madt_playdead.S

 1/* SPDX-License-Identifier: GPL-2.0 */
 2#include <linux/linkage.h>
 3#include <asm/nospec-branch.h>
 4#include <asm/page_types.h>
 5#include <asm/processor-flags.h>
 6
 7	.text
 8	.align PAGE_SIZE
 9
10/*
11 * asm_acpi_mp_play_dead() - Hand over control of the CPU to the BIOS
12 *
13 * rdi: Address of the ACPI MADT MPWK ResetVector
14 * rsi: PGD of the identity mapping
15 */
16SYM_FUNC_START(asm_acpi_mp_play_dead)
17	ANNOTATE_NOENDBR
18	/* Turn off global entries. Following CR3 write will flush them. */
19	movq	%cr4, %rdx
20	andq	$~(X86_CR4_PGE), %rdx
21	movq	%rdx, %cr4
22
23	/* Switch to identity mapping */
24	movq	%rsi, %cr3
25
26	/* Jump to reset vector */
27	ANNOTATE_RETPOLINE_SAFE
28	jmp	*%rdi
29SYM_FUNC_END(asm_acpi_mp_play_dead)