xref: /aosp_15_r20/external/coreboot/src/cpu/qemu-x86/cache_as_ram_bootblock.S (revision b9411a12aaaa7e1e6a6fb7c5e057f44ee179a49c)
1/* SPDX-License-Identifier: GPL-2.0-only */
2
3#include <cpu/x86/post_code.h>
4#include <cpu/x86/64bit/entry64.inc>
5
6#define CBFS_FILE_MAGIC 0
7#define CBFS_FILE_LEN (CBFS_FILE_MAGIC + 8)
8#define CBFS_FILE_TYPE (CBFS_FILE_LEN + 4)
9#define CBFS_FILE_CHECKSUM (CBFS_FILE_TYPE + 4)
10#define CBFS_FILE_OFFSET (CBFS_FILE_CHECKSUM + 4)
11
12.section .init, "ax", @progbits
13.code32
14
15.global bootblock_pre_c_entry
16bootblock_pre_c_entry:
17
18cache_as_ram:
19	post_code(POSTCODE_BOOTBLOCK_CAR)
20	/*
21	 * Nothing to do here on qemu, RAM works just fine without any
22	 * initialization.
23	 */
24
25	/* Clear the cache memory region. This will also clear CAR GLOBAL */
26	movl	$_car_region_start, %edi
27	movl	$_car_region_end, %ecx
28	sub	%edi, %ecx
29	shr	$2, %ecx
30	xorl	%eax, %eax
31	rep	stosl
32
33#if defined(__x86_64__)
34	/*
35	 * Copy page tables to final location in DRAM. This prevents some strange
36	 * bugs when running KVM enabled:
37	 * Accessing MMX instructions in long mode causes an abort
38	 * Some physical addresses aren't properly translated
39	 * Emulation fault on every instruction fetched due to page tables in ROM
40	 * Enabling or disabling paging causes a fault
41	 *
42	 * First, find page tables in CBFS:
43	 */
44	lea	pagetables_name, %esi
45	mov	$1f, %esp
46	jmp	walkcbfs_asm
471:
48	cmpl	$0, %eax
49	je	.Lhlt
50
51	/* Test if page tables are memory-mapped and skip relocation */
52	cmpl	$(CONFIG_ARCH_X86_64_PGTBL_LOC), %eax
53	je	pages_done
54
55	movl	CBFS_FILE_OFFSET(%eax), %ebx
56	bswap	%ebx
57	addl	%eax, %ebx
58	movl	%ebx, %esi
59
60	movl	CBFS_FILE_LEN(%eax), %ecx
61	bswap	%ecx
62	shr	$2, %ecx
63
64	movl	$(CONFIG_ARCH_X86_64_PGTBL_LOC), %edi
65
66loop:
67	movl	(%esi), %eax
68	movl	%eax, (%edi)
69	addl	$4, %esi
70	addl	$4, %edi
71	decl	%ecx
72	jnz	loop
73pages_done:
74#endif
75
76	movl	$_ecar_stack, %esp
77
78	/* Align the stack and keep aligned for call to bootblock_c_entry() */
79	and	$0xfffffff0, %esp
80
81#if ENV_X86_64
82	/* entry64.inc preserves ebx. */
83 	setup_longmode $(CONFIG_ARCH_X86_64_PGTBL_LOC)
84
85	/* Restore the BIST result and timestamps. */
86	movd	%mm2, %rdi
87	shlq	$32, %rdi
88	movd	%mm1, %rsi
89	or	%rsi, %rdi
90
91	movd	%mm0, %rsi
92#else
93	sub	$4, %esp
94
95	movd	%mm0, %ebx
96	movd	%mm1, %eax
97	movd	%mm2, %edx
98
99	pushl	%ebx
100	pushl	%edx
101	pushl	%eax
102#endif
103
104	/* Copy .data section content to Cache-As-Ram */
105#include <cpu/x86/copy_data_section.inc>
106
107before_c_entry:
108	call	bootblock_c_entry_bist
109	/* Never returns */
110.Lhlt:
111	post_code(POSTCODE_DEAD_CODE)
112	hlt
113	jmp	.Lhlt
114
115pagetables_name:
116        .string "pagetables"
117