forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
295 lines
6.0 KiB
295 lines
6.0 KiB
/* SPDX-License-Identifier: GPL-2.0-only */ |
|
/* |
|
* relocate_kernel.S - put the kernel image in place to boot |
|
* Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com> |
|
*/ |
|
|
|
#include <linux/linkage.h> |
|
#include <asm/page_types.h> |
|
#include <asm/kexec.h> |
|
#include <asm/processor-flags.h> |
|
#include <asm/pgtable_types.h> |
|
#include <asm/nospec-branch.h> |
|
#include <asm/unwind_hints.h> |
|
|
|
/* |
|
* Must be relocatable PIC code callable as a C function |
|
*/ |
|
|
|
#define PTR(x) (x << 3) |
|
#define PAGE_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY) |
|
|
|
/* |
|
* control_page + KEXEC_CONTROL_CODE_MAX_SIZE |
|
* ~ control_page + PAGE_SIZE are used as data storage and stack for |
|
* jumping back |
|
*/ |
|
#define DATA(offset) (KEXEC_CONTROL_CODE_MAX_SIZE+(offset)) |
|
|
|
/* Minimal CPU state */ |
|
#define RSP DATA(0x0) |
|
#define CR0 DATA(0x8) |
|
#define CR3 DATA(0x10) |
|
#define CR4 DATA(0x18) |
|
|
|
/* other data */ |
|
#define CP_PA_TABLE_PAGE DATA(0x20) |
|
#define CP_PA_SWAP_PAGE DATA(0x28) |
|
#define CP_PA_BACKUP_PAGES_MAP DATA(0x30) |
|
|
|
.text |
|
.align PAGE_SIZE |
|
.code64 |
|
SYM_CODE_START_NOALIGN(relocate_kernel) |
|
UNWIND_HINT_EMPTY |
|
/* |
|
* %rdi indirection_page |
|
* %rsi page_list |
|
* %rdx start address |
|
* %rcx preserve_context |
|
* %r8 sme_active |
|
*/ |
|
|
|
/* Save the CPU context, used for jumping back */ |
|
pushq %rbx |
|
pushq %rbp |
|
pushq %r12 |
|
pushq %r13 |
|
pushq %r14 |
|
pushq %r15 |
|
pushf |
|
|
|
movq PTR(VA_CONTROL_PAGE)(%rsi), %r11 |
|
movq %rsp, RSP(%r11) |
|
movq %cr0, %rax |
|
movq %rax, CR0(%r11) |
|
movq %cr3, %rax |
|
movq %rax, CR3(%r11) |
|
movq %cr4, %rax |
|
movq %rax, CR4(%r11) |
|
|
|
/* Save CR4. Required to enable the right paging mode later. */ |
|
movq %rax, %r13 |
|
|
|
/* zero out flags, and disable interrupts */ |
|
pushq $0 |
|
popfq |
|
|
|
/* Save SME active flag */ |
|
movq %r8, %r12 |
|
|
|
/* |
|
* get physical address of control page now |
|
* this is impossible after page table switch |
|
*/ |
|
movq PTR(PA_CONTROL_PAGE)(%rsi), %r8 |
|
|
|
/* get physical address of page table now too */ |
|
movq PTR(PA_TABLE_PAGE)(%rsi), %r9 |
|
|
|
/* get physical address of swap page now */ |
|
movq PTR(PA_SWAP_PAGE)(%rsi), %r10 |
|
|
|
/* save some information for jumping back */ |
|
movq %r9, CP_PA_TABLE_PAGE(%r11) |
|
movq %r10, CP_PA_SWAP_PAGE(%r11) |
|
movq %rdi, CP_PA_BACKUP_PAGES_MAP(%r11) |
|
|
|
/* Switch to the identity mapped page tables */ |
|
movq %r9, %cr3 |
|
|
|
/* setup a new stack at the end of the physical control page */ |
|
lea PAGE_SIZE(%r8), %rsp |
|
|
|
/* jump to identity mapped page */ |
|
addq $(identity_mapped - relocate_kernel), %r8 |
|
pushq %r8 |
|
ret |
|
SYM_CODE_END(relocate_kernel) |
|
|
|
SYM_CODE_START_LOCAL_NOALIGN(identity_mapped) |
|
UNWIND_HINT_EMPTY |
|
/* set return address to 0 if not preserving context */ |
|
pushq $0 |
|
/* store the start address on the stack */ |
|
pushq %rdx |
|
|
|
/* |
|
* Set cr0 to a known state: |
|
* - Paging enabled |
|
* - Alignment check disabled |
|
* - Write protect disabled |
|
* - No task switch |
|
* - Don't do FP software emulation. |
|
* - Protected mode enabled |
|
*/ |
|
movq %cr0, %rax |
|
andq $~(X86_CR0_AM | X86_CR0_WP | X86_CR0_TS | X86_CR0_EM), %rax |
|
orl $(X86_CR0_PG | X86_CR0_PE), %eax |
|
movq %rax, %cr0 |
|
|
|
/* |
|
* Set cr4 to a known state: |
|
* - physical address extension enabled |
|
* - 5-level paging, if it was enabled before |
|
*/ |
|
movl $X86_CR4_PAE, %eax |
|
testq $X86_CR4_LA57, %r13 |
|
jz 1f |
|
orl $X86_CR4_LA57, %eax |
|
1: |
|
movq %rax, %cr4 |
|
|
|
jmp 1f |
|
1: |
|
|
|
/* Flush the TLB (needed?) */ |
|
movq %r9, %cr3 |
|
|
|
/* |
|
* If SME is active, there could be old encrypted cache line |
|
* entries that will conflict with the now unencrypted memory |
|
* used by kexec. Flush the caches before copying the kernel. |
|
*/ |
|
testq %r12, %r12 |
|
jz 1f |
|
wbinvd |
|
1: |
|
|
|
movq %rcx, %r11 |
|
call swap_pages |
|
|
|
/* |
|
* To be certain of avoiding problems with self-modifying code |
|
* I need to execute a serializing instruction here. |
|
* So I flush the TLB by reloading %cr3 here, it's handy, |
|
* and not processor dependent. |
|
*/ |
|
movq %cr3, %rax |
|
movq %rax, %cr3 |
|
|
|
/* |
|
* set all of the registers to known values |
|
* leave %rsp alone |
|
*/ |
|
|
|
testq %r11, %r11 |
|
jnz 1f |
|
xorl %eax, %eax |
|
xorl %ebx, %ebx |
|
xorl %ecx, %ecx |
|
xorl %edx, %edx |
|
xorl %esi, %esi |
|
xorl %edi, %edi |
|
xorl %ebp, %ebp |
|
xorl %r8d, %r8d |
|
xorl %r9d, %r9d |
|
xorl %r10d, %r10d |
|
xorl %r11d, %r11d |
|
xorl %r12d, %r12d |
|
xorl %r13d, %r13d |
|
xorl %r14d, %r14d |
|
xorl %r15d, %r15d |
|
|
|
ret |
|
|
|
1: |
|
popq %rdx |
|
leaq PAGE_SIZE(%r10), %rsp |
|
ANNOTATE_RETPOLINE_SAFE |
|
call *%rdx |
|
|
|
/* get the re-entry point of the peer system */ |
|
movq 0(%rsp), %rbp |
|
leaq relocate_kernel(%rip), %r8 |
|
movq CP_PA_SWAP_PAGE(%r8), %r10 |
|
movq CP_PA_BACKUP_PAGES_MAP(%r8), %rdi |
|
movq CP_PA_TABLE_PAGE(%r8), %rax |
|
movq %rax, %cr3 |
|
lea PAGE_SIZE(%r8), %rsp |
|
call swap_pages |
|
movq $virtual_mapped, %rax |
|
pushq %rax |
|
ret |
|
SYM_CODE_END(identity_mapped) |
|
|
|
SYM_CODE_START_LOCAL_NOALIGN(virtual_mapped) |
|
UNWIND_HINT_EMPTY |
|
movq RSP(%r8), %rsp |
|
movq CR4(%r8), %rax |
|
movq %rax, %cr4 |
|
movq CR3(%r8), %rax |
|
movq CR0(%r8), %r8 |
|
movq %rax, %cr3 |
|
movq %r8, %cr0 |
|
movq %rbp, %rax |
|
|
|
popf |
|
popq %r15 |
|
popq %r14 |
|
popq %r13 |
|
popq %r12 |
|
popq %rbp |
|
popq %rbx |
|
ret |
|
SYM_CODE_END(virtual_mapped) |
|
|
|
/* Do the copies */ |
|
SYM_CODE_START_LOCAL_NOALIGN(swap_pages) |
|
UNWIND_HINT_EMPTY |
|
movq %rdi, %rcx /* Put the page_list in %rcx */ |
|
xorl %edi, %edi |
|
xorl %esi, %esi |
|
jmp 1f |
|
|
|
0: /* top, read another word for the indirection page */ |
|
|
|
movq (%rbx), %rcx |
|
addq $8, %rbx |
|
1: |
|
testb $0x1, %cl /* is it a destination page? */ |
|
jz 2f |
|
movq %rcx, %rdi |
|
andq $0xfffffffffffff000, %rdi |
|
jmp 0b |
|
2: |
|
testb $0x2, %cl /* is it an indirection page? */ |
|
jz 2f |
|
movq %rcx, %rbx |
|
andq $0xfffffffffffff000, %rbx |
|
jmp 0b |
|
2: |
|
testb $0x4, %cl /* is it the done indicator? */ |
|
jz 2f |
|
jmp 3f |
|
2: |
|
testb $0x8, %cl /* is it the source indicator? */ |
|
jz 0b /* Ignore it otherwise */ |
|
movq %rcx, %rsi /* For ever source page do a copy */ |
|
andq $0xfffffffffffff000, %rsi |
|
|
|
movq %rdi, %rdx |
|
movq %rsi, %rax |
|
|
|
movq %r10, %rdi |
|
movl $512, %ecx |
|
rep ; movsq |
|
|
|
movq %rax, %rdi |
|
movq %rdx, %rsi |
|
movl $512, %ecx |
|
rep ; movsq |
|
|
|
movq %rdx, %rdi |
|
movq %r10, %rsi |
|
movl $512, %ecx |
|
rep ; movsq |
|
|
|
lea PAGE_SIZE(%rax), %rsi |
|
jmp 0b |
|
3: |
|
ret |
|
SYM_CODE_END(swap_pages) |
|
|
|
.globl kexec_control_code_size |
|
.set kexec_control_code_size, . - relocate_kernel
|
|
|