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-rw-r--r--arch/x86/realmode/rm/wakeup_asm.S179
1 files changed, 179 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..02d0ba16a
--- /dev/null
+++ b/arch/x86/realmode/rm/wakeup_asm.S
@@ -0,0 +1,179 @@
+/* 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
+SYM_DATA_START(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
+SYM_DATA_END(wakeup_header)
+
+ .text
+ .code16
+
+ .balign 16
+SYM_CODE_START(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 .Lwakeup_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
+SYM_CODE_END(wakeup_start)
+
+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
+SYM_DATA_START(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 */
+SYM_DATA_END(wakeup_gdt)
+
+ .section ".rodata","a"
+ .balign 8
+
+ /* This is the standard real-mode IDT */
+ .balign 16
+SYM_DATA_START_LOCAL(.Lwakeup_idt)
+ .word 0xffff /* limit */
+ .long 0 /* address */
+ .word 0
+SYM_DATA_END(.Lwakeup_idt)