powerpc/kernel/head_64.S

1 /* SPDX-License-Identifier: GPL-2.0-or-later */
4  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
9  *  Low-level exception handlers and MMU support
16  *  This file contains the entry point for the 64-bit kernel along
17  *  with some early initialization code common to all 64-bit powerpc
28 #include <asm/head-64.h>
29 #include <asm/asm-offsets.h>
42 #include <asm/ppc-opcode.h>
43 #include <asm/feature-fixups.h>
45 #include <asm/exception-64s.h>
47 #include <asm/exception-64e.h>
52  * using the layout described in exceptions-64s.S
61  *   3. If the RTAS supports "query-cpu-stopped-state", then secondary
62  *      CPUs will enter as directed by "start-cpu" RTAS call, which is
65  *      directed by the "start-cpu" RTS call, with PIR in r3.
66  * -or- For OPAL entry:
68  *   2. The primary CPU enters at 0 with device-tree in r3, OPAL base
103 	/* Secondary processors spin on this value until it becomes non-zero.
104 	 * When non-zero, it contains the real address of the function the cpu
121 	 * is used by kexec-tools to keep the kdump kernel in the
129 #define RUN_AT_LOAD_DEFAULT 0x72756e30  /* "run0" -- relocate to 0 by default */
132 	/* Do not move this variable as kexec-tools knows about it. */
170 100:	ld	r12,(ABS_ADDR(__secondary_hold_spinloop, first_256B))(0)
172 	beq	100b
204 #include "exceptions-64s.S"
290 	 * If the old value of BUCSR is non-zero, this thread has run
309 	/* turn on 64-bit mode */
336 	li	r2,-1
341 	/* turn on 64-bit mode */
390 	addi	r11,r11,(2f - 1b)
407 	ld	r8,0(r8)		/* Get base vaddr of array	 */
498 	cmpwi	r0,0x3c		/* 970FX */
521  *   r5 != NULL -> OF entry, we go to prom_init, "legacy" parameter content
524  *   r5 == NULL -> kexec style entry. r3 is a physical pointer to the
536 	li	r2,-1
539 	 * Are we booted from a PROM Of-type client-interface ?
543 	b	__boot_from_prom		/* yes -> prom */
569 	/* OPAL doesn't pass base address in r4, have to derive it. */
572 	addis	r26,r26,(_stext - 0b)@ha
573 	addi	r26,r26,(_stext - 0b)@l	/* current runtime base addr */
580 	/* Get TOC pointer, non-virtual */
586 	addis	r26,r26,(_stext - 0b)@ha
587 	addi	r26,r26,(_stext - 0b)@l	/* current runtime base addr */
597 	 * Align the stack to 16-byte boundary
631 	mr	r25,r26		/* then use current kernel base */
633 	LOAD_REG_IMMEDIATE(r25, PAGE_OFFSET) /* else use static kernel base */
691 p_end: .8byte _end - copy_to_here
696 	 * _end - copy_to_here to the copy limit and run again.
714 	addi	r5,r5,-8
715 	addi	r6,r6,-8
768 	/* turn on 64-bit mode */
783 	addi	r11,r11,(2f - 1b)
800 	ld	r4,0(r4)		/* Get base vaddr of paca_ptrs array */
879  * zero the stack back-chain pointer and get the TOC virtual address
921  * are running at the moment, using position-independent code.
924  * TOC in -mcmodel=medium mode. After we relocate to 0 but before
933 	tdnei	r2,-1
939 	ld	r2,(p_toc - 0b)(r11)
945 p_toc:	.8byte	.TOC. - 0b
959 	 * to clear it now for kexec-style entry.
967 	addi	r8,r8,-8
999 	stdu	r0,-STACK_FRAME_MIN_SIZE(r1)