PageRenderTime 24ms CodeModel.GetById 16ms app.highlight 6ms RepoModel.GetById 0ms app.codeStats 0ms

/arch/alpha/boot/bootp.c

https://bitbucket.org/thekraven/iscream_thunderc-2.6.35
C | 215 lines | 119 code | 31 blank | 65 comment | 7 complexity | 85483bc1c3b11c281b7557f0979baebe MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
  1/*
  2 * arch/alpha/boot/bootp.c
  3 *
  4 * Copyright (C) 1997 Jay Estabrook
  5 *
  6 * This file is used for creating a bootp file for the Linux/AXP kernel
  7 *
  8 * based significantly on the arch/alpha/boot/main.c of Linus Torvalds
  9 */
 10#include <linux/kernel.h>
 11#include <linux/slab.h>
 12#include <linux/string.h>
 13#include <generated/utsrelease.h>
 14#include <linux/mm.h>
 15
 16#include <asm/system.h>
 17#include <asm/console.h>
 18#include <asm/hwrpb.h>
 19#include <asm/pgtable.h>
 20#include <asm/io.h>
 21
 22#include <stdarg.h>
 23
 24#include "ksize.h"
 25
 26extern unsigned long switch_to_osf_pal(unsigned long nr,
 27	struct pcb_struct * pcb_va, struct pcb_struct * pcb_pa,
 28	unsigned long *vptb);
 29
 30extern void move_stack(unsigned long new_stack);
 31
 32struct hwrpb_struct *hwrpb = INIT_HWRPB;
 33static struct pcb_struct pcb_va[1];
 34
 35/*
 36 * Find a physical address of a virtual object..
 37 *
 38 * This is easy using the virtual page table address.
 39 */
 40
 41static inline void *
 42find_pa(unsigned long *vptb, void *ptr)
 43{
 44	unsigned long address = (unsigned long) ptr;
 45	unsigned long result;
 46
 47	result = vptb[address >> 13];
 48	result >>= 32;
 49	result <<= 13;
 50	result |= address & 0x1fff;
 51	return (void *) result;
 52}	
 53
 54/*
 55 * This function moves into OSF/1 pal-code, and has a temporary
 56 * PCB for that. The kernel proper should replace this PCB with
 57 * the real one as soon as possible.
 58 *
 59 * The page table muckery in here depends on the fact that the boot
 60 * code has the L1 page table identity-map itself in the second PTE
 61 * in the L1 page table. Thus the L1-page is virtually addressable
 62 * itself (through three levels) at virtual address 0x200802000.
 63 */
 64
 65#define VPTB	((unsigned long *) 0x200000000)
 66#define L1	((unsigned long *) 0x200802000)
 67
 68void
 69pal_init(void)
 70{
 71	unsigned long i, rev;
 72	struct percpu_struct * percpu;
 73	struct pcb_struct * pcb_pa;
 74
 75	/* Create the dummy PCB.  */
 76	pcb_va->ksp = 0;
 77	pcb_va->usp = 0;
 78	pcb_va->ptbr = L1[1] >> 32;
 79	pcb_va->asn = 0;
 80	pcb_va->pcc = 0;
 81	pcb_va->unique = 0;
 82	pcb_va->flags = 1;
 83	pcb_va->res1 = 0;
 84	pcb_va->res2 = 0;
 85	pcb_pa = find_pa(VPTB, pcb_va);
 86
 87	/*
 88	 * a0 = 2 (OSF)
 89	 * a1 = return address, but we give the asm the vaddr of the PCB
 90	 * a2 = physical addr of PCB
 91	 * a3 = new virtual page table pointer
 92	 * a4 = KSP (but the asm sets it)
 93	 */
 94	srm_printk("Switching to OSF PAL-code .. ");
 95
 96	i = switch_to_osf_pal(2, pcb_va, pcb_pa, VPTB);
 97	if (i) {
 98		srm_printk("failed, code %ld\n", i);
 99		__halt();
100	}
101
102	percpu = (struct percpu_struct *)
103		(INIT_HWRPB->processor_offset + (unsigned long) INIT_HWRPB);
104	rev = percpu->pal_revision = percpu->palcode_avail[2];
105
106	srm_printk("Ok (rev %lx)\n", rev);
107
108	tbia(); /* do it directly in case we are SMP */
109}
110
111static inline void
112load(unsigned long dst, unsigned long src, unsigned long count)
113{
114	memcpy((void *)dst, (void *)src, count);
115}
116
117/*
118 * Start the kernel.
119 */
120static inline void
121runkernel(void)
122{
123	__asm__ __volatile__(
124		"bis %0,%0,$27\n\t"
125		"jmp ($27)"
126		: /* no outputs: it doesn't even return */
127		: "r" (START_ADDR));
128}
129
130extern char _end;
131#define KERNEL_ORIGIN \
132	((((unsigned long)&_end) + 511) & ~511)
133
134void
135start_kernel(void)
136{
137	/*
138	 * Note that this crufty stuff with static and envval
139	 * and envbuf is because:
140	 *
141	 * 1. Frequently, the stack is short, and we don't want to overrun;
142	 * 2. Frequently the stack is where we are going to copy the kernel to;
143	 * 3. A certain SRM console required the GET_ENV output to stack.
144	 *    ??? A comment in the aboot sources indicates that the GET_ENV
145	 *    destination must be quadword aligned.  Might this explain the
146	 *    behaviour, rather than requiring output to the stack, which
147	 *    seems rather far-fetched.
148	 */
149	static long nbytes;
150	static char envval[256] __attribute__((aligned(8)));
151	static unsigned long initrd_start;
152
153	srm_printk("Linux/AXP bootp loader for Linux " UTS_RELEASE "\n");
154	if (INIT_HWRPB->pagesize != 8192) {
155		srm_printk("Expected 8kB pages, got %ldkB\n",
156		           INIT_HWRPB->pagesize >> 10);
157		return;
158	}
159	if (INIT_HWRPB->vptb != (unsigned long) VPTB) {
160		srm_printk("Expected vptb at %p, got %p\n",
161			   VPTB, (void *)INIT_HWRPB->vptb);
162		return;
163	}
164	pal_init();
165
166	/* The initrd must be page-aligned.  See below for the 
167	   cause of the magic number 5.  */
168	initrd_start = ((START_ADDR + 5*KERNEL_SIZE + PAGE_SIZE) |
169			(PAGE_SIZE-1)) + 1;
170#ifdef INITRD_IMAGE_SIZE
171	srm_printk("Initrd positioned at %#lx\n", initrd_start);
172#endif
173
174	/*
175	 * Move the stack to a safe place to ensure it won't be
176	 * overwritten by kernel image.
177	 */
178	move_stack(initrd_start - PAGE_SIZE);
179
180	nbytes = callback_getenv(ENV_BOOTED_OSFLAGS, envval, sizeof(envval));
181	if (nbytes < 0 || nbytes >= sizeof(envval)) {
182		nbytes = 0;
183	}
184	envval[nbytes] = '\0';
185	srm_printk("Loading the kernel...'%s'\n", envval);
186
187	/* NOTE: *no* callbacks or printouts from here on out!!! */
188
189	/* This is a hack, as some consoles seem to get virtual 20000000 (ie
190	 * where the SRM console puts the kernel bootp image) memory
191	 * overlapping physical memory where the kernel wants to be put,
192	 * which causes real problems when attempting to copy the former to
193	 * the latter... :-(
194	 *
195	 * So, we first move the kernel virtual-to-physical way above where
196	 * we physically want the kernel to end up, then copy it from there
197	 * to its final resting place... ;-}
198	 *
199	 * Sigh...  */
200
201#ifdef INITRD_IMAGE_SIZE
202	load(initrd_start, KERNEL_ORIGIN+KERNEL_SIZE, INITRD_IMAGE_SIZE);
203#endif
204        load(START_ADDR+(4*KERNEL_SIZE), KERNEL_ORIGIN, KERNEL_SIZE);
205        load(START_ADDR, START_ADDR+(4*KERNEL_SIZE), KERNEL_SIZE);
206
207	memset((char*)ZERO_PGE, 0, PAGE_SIZE);
208	strcpy((char*)ZERO_PGE, envval);
209#ifdef INITRD_IMAGE_SIZE
210	((long *)(ZERO_PGE+256))[0] = initrd_start;
211	((long *)(ZERO_PGE+256))[1] = INITRD_IMAGE_SIZE;
212#endif
213
214	runkernel();
215}