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