148 lines
4.0 KiB
ArmAsm
148 lines
4.0 KiB
ArmAsm
/**
|
|
* PROJECT: ExectOS
|
|
* COPYRIGHT: See COPYING.md in the top level directory
|
|
* FILE: xtoskrnl/ar/amd64/boot.S
|
|
* DESCRIPTION: AMD64-specific boot code for setting up the low-level CPU environment
|
|
* DEVELOPERS: Aiken Harris <harraiken91@gmail.com>
|
|
*/
|
|
|
|
#include <ar/amd64/asmsup.h>
|
|
|
|
.altmacro
|
|
.text
|
|
|
|
|
|
/**
|
|
* Enables eXtended Physical Addressing (XPA).
|
|
*
|
|
* @param PageMap
|
|
* Supplies a pointer to the page map to be used.
|
|
*
|
|
* @return This routine does not return any value.
|
|
*
|
|
* @since XT 1.0
|
|
*/
|
|
.global ArEnableExtendedPhysicalAddressing
|
|
ArEnableExtendedPhysicalAddressing:
|
|
/* Save the original CR4 register */
|
|
movq %cr4, %rax
|
|
|
|
/* Save the state of stack pointer and non-volatile registers */
|
|
movq %rsp, XpaRegisterSaveArea(%rip)
|
|
movq %rbp, XpaRegisterSaveArea+0x08(%rip)
|
|
movq %rax, XpaRegisterSaveArea+0x10(%rip)
|
|
movq %rbx, XpaRegisterSaveArea+0x18(%rip)
|
|
|
|
/* Save the original CR0 register */
|
|
movq %cr0, %rbp
|
|
|
|
/* Load temporary GDT required for mode transitions */
|
|
leaq XpaTemporaryGdtDesc(%rip), %rax
|
|
movq %rax, XpaTemporaryGdtBase(%rip)
|
|
lgdtq XpaTemporaryGdtSize(%rip)
|
|
|
|
/* Load addresses for entering compatibility mode and re-entering long mode */
|
|
leaq XpaEnterCompatMode(%rip), %rax
|
|
leaq XpaEnterLongMode(%rip), %rbx
|
|
|
|
/* Push the 32-bit code segment selector and the target address for a far jump */
|
|
pushq $GDT_R0_CMCODE
|
|
pushq %rax
|
|
|
|
/* Perform a far return to switch to 32-bit compatibility mode */
|
|
lretq
|
|
|
|
XpaEnterCompatMode:
|
|
/* Enter 32-bit compatibility mode */
|
|
.code32
|
|
|
|
/* Store the PageMap pointer on the stack for future use */
|
|
pushl %ecx
|
|
|
|
/* Set the stack segment to the 32-bit data segment selector */
|
|
movl $GDT_R0_DATA, %eax
|
|
movl %eax, %ss
|
|
|
|
/* Disable PGE and PCIDE to ensure all TLB entries will be flushed */
|
|
movl %cr4, %eax
|
|
andl $~(CR4_PGE | CR4_PCIDE), %eax
|
|
movl %eax, %cr4
|
|
|
|
/* Temporarily disable paging */
|
|
movl %ebp, %eax
|
|
andl $~CR0_PG, %eax
|
|
movl %eax, %cr0
|
|
|
|
/* Disable Long Mode as prerequisite for enabling 5-level paging */
|
|
movl $X86_MSR_EFER, %ecx
|
|
rdmsr
|
|
andl $~X86_MSR_EFER_LME, %eax
|
|
wrmsr
|
|
|
|
/* Transition to 5-level paging (PML5/LA57) */
|
|
movl %cr4, %eax
|
|
orl $CR4_LA57, %eax
|
|
movl %eax, %cr4
|
|
|
|
/* Restore the PageMap pointer from the stack and load it into CR3 */
|
|
popl %ecx
|
|
movl %ecx, %cr3
|
|
|
|
/* Re-enable Long Mode */
|
|
movl $X86_MSR_EFER, %ecx
|
|
rdmsr
|
|
orl $X86_MSR_EFER_LME, %eax
|
|
wrmsr
|
|
|
|
/* Restore CR0 with paging enabled and flush the instruction pipeline */
|
|
movl %ebp, %cr0
|
|
call XpaFlushInstructions
|
|
|
|
XpaFlushInstructions:
|
|
/* Push the 64-bit code segment selector and the target address for a far jump */
|
|
pushl $GDT_R0_CODE
|
|
pushl %ebx
|
|
|
|
/* Perform a far return to switch to 64-bit long mode */
|
|
lretl
|
|
|
|
XpaEnterLongMode:
|
|
/* Enter 64-bit long mode */
|
|
.code64
|
|
|
|
/* Restore the stack pointer and non-volatile registers */
|
|
movq XpaRegisterSaveArea(%rip), %rsp
|
|
movq XpaRegisterSaveArea+8(%rip), %rbp
|
|
movq XpaRegisterSaveArea+0x10(%rip), %rax
|
|
movq XpaRegisterSaveArea+0x18(%rip), %rbx
|
|
|
|
/* Restore the original CR4 register with LA57 bit set */
|
|
orq $CR4_LA57, %rax
|
|
movq %rax, %cr4
|
|
|
|
/* Return to the caller */
|
|
retq
|
|
|
|
/* Data section for saving registers and temporary GDT */
|
|
XpaRegisterSaveArea: .quad 0x0000000000000000, 0x0000000000000000, 0x0000000000000000, 0x0000000000000000
|
|
XpaTemporaryGdtSize: .short ArEnableExtendedPhysicalAddressingEnd - XpaTemporaryGdtDesc - 1
|
|
XpaTemporaryGdtBase: .quad 0x0000000000000000
|
|
XpaTemporaryGdtDesc: .quad 0x0000000000000000, 0x00CF9A000000FFFF, 0x00AF9A000000FFFF, 0x00CF92000000FFFF
|
|
|
|
.global ArEnableExtendedPhysicalAddressingEnd
|
|
ArEnableExtendedPhysicalAddressingEnd:
|
|
|
|
|
|
/**
|
|
* Starts an application processor (AP). This is just a stub.
|
|
*
|
|
* @return This routine does not return any value.
|
|
*
|
|
* @since XT 1.0
|
|
*/
|
|
.global ArStartApplicationProcessor
|
|
ArStartApplicationProcessor:
|
|
|
|
.global ArStartApplicationProcessorEnd
|
|
ArStartApplicationProcessorEnd:
|