diff options
| -rw-r--r-- | arch/x86/boot/compressed/pgtable_64.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/arch/x86/boot/compressed/pgtable_64.c b/arch/x86/boot/compressed/pgtable_64.c index 9e2157371491..f8debf7aeb4c 100644 --- a/arch/x86/boot/compressed/pgtable_64.c +++ b/arch/x86/boot/compressed/pgtable_64.c @@ -1,5 +1,7 @@ +#include <linux/efi.h> #include <asm/e820/types.h> #include <asm/processor.h> +#include <asm/efi.h> #include "pgtable.h" #include "../string.h" @@ -37,9 +39,10 @@ int cmdline_find_option_bool(const char *option); static unsigned long find_trampoline_placement(void) { - unsigned long bios_start, ebda_start; + unsigned long bios_start = 0, ebda_start = 0; unsigned long trampoline_start; struct boot_e820_entry *entry; + char *signature; int i; /* @@ -47,8 +50,18 @@ static unsigned long find_trampoline_placement(void) * This code is based on reserve_bios_regions(). */ - ebda_start = *(unsigned short *)0x40e << 4; - bios_start = *(unsigned short *)0x413 << 10; + /* + * EFI systems may not provide legacy ROM. The memory may not be mapped + * at all. + * + * Only look for values in the legacy ROM for non-EFI system. + */ + signature = (char *)&boot_params->efi_info.efi_loader_signature; + if (strncmp(signature, EFI32_LOADER_SIGNATURE, 4) && + strncmp(signature, EFI64_LOADER_SIGNATURE, 4)) { + ebda_start = *(unsigned short *)0x40e << 4; + bios_start = *(unsigned short *)0x413 << 10; + } if (bios_start < BIOS_START_MIN || bios_start > BIOS_START_MAX) bios_start = BIOS_START_MAX; |