| Tom Rini | 10e4779 | 2018-05-06 17:58:06 -0400 | [diff] [blame] | 1 | /* SPDX-License-Identifier: GPL-2.0+ */ |
| Simon Glass | 463fac2 | 2014-10-10 08:21:55 -0600 | [diff] [blame] | 2 | /* |
| 3 | * (C) Copyright 2014 Google, Inc |
| 4 | * Copyright (C) 1991, 1992, 1993 Linus Torvalds |
| 5 | * |
| 6 | * Parts of this copied from Linux arch/x86/boot/compressed/head_64.S |
| Simon Glass | 463fac2 | 2014-10-10 08:21:55 -0600 | [diff] [blame] | 7 | */ |
| 8 | |
| Simon Glass | 463fac2 | 2014-10-10 08:21:55 -0600 | [diff] [blame] | 9 | #include <asm/msr-index.h> |
| 10 | #include <asm/processor-flags.h> |
| 11 | |
| 12 | .code32 |
| Sam Edwards | 7cc2ef9 | 2025-03-15 15:18:05 -0700 | [diff] [blame] | 13 | .section .text_call64, "ax" |
| Simon Glass | 463fac2 | 2014-10-10 08:21:55 -0600 | [diff] [blame] | 14 | .globl cpu_call64 |
| 15 | cpu_call64: |
| 16 | /* |
| 17 | * cpu_call64(ulong pgtable, ulong setup_base, ulong target) |
| 18 | * |
| 19 | * eax - pgtable |
| 20 | * edx - setup_base |
| 21 | * ecx - target |
| 22 | */ |
| 23 | cli |
| 24 | push %ecx /* arg2 = target */ |
| 25 | push %edx /* arg1 = setup_base */ |
| 26 | mov %eax, %ebx |
| 27 | |
| Simon Glass | 46faeea | 2025-03-15 14:25:37 +0000 | [diff] [blame^] | 28 | # disable paging |
| 29 | movl %cr0, %eax |
| 30 | andl $~X86_CR0_PG, %eax |
| 31 | movl %eax, %cr0 |
| 32 | |
| Simon Glass | 463fac2 | 2014-10-10 08:21:55 -0600 | [diff] [blame] | 33 | /* Load new GDT with the 64bit segments using 32bit descriptor */ |
| 34 | leal gdt, %eax |
| 35 | movl %eax, gdt+2 |
| 36 | lgdt gdt |
| 37 | |
| 38 | /* Enable PAE mode */ |
| 39 | movl $(X86_CR4_PAE), %eax |
| 40 | movl %eax, %cr4 |
| 41 | |
| 42 | /* Enable the boot page tables */ |
| 43 | leal (%ebx), %eax |
| 44 | movl %eax, %cr3 |
| 45 | |
| 46 | /* Enable Long mode in EFER (Extended Feature Enable Register) */ |
| 47 | movl $MSR_EFER, %ecx |
| 48 | rdmsr |
| 49 | btsl $_EFER_LME, %eax |
| 50 | wrmsr |
| 51 | |
| 52 | /* After gdt is loaded */ |
| 53 | xorl %eax, %eax |
| 54 | lldt %ax |
| 55 | movl $0x20, %eax |
| 56 | ltr %ax |
| 57 | |
| 58 | /* |
| 59 | * Setup for the jump to 64bit mode |
| 60 | * |
| 61 | * When the jump is performed we will be in long mode but |
| 62 | * in 32bit compatibility mode with EFER.LME = 1, CS.L = 0, CS.D = 1 |
| 63 | * (and in turn EFER.LMA = 1). To jump into 64bit mode we use |
| 64 | * the new gdt/idt that has __KERNEL_CS with CS.L = 1. |
| 65 | * We place all of the values on our mini stack so lret can |
| 66 | * used to perform that far jump. See the gdt below. |
| 67 | */ |
| 68 | pop %esi /* setup_base */ |
| 69 | |
| 70 | pushl $0x10 |
| 71 | leal lret_target, %eax |
| 72 | pushl %eax |
| 73 | |
| 74 | /* Enter paged protected Mode, activating Long Mode */ |
| Simon Glass | 46faeea | 2025-03-15 14:25:37 +0000 | [diff] [blame^] | 75 | movl %cr0, %eax |
| 76 | orl $X86_CR0_PG, %eax |
| Simon Glass | 463fac2 | 2014-10-10 08:21:55 -0600 | [diff] [blame] | 77 | movl %eax, %cr0 |
| 78 | |
| 79 | /* Jump from 32bit compatibility mode into 64bit mode. */ |
| 80 | lret |
| 81 | |
| 82 | code64: |
| 83 | lret_target: |
| 84 | pop %eax /* target */ |
| 85 | mov %eax, %eax /* Clear bits 63:32 */ |
| 86 | jmp *%eax /* Jump to the 64-bit target */ |
| 87 | |
| Bin Meng | 17b7b60 | 2019-01-31 08:22:13 -0800 | [diff] [blame] | 88 | .globl call64_stub_size |
| 89 | call64_stub_size: |
| 90 | .long . - cpu_call64 |
| 91 | |
| Simon Glass | 463fac2 | 2014-10-10 08:21:55 -0600 | [diff] [blame] | 92 | .data |
| Simon Glass | 1e32ede | 2017-01-16 07:04:15 -0700 | [diff] [blame] | 93 | .align 16 |
| 94 | .globl gdt64 |
| 95 | gdt64: |
| Simon Glass | 463fac2 | 2014-10-10 08:21:55 -0600 | [diff] [blame] | 96 | gdt: |
| Simon Glass | f2d1a11 | 2015-07-31 09:31:30 -0600 | [diff] [blame] | 97 | .word gdt_end - gdt - 1 |
| 98 | .long gdt /* Fixed up by code above */ |
| Simon Glass | 463fac2 | 2014-10-10 08:21:55 -0600 | [diff] [blame] | 99 | .word 0 |
| 100 | .quad 0x0000000000000000 /* NULL descriptor */ |
| 101 | .quad 0x00af9a000000ffff /* __KERNEL_CS */ |
| 102 | .quad 0x00cf92000000ffff /* __KERNEL_DS */ |
| 103 | .quad 0x0080890000000000 /* TS descriptor */ |
| 104 | .quad 0x0000000000000000 /* TS continued */ |
| 105 | gdt_end: |