diff options
Diffstat (limited to 'src/soc/intel/apollolake/exit_car.S')
| -rw-r--r-- | src/soc/intel/apollolake/exit_car.S | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/src/soc/intel/apollolake/exit_car.S b/src/soc/intel/apollolake/exit_car.S new file mode 100644 index 0000000000..339242b319 --- /dev/null +++ b/src/soc/intel/apollolake/exit_car.S @@ -0,0 +1,47 @@ +/* + * This file is part of the coreboot project. + * + * Copyright 2016 Google Inc. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; version 2 of + * the License. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <cpu/x86/mtrr.h> +#include <cpu/x86/cr.h> +#include <soc/cpu.h> + +.text +.global chipset_teardown_car +chipset_teardown_car: + /* + * Retrieve return address from stack as it will get trashed below if + * execution is utilizing the cache-as-ram stack. + */ + pop %ebx + + /* invalidate cache contents. */ + invd + /* Disable MTRRs. */ + mov $(MTRR_DEF_TYPE_MSR), %ecx + rdmsr + and $(~(MTRR_DEF_TYPE_EN | MTRR_DEF_TYPE_FIX_EN)), %eax + wrmsr + + /* Knock down bit 1 then bit 0 of NEM control not combining steps. */ + mov $(MSR_EVICT_CTL), %ecx + rdmsr + and $(~(1 << 1)), %eax + wrmsr + and $(~(1 << 0)), %eax + wrmsr + + /* Return to caller. */ + jmp *%ebx |