linux/arch/arm64/kernel/relocate_kernel.S
Pasha Tatashin 19a046f07c arm64: kexec: use ld script for relocation function
Currently, relocation code declares start and end variables
which are used to compute its size.

The better way to do this is to use ld script, and put relocation
function in its own section.

Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210930143113.1502553-11-pasha.tatashin@soleen.com
Signed-off-by: Will Deacon <will@kernel.org>
2021-10-01 13:31:00 +01:00

81 lines
2.4 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* kexec for arm64
*
* Copyright (C) Linaro.
* Copyright (C) Huawei Futurewei Technologies.
*/
#include <linux/kexec.h>
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/kexec.h>
#include <asm/page.h>
#include <asm/sysreg.h>
#include <asm/virt.h>
.section ".kexec_relocate.text", "ax"
/*
* arm64_relocate_new_kernel - Put a 2nd stage image in place and boot it.
*
* The memory that the old kernel occupies may be overwritten when copying the
* new image to its final location. To assure that the
* arm64_relocate_new_kernel routine which does that copy is not overwritten,
* all code and data needed by arm64_relocate_new_kernel must be between the
* symbols arm64_relocate_new_kernel and arm64_relocate_new_kernel_end. The
* machine_kexec() routine will copy arm64_relocate_new_kernel to the kexec
* safe memory that has been set up to be preserved during the copy operation.
*/
SYM_CODE_START(arm64_relocate_new_kernel)
/* Setup the list loop variables. */
ldr x16, [x0, #KIMAGE_HEAD] /* x16 = kimage_head */
mov x14, xzr /* x14 = entry ptr */
mov x13, xzr /* x13 = copy dest */
raw_dcache_line_size x15, x1 /* x15 = dcache line size */
.Lloop:
and x12, x16, PAGE_MASK /* x12 = addr */
/* Test the entry flags. */
.Ltest_source:
tbz x16, IND_SOURCE_BIT, .Ltest_indirection
/* Invalidate dest page to PoC. */
mov x2, x13
add x1, x2, #PAGE_SIZE
dcache_by_myline_op ivac, sy, x2, x1, x15, x20
copy_page x13, x12, x1, x2, x3, x4, x5, x6, x7, x8
b .Lnext
.Ltest_indirection:
tbz x16, IND_INDIRECTION_BIT, .Ltest_destination
mov x14, x12 /* ptr = addr */
b .Lnext
.Ltest_destination:
tbz x16, IND_DESTINATION_BIT, .Lnext
mov x13, x12 /* dest = addr */
.Lnext:
ldr x16, [x14], #8 /* entry = *ptr++ */
tbz x16, IND_DONE_BIT, .Lloop /* while (!(entry & DONE)) */
/* wait for writes from copy_page to finish */
dsb nsh
ic iallu
dsb nsh
isb
/* Start new image. */
ldr x1, [x0, #KIMAGE_ARCH_EL2_VECTORS] /* relocation start */
cbz x1, .Lel1
ldr x1, [x0, #KIMAGE_START] /* relocation start */
ldr x2, [x0, #KIMAGE_ARCH_DTB_MEM] /* dtb address */
mov x3, xzr
mov x4, xzr
mov x0, #HVC_SOFT_RESTART
hvc #0 /* Jumps from el2 */
.Lel1:
ldr x4, [x0, #KIMAGE_START] /* relocation start */
ldr x0, [x0, #KIMAGE_ARCH_DTB_MEM] /* dtb address */
mov x2, xzr
mov x3, xzr
br x4 /* Jumps from el1 */
SYM_CODE_END(arm64_relocate_new_kernel)