1 /* SPDX-License-Identifier: GPL-2.0 */
3 * relocate_kernel.S for kexec
5 * Copyright (C) 2022 Loongson Technology Corporation Limited
8 #include <linux/kexec.h>
11 #include <asm/asmmacro.h>
12 #include <asm/regdef.h>
13 #include <asm/loongarch.h>
14 #include <asm/stackframe.h>
15 #include <asm/addrspace.h>
17 SYM_CODE_START(relocate_new_kernel)
19 * a0: EFI boot flag for the new kernel
20 * a1: Command line pointer for the new kernel
21 * a2: System table pointer for the new kernel
22 * a3: Start address to jump to after relocation
23 * a4: Pointer to the current indirection page entry
28 * In case of a kdump/crash kernel, the indirection page is not
29 * populated as the kernel is directly copied to a reserved location
35 PTR_ADDI s0, s0, SZREG
37 /* destination page */
38 andi s2, s1, IND_DESTINATION
41 and s3, s1, t0 /* store destination addr in s3 */
45 /* indirection page, update s0 */
46 andi s2, s1, IND_INDIRECTION
60 andi s2, s1, IND_SOURCE
61 beqz s2, process_entry
64 li.w s5, (1 << _PAGE_SHIFT) / SZREG
67 /* copy page word by word */
70 PTR_ADDI s3, s3, SZREG
71 PTR_ADDI s1, s1, SZREG
73 beqz s5, process_entry
81 * Jump to the new kernel,
82 * make sure the values of a0, a1, a2 and a3 are not changed.
85 SYM_CODE_END(relocate_new_kernel)
89 * Other CPUs should wait until code is relocated and
90 * then start at the entry point from LOONGARCH_IOCSR_MBUF0.
92 SYM_CODE_START(kexec_smp_wait)
93 1: li.w t0, 0x100 /* wait for init loop */
94 2: addi.w t0, t0, -1 /* limit mailbox access */
96 li.w t1, LOONGARCH_IOCSR_MBUF0
97 iocsrrd.w s0, t1 /* check PC as an indicator */
99 iocsrrd.d s0, t1 /* get PC via mailbox */
102 or s0, s0, t0 /* s0 = TO_CACHE(s0) */
103 jr s0 /* jump to initial PC */
104 SYM_CODE_END(kexec_smp_wait)
107 relocate_new_kernel_end:
109 SYM_DATA_START(relocate_new_kernel_size)
110 PTR relocate_new_kernel_end - relocate_new_kernel
111 SYM_DATA_END(relocate_new_kernel_size)