| /* SPDX-License-Identifier: GPL-2.0-or-later */ |
| |
| /* |
| * input %esp: return address (not pointer to return address!) |
| * clobber the content of eax, ecx, edx |
| */ |
| |
| #include <cpu/x86/mtrr.h> |
| |
| .section .text |
| .global check_mtrr |
| |
| check_mtrr: |
| /* Use the MTRR default type MSR as a proxy for detecting INIT#. |
| * Reset the system if any known bits are set in that MSR. That is |
| * an indication of the CPU not being properly reset. */ |
| |
| check_for_clean_reset: |
| movl $MTRR_DEF_TYPE_MSR, %ecx |
| rdmsr |
| andl $(MTRR_DEF_TYPE_EN | MTRR_DEF_TYPE_FIX_EN), %eax |
| cmp $0, %eax |
| jnz warm_reset |
| jmp *%esp |
| /* perform warm reset */ |
| warm_reset: |
| movw $0xcf9, %dx |
| movb $0x06, %al |
| outb %al, %dx |
| /* Should not reach this*/ |
| .Lhlt: |
| hlt |
| jmp .Lhlt |
