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Initialize the GDT in the bootstrap assembly.
This commit is contained in:
Jonas 'Sortie' Termansen
parent
cf55531aae
commit
a422c394b8
10 changed files with 293 additions and 429 deletions
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@ -31,14 +31,14 @@ BOOTOBJS:=
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ifeq ($(CPU),x86)
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X86FAMILY:=1
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CPUDIR:=$(CPU)
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CPUOBJS:=$(CPUDIR)/boot.o $(CPUDIR)/base.o
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CPUOBJS:=$(CPUDIR)/boot.o
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endif
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ifeq ($(CPU),x64)
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X86FAMILY:=1
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CPUDIR:=$(CPU)
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CXXFLAGS:=$(CXXFLAGS) -mno-red-zone -mno-mmx -mno-sse -mno-sse2
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CPUOBJS:=$(CPUDIR)/boot.o $(CPUDIR)/base.o
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CPUOBJS:=$(CPUDIR)/boot.o
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endif
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ifndef CPUDIR
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@ -1,6 +1,6 @@
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/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2011, 2013, 2014.
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Copyright(C) Jonas 'Sortie' Termansen 2011, 2013, 2014, 2015.
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This file is part of Sortix.
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@ -30,7 +30,6 @@ namespace Sortix {
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extern "C" __attribute__((noreturn)) void HaltKernel();
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extern "C" __attribute__((noreturn)) void Panic(const char* error);
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extern "C" __attribute__((noreturn, format(printf, 1, 2))) void PanicF(const char* format, ...);
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extern "C" void WaitForInterrupt();
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} // namespace Sortix
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@ -63,6 +63,8 @@ const uint32_t UCS = 0x18;
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const uint32_t UDS = 0x20;
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const uint32_t URPL = 0x3;
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const uint32_t RPLMASK = 0x3;
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#define GDT_FS_ENTRY 6
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#define GDT_GS_ENTRY 7
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struct interrupt_context
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{
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@ -93,7 +93,7 @@
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#include "x86-family/gdt.h"
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#endif
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// Keep the stack size aligned with $CPU/base.s
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// Keep the stack size aligned with $CPU/boot.s
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const size_t STACK_SIZE = 64*1024;
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extern "C" { __attribute__((aligned(16))) size_t stack[STACK_SIZE / sizeof(size_t)]; }
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@ -276,10 +276,6 @@ extern "C" void KernelInit(unsigned long magic, multiboot_info_t* bootinfo)
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// Initialize paging and virtual memory.
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Memory::Init(bootinfo);
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// Initialize the GDT and TSS structures.
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GDT::Init();
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GDT::SetKernelStack((uintptr_t) stack + STACK_SIZE);
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// Initialize the interrupt handler table and enable interrupts.
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Interrupt::Init();
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@ -1,67 +0,0 @@
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/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2011.
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This file is part of Sortix.
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Sortix is free software: you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation, either version 3 of the License, or (at your option) any later
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version.
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Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along with
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Sortix. If not, see <http://www.gnu.org/licenses/>.
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x64/base.S
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Bootstraps the kernel and passes over control from the boot-loader to the
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kernel main function.
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*******************************************************************************/
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.section .text
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.global beginkernel
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.type beginkernel, @function
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beginkernel:
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movw $0x736, 0xB83E8
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movw $0x734, 0xB83EA
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movw $0x753, 0xB83EE
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movw $0x74F, 0xB83F0
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movw $0x752, 0xB83F2
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movw $0x754, 0xB83F4
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movw $0x749, 0xB83F6
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movw $0x758, 0xB83F8
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# Initialize the stack pointer.
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movq $stack, %rsp
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addq $65536, %rsp # 64 KiB, see kernel.cpp
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# Reset EFLAGS.
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# pushl $0
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# popf
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# Push the pointer to the Multiboot information structure.
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mov %rbx, %rsi
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# Push the magic value.
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mov %rax, %rdi
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call KernelInit
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.size beginkernel, . - beginkernel
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.global HaltKernel
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HaltKernel:
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cli
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hlt
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jmp HaltKernel
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.size HaltKernel, . - HaltKernel
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.global WaitForInterrupt
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.type WaitForInterrupt, @function # void WaitForInterrupt();
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WaitForInterrupt:
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hlt
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ret
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@ -1,6 +1,6 @@
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/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2011, 2014.
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Copyright(C) Jonas 'Sortie' Termansen 2011, 2014, 2015.
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This file is part of Sortix.
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@ -26,6 +26,12 @@
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.section .text
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.text 0x100000
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# Multiboot header.
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.align 4
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.long 0x1BADB002 # Magic.
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.long 0x00000003 # Flags.
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.long -(0x1BADB002 + 0x00000003) # Checksum
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.global _start
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.global __start
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.type _start, @function
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@ -33,34 +39,31 @@
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.code32
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_start:
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__start:
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jmp prepare_kernel_execution
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# Initialize the stack pointer. The magic value is from kernel.cpp.
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movl $(stack + 65536), %esp # 64 KiB, see kernel.cpp (See below also)
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# Align 32 bits boundary.
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.align 4
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# Finish installing the kernel stack into the Task Switch Segment.
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movl %esp, tss + 4
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movl $0, tss + 8
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# Multiboot header.
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multiboot_header:
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# Magic.
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.long 0x1BADB002
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# Flags.
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.long 0x00000003
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# Checksum.
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.long -(0x1BADB002 + 0x00000003)
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# Finish installing the Task Switch Segment into the Global Descriptor Table.
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movl $tss, %ecx
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movw %cx, gdt + 0x28 + 2
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shrl $16, %ecx
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movb %cl, gdt + 0x28 + 4
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shrl $8, %ecx
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movb %cl, gdt + 0x28 + 7
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movl $0, gdt + 0x28 + 8
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prepare_kernel_execution:
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# We got our multiboot information in various registers. But we are going
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# to need these registers. But where can we store them then? Oh hey, let's
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# store then in the code already run!
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# Store the pointer to the Multiboot information structure.
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mov %ebx, 0x100000
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# Store the magic value.
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mov %eax, 0x100004
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# We got our multiboot information in various registers.
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pushl $0
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pushl %eax # Multiboot magic value.
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pushl $0
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pushl %ebx # Multiboot information structure pointer.
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# Clear the first $0xE000 bytes following 0x21000.
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movl $0x21000, %edi
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mov %edi, %cr3
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movl %edi, %cr3
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xorl %eax, %eax
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movl $0xE000, %ecx
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rep stosl
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@ -88,45 +91,56 @@ prepare_kernel_execution:
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movl $0x3, %ebx
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movl $1024, %ecx
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SetEntry:
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mov %ebx, (%edi)
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add $0x1000, %ebx
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add $8, %edi
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loop SetEntry
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1:
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movl %ebx, (%edi)
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addl $0x1000, %ebx
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addl $8, %edi
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loop 1b
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# Enable PAE.
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mov %cr4, %eax
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movl %cr4, %eax
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orl $0x20, %eax
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mov %eax, %cr4
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movl %eax, %cr4
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# Enable long mode.
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mov $0xC0000080, %ecx
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movl $0xC0000080, %ecx
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rdmsr
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orl $0x100, %eax
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wrmsr
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# Enable paging and enter long mode (still 32-bit)
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mov %cr0, %eax
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movl %cr0, %eax
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orl $0x80000000, %eax
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mov %eax, %cr0
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movl %eax, %cr0
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# Load the long mode GDT.
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mov GDTPointer, %eax
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lgdtl GDTPointer
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# Load the Global Descriptor Table pointer register.
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subl $6, %esp
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movw gdt_size_minus_one, %cx
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movw %cx, 0(%esp)
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movl $gdt, %ecx
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movl %ecx, 2(%esp)
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lgdt 0(%esp)
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addl $6, %esp
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# Now use the 64-bit code segment, and we are in full 64-bit mode.
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ljmp $0x10, $Realm64
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ljmp $0x08, $2f
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.code64
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Realm64:
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2:
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# Switch ds, es, fs, gs, ss to the kernel data segment (0x10).
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movw $0x10, %cx
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movw %cx, %ds
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movw %cx, %es
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movw %cx, %ss
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# Now, set up the other segment registers.
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cli
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mov $0x18, %ax
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mov %ax, %ds
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mov %ax, %es
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mov %ax, %fs
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mov %ax, %gs
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# Switch the task switch segment register to the task switch segment (0x28).
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movw $(0x28 /* TSS */ | 0x3 /* RPL */), %cx
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ltr %cx
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# Switch to the thread local fs and gs segments.
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movw $(0x20 /* DS */ | 0x3 /* RPL */), %cx
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movw %cx, %fs
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movw %cx, %gs
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# Enable the floating point unit.
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mov %cr0, %rax
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@ -147,58 +161,18 @@ Realm64:
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# Store a copy of the initialial floating point registers.
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fxsave fpu_initialized_regs
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# Alright, that was the bootstrap code. Now begin preparing to run the
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# actual 64-bit kernel.
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jmp Main
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# Enter the high-level kernel proper.
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pop %rsi # Multiboot information structure pointer.
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pop %rdi # Multiboot magic value.
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call KernelInit
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jmp HaltKernel
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.size _start, . - _start
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.size __start, . - __start
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.section .data
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GDT64: # Global Descriptor Table (64-bit).
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GDTNull: # The null descriptor.
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.word 0 # Limit (low).
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.word 0 # Base (low).
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.byte 0 # Base (middle)
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.byte 0 # Access.
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.byte 0 # Granularity.
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.byte 0 # Base (high).
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GDTUnused: # The null descriptor.
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.word 0 # Limit (low).
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.word 0 # Base (low).
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.byte 0 # Base (middle)
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.byte 0 # Access.
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.byte 0 # Granularity.
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.byte 0 # Base (high).
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GDTCode: # The code descriptor.
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.word 0xFFFF # Limit (low).
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.word 0 # Base (low).
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.byte 0 # Base (middle)
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.byte 0x9A # Access.
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.byte 0xAF # Granularity.
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.byte 0 # Base (high).
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GDTData: # The data descriptor.
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.word 0xFFFF # Limit (low).
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.word 0 # Base (low).
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.byte 0 # Base (middle)
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.byte 0x92 # Access.
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.byte 0x8F # Granularity.
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.byte 0 # Base (high).
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GDTPointer: # The GDT-pointer.
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.word GDTPointer - GDT64 - 1 # Limit.
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.long GDT64 # Base.
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.long 0
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Main:
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# Copy the character B onto the screen so we know it works.
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movq $0x242, %r15
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movq %r15, %rax
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movw %ax, 0xB8000
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# Load the pointer to the Multiboot information structure.
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mov 0x100000, %ebx
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# Load the magic value.
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mov 0x100004, %eax
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jmp beginkernel
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.size Main, . - Main
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.global HaltKernel
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.type HaltKernel, @function
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HaltKernel:
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cli
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hlt
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jmp HaltKernel
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.size HaltKernel, . - HaltKernel
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@ -1,6 +1,6 @@
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/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2013, 2014.
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Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2013, 2014, 2015.
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This file is part of Sortix.
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@ -18,7 +18,7 @@
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Sortix. If not, see <http://www.gnu.org/licenses/>.
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x86-family/gdt.cpp
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Initializes and handles the GDT and TSS.
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GDT and TSS.
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*******************************************************************************/
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@ -44,6 +44,7 @@ struct gdt_entry
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uint8_t base_high;
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};
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#if defined(__x86_64__)
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struct gdt_entry64
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{
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uint16_t limit_low;
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@ -55,25 +56,15 @@ struct gdt_entry64
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uint32_t base_highest;
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uint32_t reserved0;
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};
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// TODO: Do this in another way that doesn't require a silly structure .
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struct gdt_ptr
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{
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uint16_t limit;
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#if defined(__i386__)
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uint32_t base;
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#else
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uint64_t base;
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#endif
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} __attribute__((packed));
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#if defined(__i386__)
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struct tss_entry
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{
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uint32_t prev_tss; // The previous TSS - if we used hardware task switching this would form a linked list.
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uint32_t esp0; // The stack pointer to load when we change to kernel mode.
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uint32_t ss0; // The stack segment to load when we change to kernel mode.
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uint32_t esp1; // Unused...
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uint32_t prev_tss;
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uint32_t esp0;
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uint32_t ss0;
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uint32_t esp1;
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uint32_t ss1;
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uint32_t esp2;
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uint32_t ss2;
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@ -88,13 +79,13 @@ struct tss_entry
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uint32_t ebp;
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uint32_t esi;
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uint32_t edi;
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uint32_t es; // The value to load into ES when we change to kernel mode.
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uint32_t cs; // The value to load into CS when we change to kernel mode.
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uint32_t ss; // The value to load into SS when we change to kernel mode.
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uint32_t ds; // The value to load into DS when we change to kernel mode.
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uint32_t fs; // The value to load into FS when we change to kernel mode.
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uint32_t gs; // The value to load into GS when we change to kernel mode.
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uint32_t ldt; // Unused...
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uint32_t es;
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uint32_t cs;
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uint32_t ss;
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uint32_t ds;
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uint32_t fs;
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uint32_t gs;
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uint32_t ldt;
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uint16_t trap;
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uint16_t iomap_base;
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};
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@ -105,164 +96,148 @@ struct tss_entry
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uint64_t stack0; /* This is not naturally aligned, so packed is needed. */
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uint64_t stack1;
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uint64_t stack2;
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uint64_t reserved2;
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uint64_t reserved1;
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uint64_t ist[7];
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uint64_t reserved3;
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uint16_t reserved4;
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uint64_t reserved2;
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uint16_t reserved3;
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uint16_t iomap_base;
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} __attribute__((packed));
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#endif
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#if defined(__i386__)
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const size_t GDT_NUM_ENTRIES = 9;
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const size_t GDT_FS_ENTRY = 7;
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const size_t GDT_GS_ENTRY = 8;
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#else
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const size_t GDT_NUM_ENTRIES = 7;
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#endif
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static struct gdt_entry gdt_entries[GDT_NUM_ENTRIES];
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extern "C" {
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static struct tss_entry tss_entry;
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const size_t STACK_SIZE = 64*1024;
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extern size_t stack[STACK_SIZE / sizeof(size_t)];
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const uint8_t GRAN_64_BIT_MODE = 1 << 5;
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const uint8_t GRAN_32_BIT_MODE = 1 << 6;
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const uint8_t GRAN_4KIB_BLOCKS = 1 << 7;
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void SetGate(int32_t num, uint32_t base, uint32_t limit, uint8_t access, uint8_t gran)
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struct tss_entry tss =
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{
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struct gdt_entry* entry = (struct gdt_entry*) &gdt_entries[num];
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#if defined(__i386__)
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.prev_tss = 0, /* c++ */
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.esp0 = 0 /*(uintptr_t) stack + sizeof(stack)*/,
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.ss0 = 0x10 /* Kernel Data Segment */,
|
||||
.esp1 = 0, /* c++ */
|
||||
.ss1 = 0, /* c++ */
|
||||
.esp2 = 0, /* c++ */
|
||||
.ss2 = 0, /* c++ */
|
||||
.cr3 = 0, /* c++ */
|
||||
.eip = 0, /* c++ */
|
||||
.eflags = 0, /* c++ */
|
||||
.eax = 0, /* c++ */
|
||||
.ecx = 0, /* c++ */
|
||||
.edx = 0, /* c++ */
|
||||
.ebx = 0, /* c++ */
|
||||
.esp = 0, /* c++ */
|
||||
.ebp = 0, /* c++ */
|
||||
.esi = 0, /* c++ */
|
||||
.edi = 0, /* c++ */
|
||||
.es = 0x13 /* Kernel Data Segment */,
|
||||
.cs = 0x0B /* Kernel Code Segment */,
|
||||
.ss = 0, /* c++ */
|
||||
.ds = 0x13 /* Kernel Data Segment */,
|
||||
.fs = 0x13 /* Kernel Data Segment */,
|
||||
.gs = 0x13 /* Kernel Data Segment */,
|
||||
.ldt = 0, /* c++ */
|
||||
.trap = 0, /* c++ */
|
||||
.iomap_base = 0, /* c++ */
|
||||
#elif defined(__x86_64__)
|
||||
.reserved0 = 0, /* c++ */
|
||||
.stack0 = 0 /*(uintptr_t) stack + sizeof(stack)*/,
|
||||
.stack1 = 0, /* c++ */
|
||||
.stack2 = 0, /* c++ */
|
||||
.reserved1 = 0, /* c++ */
|
||||
.ist = { 0, 0, 0, 0, 0, 0, 0},
|
||||
.reserved2 = 0,
|
||||
.reserved3 = 0,
|
||||
.iomap_base = 0,
|
||||
#endif
|
||||
};
|
||||
|
||||
entry->base_low = base >> 0 & 0xFFFF;
|
||||
entry->base_middle = base >> 16 & 0xFF;
|
||||
entry->base_high = base >> 24 & 0xFF;
|
||||
} // extern "C"
|
||||
|
||||
entry->limit_low = limit & 0xFFFF;
|
||||
entry->granularity = (limit >> 16 & 0x0F) | (gran & 0xF0);
|
||||
#define GRAN_64_BIT_MODE (1 << 5)
|
||||
#define GRAN_32_BIT_MODE (1 << 6)
|
||||
#define GRAN_4KIB_BLOCKS (1 << 7)
|
||||
|
||||
entry->access = access;
|
||||
}
|
||||
#define GDT_ENTRY(base, limit, access, granularity) \
|
||||
{ (limit) & 0xFFFF, /* limit_low */ \
|
||||
(uint16_t) ((base) >> 0 & 0xFFFF), /* base_low */ \
|
||||
(uint8_t) ((base) >> 16 & 0xFF), /* base_middle */ \
|
||||
(access) & 0xFF, /* access */ \
|
||||
((limit) >> 16 & 0x0F) | ((granularity) & 0xF0), /* granularity */ \
|
||||
(uint8_t) ((base) >> 24 & 0xFF), /* base_high */ }
|
||||
|
||||
void SetGate64(int32_t num, uint64_t base, uint32_t limit, uint8_t access, uint8_t gran)
|
||||
{
|
||||
struct gdt_entry64* entry = (struct gdt_entry64*) &gdt_entries[num];
|
||||
|
||||
entry->base_low = base >> 0 & 0xFFFF;
|
||||
entry->base_middle = base >> 16 & 0xFF;
|
||||
entry->base_high = base >> 24 & 0xFF;
|
||||
entry->base_highest = base >> 32;
|
||||
|
||||
entry->limit_low = limit & 0xFFFF;
|
||||
entry->granularity = (limit >> 16 & 0x0F) | (gran & 0xF0);
|
||||
|
||||
entry->access = access;
|
||||
entry->reserved0 = 0;
|
||||
}
|
||||
|
||||
void Init()
|
||||
#if defined(__x86_64__)
|
||||
#define GDT_ENTRY64(base, limit, access, granularity) \
|
||||
{ (limit) & 0xFFFF, /* limit_low */ \
|
||||
(uint16_t) ((base) >> 0 & 0xFFFF), /* base_low */ \
|
||||
(uint8_t) ((base) >> 16 & 0xFF), /* base_middle */ \
|
||||
(access) & 0xFF, /* access */ \
|
||||
((limit) >> 16 & 0x0F) | ((granularity) & 0xF0), /* granularity */ \
|
||||
(uint8_t) ((base) >> 24 & 0xFF), /* base_high */ }, \
|
||||
{ (uint16_t) ((base) >> 32 & 0xFFFF), /* base_highest */ \
|
||||
(uint16_t) ((base) >> 48 & 0xFFFF), /* base_highest */ \
|
||||
0, /* reserved0 */ \
|
||||
0, /* reserved0 */ \
|
||||
0, /* reserved0 */ \
|
||||
0, /* reserved0 */ }
|
||||
#endif
|
||||
|
||||
extern "C" {
|
||||
|
||||
struct gdt_entry gdt[] =
|
||||
{
|
||||
/* 0x00: Null segment */
|
||||
GDT_ENTRY(0, 0, 0, 0),
|
||||
|
||||
#if defined(__i386__)
|
||||
const uint8_t gran = GRAN_4KIB_BLOCKS | GRAN_32_BIT_MODE;
|
||||
/* 0x08: Kernel Code Segment. */
|
||||
GDT_ENTRY(0, 0xFFFFFFFF, 0x9A, GRAN_32_BIT_MODE | GRAN_4KIB_BLOCKS),
|
||||
|
||||
/* 0x10: Kernel Data Segment. */
|
||||
GDT_ENTRY(0, 0xFFFFFFFF, 0x92, GRAN_32_BIT_MODE | GRAN_4KIB_BLOCKS),
|
||||
|
||||
/* 0x18: User Code Segment. */
|
||||
GDT_ENTRY(0, 0xFFFFFFFF, 0xFA, GRAN_32_BIT_MODE | GRAN_4KIB_BLOCKS),
|
||||
|
||||
/* 0x20: User Data Segment. */
|
||||
GDT_ENTRY(0, 0xFFFFFFFF, 0xF2, GRAN_32_BIT_MODE | GRAN_4KIB_BLOCKS),
|
||||
|
||||
/* 0x28: Task Switch Segment. */
|
||||
GDT_ENTRY(0 /*((uintptr_t) &tss)*/, sizeof(tss) - 1, 0xE9, 0x00),
|
||||
|
||||
/* 0x30: F Segment. */
|
||||
GDT_ENTRY(0, 0xFFFFFFFF, 0xF2, GRAN_32_BIT_MODE | GRAN_4KIB_BLOCKS),
|
||||
|
||||
/* 0x38: G Segment. */
|
||||
GDT_ENTRY(0, 0xFFFFFFFF, 0xF2, GRAN_32_BIT_MODE | GRAN_4KIB_BLOCKS),
|
||||
#elif defined(__x86_64__)
|
||||
const uint8_t gran = GRAN_4KIB_BLOCKS | GRAN_64_BIT_MODE;
|
||||
/* 0x08: Kernel Code Segment. */
|
||||
GDT_ENTRY(0, 0xFFFFFFFF, 0x9A, GRAN_64_BIT_MODE | GRAN_4KIB_BLOCKS),
|
||||
|
||||
/* 0x10: Kernel Data Segment. */
|
||||
GDT_ENTRY(0, 0xFFFFFFFF, 0x92, GRAN_64_BIT_MODE | GRAN_4KIB_BLOCKS),
|
||||
|
||||
/* 0x18: User Code Segment. */
|
||||
GDT_ENTRY(0, 0xFFFFFFFF, 0xFA, GRAN_64_BIT_MODE | GRAN_4KIB_BLOCKS),
|
||||
|
||||
/* 0x20: User Data Segment. */
|
||||
GDT_ENTRY(0, 0xFFFFFFFF, 0xF2, GRAN_64_BIT_MODE | GRAN_4KIB_BLOCKS),
|
||||
|
||||
/* 0x28: Task Switch Segment. */
|
||||
GDT_ENTRY64((uint64_t) 0 /*((uintptr_t) &tss)*/, sizeof(tss) - 1, 0xE9, 0x00),
|
||||
#endif
|
||||
};
|
||||
|
||||
SetGate(0, 0, 0, 0, 0); // Null segment
|
||||
SetGate(1, 0, 0xFFFFFFFF, 0x9A, gran); // Code segment
|
||||
SetGate(2, 0, 0xFFFFFFFF, 0x92, gran); // Data segment
|
||||
SetGate(3, 0, 0xFFFFFFFF, 0xFA, gran); // User mode code segment
|
||||
SetGate(4, 0, 0xFFFFFFFF, 0xF2, gran); // User mode data segment
|
||||
uint16_t gdt_size_minus_one = sizeof(gdt) - 1;
|
||||
|
||||
WriteTSS(5, 0x10, 0x0);
|
||||
|
||||
#if defined(__i386__)
|
||||
SetGate(GDT_FS_ENTRY, 0, 0xFFFFFFFF, 0xF2, gran);
|
||||
SetGate(GDT_GS_ENTRY, 0, 0xFFFFFFFF, 0xF2, gran);
|
||||
#endif
|
||||
|
||||
// Reload the Global Descriptor Table.
|
||||
volatile struct gdt_ptr gdt_ptr;
|
||||
gdt_ptr.limit = (sizeof(struct gdt_entry) * GDT_NUM_ENTRIES) - 1;
|
||||
gdt_ptr.base = (uintptr_t) &gdt_entries;
|
||||
asm volatile ("lgdt (%0)" : : "r"(&gdt_ptr));
|
||||
|
||||
// Switch the current data segment.
|
||||
asm volatile ("mov %0, %%ds\n"
|
||||
"mov %0, %%es\n"
|
||||
"mov %0, %%ss\n" : :
|
||||
"r"(KDS));
|
||||
|
||||
#if defined(__i386__)
|
||||
asm volatile ("mov %0, %%fs" : : "r"(GDT_FS_ENTRY << 3 | URPL));
|
||||
asm volatile ("mov %0, %%gs" : : "r"(GDT_GS_ENTRY << 3 | URPL));
|
||||
#elif defined(__x86_64__)
|
||||
asm volatile ("mov %0, %%fs" : : "r"(UDS | URPL));
|
||||
asm volatile ("mov %0, %%gs" : : "r"(UDS | URPL));
|
||||
#endif
|
||||
|
||||
// Switch the current code segment.
|
||||
#if defined(__i386__)
|
||||
asm volatile ("push %0\n"
|
||||
"push $1f\n"
|
||||
"retf\n"
|
||||
"1:\n" : :
|
||||
"r"(KCS));
|
||||
#elif defined(__x86_64__)
|
||||
asm volatile ("push %0\n"
|
||||
"push $1f\n"
|
||||
"retfq\n"
|
||||
"1:\n" : :
|
||||
"r"(KCS));
|
||||
#endif
|
||||
|
||||
// Load the task state register - The index is 0x28, as it is the 5th
|
||||
// selector and each is 8 bytes long, but we set the bottom two bits (making
|
||||
// 0x2B) so that it has an RPL of 3, not zero.
|
||||
asm volatile ("ltr %%ax" : : "a"(0x2B));
|
||||
}
|
||||
|
||||
// Initialise our task state segment structure.
|
||||
void WriteTSS(int32_t num, uint16_t ss0, uintptr_t stack0)
|
||||
{
|
||||
// First, let's compute the base and limit of our entry in the GDT.
|
||||
uintptr_t base = (uintptr_t) &tss_entry;
|
||||
uint32_t limit = sizeof(tss_entry) - 1;
|
||||
|
||||
// Now, add our TSS descriptor's address to the GDT.
|
||||
#if defined(__i386__)
|
||||
SetGate(num, base, limit, 0xE9, 0x00);
|
||||
#elif defined(__x86_64__)
|
||||
SetGate64(num, base, limit, 0xE9, 0x00);
|
||||
#endif
|
||||
|
||||
// Ensure the descriptor is initially zero.
|
||||
memset(&tss_entry, 0, sizeof(tss_entry));
|
||||
|
||||
#if defined(__i386__)
|
||||
tss_entry.ss0 = ss0; // Set the kernel stack segment.
|
||||
tss_entry.esp0 = stack0; // Set the kernel stack pointer.
|
||||
|
||||
// Here we set the cs, ss, ds, es, fs and gs entries in the TSS.
|
||||
// These specify what segments should be loaded when the processor
|
||||
// switches to kernel mode. Therefore they are just our normal
|
||||
// kernel code/data segments - 0x08 and 0x10 respectively, but with
|
||||
// the last two bits set, making 0x0b and 0x13. The setting of these
|
||||
// bits sets the RPL (requested privilege level) to 3, meaning that
|
||||
// this TSS can be used to switch to kernel mode from ring 3.
|
||||
tss_entry.cs = KCS | 0x3;
|
||||
tss_entry.ss = tss_entry.ds = tss_entry.es = tss_entry.fs = tss_entry.gs = KDS | 0x3;
|
||||
#elif defined(__x86_64__)
|
||||
(void) ss0;
|
||||
tss_entry.stack0 = stack0;
|
||||
#endif
|
||||
}
|
||||
} // extern "C"
|
||||
|
||||
uintptr_t GetKernelStack()
|
||||
{
|
||||
#if defined(__i386__)
|
||||
return tss_entry.esp0;
|
||||
return tss.esp0;
|
||||
#elif defined(__x86_64__)
|
||||
return tss_entry.stack0;
|
||||
return tss.stack0;
|
||||
#endif
|
||||
}
|
||||
|
||||
|
|
@ -270,16 +245,16 @@ void SetKernelStack(uintptr_t stack_pointer)
|
|||
{
|
||||
assert((stack_pointer & 0xF) == 0);
|
||||
#if defined(__i386__)
|
||||
tss_entry.esp0 = (uint32_t) stack_pointer;
|
||||
tss.esp0 = (uint32_t) stack_pointer;
|
||||
#elif defined(__x86_64__)
|
||||
tss_entry.stack0 = (uint64_t) stack_pointer;
|
||||
tss.stack0 = (uint64_t) stack_pointer;
|
||||
#endif
|
||||
}
|
||||
|
||||
#if defined(__i386__)
|
||||
uint32_t GetFSBase()
|
||||
{
|
||||
struct gdt_entry* entry = gdt_entries + GDT_FS_ENTRY;
|
||||
struct gdt_entry* entry = gdt + GDT_FS_ENTRY;
|
||||
return (uint32_t) entry->base_low << 0 |
|
||||
(uint32_t) entry->base_middle << 16 |
|
||||
(uint32_t) entry->base_high << 24;
|
||||
|
|
@ -287,7 +262,7 @@ uint32_t GetFSBase()
|
|||
|
||||
uint32_t GetGSBase()
|
||||
{
|
||||
struct gdt_entry* entry = gdt_entries + GDT_GS_ENTRY;
|
||||
struct gdt_entry* entry = gdt + GDT_GS_ENTRY;
|
||||
return (uint32_t) entry->base_low << 0 |
|
||||
(uint32_t) entry->base_middle << 16 |
|
||||
(uint32_t) entry->base_high << 24;
|
||||
|
|
@ -295,7 +270,7 @@ uint32_t GetGSBase()
|
|||
|
||||
void SetFSBase(uint32_t fsbase)
|
||||
{
|
||||
struct gdt_entry* entry = gdt_entries + GDT_FS_ENTRY;
|
||||
struct gdt_entry* entry = gdt + GDT_FS_ENTRY;
|
||||
entry->base_low = fsbase >> 0 & 0xFFFF;
|
||||
entry->base_middle = fsbase >> 16 & 0xFF;
|
||||
entry->base_high = fsbase >> 24 & 0xFF;
|
||||
|
|
@ -304,7 +279,7 @@ void SetFSBase(uint32_t fsbase)
|
|||
|
||||
void SetGSBase(uint32_t gsbase)
|
||||
{
|
||||
struct gdt_entry* entry = gdt_entries + GDT_GS_ENTRY;
|
||||
struct gdt_entry* entry = gdt + GDT_GS_ENTRY;
|
||||
entry->base_low = gsbase >> 0 & 0xFFFF;
|
||||
entry->base_middle = gsbase >> 16 & 0xFF;
|
||||
entry->base_high = gsbase >> 24 & 0xFF;
|
||||
|
|
|
|||
|
|
@ -1,6 +1,6 @@
|
|||
/*******************************************************************************
|
||||
|
||||
Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2013.
|
||||
Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2013, 2014, 2015.
|
||||
|
||||
This file is part of Sortix.
|
||||
|
||||
|
|
@ -18,7 +18,7 @@
|
|||
Sortix. If not, see <http://www.gnu.org/licenses/>.
|
||||
|
||||
x86-family/gdt.h
|
||||
Initializes and handles the GDT and TSS.
|
||||
GDT and TSS.
|
||||
|
||||
*******************************************************************************/
|
||||
|
||||
|
|
@ -31,7 +31,6 @@ namespace Sortix {
|
|||
namespace GDT {
|
||||
|
||||
void Init();
|
||||
void WriteTSS(int32_t num, uint16_t ss0, uintptr_t stack0);
|
||||
uintptr_t GetKernelStack();
|
||||
void SetKernelStack(uintptr_t stack_pointer);
|
||||
#if defined(__i386__)
|
||||
|
|
|
|||
|
|
@ -1,62 +0,0 @@
|
|||
/*******************************************************************************
|
||||
|
||||
Copyright(C) Jonas 'Sortie' Termansen 2011.
|
||||
|
||||
This file is part of Sortix.
|
||||
|
||||
Sortix 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 3 of the License, or (at your option) any later
|
||||
version.
|
||||
|
||||
Sortix 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
|
||||
Sortix. If not, see <http://www.gnu.org/licenses/>.
|
||||
|
||||
x86/base.S
|
||||
Bootstraps the kernel and passes over control from the boot-loader to the
|
||||
kernel main function.
|
||||
|
||||
*******************************************************************************/
|
||||
|
||||
.section .text
|
||||
|
||||
.global beginkernel
|
||||
.type beginkernel, @function
|
||||
beginkernel:
|
||||
# Initialize the stack pointer. The magic value is from kernel.cpp.
|
||||
movl $stack, %esp
|
||||
addl $65536, %esp # 64 KiB, see kernel.cpp
|
||||
|
||||
# Reset EFLAGS.
|
||||
# pushl $0
|
||||
# popf
|
||||
|
||||
# Push the pointer to the Multiboot information structure.
|
||||
push %ebx
|
||||
# Push the magic value.
|
||||
push %eax
|
||||
|
||||
## Disable interrupts.
|
||||
cli
|
||||
|
||||
call KernelInit
|
||||
.size beginkernel, . - beginkernel
|
||||
|
||||
.global HaltKernel
|
||||
HaltKernel:
|
||||
cli
|
||||
hlt
|
||||
jmp HaltKernel
|
||||
.size HaltKernel, . - HaltKernel
|
||||
|
||||
.global WaitForInterrupt
|
||||
.type WaitForInterrupt, @function # void WaitForInterrupt();
|
||||
WaitForInterrupt:
|
||||
hlt
|
||||
ret
|
||||
.size WaitForInterrupt, . - WaitForInterrupt
|
||||
|
|
@ -1,6 +1,6 @@
|
|||
/*******************************************************************************
|
||||
|
||||
Copyright(C) Jonas 'Sortie' Termansen 2011, 2014.
|
||||
Copyright(C) Jonas 'Sortie' Termansen 2011, 2014, 2015.
|
||||
|
||||
This file is part of Sortix.
|
||||
|
||||
|
|
@ -26,48 +26,96 @@
|
|||
.section .text
|
||||
.text 0x100000
|
||||
|
||||
# Multiboot header.
|
||||
.align 4
|
||||
.long 0x1BADB002 # Magic.
|
||||
.long 0x00000003 # Flags.
|
||||
.long -(0x1BADB002 + 0x00000003) # Checksum.
|
||||
|
||||
.global _start
|
||||
.global __start
|
||||
.type _start, @function
|
||||
.type __start, @function
|
||||
_start:
|
||||
__start:
|
||||
jmp prepare_kernel_execution
|
||||
# Initialize the stack pointer. The magic value is from kernel.cpp.
|
||||
movl $(stack + 65536), %esp # 64 KiB, see kernel.cpp
|
||||
|
||||
# Align 32 bits boundary.
|
||||
.align 4
|
||||
# Finish installing the kernel stack into the Task Switch Segment.
|
||||
movl %esp, tss + 4
|
||||
|
||||
# Multiboot header.
|
||||
multiboot_header:
|
||||
# Magic.
|
||||
.long 0x1BADB002
|
||||
# Flags.
|
||||
.long 0x00000003
|
||||
# Checksum.
|
||||
.long -(0x1BADB002 + 0x00000003)
|
||||
# Finish installing the Task Switch Segment into the Global Descriptor Table.
|
||||
movl $tss, %ecx
|
||||
movw %cx, gdt + 0x28 + 2
|
||||
shrl $16, %ecx
|
||||
movb %cl, gdt + 0x28 + 4
|
||||
shrl $8, %ecx
|
||||
movb %cl, gdt + 0x28 + 7
|
||||
|
||||
# Load the Global Descriptor Table pointer register.
|
||||
subl $6, %esp
|
||||
movw gdt_size_minus_one, %cx
|
||||
movw %cx, 0(%esp)
|
||||
movl $gdt, %ecx
|
||||
movl %ecx, 2(%esp)
|
||||
lgdt 0(%esp)
|
||||
addl $6, %esp
|
||||
|
||||
# Switch cs to the kernel code segment (0x08).
|
||||
push $0x08
|
||||
push $2f
|
||||
retf
|
||||
|
||||
2:
|
||||
# Switch ds, es, fs, gs, ss to the kernel data segment (0x10).
|
||||
movw $0x10, %cx
|
||||
movw %cx, %ds
|
||||
movw %cx, %es
|
||||
movw %cx, %ss
|
||||
|
||||
# Switch the task switch segment register to the task switch segment (0x28).
|
||||
movw $(0x28 /* TSS */ | 0x3 /* RPL */), %cx
|
||||
ltr %cx
|
||||
|
||||
# Switch to the thread local fs and gs segments.
|
||||
movw $(0x30 /* FS */ | 0x3 /* RPL */), %cx
|
||||
movw %cx, %fs
|
||||
movw $(0x38 /* GS */ | 0x3 /* RPL */), %cx
|
||||
movw %cx, %gs
|
||||
|
||||
prepare_kernel_execution:
|
||||
# Enable the floating point unit.
|
||||
mov %eax, 0x100000
|
||||
mov %cr0, %eax
|
||||
and $0xFFFD, %ax
|
||||
or $0x10, %ax
|
||||
mov %eax, %cr0
|
||||
mov %cr0, %ecx
|
||||
and $0xFFFD, %cx
|
||||
or $0x10, %cx
|
||||
mov %ecx, %cr0
|
||||
fninit
|
||||
|
||||
# Enable Streaming SIMD Extensions.
|
||||
mov %cr0, %eax
|
||||
and $0xFFFB, %ax
|
||||
or $0x2, %ax
|
||||
mov %eax, %cr0
|
||||
mov %cr4, %eax
|
||||
or $0x600, %eax
|
||||
mov %eax, %cr4
|
||||
mov 0x100000, %eax
|
||||
mov %cr0, %ecx
|
||||
and $0xFFFB, %cx
|
||||
or $0x2, %cx
|
||||
mov %ecx, %cr0
|
||||
mov %cr4, %ecx
|
||||
or $0x600, %ecx
|
||||
mov %ecx, %cr4
|
||||
|
||||
# Store a copy of the initialial floating point registers.
|
||||
fxsave fpu_initialized_regs
|
||||
|
||||
jmp beginkernel
|
||||
# Enter the high-level kernel proper.
|
||||
subl $8, %esp # 16-byte align at call time.
|
||||
push %ebx # Multiboot information structure pointer.
|
||||
push %eax # Multiboot magic value.
|
||||
call KernelInit
|
||||
|
||||
jmp HaltKernel
|
||||
.size _start, . - _start
|
||||
.size __start, . - __start
|
||||
|
||||
.global HaltKernel
|
||||
.type HaltKernel, @function
|
||||
HaltKernel:
|
||||
cli
|
||||
hlt
|
||||
jmp HaltKernel
|
||||
.size HaltKernel, . - HaltKernel
|
||||
|
|
|
|||
Loading…
Reference in a new issue