diff options
Diffstat (limited to 'arch/arm/boot/compressed/efi-header.S')
| -rw-r--r-- | arch/arm/boot/compressed/efi-header.S | 22 |
1 files changed, 14 insertions, 8 deletions
diff --git a/arch/arm/boot/compressed/efi-header.S b/arch/arm/boot/compressed/efi-header.S index c0e7a745103e..230030c13085 100644 --- a/arch/arm/boot/compressed/efi-header.S +++ b/arch/arm/boot/compressed/efi-header.S @@ -9,16 +9,22 @@ #include <linux/sizes.h> .macro __nop -#ifdef CONFIG_EFI_STUB - @ This is almost but not quite a NOP, since it does clobber the - @ condition flags. But it is the best we can do for EFI, since - @ PE/COFF expects the magic string "MZ" at offset 0, while the - @ ARM/Linux boot protocol expects an executable instruction - @ there. - .inst MZ_MAGIC | (0x1310 << 16) @ tstne r0, #0x4d000 -#else AR_CLASS( mov r0, r0 ) M_CLASS( nop.w ) + .endm + + .macro __initial_nops +#ifdef CONFIG_EFI_STUB + @ This is a two-instruction NOP, which happens to bear the + @ PE/COFF signature "MZ" in the first two bytes, so the kernel + @ is accepted as an EFI binary. Booting via the UEFI stub + @ will not execute those instructions, but the ARM/Linux + @ boot protocol does, so we need some NOPs here. + .inst MZ_MAGIC | (0xe225 << 16) @ eor r5, r5, 0x4d000 + eor r5, r5, 0x4d000 @ undo previous insn +#else + __nop + __nop #endif .endm |