[PATCH 26/28] efi/libstub/x86: use ULONG_MAX as upper bound for all allocations

Ard Biesheuvel
2020-03-08T08:10:43Z

The header flag XLF_CAN_BE_LOADED_ABOVE_4G will inform us whether
allocations above 4 GiB for kernel, command line, etc are permitted,
so we take it into account when calling efi_allocate_pages() etc.

However, CONFIG_EFI_STUB implies CONFIG_RELOCATABLE, and so the flag
is guaranteed to be set on x86_64 builds, whereas i386 builds are
guaranteed to run under firmware that will not allocate above 4 GB
in the first place.

So drop the check, and just pass ULONG_MAX as the upper bound for
all allocations.

Link: https://lore.kernel.org/r/20200303225054.28741-1-ardb@kernel.org
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
drivers/firmware/efi/libstub/x86-stub.c | 17 ++++-------------
1 file changed, 4 insertions(+), 13 deletions(-)

diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
index 064941ecc36f..bf0c3f60762a 100644
--- a/drivers/firmware/efi/libstub/x86-stub.c
+++ b/drivers/firmware/efi/libstub/x86-stub.c
@@ -376,7 +376,6 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
char *cmdline_ptr;
unsigned long ramdisk_addr;
unsigned long ramdisk_size;
- bool above4g;

sys_table = sys_table_arg;

@@ -394,10 +393,8 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
image_offset = (void *)startup_32 - image_base;

hdr = &((struct boot_params *)image_base)->hdr;
- above4g = hdr->xloadflags & XLF_CAN_BE_LOADED_ABOVE_4G;

- status = efi_allocate_pages(0x4000, (unsigned long *)&boot_params,
- above4g ? ULONG_MAX : UINT_MAX);
+ status = efi_allocate_pages(0x4000, (unsigned long *)&boot_params, ULONG_MAX);
if (status != EFI_SUCCESS) {
efi_printk("Failed to allocate lowmem for boot params\n");
efi_exit(handle, status);
@@ -421,8 +418,7 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
hdr->type_of_loader = 0x21;

/* Convert unicode cmdline to ascii */
- cmdline_ptr = efi_convert_cmdline(image, &options_size,
- above4g ? ULONG_MAX : UINT_MAX);
+ cmdline_ptr = efi_convert_cmdline(image, &options_size, ULONG_MAX);
if (!cmdline_ptr)
goto fail;

@@ -442,8 +438,7 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
status = efi_load_initrd(image, &ramdisk_addr,
&ramdisk_size,
hdr->initrd_addr_max,
- above4g ? ULONG_MAX
- : hdr->initrd_addr_max);
+ ULONG_MAX);
if (status != EFI_SUCCESS)
goto fail2;
hdr->ramdisk_image = ramdisk_addr & 0xffffffff;
@@ -795,12 +790,8 @@ unsigned long efi_main(efi_handle_t handle,
*/
if (!noinitrd()) {
unsigned long addr, size;
- unsigned long max_addr = hdr->initrd_addr_max;

- if (hdr->xloadflags & XLF_CAN_BE_LOADED_ABOVE_4G)
- max_addr = ULONG_MAX;
-
- status = efi_load_initrd_dev_path(&addr, &size, max_addr);
+ status = efi_load_initrd_dev_path(&addr, &size, ULONG_MAX);
if (status == EFI_SUCCESS) {
hdr->ramdisk_image = (u32)addr;
hdr->ramdisk_size = (u32)size;
--
2.17.1