1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * arch/alpha/boot/bootpz.c
4 *
5 * Copyright (C) 1997 Jay Estabrook
6 *
7 * This file is used for creating a compressed BOOTP file for the
8 * Linux/AXP kernel
9 *
10 * based significantly on the arch/alpha/boot/main.c of Linus Torvalds
11 * and the decompression code from MILO.
12 */
13 #include <linux/kernel.h>
14 #include <linux/slab.h>
15 #include <linux/string.h>
16 #include <generated/utsrelease.h>
17 #include <linux/mm.h>
18
19 #include <asm/console.h>
20 #include <asm/hwrpb.h>
21 #include <asm/io.h>
22
23 #include <stdarg.h>
24
25 #include "kzsize.h"
26
27 /* FIXME FIXME FIXME */
28 #define MALLOC_AREA_SIZE 0x200000 /* 2MB for now */
29 /* FIXME FIXME FIXME */
30
31
32 /*
33 WARNING NOTE
34
35 It is very possible that turning on additional messages may cause
36 kernel image corruption due to stack usage to do the printing.
37
38 */
39
40 #undef DEBUG_CHECK_RANGE
41 #undef DEBUG_ADDRESSES
42 #undef DEBUG_LAST_STEPS
43
44 extern unsigned long switch_to_osf_pal(unsigned long nr,
45 struct pcb_struct * pcb_va, struct pcb_struct * pcb_pa,
46 unsigned long *vptb);
47
48 extern int decompress_kernel(void* destination, void *source,
49 size_t ksize, size_t kzsize);
50
51 extern void move_stack(unsigned long new_stack);
52
53 struct hwrpb_struct *hwrpb = INIT_HWRPB;
54 static struct pcb_struct pcb_va[1];
55
56 /*
57 * Find a physical address of a virtual object..
58 *
59 * This is easy using the virtual page table address.
60 */
61 #define VPTB ((unsigned long *) 0x200000000)
62
63 static inline unsigned long
find_pa(unsigned long address)64 find_pa(unsigned long address)
65 {
66 unsigned long result;
67
68 result = VPTB[address >> 13];
69 result >>= 32;
70 result <<= 13;
71 result |= address & 0x1fff;
72 return result;
73 }
74
75 int
check_range(unsigned long vstart,unsigned long vend,unsigned long kstart,unsigned long kend)76 check_range(unsigned long vstart, unsigned long vend,
77 unsigned long kstart, unsigned long kend)
78 {
79 unsigned long vaddr, kaddr;
80
81 #ifdef DEBUG_CHECK_RANGE
82 srm_printk("check_range: V[0x%lx:0x%lx] K[0x%lx:0x%lx]\n",
83 vstart, vend, kstart, kend);
84 #endif
85 /* do some range checking for detecting an overlap... */
86 for (vaddr = vstart; vaddr <= vend; vaddr += PAGE_SIZE)
87 {
88 kaddr = (find_pa(vaddr) | PAGE_OFFSET);
89 if (kaddr >= kstart && kaddr <= kend)
90 {
91 #ifdef DEBUG_CHECK_RANGE
92 srm_printk("OVERLAP: vaddr 0x%lx kaddr 0x%lx"
93 " [0x%lx:0x%lx]\n",
94 vaddr, kaddr, kstart, kend);
95 #endif
96 return 1;
97 }
98 }
99 return 0;
100 }
101
102 /*
103 * This function moves into OSF/1 pal-code, and has a temporary
104 * PCB for that. The kernel proper should replace this PCB with
105 * the real one as soon as possible.
106 *
107 * The page table muckery in here depends on the fact that the boot
108 * code has the L1 page table identity-map itself in the second PTE
109 * in the L1 page table. Thus the L1-page is virtually addressable
110 * itself (through three levels) at virtual address 0x200802000.
111 */
112
113 #define L1 ((unsigned long *) 0x200802000)
114
115 void
pal_init(void)116 pal_init(void)
117 {
118 unsigned long i, rev;
119 struct percpu_struct * percpu;
120 struct pcb_struct * pcb_pa;
121
122 /* Create the dummy PCB. */
123 pcb_va->ksp = 0;
124 pcb_va->usp = 0;
125 pcb_va->ptbr = L1[1] >> 32;
126 pcb_va->asn = 0;
127 pcb_va->pcc = 0;
128 pcb_va->unique = 0;
129 pcb_va->flags = 1;
130 pcb_va->res1 = 0;
131 pcb_va->res2 = 0;
132 pcb_pa = (struct pcb_struct *)find_pa((unsigned long)pcb_va);
133
134 /*
135 * a0 = 2 (OSF)
136 * a1 = return address, but we give the asm the vaddr of the PCB
137 * a2 = physical addr of PCB
138 * a3 = new virtual page table pointer
139 * a4 = KSP (but the asm sets it)
140 */
141 srm_printk("Switching to OSF PAL-code... ");
142
143 i = switch_to_osf_pal(2, pcb_va, pcb_pa, VPTB);
144 if (i) {
145 srm_printk("failed, code %ld\n", i);
146 __halt();
147 }
148
149 percpu = (struct percpu_struct *)
150 (INIT_HWRPB->processor_offset + (unsigned long) INIT_HWRPB);
151 rev = percpu->pal_revision = percpu->palcode_avail[2];
152
153 srm_printk("OK (rev %lx)\n", rev);
154
155 tbia(); /* do it directly in case we are SMP */
156 }
157
158 /*
159 * Start the kernel.
160 */
161 static inline void
runkernel(void)162 runkernel(void)
163 {
164 __asm__ __volatile__(
165 "bis %0,%0,$27\n\t"
166 "jmp ($27)"
167 : /* no outputs: it doesn't even return */
168 : "r" (START_ADDR));
169 }
170
171 /* Must record the SP (it is virtual) on entry, so we can make sure
172 not to overwrite it during movement or decompression. */
173 unsigned long SP_on_entry;
174
175 /* Calculate the kernel image address based on the end of the BOOTP
176 bootstrapper (ie this program).
177 */
178 extern char _end;
179 #define KERNEL_ORIGIN \
180 ((((unsigned long)&_end) + 511) & ~511)
181
182 /* Round address to next higher page boundary. */
183 #define NEXT_PAGE(a) (((a) | (PAGE_SIZE - 1)) + 1)
184
185 #ifdef INITRD_IMAGE_SIZE
186 # define REAL_INITRD_SIZE INITRD_IMAGE_SIZE
187 #else
188 # define REAL_INITRD_SIZE 0
189 #endif
190
191 /* Defines from include/asm-alpha/system.h
192
193 BOOT_ADDR Virtual address at which the consoles loads
194 the BOOTP image.
195
196 KERNEL_START KSEG address at which the kernel is built to run,
197 which includes some initial data pages before the
198 code.
199
200 START_ADDR KSEG address of the entry point of kernel code.
201
202 ZERO_PGE KSEG address of page full of zeroes, but
203 upon entry to kerne cvan be expected
204 to hold the parameter list and possible
205 INTRD information.
206
207 These are used in the local defines below.
208 */
209
210
211 /* Virtual addresses for the BOOTP image. Note that this includes the
212 bootstrapper code as well as the compressed kernel image, and
213 possibly the INITRD image.
214
215 Oh, and do NOT forget the STACK, which appears to be placed virtually
216 beyond the end of the loaded image.
217 */
218 #define V_BOOT_IMAGE_START BOOT_ADDR
219 #define V_BOOT_IMAGE_END SP_on_entry
220
221 /* Virtual addresses for just the bootstrapper part of the BOOTP image. */
222 #define V_BOOTSTRAPPER_START BOOT_ADDR
223 #define V_BOOTSTRAPPER_END KERNEL_ORIGIN
224
225 /* Virtual addresses for just the data part of the BOOTP
226 image. This may also include the INITRD image, but always
227 includes the STACK.
228 */
229 #define V_DATA_START KERNEL_ORIGIN
230 #define V_INITRD_START (KERNEL_ORIGIN + KERNEL_Z_SIZE)
231 #define V_INTRD_END (V_INITRD_START + REAL_INITRD_SIZE)
232 #define V_DATA_END V_BOOT_IMAGE_END
233
234 /* KSEG addresses for the uncompressed kernel.
235
236 Note that the end address includes workspace for the decompression.
237 Note also that the DATA_START address is ZERO_PGE, to which we write
238 just before jumping to the kernel image at START_ADDR.
239 */
240 #define K_KERNEL_DATA_START ZERO_PGE
241 #define K_KERNEL_IMAGE_START START_ADDR
242 #define K_KERNEL_IMAGE_END (START_ADDR + KERNEL_SIZE)
243
244 /* Define to where we may have to decompress the kernel image, before
245 we move it to the final position, in case of overlap. This will be
246 above the final position of the kernel.
247
248 Regardless of overlap, we move the INITRD image to the end of this
249 copy area, because there needs to be a buffer area after the kernel
250 for "bootmem" anyway.
251 */
252 #define K_COPY_IMAGE_START NEXT_PAGE(K_KERNEL_IMAGE_END)
253 /* Reserve one page below INITRD for the new stack. */
254 #define K_INITRD_START \
255 NEXT_PAGE(K_COPY_IMAGE_START + KERNEL_SIZE + PAGE_SIZE)
256 #define K_COPY_IMAGE_END \
257 (K_INITRD_START + REAL_INITRD_SIZE + MALLOC_AREA_SIZE)
258 #define K_COPY_IMAGE_SIZE \
259 NEXT_PAGE(K_COPY_IMAGE_END - K_COPY_IMAGE_START)
260
261 void
start_kernel(void)262 start_kernel(void)
263 {
264 int must_move = 0;
265
266 /* Initialize these for the decompression-in-place situation,
267 which is the smallest amount of work and most likely to
268 occur when using the normal START_ADDR of the kernel
269 (currently set to 16MB, to clear all console code.
270 */
271 unsigned long uncompressed_image_start = K_KERNEL_IMAGE_START;
272 unsigned long uncompressed_image_end = K_KERNEL_IMAGE_END;
273
274 unsigned long initrd_image_start = K_INITRD_START;
275
276 /*
277 * Note that this crufty stuff with static and envval
278 * and envbuf is because:
279 *
280 * 1. Frequently, the stack is short, and we don't want to overrun;
281 * 2. Frequently the stack is where we are going to copy the kernel to;
282 * 3. A certain SRM console required the GET_ENV output to stack.
283 * ??? A comment in the aboot sources indicates that the GET_ENV
284 * destination must be quadword aligned. Might this explain the
285 * behaviour, rather than requiring output to the stack, which
286 * seems rather far-fetched.
287 */
288 static long nbytes;
289 static char envval[256] __attribute__((aligned(8)));
290 register unsigned long asm_sp asm("30");
291
292 SP_on_entry = asm_sp;
293
294 srm_printk("Linux/Alpha BOOTPZ Loader for Linux " UTS_RELEASE "\n");
295
296 /* Validity check the HWRPB. */
297 if (INIT_HWRPB->pagesize != 8192) {
298 srm_printk("Expected 8kB pages, got %ldkB\n",
299 INIT_HWRPB->pagesize >> 10);
300 return;
301 }
302 if (INIT_HWRPB->vptb != (unsigned long) VPTB) {
303 srm_printk("Expected vptb at %p, got %p\n",
304 VPTB, (void *)INIT_HWRPB->vptb);
305 return;
306 }
307
308 /* PALcode (re)initialization. */
309 pal_init();
310
311 /* Get the parameter list from the console environment variable. */
312 nbytes = callback_getenv(ENV_BOOTED_OSFLAGS, envval, sizeof(envval));
313 if (nbytes < 0 || nbytes >= sizeof(envval)) {
314 nbytes = 0;
315 }
316 envval[nbytes] = '\0';
317
318 #ifdef DEBUG_ADDRESSES
319 srm_printk("START_ADDR 0x%lx\n", START_ADDR);
320 srm_printk("KERNEL_ORIGIN 0x%lx\n", KERNEL_ORIGIN);
321 srm_printk("KERNEL_SIZE 0x%x\n", KERNEL_SIZE);
322 srm_printk("KERNEL_Z_SIZE 0x%x\n", KERNEL_Z_SIZE);
323 #endif
324
325 /* Since all the SRM consoles load the BOOTP image at virtual
326 * 0x20000000, we have to ensure that the physical memory
327 * pages occupied by that image do NOT overlap the physical
328 * address range where the kernel wants to be run. This
329 * causes real problems when attempting to cdecompress the
330 * former into the latter... :-(
331 *
332 * So, we may have to decompress/move the kernel/INITRD image
333 * virtual-to-physical someplace else first before moving
334 * kernel /INITRD to their final resting places... ;-}
335 *
336 * Sigh...
337 */
338
339 /* First, check to see if the range of addresses occupied by
340 the bootstrapper part of the BOOTP image include any of the
341 physical pages into which the kernel will be placed for
342 execution.
343
344 We only need check on the final kernel image range, since we
345 will put the INITRD someplace that we can be sure is not
346 in conflict.
347 */
348 if (check_range(V_BOOTSTRAPPER_START, V_BOOTSTRAPPER_END,
349 K_KERNEL_DATA_START, K_KERNEL_IMAGE_END))
350 {
351 srm_printk("FATAL ERROR: overlap of bootstrapper code\n");
352 __halt();
353 }
354
355 /* Next, check to see if the range of addresses occupied by
356 the compressed kernel/INITRD/stack portion of the BOOTP
357 image include any of the physical pages into which the
358 decompressed kernel or the INITRD will be placed for
359 execution.
360 */
361 if (check_range(V_DATA_START, V_DATA_END,
362 K_KERNEL_IMAGE_START, K_COPY_IMAGE_END))
363 {
364 #ifdef DEBUG_ADDRESSES
365 srm_printk("OVERLAP: cannot decompress in place\n");
366 #endif
367 uncompressed_image_start = K_COPY_IMAGE_START;
368 uncompressed_image_end = K_COPY_IMAGE_END;
369 must_move = 1;
370
371 /* Finally, check to see if the range of addresses
372 occupied by the compressed kernel/INITRD part of
373 the BOOTP image include any of the physical pages
374 into which that part is to be copied for
375 decompression.
376 */
377 while (check_range(V_DATA_START, V_DATA_END,
378 uncompressed_image_start,
379 uncompressed_image_end))
380 {
381 #if 0
382 uncompressed_image_start += K_COPY_IMAGE_SIZE;
383 uncompressed_image_end += K_COPY_IMAGE_SIZE;
384 initrd_image_start += K_COPY_IMAGE_SIZE;
385 #else
386 /* Keep as close as possible to end of BOOTP image. */
387 uncompressed_image_start += PAGE_SIZE;
388 uncompressed_image_end += PAGE_SIZE;
389 initrd_image_start += PAGE_SIZE;
390 #endif
391 }
392 }
393
394 srm_printk("Starting to load the kernel with args '%s'\n", envval);
395
396 #ifdef DEBUG_ADDRESSES
397 srm_printk("Decompressing the kernel...\n"
398 "...from 0x%lx to 0x%lx size 0x%x\n",
399 V_DATA_START,
400 uncompressed_image_start,
401 KERNEL_SIZE);
402 #endif
403 decompress_kernel((void *)uncompressed_image_start,
404 (void *)V_DATA_START,
405 KERNEL_SIZE, KERNEL_Z_SIZE);
406
407 /*
408 * Now, move things to their final positions, if/as required.
409 */
410
411 #ifdef INITRD_IMAGE_SIZE
412
413 /* First, we always move the INITRD image, if present. */
414 #ifdef DEBUG_ADDRESSES
415 srm_printk("Moving the INITRD image...\n"
416 " from 0x%lx to 0x%lx size 0x%x\n",
417 V_INITRD_START,
418 initrd_image_start,
419 INITRD_IMAGE_SIZE);
420 #endif
421 memcpy((void *)initrd_image_start, (void *)V_INITRD_START,
422 INITRD_IMAGE_SIZE);
423
424 #endif /* INITRD_IMAGE_SIZE */
425
426 /* Next, we may have to move the uncompressed kernel to the
427 final destination.
428 */
429 if (must_move) {
430 #ifdef DEBUG_ADDRESSES
431 srm_printk("Moving the uncompressed kernel...\n"
432 "...from 0x%lx to 0x%lx size 0x%x\n",
433 uncompressed_image_start,
434 K_KERNEL_IMAGE_START,
435 (unsigned)KERNEL_SIZE);
436 #endif
437 /*
438 * Move the stack to a safe place to ensure it won't be
439 * overwritten by kernel image.
440 */
441 move_stack(initrd_image_start - PAGE_SIZE);
442
443 memcpy((void *)K_KERNEL_IMAGE_START,
444 (void *)uncompressed_image_start, KERNEL_SIZE);
445 }
446
447 /* Clear the zero page, then move the argument list in. */
448 #ifdef DEBUG_LAST_STEPS
449 srm_printk("Preparing ZERO_PGE...\n");
450 #endif
451 memset((char*)ZERO_PGE, 0, PAGE_SIZE);
452 strcpy((char*)ZERO_PGE, envval);
453
454 #ifdef INITRD_IMAGE_SIZE
455
456 #ifdef DEBUG_LAST_STEPS
457 srm_printk("Preparing INITRD info...\n");
458 #endif
459 /* Finally, set the INITRD paramenters for the kernel. */
460 ((long *)(ZERO_PGE+256))[0] = initrd_image_start;
461 ((long *)(ZERO_PGE+256))[1] = INITRD_IMAGE_SIZE;
462
463 #endif /* INITRD_IMAGE_SIZE */
464
465 #ifdef DEBUG_LAST_STEPS
466 srm_printk("Doing 'runkernel()'...\n");
467 #endif
468 runkernel();
469 }
470
471 /* dummy function, should never be called. */
__kmalloc(size_t size,gfp_t flags)472 void *__kmalloc(size_t size, gfp_t flags)
473 {
474 return (void *)NULL;
475 }
476