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>
51  * spin code sits at 0x0000...0x00ff. On server, the vectors follow
52  * using the layout described in exceptions-64s.S
60  *   2. The primary CPU enters at __start.
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
112 	/* Secondary processors write this value with their 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. */
158 	/* Grab our physical cpu number */
163 	/* Tell the master cpu we're here */
199  * On server, we include the exception vectors code here as it
204 #include "exceptions-64s.S"
215  * The booting_thread_hwid holds the thread id we want to boot in cpu
216  * hotplug case. It is set by cpu hotplug code, and is invalid by default.
287 	 * but the low bit right by two bits so that the cpu numbering is
290 	 * If the old value of BUCSR is non-zero, this thread has run
309 	/* turn on 64-bit mode */
324  * At entry, r3 = this processor's number (physical cpu id)
336 	li	r2,-1
341 	/* turn on 64-bit mode */
390 	addi	r11,r11,(2f - 1b)
400 	 * physical cpu id in r24, we need to search the pacas to find
414 	li	r5,0			/* logical cpu id                */
416 	sldi	r9,r5,3			/* get paca_ptrs[] index from cpu id */
417 	ldx	r13,r9,r8		/* r13 = paca_ptrs[cpu id]       */
441 	/* See if we need to call a cpu state restore handler */
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 */
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
645  * real memory, which are reserved for software use.
647  * Note: This process overwrites the OF exception vectors.
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)
790 	/* Copy some CPU settings from CPU 0 */
801 	sldi	r5,r24,3		/* get paca_ptrs[] index from cpu id */
802 	ldx	r13,r5,r4		/* r13 = paca_ptrs[cpu id]       */
822  * This function is called after the master CPU has released the
830  *   r24       = cpu# (in Linux terms)
843 	 * Do early setup for this CPU, in particular initialising the MMU so we
879  * zero the stack back-chain pointer and get the TOC virtual address
891  * from cede in cpu offline.
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)