diff options
Diffstat (limited to 'arch/x86/realmode/rm/wakeup_asm.S')
| -rw-r--r-- | arch/x86/realmode/rm/wakeup_asm.S | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/arch/x86/realmode/rm/wakeup_asm.S b/arch/x86/realmode/rm/wakeup_asm.S new file mode 100644 index 000000000..05ac9c17c --- /dev/null +++ b/arch/x86/realmode/rm/wakeup_asm.S @@ -0,0 +1,178 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * ACPI wakeup real mode startup stub + */ +#include <linux/linkage.h> +#include <asm/segment.h> +#include <asm/msr-index.h> +#include <asm/page_types.h> +#include <asm/pgtable_types.h> +#include <asm/processor-flags.h> +#include "realmode.h" +#include "wakeup.h" + + .code16 + +/* This should match the structure in wakeup.h */ + .section ".data", "aw" + + .balign 16 +GLOBAL(wakeup_header) + video_mode: .short 0 /* Video mode number */ + pmode_entry: .long 0 + pmode_cs: .short __KERNEL_CS + pmode_cr0: .long 0 /* Saved %cr0 */ + pmode_cr3: .long 0 /* Saved %cr3 */ + pmode_cr4: .long 0 /* Saved %cr4 */ + pmode_efer: .quad 0 /* Saved EFER */ + pmode_gdt: .quad 0 + pmode_misc_en: .quad 0 /* Saved MISC_ENABLE MSR */ + pmode_behavior: .long 0 /* Wakeup behavior flags */ + realmode_flags: .long 0 + real_magic: .long 0 + signature: .long WAKEUP_HEADER_SIGNATURE +END(wakeup_header) + + .text + .code16 + + .balign 16 +ENTRY(wakeup_start) + cli + cld + + LJMPW_RM(3f) +3: + /* Apparently some dimwit BIOS programmers don't know how to + program a PM to RM transition, and we might end up here with + junk in the data segment descriptor registers. The only way + to repair that is to go into PM and fix it ourselves... */ + movw $16, %cx + lgdtl %cs:wakeup_gdt + movl %cr0, %eax + orb $X86_CR0_PE, %al + movl %eax, %cr0 + ljmpw $8, $2f +2: + movw %cx, %ds + movw %cx, %es + movw %cx, %ss + movw %cx, %fs + movw %cx, %gs + + andb $~X86_CR0_PE, %al + movl %eax, %cr0 + LJMPW_RM(3f) +3: + /* Set up segments */ + movw %cs, %ax + movw %ax, %ss + movl $rm_stack_end, %esp + movw %ax, %ds + movw %ax, %es + movw %ax, %fs + movw %ax, %gs + + lidtl wakeup_idt + + /* Clear the EFLAGS */ + pushl $0 + popfl + + /* Check header signature... */ + movl signature, %eax + cmpl $WAKEUP_HEADER_SIGNATURE, %eax + jne bogus_real_magic + + /* Check we really have everything... */ + movl end_signature, %eax + cmpl $REALMODE_END_SIGNATURE, %eax + jne bogus_real_magic + + /* Call the C code */ + calll main + + /* Restore MISC_ENABLE before entering protected mode, in case + BIOS decided to clear XD_DISABLE during S3. */ + movl pmode_behavior, %edi + btl $WAKEUP_BEHAVIOR_RESTORE_MISC_ENABLE, %edi + jnc 1f + + movl pmode_misc_en, %eax + movl pmode_misc_en + 4, %edx + movl $MSR_IA32_MISC_ENABLE, %ecx + wrmsr +1: + + /* Do any other stuff... */ + +#ifndef CONFIG_64BIT + /* This could also be done in C code... */ + movl pmode_cr3, %eax + movl %eax, %cr3 + + btl $WAKEUP_BEHAVIOR_RESTORE_CR4, %edi + jnc 1f + movl pmode_cr4, %eax + movl %eax, %cr4 +1: + btl $WAKEUP_BEHAVIOR_RESTORE_EFER, %edi + jnc 1f + movl pmode_efer, %eax + movl pmode_efer + 4, %edx + movl $MSR_EFER, %ecx + wrmsr +1: + + lgdtl pmode_gdt + + /* This really couldn't... */ + movl pmode_entry, %eax + movl pmode_cr0, %ecx + movl %ecx, %cr0 + ljmpl $__KERNEL_CS, $pa_startup_32 + /* -> jmp *%eax in trampoline_32.S */ +#else + jmp trampoline_start +#endif + +bogus_real_magic: +1: + hlt + jmp 1b + + .section ".rodata","a" + + /* + * Set up the wakeup GDT. We set these up as Big Real Mode, + * that is, with limits set to 4 GB. At least the Lenovo + * Thinkpad X61 is known to need this for the video BIOS + * initialization quirk to work; this is likely to also + * be the case for other laptops or integrated video devices. + */ + + .balign 16 +GLOBAL(wakeup_gdt) + .word 3*8-1 /* Self-descriptor */ + .long pa_wakeup_gdt + .word 0 + + .word 0xffff /* 16-bit code segment @ real_mode_base */ + .long 0x9b000000 + pa_real_mode_base + .word 0x008f /* big real mode */ + + .word 0xffff /* 16-bit data segment @ real_mode_base */ + .long 0x93000000 + pa_real_mode_base + .word 0x008f /* big real mode */ +END(wakeup_gdt) + + .section ".rodata","a" + .balign 8 + + /* This is the standard real-mode IDT */ + .balign 16 +GLOBAL(wakeup_idt) + .word 0xffff /* limit */ + .long 0 /* address */ + .word 0 +END(wakeup_idt) |