168 строки
4.2 KiB
ArmAsm
168 строки
4.2 KiB
ArmAsm
/*
|
|
*
|
|
* Trampoline.S Derived from Setup.S by Linus Torvalds
|
|
*
|
|
* 4 Jan 1997 Michael Chastain: changed to gnu as.
|
|
* 15 Sept 2005 Eric Biederman: 64bit PIC support
|
|
*
|
|
* Entry: CS:IP point to the start of our code, we are
|
|
* in real mode with no stack, but the rest of the
|
|
* trampoline page to make our stack and everything else
|
|
* is a mystery.
|
|
*
|
|
* On entry to trampoline_data, the processor is in real mode
|
|
* with 16-bit addressing and 16-bit data. CS has some value
|
|
* and IP is zero. Thus, data addresses need to be absolute
|
|
* (no relocation) and are taken with regard to r_base.
|
|
*
|
|
* With the addition of trampoline_level4_pgt this code can
|
|
* now enter a 64bit kernel that lives at arbitrary 64bit
|
|
* physical addresses.
|
|
*
|
|
* If you work on this file, check the object module with objdump
|
|
* --full-contents --reloc to make sure there are no relocation
|
|
* entries.
|
|
*/
|
|
|
|
#include <linux/linkage.h>
|
|
#include <linux/init.h>
|
|
#include <asm/pgtable_types.h>
|
|
#include <asm/page_types.h>
|
|
#include <asm/msr.h>
|
|
#include <asm/segment.h>
|
|
#include <asm/processor-flags.h>
|
|
|
|
#ifdef CONFIG_ACPI_SLEEP
|
|
.section .rodata, "a", @progbits
|
|
#else
|
|
/* We can free up the trampoline after bootup if cpu hotplug is not supported. */
|
|
__CPUINITRODATA
|
|
#endif
|
|
.code16
|
|
|
|
ENTRY(trampoline_data)
|
|
r_base = .
|
|
cli # We should be safe anyway
|
|
wbinvd
|
|
mov %cs, %ax # Code and data in the same place
|
|
mov %ax, %ds
|
|
mov %ax, %es
|
|
mov %ax, %ss
|
|
|
|
|
|
movl $0xA5A5A5A5, trampoline_data - r_base
|
|
# write marker for master knows we're running
|
|
|
|
# Setup stack
|
|
movw $(trampoline_stack_end - r_base), %sp
|
|
|
|
call verify_cpu # Verify the cpu supports long mode
|
|
testl %eax, %eax # Check for return code
|
|
jnz no_longmode
|
|
|
|
mov %cs, %ax
|
|
movzx %ax, %esi # Find the 32bit trampoline location
|
|
shll $4, %esi
|
|
|
|
# Fixup the vectors
|
|
addl %esi, startup_32_vector - r_base
|
|
addl %esi, startup_64_vector - r_base
|
|
addl %esi, tgdt + 2 - r_base # Fixup the gdt pointer
|
|
|
|
/*
|
|
* GDT tables in non default location kernel can be beyond 16MB and
|
|
* lgdt will not be able to load the address as in real mode default
|
|
* operand size is 16bit. Use lgdtl instead to force operand size
|
|
* to 32 bit.
|
|
*/
|
|
|
|
lidtl tidt - r_base # load idt with 0, 0
|
|
lgdtl tgdt - r_base # load gdt with whatever is appropriate
|
|
|
|
mov $X86_CR0_PE, %ax # protected mode (PE) bit
|
|
lmsw %ax # into protected mode
|
|
|
|
# flush prefetch and jump to startup_32
|
|
ljmpl *(startup_32_vector - r_base)
|
|
|
|
.code32
|
|
.balign 4
|
|
startup_32:
|
|
movl $__KERNEL_DS, %eax # Initialize the %ds segment register
|
|
movl %eax, %ds
|
|
|
|
movl $X86_CR4_PAE, %eax
|
|
movl %eax, %cr4 # Enable PAE mode
|
|
|
|
# Setup trampoline 4 level pagetables
|
|
leal (trampoline_level4_pgt - r_base)(%esi), %eax
|
|
movl %eax, %cr3
|
|
|
|
movl $MSR_EFER, %ecx
|
|
movl $(1 << _EFER_LME), %eax # Enable Long Mode
|
|
xorl %edx, %edx
|
|
wrmsr
|
|
|
|
# Enable paging and in turn activate Long Mode
|
|
# Enable protected mode
|
|
movl $(X86_CR0_PG | X86_CR0_PE), %eax
|
|
movl %eax, %cr0
|
|
|
|
/*
|
|
* At this point we're in long mode but in 32bit compatibility mode
|
|
* with EFER.LME = 1, CS.L = 0, CS.D = 1 (and in turn
|
|
* EFER.LMA = 1). Now we want to jump in 64bit mode, to do that we use
|
|
* the new gdt/idt that has __KERNEL_CS with CS.L = 1.
|
|
*/
|
|
ljmp *(startup_64_vector - r_base)(%esi)
|
|
|
|
.code64
|
|
.balign 4
|
|
startup_64:
|
|
# Now jump into the kernel using virtual addresses
|
|
movq $secondary_startup_64, %rax
|
|
jmp *%rax
|
|
|
|
.code16
|
|
no_longmode:
|
|
hlt
|
|
jmp no_longmode
|
|
#include "verify_cpu.S"
|
|
|
|
# Careful these need to be in the same 64K segment as the above;
|
|
tidt:
|
|
.word 0 # idt limit = 0
|
|
.word 0, 0 # idt base = 0L
|
|
|
|
# Duplicate the global descriptor table
|
|
# so the kernel can live anywhere
|
|
.balign 4
|
|
tgdt:
|
|
.short tgdt_end - tgdt # gdt limit
|
|
.long tgdt - r_base
|
|
.short 0
|
|
.quad 0x00cf9b000000ffff # __KERNEL32_CS
|
|
.quad 0x00af9b000000ffff # __KERNEL_CS
|
|
.quad 0x00cf93000000ffff # __KERNEL_DS
|
|
tgdt_end:
|
|
|
|
.balign 4
|
|
startup_32_vector:
|
|
.long startup_32 - r_base
|
|
.word __KERNEL32_CS, 0
|
|
|
|
.balign 4
|
|
startup_64_vector:
|
|
.long startup_64 - r_base
|
|
.word __KERNEL_CS, 0
|
|
|
|
trampoline_stack:
|
|
.org 0x1000
|
|
trampoline_stack_end:
|
|
ENTRY(trampoline_level4_pgt)
|
|
.quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
|
|
.fill 510,8,0
|
|
.quad level3_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE
|
|
|
|
ENTRY(trampoline_end)
|