1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * arch/alpha/boot/bootp.c 4 * 5 * Copyright (C) 1997 Jay Estabrook 6 * 7 * This file is used for creating a bootp file for the Linux/AXP kernel 8 * 9 * based significantly on the arch/alpha/boot/main.c of Linus Torvalds 10 */ 11 #include <linux/kernel.h> 12 #include <linux/slab.h> 13 #include <linux/string.h> 14 #include <generated/utsrelease.h> 15 #include <linux/mm.h> 16 17 #include <asm/console.h> 18 #include <asm/hwrpb.h> 19 #include <asm/io.h> 20 21 #include <linux/stdarg.h> 22 23 #include "ksize.h" 24 25 extern unsigned long switch_to_osf_pal(unsigned long nr, 26 struct pcb_struct *pcb_va, struct pcb_struct *pcb_pa, 27 unsigned long *vptb); 28 29 extern void move_stack(unsigned long new_stack); 30 31 struct hwrpb_struct *hwrpb = INIT_HWRPB; 32 static struct pcb_struct pcb_va[1]; 33 34 /* 35 * Find a physical address of a virtual object.. 36 * 37 * This is easy using the virtual page table address. 38 */ 39 40 static inline void * 41 find_pa(unsigned long *vptb, void *ptr) 42 { 43 unsigned long address = (unsigned long) ptr; 44 unsigned long result; 45 46 result = vptb[address >> 13]; 47 result >>= 32; 48 result <<= 13; 49 result |= address & 0x1fff; 50 return (void *) result; 51 } 52 53 /* 54 * This function moves into OSF/1 pal-code, and has a temporary 55 * PCB for that. The kernel proper should replace this PCB with 56 * the real one as soon as possible. 57 * 58 * The page table muckery in here depends on the fact that the boot 59 * code has the L1 page table identity-map itself in the second PTE 60 * in the L1 page table. Thus the L1-page is virtually addressable 61 * itself (through three levels) at virtual address 0x200802000. 62 */ 63 64 #define VPTB ((unsigned long *) 0x200000000) 65 #define L1 ((unsigned long *) 0x200802000) 66 67 void 68 pal_init(void) 69 { 70 unsigned long i, rev; 71 struct percpu_struct * percpu; 72 struct pcb_struct * pcb_pa; 73 74 /* Create the dummy PCB. */ 75 pcb_va->ksp = 0; 76 pcb_va->usp = 0; 77 pcb_va->ptbr = L1[1] >> 32; 78 pcb_va->asn = 0; 79 pcb_va->pcc = 0; 80 pcb_va->unique = 0; 81 pcb_va->flags = 1; 82 pcb_va->res1 = 0; 83 pcb_va->res2 = 0; 84 pcb_pa = find_pa(VPTB, pcb_va); 85 86 /* 87 * a0 = 2 (OSF) 88 * a1 = return address, but we give the asm the vaddr of the PCB 89 * a2 = physical addr of PCB 90 * a3 = new virtual page table pointer 91 * a4 = KSP (but the asm sets it) 92 */ 93 srm_printk("Switching to OSF PAL-code .. "); 94 95 i = switch_to_osf_pal(2, pcb_va, pcb_pa, VPTB); 96 if (i) { 97 srm_printk("failed, code %ld\n", i); 98 __halt(); 99 } 100 101 percpu = (struct percpu_struct *) 102 (INIT_HWRPB->processor_offset + (unsigned long) INIT_HWRPB); 103 rev = percpu->pal_revision = percpu->palcode_avail[2]; 104 105 srm_printk("Ok (rev %lx)\n", rev); 106 107 tbia(); /* do it directly in case we are SMP */ 108 } 109 110 static inline void 111 load(unsigned long dst, unsigned long src, unsigned long count) 112 { 113 memcpy((void *)dst, (void *)src, count); 114 } 115 116 /* 117 * Start the kernel. 118 */ 119 static inline void 120 runkernel(void) 121 { 122 __asm__ __volatile__( 123 "bis %0,%0,$27\n\t" 124 "jmp ($27)" 125 : /* no outputs: it doesn't even return */ 126 : "r" (START_ADDR)); 127 } 128 129 extern char _end; 130 #define KERNEL_ORIGIN \ 131 ((((unsigned long)&_end) + 511) & ~511) 132 133 void 134 start_kernel(void) 135 { 136 /* 137 * Note that this crufty stuff with static and envval 138 * and envbuf is because: 139 * 140 * 1. Frequently, the stack is short, and we don't want to overrun; 141 * 2. Frequently the stack is where we are going to copy the kernel to; 142 * 3. A certain SRM console required the GET_ENV output to stack. 143 * ??? A comment in the aboot sources indicates that the GET_ENV 144 * destination must be quadword aligned. Might this explain the 145 * behaviour, rather than requiring output to the stack, which 146 * seems rather far-fetched. 147 */ 148 static long nbytes; 149 static char envval[256] __attribute__((aligned(8))); 150 static unsigned long initrd_start; 151 152 srm_printk("Linux/AXP bootp loader for Linux " UTS_RELEASE "\n"); 153 if (INIT_HWRPB->pagesize != 8192) { 154 srm_printk("Expected 8kB pages, got %ldkB\n", 155 INIT_HWRPB->pagesize >> 10); 156 return; 157 } 158 if (INIT_HWRPB->vptb != (unsigned long) VPTB) { 159 srm_printk("Expected vptb at %p, got %p\n", 160 VPTB, (void *)INIT_HWRPB->vptb); 161 return; 162 } 163 pal_init(); 164 165 /* The initrd must be page-aligned. See below for the 166 cause of the magic number 5. */ 167 initrd_start = ((START_ADDR + 5*KERNEL_SIZE + PAGE_SIZE) | 168 (PAGE_SIZE-1)) + 1; 169 #ifdef INITRD_IMAGE_SIZE 170 srm_printk("Initrd positioned at %#lx\n", initrd_start); 171 #endif 172 173 /* 174 * Move the stack to a safe place to ensure it won't be 175 * overwritten by kernel image. 176 */ 177 move_stack(initrd_start - PAGE_SIZE); 178 179 nbytes = callback_getenv(ENV_BOOTED_OSFLAGS, envval, sizeof(envval)); 180 if (nbytes < 0 || nbytes >= sizeof(envval)) { 181 nbytes = 0; 182 } 183 envval[nbytes] = '\0'; 184 srm_printk("Loading the kernel...'%s'\n", envval); 185 186 /* NOTE: *no* callbacks or printouts from here on out!!! */ 187 188 /* This is a hack, as some consoles seem to get virtual 20000000 (ie 189 * where the SRM console puts the kernel bootp image) memory 190 * overlapping physical memory where the kernel wants to be put, 191 * which causes real problems when attempting to copy the former to 192 * the latter... :-( 193 * 194 * So, we first move the kernel virtual-to-physical way above where 195 * we physically want the kernel to end up, then copy it from there 196 * to its final resting place... ;-} 197 * 198 * Sigh... */ 199 200 #ifdef INITRD_IMAGE_SIZE 201 load(initrd_start, KERNEL_ORIGIN+KERNEL_SIZE, INITRD_IMAGE_SIZE); 202 #endif 203 load(START_ADDR+(4*KERNEL_SIZE), KERNEL_ORIGIN, KERNEL_SIZE); 204 load(START_ADDR, START_ADDR+(4*KERNEL_SIZE), KERNEL_SIZE); 205 206 memset((char*)ZERO_PGE, 0, PAGE_SIZE); 207 strcpy((char*)ZERO_PGE, envval); 208 #ifdef INITRD_IMAGE_SIZE 209 ((long *)(ZERO_PGE+256))[0] = initrd_start; 210 ((long *)(ZERO_PGE+256))[1] = INITRD_IMAGE_SIZE; 211 #endif 212 213 runkernel(); 214 } 215