diff options
Diffstat (limited to 'arch/loongarch/kernel/relocate_kernel.S')
| -rw-r--r-- | arch/loongarch/kernel/relocate_kernel.S | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/arch/loongarch/kernel/relocate_kernel.S b/arch/loongarch/kernel/relocate_kernel.S new file mode 100644 index 000000000000..f49f6b053763 --- /dev/null +++ b/arch/loongarch/kernel/relocate_kernel.S @@ -0,0 +1,111 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * relocate_kernel.S for kexec + * + * Copyright (C) 2022 Loongson Technology Corporation Limited + */ + +#include <linux/kexec.h> + +#include <asm/asm.h> +#include <asm/asmmacro.h> +#include <asm/regdef.h> +#include <asm/loongarch.h> +#include <asm/stackframe.h> +#include <asm/addrspace.h> + +SYM_CODE_START(relocate_new_kernel) + /* + * a0: EFI boot flag for the new kernel + * a1: Command line pointer for the new kernel + * a2: System table pointer for the new kernel + * a3: Start address to jump to after relocation + * a4: Pointer to the current indirection page entry + */ + move s0, a4 + + /* + * In case of a kdump/crash kernel, the indirection page is not + * populated as the kernel is directly copied to a reserved location + */ + beqz s0, done + +process_entry: + PTR_L s1, s0, 0 + PTR_ADDI s0, s0, SZREG + + /* destination page */ + andi s2, s1, IND_DESTINATION + beqz s2, 1f + li.w t0, ~0x1 + and s3, s1, t0 /* store destination addr in s3 */ + b process_entry + +1: + /* indirection page, update s0 */ + andi s2, s1, IND_INDIRECTION + beqz s2, 1f + li.w t0, ~0x2 + and s0, s1, t0 + b process_entry + +1: + /* done page */ + andi s2, s1, IND_DONE + beqz s2, 1f + b done + +1: + /* source page */ + andi s2, s1, IND_SOURCE + beqz s2, process_entry + li.w t0, ~0x8 + and s1, s1, t0 + li.w s5, (1 << _PAGE_SHIFT) / SZREG + +copy_word: + /* copy page word by word */ + REG_L s4, s1, 0 + REG_S s4, s3, 0 + PTR_ADDI s3, s3, SZREG + PTR_ADDI s1, s1, SZREG + LONG_ADDI s5, s5, -1 + beqz s5, process_entry + b copy_word + +done: + ibar 0 + dbar 0 + + /* + * Jump to the new kernel, + * make sure the values of a0, a1, a2 and a3 are not changed. + */ + jr a3 +SYM_CODE_END(relocate_new_kernel) + +#ifdef CONFIG_SMP +/* + * Other CPUs should wait until code is relocated and + * then start at the entry point from LOONGARCH_IOCSR_MBUF0. + */ +SYM_CODE_START(kexec_smp_wait) +1: li.w t0, 0x100 /* wait for init loop */ +2: addi.w t0, t0, -1 /* limit mailbox access */ + bnez t0, 2b + li.w t1, LOONGARCH_IOCSR_MBUF0 + iocsrrd.w s0, t1 /* check PC as an indicator */ + beqz s0, 1b + iocsrrd.d s0, t1 /* get PC via mailbox */ + + li.d t0, CACHE_BASE + or s0, s0, t0 /* s0 = TO_CACHE(s0) */ + jr s0 /* jump to initial PC */ +SYM_CODE_END(kexec_smp_wait) +#endif + +relocate_new_kernel_end: + +SYM_DATA_START(relocate_new_kernel_size) + PTR relocate_new_kernel_end - relocate_new_kernel +SYM_DATA_END(relocate_new_kernel_size) |