efi: 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.
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@linaro.org>
Acked-by: Mark Salter <msalter@redhat.com>
Reviewed-by: Grant Likely <grant.likely@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

diff --git a/drivers/firmware/efi/efi-stub-helper.c b/drivers/firmware/efi/efi-stub-helper.c
index 2f528fb541f9f188e09bc9dc91418ce013f9b44c..a25675833598c358dec976e14850cba58571803b 100644 (file)
--- a/drivers/firmware/efi/efi-stub-helper.c
+++ b/drivers/firmware/efi/efi-stub-helper.c
@@ -101,6 +101,14 @@ 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++) {
@@ -179,6 +187,14 @@ 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;