[PATCH 07/17] Enforce minimum alignment of 1 page on allocations. The efi_high_alloc() and efi_low_alloc() functions use the EFI_ALLOCATE_ADDRESS option to the EFI function allocate_pages(), which requires a minimum of page alignment, and rejects all other requests.

[Roy Franz]

The existing code could fail to allocate depending
on allocation size, as although repeated allocation
attempts were made, none were guaranteed to be page
aligned.



Signed-off-by: Roy Franz <roy.franz at linaro.org>
---
 drivers/firmware/efi/efi-stub-helper.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/firmware/efi/efi-stub-helper.c b/drivers/firmware/efi/efi-stub-helper.c
index cd7701f..8582650 100644
--- a/drivers/firmware/efi/efi-stub-helper.c
+++ b/drivers/firmware/efi/efi-stub-helper.c
@@ -105,6 +105,13 @@ static efi_status_t efi_high_alloc(efi_system_table_t *sys_table_arg,
 	if (status != EFI_SUCCESS)
 		goto fail;
 
+	/* Enforce minimum alignment that EFI requires when requesting
+	 * a specific address.  We are doing page-based allocations,
+	 * so we must be aligned to a page.
+	 */
+	if (align < EFI_PAGE_SIZE)
+		align = EFI_PAGE_SIZE;
+
 	nr_pages = round_up(size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
 again:
 	for (i = 0; i < map_size / desc_size; i++) {
@@ -184,6 +191,13 @@ static efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg,
 	if (status != EFI_SUCCESS)
 		goto fail;
 
+	/* Enforce minimum alignment that EFI requires when requesting
+	 * a specific address.  We are doing page-based allocations,
+	 * so we must be aligned to a page.
+	 */
+	if (align < EFI_PAGE_SIZE)
+		align = EFI_PAGE_SIZE;
+
 	nr_pages = round_up(size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
 	for (i = 0; i < map_size / desc_size; i++) {
 		efi_memory_desc_t *desc;
-- 
1.7.10.4