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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /arch/x86/boot/pmjump.S | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/boot/pmjump.S')
-rw-r--r-- | arch/x86/boot/pmjump.S | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/arch/x86/boot/pmjump.S b/arch/x86/boot/pmjump.S new file mode 100644 index 000000000..cbec8bd08 --- /dev/null +++ b/arch/x86/boot/pmjump.S @@ -0,0 +1,75 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* ----------------------------------------------------------------------- * + * + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright 2007 rPath, Inc. - All Rights Reserved + * + * ----------------------------------------------------------------------- */ + +/* + * The actual transition into protected mode + */ + +#include <asm/boot.h> +#include <asm/processor-flags.h> +#include <asm/segment.h> +#include <linux/linkage.h> + + .text + .code16 + +/* + * void protected_mode_jump(u32 entrypoint, u32 bootparams); + */ +SYM_FUNC_START_NOALIGN(protected_mode_jump) + movl %edx, %esi # Pointer to boot_params table + + xorl %ebx, %ebx + movw %cs, %bx + shll $4, %ebx + addl %ebx, 2f + jmp 1f # Short jump to serialize on 386/486 +1: + + movw $__BOOT_DS, %cx + movw $__BOOT_TSS, %di + + movl %cr0, %edx + orb $X86_CR0_PE, %dl # Protected mode + movl %edx, %cr0 + + # Transition to 32-bit mode + .byte 0x66, 0xea # ljmpl opcode +2: .long .Lin_pm32 # offset + .word __BOOT_CS # segment +SYM_FUNC_END(protected_mode_jump) + + .code32 + .section ".text32","ax" +SYM_FUNC_START_LOCAL_NOALIGN(.Lin_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 +SYM_FUNC_END(.Lin_pm32) |