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-rw-r--r--arch/x86/boot/compressed/pgtable_64.c19
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;