diff options
Diffstat (limited to 'Kernel/Arch/i386')
| -rw-r--r-- | Kernel/Arch/i386/Boot/boot.S | 169 | ||||
| -rw-r--r-- | Kernel/Arch/i386/CPU.cpp | 32 | ||||
| -rw-r--r-- | Kernel/Arch/i386/CPU.h | 10 |
3 files changed, 204 insertions, 7 deletions
diff --git a/Kernel/Arch/i386/Boot/boot.S b/Kernel/Arch/i386/Boot/boot.S index f52db9d726..8c8ea06a8d 100644 --- a/Kernel/Arch/i386/Boot/boot.S +++ b/Kernel/Arch/i386/Boot/boot.S @@ -218,7 +218,6 @@ start: pushl $exit_message call kprintf add $4, %esp - cli loop: @@ -227,3 +226,171 @@ loop: exit_message: .asciz "Kernel exited." + +.extern init_ap +.type init_ap, @function + +/* + The apic_ap_start function will be loaded to P0x00008000 where the APIC + will boot the AP from in real mode. This code also contains space for + special variables that *must* remain here. When initializing the APIC, + the code here gets copied to P0x00008000, the variables in here get + populated and then the the boot of the APs will be triggered. Having + the variables here allows us to access them from real mode. Also, the + code here avoids the need for relocation entries. + + Basically, the variables between apic_ap_start and end_apic_ap_start + *MUST* remain here and cannot be moved into a .bss or any other location. +*/ +.global apic_ap_start +.type apic_ap_start, @function +apic_ap_start: +.code16 + cli + jmp $0x800, $(1f - apic_ap_start) /* avoid relocation entries */ +1: + mov %cs, %ax + mov %ax, %ds + + /* Generate a new processor id. This is not the APIC id. We just + need a way to find ourselves a stack without stomping on other + APs that may be doing this concurrently. */ + xor %ax, %ax + mov %ax, %bp + inc %ax + lock; xaddw %ax, %ds:(ap_cpu_id - apic_ap_start)(%bp) /* avoid relocation entries */ + mov %ax, %bx + + xor %ax, %ax + mov %ax, %sp + + /* load the first temporary gdt */ + lgdt (ap_cpu_gdtr_initial - apic_ap_start) + + /* enable PM */ + movl %cr0, %eax + orl $1, %eax + movl %eax, %cr0 + + ljmpl $8, $(apic_ap_start32 - apic_ap_start + 0x8000) +apic_ap_start32: +.code32 + mov $0x10, %ax + mov %ax, %ss + mov %ax, %ds + mov %ax, %es + mov %ax, %fs + mov %ax, %gs + + movl $0x8000, %ebp + + /* find our allocated stack based on the generated id */ + andl 0x0000FFFF, %ebx + movl %ebx, %esi + movl (ap_cpu_init_stacks - apic_ap_start)(%ebp, %ebx, 4), %esp + + /* check if we support NX and enable it if we do */ + movl $0x80000001, %eax + cpuid + testl $0x100000, %edx + je (1f - apic_ap_start + 0x8000) + /* turn on IA32_EFER.NXE */ + movl $0xc0000080, %ecx + rdmsr + orl $0x800, %eax + wrmsr +1: + + /* load the bsp's cr3 value */ + movl (ap_cpu_init_cr3 - apic_ap_start)(%ebp), %eax + movl %eax, %cr3 + + /* enable PAE + PSE */ + movl %cr4, %eax + orl $0x60, %eax + movl %eax, %cr4 + + /* enable PG */ + movl %cr0, %eax + orl $0x80000000, %eax + movl %eax, %cr0 + + /* load a second temporary gdt that points above 3GB */ + lgdt (ap_cpu_gdtr_initial2 - apic_ap_start + 0xc0008000) + + /* jump above 3GB into our identity mapped area now */ + ljmp $8, $(1f - apic_ap_start + 0xc0008000) +1: + /* flush the TLB */ + movl %cr3, %eax + movl %eax, %cr3 + + movl $0xc0008000, %ebp + + /* now load the final gdt and idt from the identity mapped area */ + movl (ap_cpu_gdtr - apic_ap_start)(%ebp), %eax + lgdt (%eax) + movl (ap_cpu_idtr - apic_ap_start)(%ebp), %eax + lidt (%eax) + + /* set same cr0 and cr4 values as the BSP */ + movl (ap_cpu_init_cr0 - apic_ap_start)(%ebp), %eax + movl %eax, %cr0 + movl (ap_cpu_init_cr4 - apic_ap_start)(%ebp), %eax + movl %eax, %cr4 + + xor %ebp, %ebp + cld + + /* push the arbitrary cpu id, 0 representing the bsp and call into c++ */ + inc %esi + push %esi + /* We are in identity mapped P0x8000 and the BSP will unload this code + once all APs are initialized, so call init_ap but return to our + infinite loop */ + push $loop + ljmp $8, $init_ap + +.align 4 +.global apic_ap_start_size +apic_ap_start_size: + .2byte end_apic_ap_start - apic_ap_start +ap_cpu_id: + .2byte 0x0 +ap_cpu_gdt: + /* null */ + .8byte 0x0 + /* code */ + .4byte 0x0000FFFF + .4byte 0x00cf9a00 + /* data */ + .4byte 0x0000FFFF + .4byte 0x00cf9200 +ap_cpu_gdt_end: +ap_cpu_gdtr_initial: + .2byte ap_cpu_gdt_end - ap_cpu_gdt - 1 + .4byte (ap_cpu_gdt - apic_ap_start) + 0x8000 +ap_cpu_gdtr_initial2: + .2byte ap_cpu_gdt_end - ap_cpu_gdt - 1 + .4byte (ap_cpu_gdt - apic_ap_start) + 0xc0008000 +.global ap_cpu_gdtr +ap_cpu_gdtr: + .4byte 0x0 /* will be set at runtime */ +.global ap_cpu_idtr +ap_cpu_idtr: + .4byte 0x0 /* will be set at runtime */ +.global ap_cpu_init_cr0 +ap_cpu_init_cr0: + .4byte 0x0 /* will be set at runtime */ +.global ap_cpu_init_cr3 +ap_cpu_init_cr3: + .4byte 0x0 /* will be set at runtime */ +.global ap_cpu_init_cr4 +ap_cpu_init_cr4: + .4byte 0x0 /* will be set at runtime */ +.global ap_cpu_init_stacks +ap_cpu_init_stacks: + /* array of allocated stack pointers */ + /* NOTE: ap_cpu_init_stacks must be the last variable before + end_apic_ap_start! */ +.set end_apic_ap_start, . diff --git a/Kernel/Arch/i386/CPU.cpp b/Kernel/Arch/i386/CPU.cpp index affd7705d1..3fce021fcb 100644 --- a/Kernel/Arch/i386/CPU.cpp +++ b/Kernel/Arch/i386/CPU.cpp @@ -46,12 +46,6 @@ namespace Kernel { -struct [[gnu::packed]] DescriptorTablePointer -{ - u16 limit; - void* address; -}; - static DescriptorTablePointer s_idtr; static DescriptorTablePointer s_gdtr; static Descriptor s_idt[256]; @@ -391,6 +385,16 @@ void flush_gdt() : "memory"); } +const DescriptorTablePointer& get_gdtr() +{ + return s_gdtr; +} + +const DescriptorTablePointer& get_idtr() +{ + return s_idtr; +} + void gdt_init() { s_gdt_length = 5; @@ -819,6 +823,14 @@ void cpu_setup() } } +u32 read_cr0() +{ + u32 cr0; + asm("movl %%cr0, %%eax" + : "=a"(cr0)); + return cr0; +} + u32 read_cr3() { u32 cr3; @@ -833,6 +845,14 @@ void write_cr3(u32 cr3) : "memory"); } +u32 read_cr4() +{ + u32 cr4; + asm("movl %%cr4, %%eax" + : "=a"(cr4)); + return cr4; +} + u32 read_dr6() { u32 dr6; diff --git a/Kernel/Arch/i386/CPU.h b/Kernel/Arch/i386/CPU.h index 9b6e771be0..b59819bc3f 100644 --- a/Kernel/Arch/i386/CPU.h +++ b/Kernel/Arch/i386/CPU.h @@ -41,6 +41,12 @@ class MemoryManager; class PageDirectory; class PageTableEntry; +struct [[gnu::packed]] DescriptorTablePointer +{ + u16 limit; + void* address; +}; + struct [[gnu::packed]] TSS32 { u16 backlink, __blh; @@ -248,6 +254,8 @@ public: class GenericInterruptHandler; struct RegisterState; +const DescriptorTablePointer& get_gdtr(); +const DescriptorTablePointer& get_idtr(); void gdt_init(); void idt_init(); void sse_init(); @@ -477,8 +485,10 @@ inline FlatPtr offset_in_page(const void* address) return offset_in_page((FlatPtr)address); } +u32 read_cr0(); u32 read_cr3(); void write_cr3(u32); +u32 read_cr4(); u32 read_dr6(); |