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/* 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>
.code32
.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
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