1 // SPDX-License-Identifier: GPL-2.0
2 #define boot_fmt(fmt) "startup: " fmt
3 #include <linux/string.h>
4 #include <linux/elf.h>
5 #include <asm/page-states.h>
6 #include <asm/boot_data.h>
7 #include <asm/extmem.h>
8 #include <asm/sections.h>
9 #include <asm/diag288.h>
10 #include <asm/maccess.h>
11 #include <asm/machine.h>
12 #include <asm/sysinfo.h>
13 #include <asm/cpu_mf.h>
14 #include <asm/setup.h>
15 #include <asm/timex.h>
16 #include <asm/kasan.h>
17 #include <asm/kexec.h>
18 #include <asm/sclp.h>
19 #include <asm/diag.h>
20 #include <asm/uv.h>
21 #include <asm/abs_lowcore.h>
22 #include <asm/physmem_info.h>
23 #include "decompressor.h"
24 #include "boot.h"
25 #include "uv.h"
26
27 struct vm_layout __bootdata_preserved(vm_layout);
28 unsigned long __bootdata_preserved(__abs_lowcore);
29 unsigned long __bootdata_preserved(__memcpy_real_area);
30 pte_t *__bootdata_preserved(memcpy_real_ptep);
31 unsigned long __bootdata_preserved(VMALLOC_START);
32 unsigned long __bootdata_preserved(VMALLOC_END);
33 struct page *__bootdata_preserved(vmemmap);
34 unsigned long __bootdata_preserved(vmemmap_size);
35 unsigned long __bootdata_preserved(MODULES_VADDR);
36 unsigned long __bootdata_preserved(MODULES_END);
37 unsigned long __bootdata_preserved(max_mappable);
38 unsigned long __bootdata_preserved(page_noexec_mask);
39 unsigned long __bootdata_preserved(segment_noexec_mask);
40 unsigned long __bootdata_preserved(region_noexec_mask);
41 union tod_clock __bootdata_preserved(tod_clock_base);
42 u64 __bootdata_preserved(clock_comparator_max) = -1UL;
43
44 u64 __bootdata_preserved(stfle_fac_list[16]);
45 struct oldmem_data __bootdata_preserved(oldmem_data);
46
error(char * x)47 void error(char *x)
48 {
49 boot_emerg("%s\n", x);
50 boot_emerg(" -- System halted\n");
51 disabled_wait();
52 }
53
54 static char sysinfo_page[PAGE_SIZE] __aligned(PAGE_SIZE);
55
detect_machine_type(void)56 static void detect_machine_type(void)
57 {
58 struct sysinfo_3_2_2 *vmms = (struct sysinfo_3_2_2 *)&sysinfo_page;
59
60 /* Check current-configuration-level */
61 if (stsi(NULL, 0, 0, 0) <= 2) {
62 set_machine_feature(MFEATURE_LPAR);
63 return;
64 }
65 /* Get virtual-machine cpu information. */
66 if (stsi(vmms, 3, 2, 2) || !vmms->count)
67 return;
68 /* Detect known hypervisors */
69 if (!memcmp(vmms->vm[0].cpi, "\xd2\xe5\xd4", 3))
70 set_machine_feature(MFEATURE_KVM);
71 else if (!memcmp(vmms->vm[0].cpi, "\xa9\x61\xe5\xd4", 4))
72 set_machine_feature(MFEATURE_VM);
73 }
74
detect_diag288(void)75 static void detect_diag288(void)
76 {
77 /* "BEGIN" in EBCDIC character set */
78 static const char cmd[] = "\xc2\xc5\xc7\xc9\xd5";
79 unsigned long action, len;
80
81 action = machine_is_vm() ? (unsigned long)cmd : LPARWDT_RESTART;
82 len = machine_is_vm() ? sizeof(cmd) : 0;
83 if (__diag288(WDT_FUNC_INIT, MIN_INTERVAL, action, len))
84 return;
85 __diag288(WDT_FUNC_CANCEL, 0, 0, 0);
86 set_machine_feature(MFEATURE_DIAG288);
87 }
88
detect_diag9c(void)89 static void detect_diag9c(void)
90 {
91 unsigned int cpu;
92 int rc = 1;
93
94 cpu = stap();
95 asm_inline volatile(
96 " diag %[cpu],%%r0,0x9c\n"
97 "0: lhi %[rc],0\n"
98 "1:\n"
99 EX_TABLE(0b, 1b)
100 : [rc] "+d" (rc)
101 : [cpu] "d" (cpu)
102 : "cc", "memory");
103 if (!rc)
104 set_machine_feature(MFEATURE_DIAG9C);
105 }
106
reset_tod_clock(void)107 static void reset_tod_clock(void)
108 {
109 union tod_clock clk;
110
111 if (store_tod_clock_ext_cc(&clk) == 0)
112 return;
113 /* TOD clock not running. Set the clock to Unix Epoch. */
114 if (set_tod_clock(TOD_UNIX_EPOCH) || store_tod_clock_ext_cc(&clk))
115 disabled_wait();
116 memset(&tod_clock_base, 0, sizeof(tod_clock_base));
117 tod_clock_base.tod = TOD_UNIX_EPOCH;
118 get_lowcore()->last_update_clock = TOD_UNIX_EPOCH;
119 }
120
detect_facilities(void)121 static void detect_facilities(void)
122 {
123 if (cpu_has_edat1())
124 local_ctl_set_bit(0, CR0_EDAT_BIT);
125 page_noexec_mask = -1UL;
126 segment_noexec_mask = -1UL;
127 region_noexec_mask = -1UL;
128 if (!cpu_has_nx()) {
129 page_noexec_mask &= ~_PAGE_NOEXEC;
130 segment_noexec_mask &= ~_SEGMENT_ENTRY_NOEXEC;
131 region_noexec_mask &= ~_REGION_ENTRY_NOEXEC;
132 }
133 if (IS_ENABLED(CONFIG_PCI) && test_facility(153))
134 set_machine_feature(MFEATURE_PCI_MIO);
135 reset_tod_clock();
136 if (test_facility(139) && (tod_clock_base.tod >> 63)) {
137 /* Enable signed clock comparator comparisons */
138 set_machine_feature(MFEATURE_SCC);
139 clock_comparator_max = -1UL >> 1;
140 local_ctl_set_bit(0, CR0_CLOCK_COMPARATOR_SIGN_BIT);
141 }
142 if (test_facility(50) && test_facility(73)) {
143 set_machine_feature(MFEATURE_TX);
144 local_ctl_set_bit(0, CR0_TRANSACTIONAL_EXECUTION_BIT);
145 }
146 if (cpu_has_vx())
147 local_ctl_set_bit(0, CR0_VECTOR_BIT);
148 }
149
cmma_test_essa(void)150 static int cmma_test_essa(void)
151 {
152 unsigned long tmp = 0;
153 int rc = 1;
154
155 /* Test ESSA_GET_STATE */
156 asm_inline volatile(
157 " .insn rrf,0xb9ab0000,%[tmp],%[tmp],%[cmd],0\n"
158 "0: lhi %[rc],0\n"
159 "1:\n"
160 EX_TABLE(0b, 1b)
161 : [rc] "+d" (rc), [tmp] "+d" (tmp)
162 : [cmd] "i" (ESSA_GET_STATE)
163 : "cc", "memory");
164 return rc;
165 }
166
cmma_init(void)167 static void cmma_init(void)
168 {
169 if (!cmma_flag)
170 return;
171 if (cmma_test_essa()) {
172 cmma_flag = 0;
173 return;
174 }
175 if (test_facility(147))
176 cmma_flag = 2;
177 }
178
setup_lpp(void)179 static void setup_lpp(void)
180 {
181 get_lowcore()->current_pid = 0;
182 get_lowcore()->lpp = LPP_MAGIC;
183 if (test_facility(40))
184 lpp(&get_lowcore()->lpp);
185 }
186
187 #ifdef CONFIG_KERNEL_UNCOMPRESSED
mem_safe_offset(void)188 static unsigned long mem_safe_offset(void)
189 {
190 return (unsigned long)_compressed_start;
191 }
192
deploy_kernel(void * output)193 static void deploy_kernel(void *output)
194 {
195 void *uncompressed_start = (void *)_compressed_start;
196
197 if (output == uncompressed_start)
198 return;
199 memmove(output, uncompressed_start, vmlinux.image_size);
200 memset(uncompressed_start, 0, vmlinux.image_size);
201 }
202 #endif
203
rescue_initrd(unsigned long min,unsigned long max)204 static void rescue_initrd(unsigned long min, unsigned long max)
205 {
206 unsigned long old_addr, addr, size;
207
208 if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD))
209 return;
210 if (!get_physmem_reserved(RR_INITRD, &addr, &size))
211 return;
212 if (addr >= min && addr + size <= max)
213 return;
214 old_addr = addr;
215 physmem_free(RR_INITRD);
216 addr = physmem_alloc_or_die(RR_INITRD, size, 0);
217 memmove((void *)addr, (void *)old_addr, size);
218 }
219
copy_bootdata(void)220 static void copy_bootdata(void)
221 {
222 if (__boot_data_end - __boot_data_start != vmlinux.bootdata_size)
223 error(".boot.data section size mismatch");
224 memcpy((void *)vmlinux.bootdata_off, __boot_data_start, vmlinux.bootdata_size);
225 if (__boot_data_preserved_end - __boot_data_preserved_start != vmlinux.bootdata_preserved_size)
226 error(".boot.preserved.data section size mismatch");
227 memcpy((void *)vmlinux.bootdata_preserved_off, __boot_data_preserved_start, vmlinux.bootdata_preserved_size);
228 }
229
kaslr_adjust_relocs(unsigned long min_addr,unsigned long max_addr,unsigned long offset,unsigned long phys_offset)230 static void kaslr_adjust_relocs(unsigned long min_addr, unsigned long max_addr,
231 unsigned long offset, unsigned long phys_offset)
232 {
233 int *reloc;
234 long loc;
235
236 /* Adjust R_390_64 relocations */
237 for (reloc = (int *)__vmlinux_relocs_64_start; reloc < (int *)__vmlinux_relocs_64_end; reloc++) {
238 loc = (long)*reloc + phys_offset;
239 if (loc < min_addr || loc > max_addr)
240 error("64-bit relocation outside of kernel!\n");
241 *(u64 *)loc += offset;
242 }
243 }
244
kaslr_adjust_got(unsigned long offset)245 static void kaslr_adjust_got(unsigned long offset)
246 {
247 u64 *entry;
248
249 /*
250 * Adjust GOT entries, except for ones for undefined weak symbols
251 * that resolved to zero. This also skips the first three reserved
252 * entries on s390x that are zero.
253 */
254 for (entry = (u64 *)vmlinux.got_start; entry < (u64 *)vmlinux.got_end; entry++) {
255 if (*entry)
256 *entry += offset;
257 }
258 }
259
260 /*
261 * Merge information from several sources into a single ident_map_size value.
262 * "ident_map_size" represents the upper limit of physical memory we may ever
263 * reach. It might not be all online memory, but also include standby (offline)
264 * memory or memory areas reserved for other means (e.g., memory devices such as
265 * virtio-mem).
266 *
267 * "ident_map_size" could be lower then actual standby/reserved or even online
268 * memory present, due to limiting factors. We should never go above this limit.
269 * It is the size of our identity mapping.
270 *
271 * Consider the following factors:
272 * 1. max_physmem_end - end of physical memory online, standby or reserved.
273 * Always >= end of the last online memory range (get_physmem_online_end()).
274 * 2. CONFIG_MAX_PHYSMEM_BITS - the maximum size of physical memory the
275 * kernel is able to support.
276 * 3. "mem=" kernel command line option which limits physical memory usage.
277 * 4. OLDMEM_BASE which is a kdump memory limit when the kernel is executed as
278 * crash kernel.
279 * 5. "hsa" size which is a memory limit when the kernel is executed during
280 * zfcp/nvme dump.
281 */
setup_ident_map_size(unsigned long max_physmem_end)282 static void setup_ident_map_size(unsigned long max_physmem_end)
283 {
284 unsigned long hsa_size;
285
286 ident_map_size = max_physmem_end;
287 if (memory_limit)
288 ident_map_size = min(ident_map_size, memory_limit);
289 ident_map_size = min(ident_map_size, 1UL << MAX_PHYSMEM_BITS);
290
291 #ifdef CONFIG_CRASH_DUMP
292 if (oldmem_data.start) {
293 __kaslr_enabled = 0;
294 ident_map_size = min(ident_map_size, oldmem_data.size);
295 boot_debug("kdump memory limit: 0x%016lx\n", oldmem_data.size);
296 } else if (ipl_block_valid && is_ipl_block_dump()) {
297 __kaslr_enabled = 0;
298 if (!sclp_early_get_hsa_size(&hsa_size) && hsa_size) {
299 ident_map_size = min(ident_map_size, hsa_size);
300 boot_debug("Stand-alone dump limit: 0x%016lx\n", hsa_size);
301 }
302 }
303 #endif
304 boot_debug("Identity map size: 0x%016lx\n", ident_map_size);
305 }
306
307 #define FIXMAP_SIZE round_up(MEMCPY_REAL_SIZE + ABS_LOWCORE_MAP_SIZE, sizeof(struct lowcore))
308
get_vmem_size(unsigned long identity_size,unsigned long vmemmap_size,unsigned long vmalloc_size,unsigned long rte_size)309 static unsigned long get_vmem_size(unsigned long identity_size,
310 unsigned long vmemmap_size,
311 unsigned long vmalloc_size,
312 unsigned long rte_size)
313 {
314 unsigned long max_mappable, vsize;
315
316 max_mappable = max(identity_size, MAX_DCSS_ADDR);
317 vsize = round_up(SZ_2G + max_mappable, rte_size) +
318 round_up(vmemmap_size, rte_size) +
319 FIXMAP_SIZE + MODULES_LEN + KASLR_LEN;
320 if (IS_ENABLED(CONFIG_KMSAN))
321 vsize += MODULES_LEN * 2;
322 return size_add(vsize, vmalloc_size);
323 }
324
setup_kernel_memory_layout(unsigned long kernel_size)325 static unsigned long setup_kernel_memory_layout(unsigned long kernel_size)
326 {
327 unsigned long vmemmap_start;
328 unsigned long kernel_start;
329 unsigned long asce_limit;
330 unsigned long rte_size;
331 unsigned long pages;
332 unsigned long vsize;
333 unsigned long vmax;
334
335 pages = ident_map_size / PAGE_SIZE;
336 /* vmemmap contains a multiple of PAGES_PER_SECTION struct pages */
337 vmemmap_size = SECTION_ALIGN_UP(pages) * sizeof(struct page);
338
339 /* choose kernel address space layout: 4 or 3 levels. */
340 BUILD_BUG_ON(!IS_ALIGNED(TEXT_OFFSET, THREAD_SIZE));
341 BUILD_BUG_ON(!IS_ALIGNED(__NO_KASLR_START_KERNEL, THREAD_SIZE));
342 BUILD_BUG_ON(__NO_KASLR_END_KERNEL > _REGION1_SIZE);
343 vsize = get_vmem_size(ident_map_size, vmemmap_size, vmalloc_size, _REGION3_SIZE);
344 boot_debug("vmem size estimated: 0x%016lx\n", vsize);
345 if (IS_ENABLED(CONFIG_KASAN) || __NO_KASLR_END_KERNEL > _REGION2_SIZE ||
346 (vsize > _REGION2_SIZE && kaslr_enabled())) {
347 asce_limit = _REGION1_SIZE;
348 if (__NO_KASLR_END_KERNEL > _REGION2_SIZE) {
349 rte_size = _REGION2_SIZE;
350 vsize = get_vmem_size(ident_map_size, vmemmap_size, vmalloc_size, _REGION2_SIZE);
351 } else {
352 rte_size = _REGION3_SIZE;
353 }
354 } else {
355 asce_limit = _REGION2_SIZE;
356 rte_size = _REGION3_SIZE;
357 }
358
359 /*
360 * Forcing modules and vmalloc area under the ultravisor
361 * secure storage limit, so that any vmalloc allocation
362 * we do could be used to back secure guest storage.
363 *
364 * Assume the secure storage limit always exceeds _REGION2_SIZE,
365 * otherwise asce_limit and rte_size would have been adjusted.
366 */
367 vmax = adjust_to_uv_max(asce_limit);
368 boot_debug("%d level paging 0x%016lx vmax\n", vmax == _REGION1_SIZE ? 4 : 3, vmax);
369 #ifdef CONFIG_KASAN
370 BUILD_BUG_ON(__NO_KASLR_END_KERNEL > KASAN_SHADOW_START);
371 boot_debug("KASAN shadow area: 0x%016lx-0x%016lx\n", KASAN_SHADOW_START, KASAN_SHADOW_END);
372 /* force vmalloc and modules below kasan shadow */
373 vmax = min(vmax, KASAN_SHADOW_START);
374 #endif
375 vsize = min(vsize, vmax);
376 if (kaslr_enabled()) {
377 unsigned long kernel_end, kaslr_len, slots, pos;
378
379 kaslr_len = max(KASLR_LEN, vmax - vsize);
380 slots = DIV_ROUND_UP(kaslr_len - kernel_size, THREAD_SIZE);
381 if (get_random(slots, &pos))
382 pos = 0;
383 kernel_end = vmax - pos * THREAD_SIZE;
384 kernel_start = round_down(kernel_end - kernel_size, THREAD_SIZE);
385 boot_debug("Randomization range: 0x%016lx-0x%016lx\n", vmax - kaslr_len, vmax);
386 boot_debug("kernel image: 0x%016lx-0x%016lx (kaslr)\n", kernel_start,
387 kernel_start + kernel_size);
388 } else if (vmax < __NO_KASLR_END_KERNEL || vsize > __NO_KASLR_END_KERNEL) {
389 kernel_start = round_down(vmax - kernel_size, THREAD_SIZE);
390 boot_debug("kernel image: 0x%016lx-0x%016lx (constrained)\n", kernel_start,
391 kernel_start + kernel_size);
392 } else {
393 kernel_start = __NO_KASLR_START_KERNEL;
394 boot_debug("kernel image: 0x%016lx-0x%016lx (nokaslr)\n", kernel_start,
395 kernel_start + kernel_size);
396 }
397 __kaslr_offset = kernel_start;
398 boot_debug("__kaslr_offset: 0x%016lx\n", __kaslr_offset);
399
400 MODULES_END = round_down(kernel_start, _SEGMENT_SIZE);
401 MODULES_VADDR = MODULES_END - MODULES_LEN;
402 VMALLOC_END = MODULES_VADDR;
403 if (IS_ENABLED(CONFIG_KMSAN))
404 VMALLOC_END -= MODULES_LEN * 2;
405 boot_debug("modules area: 0x%016lx-0x%016lx\n", MODULES_VADDR, MODULES_END);
406
407 /* allow vmalloc area to occupy up to about 1/2 of the rest virtual space left */
408 vsize = (VMALLOC_END - FIXMAP_SIZE) / 2;
409 vsize = round_down(vsize, _SEGMENT_SIZE);
410 vmalloc_size = min(vmalloc_size, vsize);
411 if (IS_ENABLED(CONFIG_KMSAN)) {
412 /* take 2/3 of vmalloc area for KMSAN shadow and origins */
413 vmalloc_size = round_down(vmalloc_size / 3, _SEGMENT_SIZE);
414 VMALLOC_END -= vmalloc_size * 2;
415 }
416 VMALLOC_START = VMALLOC_END - vmalloc_size;
417 boot_debug("vmalloc area: 0x%016lx-0x%016lx\n", VMALLOC_START, VMALLOC_END);
418
419 __memcpy_real_area = round_down(VMALLOC_START - MEMCPY_REAL_SIZE, PAGE_SIZE);
420 boot_debug("memcpy real area: 0x%016lx-0x%016lx\n", __memcpy_real_area,
421 __memcpy_real_area + MEMCPY_REAL_SIZE);
422 __abs_lowcore = round_down(__memcpy_real_area - ABS_LOWCORE_MAP_SIZE,
423 sizeof(struct lowcore));
424 boot_debug("abs lowcore: 0x%016lx-0x%016lx\n", __abs_lowcore,
425 __abs_lowcore + ABS_LOWCORE_MAP_SIZE);
426
427 /* split remaining virtual space between 1:1 mapping & vmemmap array */
428 pages = __abs_lowcore / (PAGE_SIZE + sizeof(struct page));
429 pages = SECTION_ALIGN_UP(pages);
430 /* keep vmemmap_start aligned to a top level region table entry */
431 vmemmap_start = round_down(__abs_lowcore - pages * sizeof(struct page), rte_size);
432 /* make sure identity map doesn't overlay with vmemmap */
433 ident_map_size = min(ident_map_size, vmemmap_start);
434 vmemmap_size = SECTION_ALIGN_UP(ident_map_size / PAGE_SIZE) * sizeof(struct page);
435 /* make sure vmemmap doesn't overlay with absolute lowcore area */
436 if (vmemmap_start + vmemmap_size > __abs_lowcore) {
437 vmemmap_size = SECTION_ALIGN_DOWN(ident_map_size / PAGE_SIZE) * sizeof(struct page);
438 ident_map_size = vmemmap_size / sizeof(struct page) * PAGE_SIZE;
439 }
440 vmemmap = (struct page *)vmemmap_start;
441 /* maximum address for which linear mapping could be created (DCSS, memory) */
442 BUILD_BUG_ON(MAX_DCSS_ADDR > (1UL << MAX_PHYSMEM_BITS));
443 max_mappable = max(ident_map_size, MAX_DCSS_ADDR);
444 max_mappable = min(max_mappable, vmemmap_start);
445 #ifdef CONFIG_RANDOMIZE_IDENTITY_BASE
446 __identity_base = round_down(vmemmap_start - max_mappable, rte_size);
447 #endif
448 boot_debug("identity map: 0x%016lx-0x%016lx\n", __identity_base,
449 __identity_base + ident_map_size);
450
451 return asce_limit;
452 }
453
454 /*
455 * This function clears the BSS section of the decompressed Linux kernel and NOT the decompressor's.
456 */
clear_bss_section(unsigned long kernel_start)457 static void clear_bss_section(unsigned long kernel_start)
458 {
459 memset((void *)kernel_start + vmlinux.image_size, 0, vmlinux.bss_size);
460 }
461
462 /*
463 * Set vmalloc area size to an 8th of (potential) physical memory
464 * size, unless size has been set by kernel command line parameter.
465 */
setup_vmalloc_size(void)466 static void setup_vmalloc_size(void)
467 {
468 unsigned long size;
469
470 if (vmalloc_size_set)
471 return;
472 size = round_up(ident_map_size / 8, _SEGMENT_SIZE);
473 vmalloc_size = max(size, vmalloc_size);
474 }
475
kaslr_adjust_vmlinux_info(long offset)476 static void kaslr_adjust_vmlinux_info(long offset)
477 {
478 vmlinux.bootdata_off += offset;
479 vmlinux.bootdata_preserved_off += offset;
480 vmlinux.got_start += offset;
481 vmlinux.got_end += offset;
482 vmlinux.init_mm_off += offset;
483 vmlinux.swapper_pg_dir_off += offset;
484 vmlinux.invalid_pg_dir_off += offset;
485 vmlinux.alt_instructions += offset;
486 vmlinux.alt_instructions_end += offset;
487 #ifdef CONFIG_KASAN
488 vmlinux.kasan_early_shadow_page_off += offset;
489 vmlinux.kasan_early_shadow_pte_off += offset;
490 vmlinux.kasan_early_shadow_pmd_off += offset;
491 vmlinux.kasan_early_shadow_pud_off += offset;
492 vmlinux.kasan_early_shadow_p4d_off += offset;
493 #endif
494 }
495
startup_kernel(void)496 void startup_kernel(void)
497 {
498 unsigned long vmlinux_size = vmlinux.image_size + vmlinux.bss_size;
499 unsigned long nokaslr_text_lma, text_lma = 0, amode31_lma = 0;
500 unsigned long kernel_size = TEXT_OFFSET + vmlinux_size;
501 unsigned long kaslr_large_page_offset;
502 unsigned long max_physmem_end;
503 unsigned long asce_limit;
504 unsigned long safe_addr;
505 psw_t psw;
506
507 setup_lpp();
508 store_ipl_parmblock();
509 uv_query_info();
510 setup_boot_command_line();
511 parse_boot_command_line();
512
513 /*
514 * Non-randomized kernel physical start address must be _SEGMENT_SIZE
515 * aligned (see blow).
516 */
517 nokaslr_text_lma = ALIGN(mem_safe_offset(), _SEGMENT_SIZE);
518 safe_addr = PAGE_ALIGN(nokaslr_text_lma + vmlinux_size);
519
520 /*
521 * Reserve decompressor memory together with decompression heap,
522 * buffer and memory which might be occupied by uncompressed kernel
523 * (if KASLR is off or failed).
524 */
525 physmem_reserve(RR_DECOMPRESSOR, 0, safe_addr);
526 if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && parmarea.initrd_size)
527 physmem_reserve(RR_INITRD, parmarea.initrd_start, parmarea.initrd_size);
528 oldmem_data.start = parmarea.oldmem_base;
529 oldmem_data.size = parmarea.oldmem_size;
530
531 read_ipl_report();
532 sclp_early_read_info();
533 sclp_early_detect_machine_features();
534 detect_facilities();
535 detect_diag9c();
536 detect_machine_type();
537 /* detect_diag288() needs machine type */
538 detect_diag288();
539 cmma_init();
540 sanitize_prot_virt_host();
541 max_physmem_end = detect_max_physmem_end();
542 setup_ident_map_size(max_physmem_end);
543 setup_vmalloc_size();
544 asce_limit = setup_kernel_memory_layout(kernel_size);
545 /* got final ident_map_size, physmem allocations could be performed now */
546 physmem_set_usable_limit(ident_map_size);
547 detect_physmem_online_ranges(max_physmem_end);
548 save_ipl_cert_comp_list();
549 rescue_initrd(safe_addr, ident_map_size);
550
551 /*
552 * __kaslr_offset_phys must be _SEGMENT_SIZE aligned, so the lower
553 * 20 bits (the offset within a large page) are zero. Copy the last
554 * 20 bits of __kaslr_offset, which is THREAD_SIZE aligned, to
555 * __kaslr_offset_phys.
556 *
557 * With this the last 20 bits of __kaslr_offset_phys and __kaslr_offset
558 * are identical, which is required to allow for large mappings of the
559 * kernel image.
560 */
561 kaslr_large_page_offset = __kaslr_offset & ~_SEGMENT_MASK;
562 if (kaslr_enabled()) {
563 unsigned long size = vmlinux_size + kaslr_large_page_offset;
564
565 text_lma = randomize_within_range(size, _SEGMENT_SIZE, TEXT_OFFSET, ident_map_size);
566 }
567 if (!text_lma)
568 text_lma = nokaslr_text_lma;
569 text_lma |= kaslr_large_page_offset;
570
571 /*
572 * [__kaslr_offset_phys..__kaslr_offset_phys + TEXT_OFFSET] region is
573 * never accessed via the kernel image mapping as per the linker script:
574 *
575 * . = TEXT_OFFSET;
576 *
577 * Therefore, this region could be used for something else and does
578 * not need to be reserved. See how it is skipped in setup_vmem().
579 */
580 __kaslr_offset_phys = text_lma - TEXT_OFFSET;
581 kaslr_adjust_vmlinux_info(__kaslr_offset_phys);
582 physmem_reserve(RR_VMLINUX, text_lma, vmlinux_size);
583 deploy_kernel((void *)text_lma);
584
585 /* vmlinux decompression is done, shrink reserved low memory */
586 physmem_reserve(RR_DECOMPRESSOR, 0, (unsigned long)_decompressor_end);
587
588 /*
589 * In case KASLR is enabled the randomized location of .amode31
590 * section might overlap with .vmlinux.relocs section. To avoid that
591 * the below randomize_within_range() could have been called with
592 * __vmlinux_relocs_64_end as the lower range address. However,
593 * .amode31 section is written to by the decompressed kernel - at
594 * that time the contents of .vmlinux.relocs is not needed anymore.
595 * Conversely, .vmlinux.relocs is read only by the decompressor, even
596 * before the kernel started. Therefore, in case the two sections
597 * overlap there is no risk of corrupting any data.
598 */
599 if (kaslr_enabled()) {
600 unsigned long amode31_min;
601
602 amode31_min = (unsigned long)_decompressor_end;
603 amode31_lma = randomize_within_range(vmlinux.amode31_size, PAGE_SIZE, amode31_min, SZ_2G);
604 }
605 if (!amode31_lma)
606 amode31_lma = text_lma - vmlinux.amode31_size;
607 physmem_reserve(RR_AMODE31, amode31_lma, vmlinux.amode31_size);
608
609 /*
610 * The order of the following operations is important:
611 *
612 * - kaslr_adjust_relocs() must follow clear_bss_section() to establish
613 * static memory references to data in .bss to be used by setup_vmem()
614 * (i.e init_mm.pgd)
615 *
616 * - setup_vmem() must follow kaslr_adjust_relocs() to be able using
617 * static memory references to data in .bss (i.e init_mm.pgd)
618 *
619 * - copy_bootdata() must follow setup_vmem() to propagate changes
620 * to bootdata made by setup_vmem()
621 */
622 clear_bss_section(text_lma);
623 kaslr_adjust_relocs(text_lma, text_lma + vmlinux.image_size,
624 __kaslr_offset, __kaslr_offset_phys);
625 kaslr_adjust_got(__kaslr_offset);
626 setup_vmem(__kaslr_offset, __kaslr_offset + kernel_size, asce_limit);
627 dump_physmem_reserved();
628 copy_bootdata();
629 __apply_alternatives((struct alt_instr *)_vmlinux_info.alt_instructions,
630 (struct alt_instr *)_vmlinux_info.alt_instructions_end,
631 ALT_CTX_EARLY);
632
633 /*
634 * Save KASLR offset for early dumps, before vmcore_info is set.
635 * Mark as uneven to distinguish from real vmcore_info pointer.
636 */
637 get_lowcore()->vmcore_info = __kaslr_offset_phys ? __kaslr_offset_phys | 0x1UL : 0;
638
639 /*
640 * Jump to the decompressed kernel entry point and switch DAT mode on.
641 */
642 psw.addr = __kaslr_offset + vmlinux.entry;
643 psw.mask = PSW_KERNEL_BITS;
644 boot_debug("Starting kernel at: 0x%016lx\n", psw.addr);
645 jump_to_kernel(&psw);
646 }
647