than 4k/8k/12k/etc this will skip first 4k pages, + * because they bear no value data for OP-TEE. + */ + optee_page = page_to_phys(*pages) + + round_down(page_offset, OPTEE_MSG_NONCONTIG_PAGE_SIZE); + + while (true) { + pages_data->pages_list[n++] = optee_page; + + if (n == PAGELIST_ENTRIES_PER_PAGE) { + pages_data->next_page_data = + virt_to_phys(pages_data + 1); + pages_data++; + n = 0; + } + + optee_page += OPTEE_MSG_NONCONTIG_PAGE_SIZE; + if (!(optee_page & ~PAGE_MASK)) { + if (!--num_pages) + break; + pages++; + optee_page = page_to_phys(*pages); + } + } +} + +/* + * The final entry in each pagelist page is a pointer to the next + * pagelist page. + */ +static size_t get_pages_list_size(size_t num_entries) +{ + int pages = DIV_ROUND_UP(num_entries, PAGELIST_ENTRIES_PER_PAGE); + + return pages * OPTEE_MSG_NONCONTIG_PAGE_SIZE; +} + +u64 *optee_allocate_pages_list(size_t num_entries) +{ + return alloc_pages_exact(get_pages_list_size(num_entries), GFP_KERNEL); +} + +void optee_free_pages_list(void *list, size_t num_entries) +{ + free_pages_exact(list, get_pages_list_size(num_entries)); +} + diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h index c374cd5..b63213d 100644 --- a/drivers/tee/optee/optee_private.h +++ b/drivers/tee/optee/optee_private.h @@ -165,6 +165,11 @@ int optee_from_msg_param(struct tee_param *params, size_t num_params, int optee_to_msg_param(struct optee_msg_param *msg_params, size_t num_params, const struct tee_param *params);
+u64 *optee_allocate_pages_list(size_t num_entries); +void optee_free_pages_list(void *array, size_t num_entries); +void optee_fill_pages_list(u64 *dst, struct page **pages, int num_pages, + size_t page_offset); + /* * Small helpers */