diff options
Diffstat (limited to 'arch/x86/boot/pmjump.S')
| -rw-r--r-- | arch/x86/boot/pmjump.S | 56 |
1 files changed, 43 insertions, 13 deletions
diff --git a/arch/x86/boot/pmjump.S b/arch/x86/boot/pmjump.S index 2e559233725..f5402d51f7c 100644 --- a/arch/x86/boot/pmjump.S +++ b/arch/x86/boot/pmjump.S @@ -15,6 +15,7 @@ */ #include <asm/boot.h> +#include <asm/processor-flags.h> #include <asm/segment.h> .text @@ -28,27 +29,56 @@ * void protected_mode_jump(u32 entrypoint, u32 bootparams); */ protected_mode_jump: - xorl %ebx, %ebx # Flag to indicate this is a boot movl %edx, %esi # Pointer to boot_params table - movl %eax, 2f # Patch ljmpl instruction - jmp 1f # Short jump to flush instruction q. -1: + xorl %ebx, %ebx + movw %cs, %bx + shll $4, %ebx + addl %ebx, 2f + movw $__BOOT_DS, %cx + movw $__BOOT_TSS, %di movl %cr0, %edx - orb $1, %dl # Protected mode (PE) bit + orb $X86_CR0_PE, %dl # Protected mode movl %edx, %cr0 + jmp 1f # Short jump to serialize on 386/486 +1: - movw %cx, %ds - movw %cx, %es - movw %cx, %fs - movw %cx, %gs - movw %cx, %ss - - # Jump to the 32-bit entrypoint + # Transition to 32-bit mode .byte 0x66, 0xea # ljmpl opcode -2: .long 0 # offset +2: .long in_pm32 # offset .word __BOOT_CS # segment .size protected_mode_jump, .-protected_mode_jump + + .code32 + .type in_pm32, @function +in_pm32: + # Set up data segments for flat 32-bit mode + movl %ecx, %ds + movl %ecx, %es + movl %ecx, %fs + movl %ecx, %gs + movl %ecx, %ss + # The 32-bit code sets up its own stack, but this way we do have + # a valid stack if some debugging hack wants to use it. + addl %ebx, %esp + + # Set up TR to make Intel VT happy + ltr %di + + # Clear registers to allow for future extensions to the + # 32-bit boot protocol + xorl %ecx, %ecx + xorl %edx, %edx + xorl %ebx, %ebx + xorl %ebp, %ebp + xorl %edi, %edi + + # Set up LDTR to make Intel VT happy + lldt %cx + + jmpl *%eax # Jump to the 32-bit entrypoint + + .size in_pm32, .-in_pm32 |