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OpenCloudOS-Kernel
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efi: libstub: use EFI_LOADER_CODE region when moving the kernel in memory 

The EFI spec is not very clear about which permissions are being given
when allocating pages of a certain type. However, it is quite obvious
that EFI_LOADER_CODE is more likely to permit execution than
EFI_LOADER_DATA, which becomes relevant once we permit booting the
kernel proper with the firmware's 1:1 mapping still active.

Ostensibly, recent systems such as the Surface Pro X grant executable
permissions to EFI_LOADER_CODE regions but not EFI_LOADER_DATA regions.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
This commit is contained in:
Ard Biesheuvel 2022-08-02 11:00:16 +02:00
parent 977122898e
commit 9cf42bca30
5 changed files with 16 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/firmware/efi/libstub/alignedmem.c
View File

@ -22,7 +22,8 @@
* Return: status code
*/
efi_status_t efi_allocate_pages_aligned(unsigned long size, unsigned long *addr,
unsigned long max, unsigned long align)
unsigned long max, unsigned long align,
int memory_type)
{
efi_physical_addr_t alloc_addr;
efi_status_t status;
@ -36,7 +37,7 @@ efi_status_t efi_allocate_pages_aligned(unsigned long size, unsigned long *addr,
slack = align / EFI_PAGE_SIZE - 1;
status = efi_bs_call(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS,
EFI_LOADER_DATA, size / EFI_PAGE_SIZE + slack,
memory_type, size / EFI_PAGE_SIZE + slack,
&alloc_addr);
if (status != EFI_SUCCESS)
return status;

6
drivers/firmware/efi/libstub/arm64-stub.c
View File

@ -102,7 +102,8 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
* locate the kernel at a randomized offset in physical memory.
*/
status = efi_random_alloc(*reserve_size, min_kimg_align,
reserve_addr, phys_seed);
reserve_addr, phys_seed,
EFI_LOADER_CODE);
if (status != EFI_SUCCESS)
efi_warn("efi_random_alloc() failed: 0x%lx\n", status);
} else {
@ -123,7 +124,8 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
}
status = efi_allocate_pages_aligned(*reserve_size, reserve_addr,
ULONG_MAX, min_kimg_align);
ULONG_MAX, min_kimg_align,
EFI_LOADER_CODE);
if (status != EFI_SUCCESS) {
efi_err("Failed to relocate kernel\n");

6
drivers/firmware/efi/libstub/efistub.h
View File

@ -880,7 +880,8 @@ void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
efi_status_t efi_get_random_bytes(unsigned long size, u8 *out);
efi_status_t efi_random_alloc(unsigned long size, unsigned long align,
unsigned long *addr, unsigned long random_seed);
unsigned long *addr, unsigned long random_seed,
int memory_type);
efi_status_t check_platform_features(void);
@ -905,7 +906,8 @@ efi_status_t efi_allocate_pages(unsigned long size, unsigned long *addr,
unsigned long max);
efi_status_t efi_allocate_pages_aligned(unsigned long size, unsigned long *addr,
unsigned long max, unsigned long align);
unsigned long max, unsigned long align,
int memory_type);
efi_status_t efi_low_alloc_above(unsigned long size, unsigned long align,
unsigned long *addr, unsigned long min);

3
drivers/firmware/efi/libstub/mem.c
View File

@ -91,7 +91,8 @@ efi_status_t efi_allocate_pages(unsigned long size, unsigned long *addr,
if (EFI_ALLOC_ALIGN > EFI_PAGE_SIZE)
return efi_allocate_pages_aligned(size, addr, max,
EFI_ALLOC_ALIGN);
EFI_ALLOC_ALIGN,
EFI_LOADER_DATA);
alloc_addr = ALIGN_DOWN(max + 1, EFI_ALLOC_ALIGN) - 1;
status = efi_bs_call(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS,

5
drivers/firmware/efi/libstub/randomalloc.c
View File

@ -53,7 +53,8 @@ static unsigned long get_entry_num_slots(efi_memory_desc_t *md,
efi_status_t efi_random_alloc(unsigned long size,
unsigned long align,
unsigned long *addr,
unsigned long random_seed)
unsigned long random_seed,
int memory_type)
{
unsigned long total_slots = 0, target_slot;
unsigned long total_mirrored_slots = 0;
@ -118,7 +119,7 @@ efi_status_t efi_random_alloc(unsigned long size,
pages = size / EFI_PAGE_SIZE;
status = efi_bs_call(allocate_pages, EFI_ALLOCATE_ADDRESS,
EFI_LOADER_DATA, pages, &target);
memory_type, pages, &target);
if (status == EFI_SUCCESS)
*addr = target;
break;