mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-16 23:26:42 +07:00
97c4cb71c1
Add code needed for basic suspend/resume of the XO-1 laptop. Based on earlier work by Jordan Crouse, Andres Salomon, and others. This patch incorporates all earlier feedback from Thomas Gleixner. To clarify a certain point (now more obvious in the code itself): On resume, OpenFirmware returns execution to Linux in protected mode with a kernel-compatible GDT already set up. The changes and simplifications suggested have all been included. Signed-off-by: Daniel Drake <dsd@laptop.org> Link: http://lkml.kernel.org/r/1309019658-1712-5-git-send-email-dsd@laptop.org Acked-by: Andres Salomon <dilinger@queued.net> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
125 lines
2.1 KiB
ArmAsm
125 lines
2.1 KiB
ArmAsm
.text
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#include <linux/linkage.h>
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#include <asm/segment.h>
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#include <asm/page.h>
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#include <asm/pgtable_32.h>
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.macro writepost,value
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movb $0x34, %al
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outb %al, $0x70
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movb $\value, %al
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outb %al, $0x71
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.endm
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wakeup_start:
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# OFW lands us here, running in protected mode, with a
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# kernel-compatible GDT already setup.
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# Clear any dangerous flags
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pushl $0
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popfl
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writepost 0x31
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# Set up %cr3
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movl $initial_page_table - __PAGE_OFFSET, %eax
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movl %eax, %cr3
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movl saved_cr4, %eax
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movl %eax, %cr4
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movl saved_cr0, %eax
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movl %eax, %cr0
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# Control registers were modified, pipeline resync is needed
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jmp 1f
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1:
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movw $__KERNEL_DS, %ax
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movw %ax, %ss
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movw %ax, %ds
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movw %ax, %es
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movw %ax, %fs
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movw %ax, %gs
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lgdt saved_gdt
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lidt saved_idt
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lldt saved_ldt
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ljmp $(__KERNEL_CS),$1f
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1:
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movl %cr3, %eax
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movl %eax, %cr3
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wbinvd
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# Go back to the return point
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jmp ret_point
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save_registers:
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sgdt saved_gdt
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sidt saved_idt
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sldt saved_ldt
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pushl %edx
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movl %cr4, %edx
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movl %edx, saved_cr4
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movl %cr0, %edx
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movl %edx, saved_cr0
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popl %edx
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movl %ebx, saved_context_ebx
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movl %ebp, saved_context_ebp
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movl %esi, saved_context_esi
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movl %edi, saved_context_edi
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pushfl
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popl saved_context_eflags
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ret
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restore_registers:
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movl saved_context_ebp, %ebp
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movl saved_context_ebx, %ebx
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movl saved_context_esi, %esi
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movl saved_context_edi, %edi
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pushl saved_context_eflags
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popfl
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ret
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ENTRY(do_olpc_suspend_lowlevel)
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call save_processor_state
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call save_registers
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# This is the stack context we want to remember
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movl %esp, saved_context_esp
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pushl $3
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call xo1_do_sleep
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jmp wakeup_start
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.p2align 4,,7
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ret_point:
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movl saved_context_esp, %esp
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writepost 0x32
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call restore_registers
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call restore_processor_state
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ret
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.data
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saved_gdt: .long 0,0
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saved_idt: .long 0,0
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saved_ldt: .long 0
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saved_cr4: .long 0
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saved_cr0: .long 0
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saved_context_esp: .long 0
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saved_context_edi: .long 0
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saved_context_esi: .long 0
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saved_context_ebx: .long 0
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saved_context_ebp: .long 0
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saved_context_eflags: .long 0
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