/* 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)	UNWIND_HINT_UNDEFINED	/*	 * 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		a3SYM_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)	UNWIND_HINT_UNDEFINED1:	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: 	.section ".data"SYM_DATA(relocate_new_kernel_size, .quad relocate_new_kernel_end - relocate_new_kernel)