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1// SPDX-License-Identifier: GPL-2.0
2#include <linux/string.h>
3#include <linux/elf.h>
4#include <asm/page-states.h>
5#include <asm/boot_data.h>
6#include <asm/sections.h>
7#include <asm/maccess.h>
8#include <asm/cpu_mf.h>
9#include <asm/setup.h>
10#include <asm/kasan.h>
11#include <asm/kexec.h>
12#include <asm/sclp.h>
13#include <asm/diag.h>
14#include <asm/uv.h>
15#include <asm/abs_lowcore.h>
16#include <asm/physmem_info.h>
17#include "decompressor.h"
18#include "boot.h"
19#include "uv.h"
20
21unsigned long __bootdata_preserved(__kaslr_offset);
22unsigned long __bootdata_preserved(__abs_lowcore);
23unsigned long __bootdata_preserved(__memcpy_real_area);
24pte_t *__bootdata_preserved(memcpy_real_ptep);
25unsigned long __bootdata_preserved(VMALLOC_START);
26unsigned long __bootdata_preserved(VMALLOC_END);
27struct page *__bootdata_preserved(vmemmap);
28unsigned long __bootdata_preserved(vmemmap_size);
29unsigned long __bootdata_preserved(MODULES_VADDR);
30unsigned long __bootdata_preserved(MODULES_END);
31unsigned long __bootdata_preserved(max_mappable);
32unsigned long __bootdata(ident_map_size);
33
34u64 __bootdata_preserved(stfle_fac_list[16]);
35u64 __bootdata_preserved(alt_stfle_fac_list[16]);
36struct oldmem_data __bootdata_preserved(oldmem_data);
37
38struct machine_info machine;
39
40void error(char *x)
41{
42 sclp_early_printk("\n\n");
43 sclp_early_printk(x);
44 sclp_early_printk("\n\n -- System halted");
45
46 disabled_wait();
47}
48
49static void detect_facilities(void)
50{
51 if (test_facility(8)) {
52 machine.has_edat1 = 1;
53 local_ctl_set_bit(0, CR0_EDAT_BIT);
54 }
55 if (test_facility(78))
56 machine.has_edat2 = 1;
57 if (test_facility(130))
58 machine.has_nx = 1;
59}
60
61static int cmma_test_essa(void)
62{
63 unsigned long reg1, reg2, tmp = 0;
64 int rc = 1;
65 psw_t old;
66
67 /* Test ESSA_GET_STATE */
68 asm volatile(
69 " mvc 0(16,%[psw_old]),0(%[psw_pgm])\n"
70 " epsw %[reg1],%[reg2]\n"
71 " st %[reg1],0(%[psw_pgm])\n"
72 " st %[reg2],4(%[psw_pgm])\n"
73 " larl %[reg1],1f\n"
74 " stg %[reg1],8(%[psw_pgm])\n"
75 " .insn rrf,0xb9ab0000,%[tmp],%[tmp],%[cmd],0\n"
76 " la %[rc],0\n"
77 "1: mvc 0(16,%[psw_pgm]),0(%[psw_old])\n"
78 : [reg1] "=&d" (reg1),
79 [reg2] "=&a" (reg2),
80 [rc] "+&d" (rc),
81 [tmp] "=&d" (tmp),
82 "+Q" (S390_lowcore.program_new_psw),
83 "=Q" (old)
84 : [psw_old] "a" (&old),
85 [psw_pgm] "a" (&S390_lowcore.program_new_psw),
86 [cmd] "i" (ESSA_GET_STATE)
87 : "cc", "memory");
88 return rc;
89}
90
91static void cmma_init(void)
92{
93 if (!cmma_flag)
94 return;
95 if (cmma_test_essa()) {
96 cmma_flag = 0;
97 return;
98 }
99 if (test_facility(147))
100 cmma_flag = 2;
101}
102
103static void setup_lpp(void)
104{
105 S390_lowcore.current_pid = 0;
106 S390_lowcore.lpp = LPP_MAGIC;
107 if (test_facility(40))
108 lpp(&S390_lowcore.lpp);
109}
110
111#ifdef CONFIG_KERNEL_UNCOMPRESSED
112unsigned long mem_safe_offset(void)
113{
114 return vmlinux.default_lma + vmlinux.image_size + vmlinux.bss_size;
115}
116#endif
117
118static void rescue_initrd(unsigned long min, unsigned long max)
119{
120 unsigned long old_addr, addr, size;
121
122 if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD))
123 return;
124 if (!get_physmem_reserved(RR_INITRD, &addr, &size))
125 return;
126 if (addr >= min && addr + size <= max)
127 return;
128 old_addr = addr;
129 physmem_free(RR_INITRD);
130 addr = physmem_alloc_top_down(RR_INITRD, size, 0);
131 memmove((void *)addr, (void *)old_addr, size);
132}
133
134static void copy_bootdata(void)
135{
136 if (__boot_data_end - __boot_data_start != vmlinux.bootdata_size)
137 error(".boot.data section size mismatch");
138 memcpy((void *)vmlinux.bootdata_off, __boot_data_start, vmlinux.bootdata_size);
139 if (__boot_data_preserved_end - __boot_data_preserved_start != vmlinux.bootdata_preserved_size)
140 error(".boot.preserved.data section size mismatch");
141 memcpy((void *)vmlinux.bootdata_preserved_off, __boot_data_preserved_start, vmlinux.bootdata_preserved_size);
142}
143
144static void handle_relocs(unsigned long offset)
145{
146 Elf64_Rela *rela_start, *rela_end, *rela;
147 int r_type, r_sym, rc;
148 Elf64_Addr loc, val;
149 Elf64_Sym *dynsym;
150
151 rela_start = (Elf64_Rela *) vmlinux.rela_dyn_start;
152 rela_end = (Elf64_Rela *) vmlinux.rela_dyn_end;
153 dynsym = (Elf64_Sym *) vmlinux.dynsym_start;
154 for (rela = rela_start; rela < rela_end; rela++) {
155 loc = rela->r_offset + offset;
156 val = rela->r_addend;
157 r_sym = ELF64_R_SYM(rela->r_info);
158 if (r_sym) {
159 if (dynsym[r_sym].st_shndx != SHN_UNDEF)
160 val += dynsym[r_sym].st_value + offset;
161 } else {
162 /*
163 * 0 == undefined symbol table index (STN_UNDEF),
164 * used for R_390_RELATIVE, only add KASLR offset
165 */
166 val += offset;
167 }
168 r_type = ELF64_R_TYPE(rela->r_info);
169 rc = arch_kexec_do_relocs(r_type, (void *) loc, val, 0);
170 if (rc)
171 error("Unknown relocation type");
172 }
173}
174
175/*
176 * Merge information from several sources into a single ident_map_size value.
177 * "ident_map_size" represents the upper limit of physical memory we may ever
178 * reach. It might not be all online memory, but also include standby (offline)
179 * memory. "ident_map_size" could be lower then actual standby or even online
180 * memory present, due to limiting factors. We should never go above this limit.
181 * It is the size of our identity mapping.
182 *
183 * Consider the following factors:
184 * 1. max_physmem_end - end of physical memory online or standby.
185 * Always >= end of the last online memory range (get_physmem_online_end()).
186 * 2. CONFIG_MAX_PHYSMEM_BITS - the maximum size of physical memory the
187 * kernel is able to support.
188 * 3. "mem=" kernel command line option which limits physical memory usage.
189 * 4. OLDMEM_BASE which is a kdump memory limit when the kernel is executed as
190 * crash kernel.
191 * 5. "hsa" size which is a memory limit when the kernel is executed during
192 * zfcp/nvme dump.
193 */
194static void setup_ident_map_size(unsigned long max_physmem_end)
195{
196 unsigned long hsa_size;
197
198 ident_map_size = max_physmem_end;
199 if (memory_limit)
200 ident_map_size = min(ident_map_size, memory_limit);
201 ident_map_size = min(ident_map_size, 1UL << MAX_PHYSMEM_BITS);
202
203#ifdef CONFIG_CRASH_DUMP
204 if (oldmem_data.start) {
205 __kaslr_enabled = 0;
206 ident_map_size = min(ident_map_size, oldmem_data.size);
207 } else if (ipl_block_valid && is_ipl_block_dump()) {
208 __kaslr_enabled = 0;
209 if (!sclp_early_get_hsa_size(&hsa_size) && hsa_size)
210 ident_map_size = min(ident_map_size, hsa_size);
211 }
212#endif
213}
214
215static unsigned long setup_kernel_memory_layout(void)
216{
217 unsigned long vmemmap_start;
218 unsigned long asce_limit;
219 unsigned long rte_size;
220 unsigned long pages;
221 unsigned long vsize;
222 unsigned long vmax;
223
224 pages = ident_map_size / PAGE_SIZE;
225 /* vmemmap contains a multiple of PAGES_PER_SECTION struct pages */
226 vmemmap_size = SECTION_ALIGN_UP(pages) * sizeof(struct page);
227
228 /* choose kernel address space layout: 4 or 3 levels. */
229 vsize = round_up(ident_map_size, _REGION3_SIZE) + vmemmap_size +
230 MODULES_LEN + MEMCPY_REAL_SIZE + ABS_LOWCORE_MAP_SIZE;
231 vsize = size_add(vsize, vmalloc_size);
232 if (IS_ENABLED(CONFIG_KASAN) || (vsize > _REGION2_SIZE)) {
233 asce_limit = _REGION1_SIZE;
234 rte_size = _REGION2_SIZE;
235 } else {
236 asce_limit = _REGION2_SIZE;
237 rte_size = _REGION3_SIZE;
238 }
239
240 /*
241 * Forcing modules and vmalloc area under the ultravisor
242 * secure storage limit, so that any vmalloc allocation
243 * we do could be used to back secure guest storage.
244 */
245 vmax = adjust_to_uv_max(asce_limit);
246#ifdef CONFIG_KASAN
247 /* force vmalloc and modules below kasan shadow */
248 vmax = min(vmax, KASAN_SHADOW_START);
249#endif
250 __memcpy_real_area = round_down(vmax - MEMCPY_REAL_SIZE, PAGE_SIZE);
251 __abs_lowcore = round_down(__memcpy_real_area - ABS_LOWCORE_MAP_SIZE,
252 sizeof(struct lowcore));
253 MODULES_END = round_down(__abs_lowcore, _SEGMENT_SIZE);
254 MODULES_VADDR = MODULES_END - MODULES_LEN;
255 VMALLOC_END = MODULES_VADDR;
256
257 /* allow vmalloc area to occupy up to about 1/2 of the rest virtual space left */
258 vsize = round_down(VMALLOC_END / 2, _SEGMENT_SIZE);
259 vmalloc_size = min(vmalloc_size, vsize);
260 VMALLOC_START = VMALLOC_END - vmalloc_size;
261
262 /* split remaining virtual space between 1:1 mapping & vmemmap array */
263 pages = VMALLOC_START / (PAGE_SIZE + sizeof(struct page));
264 pages = SECTION_ALIGN_UP(pages);
265 /* keep vmemmap_start aligned to a top level region table entry */
266 vmemmap_start = round_down(VMALLOC_START - pages * sizeof(struct page), rte_size);
267 vmemmap_start = min(vmemmap_start, 1UL << MAX_PHYSMEM_BITS);
268 /* maximum mappable address as seen by arch_get_mappable_range() */
269 max_mappable = vmemmap_start;
270 /* make sure identity map doesn't overlay with vmemmap */
271 ident_map_size = min(ident_map_size, vmemmap_start);
272 vmemmap_size = SECTION_ALIGN_UP(ident_map_size / PAGE_SIZE) * sizeof(struct page);
273 /* make sure vmemmap doesn't overlay with vmalloc area */
274 VMALLOC_START = max(vmemmap_start + vmemmap_size, VMALLOC_START);
275 vmemmap = (struct page *)vmemmap_start;
276
277 return asce_limit;
278}
279
280/*
281 * This function clears the BSS section of the decompressed Linux kernel and NOT the decompressor's.
282 */
283static void clear_bss_section(unsigned long vmlinux_lma)
284{
285 memset((void *)vmlinux_lma + vmlinux.image_size, 0, vmlinux.bss_size);
286}
287
288/*
289 * Set vmalloc area size to an 8th of (potential) physical memory
290 * size, unless size has been set by kernel command line parameter.
291 */
292static void setup_vmalloc_size(void)
293{
294 unsigned long size;
295
296 if (vmalloc_size_set)
297 return;
298 size = round_up(ident_map_size / 8, _SEGMENT_SIZE);
299 vmalloc_size = max(size, vmalloc_size);
300}
301
302static void offset_vmlinux_info(unsigned long offset)
303{
304 *(unsigned long *)(&vmlinux.entry) += offset;
305 vmlinux.bootdata_off += offset;
306 vmlinux.bootdata_preserved_off += offset;
307 vmlinux.rela_dyn_start += offset;
308 vmlinux.rela_dyn_end += offset;
309 vmlinux.dynsym_start += offset;
310 vmlinux.init_mm_off += offset;
311 vmlinux.swapper_pg_dir_off += offset;
312 vmlinux.invalid_pg_dir_off += offset;
313#ifdef CONFIG_KASAN
314 vmlinux.kasan_early_shadow_page_off += offset;
315 vmlinux.kasan_early_shadow_pte_off += offset;
316 vmlinux.kasan_early_shadow_pmd_off += offset;
317 vmlinux.kasan_early_shadow_pud_off += offset;
318 vmlinux.kasan_early_shadow_p4d_off += offset;
319#endif
320}
321
322void startup_kernel(void)
323{
324 unsigned long max_physmem_end;
325 unsigned long vmlinux_lma = 0;
326 unsigned long amode31_lma = 0;
327 unsigned long asce_limit;
328 unsigned long safe_addr;
329 void *img;
330 psw_t psw;
331
332 setup_lpp();
333 safe_addr = mem_safe_offset();
334
335 /*
336 * Reserve decompressor memory together with decompression heap, buffer and
337 * memory which might be occupied by uncompressed kernel at default 1Mb
338 * position (if KASLR is off or failed).
339 */
340 physmem_reserve(RR_DECOMPRESSOR, 0, safe_addr);
341 if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && parmarea.initrd_size)
342 physmem_reserve(RR_INITRD, parmarea.initrd_start, parmarea.initrd_size);
343 oldmem_data.start = parmarea.oldmem_base;
344 oldmem_data.size = parmarea.oldmem_size;
345
346 store_ipl_parmblock();
347 read_ipl_report();
348 uv_query_info();
349 sclp_early_read_info();
350 setup_boot_command_line();
351 parse_boot_command_line();
352 detect_facilities();
353 cmma_init();
354 sanitize_prot_virt_host();
355 max_physmem_end = detect_max_physmem_end();
356 setup_ident_map_size(max_physmem_end);
357 setup_vmalloc_size();
358 asce_limit = setup_kernel_memory_layout();
359 /* got final ident_map_size, physmem allocations could be performed now */
360 physmem_set_usable_limit(ident_map_size);
361 detect_physmem_online_ranges(max_physmem_end);
362 save_ipl_cert_comp_list();
363 rescue_initrd(safe_addr, ident_map_size);
364
365 if (kaslr_enabled()) {
366 vmlinux_lma = randomize_within_range(vmlinux.image_size + vmlinux.bss_size,
367 THREAD_SIZE, vmlinux.default_lma,
368 ident_map_size);
369 if (vmlinux_lma) {
370 __kaslr_offset = vmlinux_lma - vmlinux.default_lma;
371 offset_vmlinux_info(__kaslr_offset);
372 }
373 }
374 vmlinux_lma = vmlinux_lma ?: vmlinux.default_lma;
375 physmem_reserve(RR_VMLINUX, vmlinux_lma, vmlinux.image_size + vmlinux.bss_size);
376
377 if (!IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED)) {
378 img = decompress_kernel();
379 memmove((void *)vmlinux_lma, img, vmlinux.image_size);
380 } else if (__kaslr_offset) {
381 img = (void *)vmlinux.default_lma;
382 memmove((void *)vmlinux_lma, img, vmlinux.image_size);
383 memset(img, 0, vmlinux.image_size);
384 }
385
386 /* vmlinux decompression is done, shrink reserved low memory */
387 physmem_reserve(RR_DECOMPRESSOR, 0, (unsigned long)_decompressor_end);
388 if (kaslr_enabled())
389 amode31_lma = randomize_within_range(vmlinux.amode31_size, PAGE_SIZE, 0, SZ_2G);
390 amode31_lma = amode31_lma ?: vmlinux.default_lma - vmlinux.amode31_size;
391 physmem_reserve(RR_AMODE31, amode31_lma, vmlinux.amode31_size);
392
393 /*
394 * The order of the following operations is important:
395 *
396 * - handle_relocs() must follow clear_bss_section() to establish static
397 * memory references to data in .bss to be used by setup_vmem()
398 * (i.e init_mm.pgd)
399 *
400 * - setup_vmem() must follow handle_relocs() to be able using
401 * static memory references to data in .bss (i.e init_mm.pgd)
402 *
403 * - copy_bootdata() must follow setup_vmem() to propagate changes to
404 * bootdata made by setup_vmem()
405 */
406 clear_bss_section(vmlinux_lma);
407 handle_relocs(__kaslr_offset);
408 setup_vmem(asce_limit);
409 copy_bootdata();
410
411 /*
412 * Save KASLR offset for early dumps, before vmcore_info is set.
413 * Mark as uneven to distinguish from real vmcore_info pointer.
414 */
415 S390_lowcore.vmcore_info = __kaslr_offset ? __kaslr_offset | 0x1UL : 0;
416
417 /*
418 * Jump to the decompressed kernel entry point and switch DAT mode on.
419 */
420 psw.addr = vmlinux.entry;
421 psw.mask = PSW_KERNEL_BITS;
422 __load_psw(psw);
423}