diff options
Diffstat (limited to 'i386/i386/cpuboot.S')
| -rw-r--r-- | i386/i386/cpuboot.S | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/i386/i386/cpuboot.S b/i386/i386/cpuboot.S new file mode 100644 index 00000000..7e6c4770 --- /dev/null +++ b/i386/i386/cpuboot.S @@ -0,0 +1,245 @@ +/* + * Copyright (c) 2022 Free Software Foundation, Inc. + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#if NCPUS > 1 +#include <mach/machine/asm.h> +#include <i386/i386asm.h> +#include <i386/proc_reg.h> +#include <i386/apic.h> +#include <i386/cpu_number.h> +#include <i386/seg.h> +#include <i386/gdt.h> + +#define M(addr) (addr - apboot) +#define CR0_CLEAR_FLAGS_CACHE_ENABLE (CR0_CD | CR0_NW) +#define CR0_SET_FLAGS (CR0_CLEAR_FLAGS_CACHE_ENABLE | CR0_PE) +#define CR0_CLEAR_FLAGS (CR0_PG | CR0_AM | CR0_WP | CR0_NE | CR0_TS | CR0_EM | CR0_MP) +#define BOOT_CS 0x8 +#define BOOT_DS 0x10 + +.data + +.align 16 +apboot_idt_ptr: + .long 0 +.align 16 + .word 0 +apboot_gdt_descr: + .word 14*8-1 + .long apboot_gdt - KERNELBASE +.align 16 +apboot_gdt: + /* NULL segment = 0x0 */ + .quad 0 + + /* KERNEL_CS = 0x8 */ + .word 0xffff /* Segment limit first 0-15 bits*/ + .word (-KERNELBASE) & 0xffff /*Base first 0-15 bits*/ + .byte ((-KERNELBASE) >> 16) & 0xff /*Base 16-23 bits */ + .byte ACC_PL_K | ACC_CODE_R | ACC_P /*Access byte */ + .byte ((SZ_32 | SZ_G) << 4) | 0xf /* High 4 bits */ + .byte ((-KERNELBASE) >> 24) & 0xff /*Base 24-31 bits */ + + /* KERNEL_DS = 0x10 */ + .word 0xffff /*Segment limit */ + .word (-KERNELBASE) & 0xffff /*Base first 0-15 bits*/ + .byte ((-KERNELBASE) >> 16) & 0xff + .byte ACC_PL_K | ACC_DATA_W | ACC_P /*Access byte*/ + .byte ((SZ_32 | SZ_G) << 4) | 0xf /* High 4 bits */ + .byte ((-KERNELBASE) >> 24) & 0xff /*Base 24-31 bits */ + + /* LDT = 0x18 */ + .quad 0 + + /* TSS = 0x20 */ + .quad 0 + + /* USER_LDT = 0x28 */ + .quad 0 + + /* USER_TSS = 0x30 */ + .quad 0 + + /* LINEAR = 0x38 */ + .quad 0 + + /* FPREGS = 0x40 */ + .quad 0 + + /* USER_GDT = 0x48 and 0x50 */ + .quad 0 + .quad 0 + + /* USER_TSS64 = 0x58 */ + .quad 0 + + /* USER_TSS64 = 0x60 */ + .quad 0 + + /* boot GS = 0x68 */ + .word 0xffff +apboot_percpu_low: + .word 0 +apboot_percpu_med: + .byte 0 + .byte ACC_PL_K | ACC_DATA_W | ACC_P + .byte ((SZ_32 | SZ_G) << 4) | 0xf +apboot_percpu_high: + .byte 0 + +.globl apboot, apbootend, gdt_descr_tmp, apboot_jmp_offset +.align 16 +.code16 + +apboot: +_apboot: + /* This is now address CS:0 in real mode */ + + /* Set data seg same as code seg */ + mov %cs, %dx + mov %dx, %ds + + cli + xorl %eax, %eax + movl %eax, %cr3 + + mov %ax, %es + mov %ax, %fs + mov %ax, %gs + mov %ax, %ss + + lgdt M(gdt_descr_tmp) + + movl %cr0, %eax + andl $~CR0_CLEAR_FLAGS, %eax + orl $CR0_SET_FLAGS, %eax + movl %eax, %cr0 + + /* ljmpl with relocation from machine_init */ + .byte 0x66 + .byte 0xea +apboot_jmp_offset: + .long M(0f) + .word BOOT_CS + +0: + .code32 + /* Protected mode! */ + movw $BOOT_DS, %ax + movw %ax, %ds + movw %ax, %es + movw %ax, %ss + + lgdtl apboot_gdt_descr - KERNELBASE + ljmpl $KERNEL_CS, $1f +1: + xorl %eax, %eax + movw %ax, %ds + movw %ax, %es + movw %ax, %fs + movw %ax, %gs + movw $KERNEL_DS, %ax + movw %ax, %ds + movw %ax, %es + movw %ax, %fs + movw %ax, %gs + movw %ax, %ss + + /* Get CPU number */ + movl $1, %eax + cpuid + shrl $24, %ebx + movl %cs:CX(cpu_id_lut, %ebx), %ecx + + /* Access per_cpu area */ + movl %ecx,%eax + movl $PC_SIZE,%ebx + mul %ebx + addl $percpu_array - KERNELBASE, %eax + + /* Record our cpu number */ + movl %ecx, (PERCPU_CPU_ID + KERNELBASE)(%eax) + + /* Set up temporary percpu descriptor */ + movw %ax, apboot_percpu_low + shr $16, %eax + movb %al, apboot_percpu_med + shr $8, %ax + movb %al, apboot_percpu_high + + movw $PERCPU_DS, %ax + movw %ax, %gs + + /* Load null Interrupt descriptor table */ + mov apboot_idt_ptr, %ebx + lidt (%ebx) + + /* Enable local apic in xAPIC mode */ + xorl %eax, %eax + xorl %edx, %edx + movl $APIC_MSR, %ecx + rdmsr + orl $APIC_MSR_ENABLE, %eax + andl $(~(APIC_MSR_BSP | APIC_MSR_X2APIC)), %eax + movl $APIC_MSR, %ecx + wrmsr + + /* Load int_stack_top[cpu] -> esp */ + CPU_NUMBER_NO_STACK(%edx) + movl CX(EXT(int_stack_top), %edx), %esp + + /* Ensure stack alignment */ + andl $0xfffffff0, %esp + + /* Reset EFLAGS to a known state */ + pushl $0 + popfl + + /* Finish the cpu configuration */ + call EXT(cpu_ap_main) + + /* NOT REACHED */ + hlt + +.align 16 + .word 0 +gdt_descr_tmp: + .short 3*8-1 + .long M(gdt_tmp) + +.align 16 +gdt_tmp: + /* 0 */ + .quad 0 + /* BOOT_CS */ + .word 0xffff + .word 0x0000 + .byte 0x00 + .byte ACC_PL_K | ACC_CODE_R | ACC_P + .byte ((SZ_32 | SZ_G) << 4) | 0xf + .byte 0x00 + /* BOOT_DS */ + .word 0xffff + .word 0x0000 + .byte 0x00 + .byte ACC_PL_K | ACC_DATA_W | ACC_P + .byte ((SZ_32 | SZ_G) << 4) | 0xf + .byte 0x00 + +_apbootend: +apbootend: +#endif |