linux/arch/x86_64/kernel/suspend_asm.S
Vivek Goyal 1ab60e0f72 [PATCH] x86-64: Relocatable Kernel Support
This patch modifies the x86_64 kernel so that it can be loaded and run
at any 2M aligned address, below 512G.  The technique used is to
compile the decompressor with -fPIC and modify it so the decompressor
is fully relocatable.  For the main kernel the page tables are
modified so the kernel remains at the same virtual address.  In
addition a variable phys_base is kept that holds the physical address
the kernel is loaded at.  __pa_symbol is modified to add that when
we take the address of a kernel symbol.

When loaded with a normal bootloader the decompressor will decompress
the kernel to 2M and it will run there.  This both ensures the
relocation code is always working, and makes it easier to use 2M
pages for the kernel and the cpu.

AK: changed to not make RELOCATABLE default in Kconfig

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:07 +02:00

111 lines
2.9 KiB
ArmAsm

/* Copyright 2004,2005 Pavel Machek <pavel@suse.cz>, Andi Kleen <ak@suse.de>, Rafael J. Wysocki <rjw@sisk.pl>
*
* Distribute under GPLv2.
*
* swsusp_arch_resume may not use any stack, nor any variable that is
* not "NoSave" during copying pages:
*
* Its rewriting one kernel image with another. What is stack in "old"
* image could very well be data page in "new" image, and overwriting
* your own stack under you is bad idea.
*/
.text
#include <linux/linkage.h>
#include <asm/segment.h>
#include <asm/page.h>
#include <asm/asm-offsets.h>
ENTRY(swsusp_arch_suspend)
movq %rsp, saved_context_esp(%rip)
movq %rax, saved_context_eax(%rip)
movq %rbx, saved_context_ebx(%rip)
movq %rcx, saved_context_ecx(%rip)
movq %rdx, saved_context_edx(%rip)
movq %rbp, saved_context_ebp(%rip)
movq %rsi, saved_context_esi(%rip)
movq %rdi, saved_context_edi(%rip)
movq %r8, saved_context_r08(%rip)
movq %r9, saved_context_r09(%rip)
movq %r10, saved_context_r10(%rip)
movq %r11, saved_context_r11(%rip)
movq %r12, saved_context_r12(%rip)
movq %r13, saved_context_r13(%rip)
movq %r14, saved_context_r14(%rip)
movq %r15, saved_context_r15(%rip)
pushfq ; popq saved_context_eflags(%rip)
call swsusp_save
ret
ENTRY(restore_image)
/* switch to temporary page tables */
movq $__PAGE_OFFSET, %rdx
movq temp_level4_pgt(%rip), %rax
subq %rdx, %rax
movq %rax, %cr3
/* Flush TLB */
movq mmu_cr4_features(%rip), %rax
movq %rax, %rdx
andq $~(1<<7), %rdx # PGE
movq %rdx, %cr4; # turn off PGE
movq %cr3, %rcx; # flush TLB
movq %rcx, %cr3;
movq %rax, %cr4; # turn PGE back on
movq restore_pblist(%rip), %rdx
loop:
testq %rdx, %rdx
jz done
/* get addresses from the pbe and copy the page */
movq pbe_address(%rdx), %rsi
movq pbe_orig_address(%rdx), %rdi
movq $512, %rcx
rep
movsq
/* progress to the next pbe */
movq pbe_next(%rdx), %rdx
jmp loop
done:
/* go back to the original page tables */
movq $(init_level4_pgt - __START_KERNEL_map), %rax
addq phys_base(%rip), %rax
movq %rax, %cr3
/* Flush TLB, including "global" things (vmalloc) */
movq mmu_cr4_features(%rip), %rax
movq %rax, %rdx
andq $~(1<<7), %rdx; # PGE
movq %rdx, %cr4; # turn off PGE
movq %cr3, %rcx; # flush TLB
movq %rcx, %cr3
movq %rax, %cr4; # turn PGE back on
movl $24, %eax
movl %eax, %ds
movq saved_context_esp(%rip), %rsp
movq saved_context_ebp(%rip), %rbp
/* Don't restore %rax, it must be 0 anyway */
movq saved_context_ebx(%rip), %rbx
movq saved_context_ecx(%rip), %rcx
movq saved_context_edx(%rip), %rdx
movq saved_context_esi(%rip), %rsi
movq saved_context_edi(%rip), %rdi
movq saved_context_r08(%rip), %r8
movq saved_context_r09(%rip), %r9
movq saved_context_r10(%rip), %r10
movq saved_context_r11(%rip), %r11
movq saved_context_r12(%rip), %r12
movq saved_context_r13(%rip), %r13
movq saved_context_r14(%rip), %r14
movq saved_context_r15(%rip), %r15
pushq saved_context_eflags(%rip) ; popfq
xorq %rax, %rax
ret