1// SPDX-License-Identifier: GPL-2.0
2/*
3 * arch/alpha/boot/main.c
4 *
5 * Copyright (C) 1994, 1995 Linus Torvalds
6 *
7 * This file is the bootloader for the Linux/AXP kernel
8 */
9#include <linux/kernel.h>
10#include <linux/slab.h>
11#include <linux/string.h>
12#include <generated/utsrelease.h>
13#include <linux/mm.h>
14
15#include <asm/console.h>
16#include <asm/hwrpb.h>
17
18#include <linux/stdarg.h>
19
20#include "ksize.h"
21
22extern unsigned long switch_to_osf_pal(unsigned long nr,
23	struct pcb_struct * pcb_va, struct pcb_struct * pcb_pa,
24	unsigned long *vptb);
25struct hwrpb_struct *hwrpb = INIT_HWRPB;
26static struct pcb_struct pcb_va[1];
27
28/*
29 * Find a physical address of a virtual object..
30 *
31 * This is easy using the virtual page table address.
32 */
33
34static inline void *
35find_pa(unsigned long *vptb, void *ptr)
36{
37	unsigned long address = (unsigned long) ptr;
38	unsigned long result;
39
40	result = vptb[address >> 13];
41	result >>= 32;
42	result <<= 13;
43	result |= address & 0x1fff;
44	return (void *) result;
45}
46
47/*
48 * This function moves into OSF/1 pal-code, and has a temporary
49 * PCB for that. The kernel proper should replace this PCB with
50 * the real one as soon as possible.
51 *
52 * The page table muckery in here depends on the fact that the boot
53 * code has the L1 page table identity-map itself in the second PTE
54 * in the L1 page table. Thus the L1-page is virtually addressable
55 * itself (through three levels) at virtual address 0x200802000.
56 */
57
58#define VPTB	((unsigned long *) 0x200000000)
59#define L1	((unsigned long *) 0x200802000)
60
61void
62pal_init(void)
63{
64	unsigned long i, rev;
65	struct percpu_struct * percpu;
66	struct pcb_struct * pcb_pa;
67
68	/* Create the dummy PCB.  */
69	pcb_va->ksp = 0;
70	pcb_va->usp = 0;
71	pcb_va->ptbr = L1[1] >> 32;
72	pcb_va->asn = 0;
73	pcb_va->pcc = 0;
74	pcb_va->unique = 0;
75	pcb_va->flags = 1;
76	pcb_va->res1 = 0;
77	pcb_va->res2 = 0;
78	pcb_pa = find_pa(VPTB, pcb_va);
79
80	/*
81	 * a0 = 2 (OSF)
82	 * a1 = return address, but we give the asm the vaddr of the PCB
83	 * a2 = physical addr of PCB
84	 * a3 = new virtual page table pointer
85	 * a4 = KSP (but the asm sets it)
86	 */
87	srm_printk("Switching to OSF PAL-code .. ");
88
89	i = switch_to_osf_pal(2, pcb_va, pcb_pa, VPTB);
90	if (i) {
91		srm_printk("failed, code %ld\n", i);
92		__halt();
93	}
94
95	percpu = (struct percpu_struct *)
96		(INIT_HWRPB->processor_offset + (unsigned long) INIT_HWRPB);
97	rev = percpu->pal_revision = percpu->palcode_avail[2];
98
99	srm_printk("Ok (rev %lx)\n", rev);
100
101	tbia(); /* do it directly in case we are SMP */
102}
103
104static inline long openboot(void)
105{
106	char bootdev[256];
107	long result;
108
109	result = callback_getenv(ENV_BOOTED_DEV, bootdev, 255);
110	if (result < 0)
111		return result;
112	return callback_open(bootdev, result & 255);
113}
114
115static inline long close(long dev)
116{
117	return callback_close(dev);
118}
119
120static inline long load(long dev, unsigned long addr, unsigned long count)
121{
122	char bootfile[256];
123	extern char _end;
124	long result, boot_size = &_end - (char *) BOOT_ADDR;
125
126	result = callback_getenv(ENV_BOOTED_FILE, bootfile, 255);
127	if (result < 0)
128		return result;
129	result &= 255;
130	bootfile[result] = '\0';
131	if (result)
132		srm_printk("Boot file specification (%s) not implemented\n",
133		       bootfile);
134	return callback_read(dev, count, (void *)addr, boot_size/512 + 1);
135}
136
137/*
138 * Start the kernel.
139 */
140static void runkernel(void)
141{
142	__asm__ __volatile__(
143		"bis %1,%1,$30\n\t"
144		"bis %0,%0,$26\n\t"
145		"ret ($26)"
146		: /* no outputs: it doesn't even return */
147		: "r" (START_ADDR),
148		  "r" (PAGE_SIZE + INIT_STACK));
149}
150
151void start_kernel(void)
152{
153	long i;
154	long dev;
155	int nbytes;
156	char envval[256];
157
158	srm_printk("Linux/AXP bootloader for Linux " UTS_RELEASE "\n");
159	if (INIT_HWRPB->pagesize != 8192) {
160		srm_printk("Expected 8kB pages, got %ldkB\n", INIT_HWRPB->pagesize >> 10);
161		return;
162	}
163	pal_init();
164	dev = openboot();
165	if (dev < 0) {
166		srm_printk("Unable to open boot device: %016lx\n", dev);
167		return;
168	}
169	dev &= 0xffffffff;
170	srm_printk("Loading vmlinux ...");
171	i = load(dev, START_ADDR, KERNEL_SIZE);
172	close(dev);
173	if (i != KERNEL_SIZE) {
174		srm_printk("Failed (%lx)\n", i);
175		return;
176	}
177
178	nbytes = callback_getenv(ENV_BOOTED_OSFLAGS, envval, sizeof(envval));
179	if (nbytes < 0) {
180		nbytes = 0;
181	}
182	envval[nbytes] = '\0';
183	strcpy((char*)ZERO_PGE, envval);
184
185	srm_printk(" Ok\nNow booting the kernel\n");
186	runkernel();
187	for (i = 0 ; i < 0x100000000 ; i++)
188		/* nothing */;
189	__halt();
190}
191