1/* SPDX-License-Identifier: GPL-2.0 */ 2/* 3 * relocate_kernel.S for kexec 4 * 5 * Copyright (C) 2022 Loongson Technology Corporation Limited 6 */ 7 8#include <linux/kexec.h> 9 10#include <asm/asm.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> 16 17SYM_CODE_START(relocate_new_kernel) 18 /* 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 24 */ 25 move s0, a4 26 27 /* 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 30 */ 31 beqz s0, done 32 33process_entry: 34 PTR_L s1, s0, 0 35 PTR_ADDI s0, s0, SZREG 36 37 /* destination page */ 38 andi s2, s1, IND_DESTINATION 39 beqz s2, 1f 40 li.w t0, ~0x1 41 and s3, s1, t0 /* store destination addr in s3 */ 42 b process_entry 43 441: 45 /* indirection page, update s0 */ 46 andi s2, s1, IND_INDIRECTION 47 beqz s2, 1f 48 li.w t0, ~0x2 49 and s0, s1, t0 50 b process_entry 51 521: 53 /* done page */ 54 andi s2, s1, IND_DONE 55 beqz s2, 1f 56 b done 57 581: 59 /* source page */ 60 andi s2, s1, IND_SOURCE 61 beqz s2, process_entry 62 li.w t0, ~0x8 63 and s1, s1, t0 64 li.w s5, (1 << _PAGE_SHIFT) / SZREG 65 66copy_word: 67 /* copy page word by word */ 68 REG_L s4, s1, 0 69 REG_S s4, s3, 0 70 PTR_ADDI s3, s3, SZREG 71 PTR_ADDI s1, s1, SZREG 72 LONG_ADDI s5, s5, -1 73 beqz s5, process_entry 74 b copy_word 75 b process_entry 76 77done: 78 ibar 0 79 dbar 0 80 81 /* 82 * Jump to the new kernel, 83 * make sure the values of a0, a1, a2 and a3 are not changed. 84 */ 85 jr a3 86SYM_CODE_END(relocate_new_kernel) 87 88#ifdef CONFIG_SMP 89/* 90 * Other CPUs should wait until code is relocated and 91 * then start at the entry point from LOONGARCH_IOCSR_MBUF0. 92 */ 93SYM_CODE_START(kexec_smp_wait) 941: li.w t0, 0x100 /* wait for init loop */ 952: addi.w t0, t0, -1 /* limit mailbox access */ 96 bnez t0, 2b 97 li.w t1, LOONGARCH_IOCSR_MBUF0 98 iocsrrd.w s0, t1 /* check PC as an indicator */ 99 beqz s0, 1b 100 iocsrrd.d s0, t1 /* get PC via mailbox */ 101 102 li.d t0, CACHE_BASE 103 or s0, s0, t0 /* s0 = TO_CACHE(s0) */ 104 jr s0 /* jump to initial PC */ 105SYM_CODE_END(kexec_smp_wait) 106#endif 107 108relocate_new_kernel_end: 109 110SYM_DATA_START(relocate_new_kernel_size) 111 PTR relocate_new_kernel_end - relocate_new_kernel 112SYM_DATA_END(relocate_new_kernel_size) 113