diff options
Diffstat (limited to 'arch/x86/platform/olpc/xo1-wakeup.S')
| -rw-r--r-- | arch/x86/platform/olpc/xo1-wakeup.S | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/arch/x86/platform/olpc/xo1-wakeup.S b/arch/x86/platform/olpc/xo1-wakeup.S new file mode 100644 index 000000000..3a5abffe5 --- /dev/null +++ b/arch/x86/platform/olpc/xo1-wakeup.S @@ -0,0 +1,126 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +.text +#include <linux/linkage.h> +#include <asm/segment.h> +#include <asm/page.h> +#include <asm/pgtable_32.h> + + .macro writepost,value + movb $0x34, %al + outb %al, $0x70 + movb $\value, %al + outb %al, $0x71 + .endm + +wakeup_start: + # OFW lands us here, running in protected mode, with a + # kernel-compatible GDT already setup. + + # Clear any dangerous flags + pushl $0 + popfl + + writepost 0x31 + + # Set up %cr3 + movl $initial_page_table - __PAGE_OFFSET, %eax + movl %eax, %cr3 + + movl saved_cr4, %eax + movl %eax, %cr4 + + movl saved_cr0, %eax + movl %eax, %cr0 + + # Control registers were modified, pipeline resync is needed + jmp 1f +1: + + movw $__KERNEL_DS, %ax + movw %ax, %ss + movw %ax, %ds + movw %ax, %es + movw %ax, %fs + movw %ax, %gs + + lgdt saved_gdt + lidt saved_idt + lldt saved_ldt + ljmp $(__KERNEL_CS),$1f +1: + movl %cr3, %eax + movl %eax, %cr3 + wbinvd + + # Go back to the return point + jmp ret_point + +save_registers: + sgdt saved_gdt + sidt saved_idt + sldt saved_ldt + + pushl %edx + movl %cr4, %edx + movl %edx, saved_cr4 + + movl %cr0, %edx + movl %edx, saved_cr0 + + popl %edx + + movl %ebx, saved_context_ebx + movl %ebp, saved_context_ebp + movl %esi, saved_context_esi + movl %edi, saved_context_edi + + pushfl + popl saved_context_eflags + + RET + +restore_registers: + movl saved_context_ebp, %ebp + movl saved_context_ebx, %ebx + movl saved_context_esi, %esi + movl saved_context_edi, %edi + + pushl saved_context_eflags + popfl + + RET + +SYM_CODE_START(do_olpc_suspend_lowlevel) + call save_processor_state + call save_registers + + # This is the stack context we want to remember + movl %esp, saved_context_esp + + pushl $3 + call xo1_do_sleep + + jmp wakeup_start + .p2align 4,,7 +ret_point: + movl saved_context_esp, %esp + + writepost 0x32 + + call restore_registers + call restore_processor_state + RET +SYM_CODE_END(do_olpc_suspend_lowlevel) + +.data +saved_gdt: .long 0,0 +saved_idt: .long 0,0 +saved_ldt: .long 0 +saved_cr4: .long 0 +saved_cr0: .long 0 +saved_context_esp: .long 0 +saved_context_edi: .long 0 +saved_context_esi: .long 0 +saved_context_ebx: .long 0 +saved_context_ebp: .long 0 +saved_context_eflags: .long 0 |