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} 143 144#ifdef CONFIG_PIE_BUILD 145static void kaslr_adjust_relocs(unsigned long min_addr, unsigned long max_addr, unsigned long offset) 146{ 147 Elf64_Rela *rela_start, *rela_end, *rela; 148 int r_type, r_sym, rc; 149 Elf64_Addr loc, val; 150 Elf64_Sym *dynsym; 151 152 rela_start = (Elf64_Rela *) vmlinux.rela_dyn_start; 153 rela_end = (Elf64_Rela *) vmlinux.rela_dyn_end; 154 dynsym = (Elf64_Sym *) vmlinux.dynsym_start; 155 for (rela = rela_start; rela < rela_end; rela++) { 156 loc = rela->r_offset + offset; 157 val = rela->r_addend; 158 r_sym = ELF64_R_SYM(rela->r_info); 159 if (r_sym) { 160 if (dynsym[r_sym].st_shndx != SHN_UNDEF) 161 val += dynsym[r_sym].st_value + offset; 162 } else { 163 /* 164 * 0 == undefined symbol table index (STN_UNDEF), 165 * used for R_390_RELATIVE, only add KASLR offset 166 */ 167 val += offset; 168 } 169 r_type = ELF64_R_TYPE(rela->r_info); 170 rc = arch_kexec_do_relocs(r_type, (void *) loc, val, 0); 171 if (rc) 172 error("Unknown relocation type"); 173 } 174} 175 176static void kaslr_adjust_got(unsigned long offset) {} 177static void rescue_relocs(void) {} 178static void free_relocs(void) {} 179#else 180static int *vmlinux_relocs_64_start; 181static int *vmlinux_relocs_64_end; 182 183static void rescue_relocs(void) 184{ 185 unsigned long size = __vmlinux_relocs_64_end - __vmlinux_relocs_64_start; 186 187 vmlinux_relocs_64_start = (void *)physmem_alloc_top_down(RR_RELOC, size, 0); 188 vmlinux_relocs_64_end = (void *)vmlinux_relocs_64_start + size; 189 memmove(vmlinux_relocs_64_start, __vmlinux_relocs_64_start, size); 190} 191 192static void free_relocs(void) 193{ 194 physmem_free(RR_RELOC); 195} 196 197static void kaslr_adjust_relocs(unsigned long min_addr, unsigned long max_addr, unsigned long offset) 198{ 199 int *reloc; 200 long loc; 201 202 /* Adjust R_390_64 relocations */ 203 for (reloc = vmlinux_relocs_64_start; reloc < vmlinux_relocs_64_end; reloc++) { 204 loc = (long)*reloc + offset; 205 if (loc < min_addr || loc > max_addr) 206 error("64-bit relocation outside of kernel!\n"); 207 *(u64 *)loc += offset; 208 } 209} 210 211static void kaslr_adjust_got(unsigned long offset) 212{ 213 u64 *entry; 214 215 /* 216 * Even without -fPIE, Clang still uses a global offset table for some 217 * reason. Adjust the GOT entries. 218 */ 219 for (entry = (u64 *)vmlinux.got_start; entry < (u64 *)vmlinux.got_end; entry++) 220 *entry += offset; 221} 222#endif 223 224/* 225 * Merge information from several sources into a single ident_map_size value. 226 * "ident_map_size" represents the upper limit of physical memory we may ever 227 * reach. It might not be all online memory, but also include standby (offline) 228 * memory. "ident_map_size" could be lower then actual standby or even online 229 * memory present, due to limiting factors. We should never go above this limit. 230 * It is the size of our identity mapping. 231 * 232 * Consider the following factors: 233 * 1. max_physmem_end - end of physical memory online or standby. 234 * Always >= end of the last online memory range (get_physmem_online_end()). 235 * 2. CONFIG_MAX_PHYSMEM_BITS - the maximum size of physical memory the 236 * kernel is able to support. 237 * 3. "mem=" kernel command line option which limits physical memory usage. 238 * 4. OLDMEM_BASE which is a kdump memory limit when the kernel is executed as 239 * crash kernel. 240 * 5. "hsa" size which is a memory limit when the kernel is executed during 241 * zfcp/nvme dump. 242 */ 243static void setup_ident_map_size(unsigned long max_physmem_end) 244{ 245 unsigned long hsa_size; 246 247 ident_map_size = max_physmem_end; 248 if (memory_limit) 249 ident_map_size = min(ident_map_size, memory_limit); 250 ident_map_size = min(ident_map_size, 1UL << MAX_PHYSMEM_BITS); 251 252#ifdef CONFIG_CRASH_DUMP 253 if (oldmem_data.start) { 254 __kaslr_enabled = 0; 255 ident_map_size = min(ident_map_size, oldmem_data.size); 256 } else if (ipl_block_valid && is_ipl_block_dump()) { 257 __kaslr_enabled = 0; 258 if (!sclp_early_get_hsa_size(&hsa_size) && hsa_size) 259 ident_map_size = min(ident_map_size, hsa_size); 260 } 261#endif 262} 263 264static unsigned long setup_kernel_memory_layout(void) 265{ 266 unsigned long vmemmap_start; 267 unsigned long asce_limit; 268 unsigned long rte_size; 269 unsigned long pages; 270 unsigned long vsize; 271 unsigned long vmax; 272 273 pages = ident_map_size / PAGE_SIZE; 274 /* vmemmap contains a multiple of PAGES_PER_SECTION struct pages */ 275 vmemmap_size = SECTION_ALIGN_UP(pages) * sizeof(struct page); 276 277 /* choose kernel address space layout: 4 or 3 levels. */ 278 vsize = round_up(ident_map_size, _REGION3_SIZE) + vmemmap_size + 279 MODULES_LEN + MEMCPY_REAL_SIZE + ABS_LOWCORE_MAP_SIZE; 280 vsize = size_add(vsize, vmalloc_size); 281 if (IS_ENABLED(CONFIG_KASAN) || (vsize > _REGION2_SIZE)) { 282 asce_limit = _REGION1_SIZE; 283 rte_size = _REGION2_SIZE; 284 } else { 285 asce_limit = _REGION2_SIZE; 286 rte_size = _REGION3_SIZE; 287 } 288 289 /* 290 * Forcing modules and vmalloc area under the ultravisor 291 * secure storage limit, so that any vmalloc allocation 292 * we do could be used to back secure guest storage. 293 */ 294 vmax = adjust_to_uv_max(asce_limit); 295#ifdef CONFIG_KASAN 296 /* force vmalloc and modules below kasan shadow */ 297 vmax = min(vmax, KASAN_SHADOW_START); 298#endif 299 __memcpy_real_area = round_down(vmax - MEMCPY_REAL_SIZE, PAGE_SIZE); 300 __abs_lowcore = round_down(__memcpy_real_area - ABS_LOWCORE_MAP_SIZE, 301 sizeof(struct lowcore)); 302 MODULES_END = round_down(__abs_lowcore, _SEGMENT_SIZE); 303 MODULES_VADDR = MODULES_END - MODULES_LEN; 304 VMALLOC_END = MODULES_VADDR; 305 306 /* allow vmalloc area to occupy up to about 1/2 of the rest virtual space left */ 307 vsize = round_down(VMALLOC_END / 2, _SEGMENT_SIZE); 308 vmalloc_size = min(vmalloc_size, vsize); 309 VMALLOC_START = VMALLOC_END - vmalloc_size; 310 311 /* split remaining virtual space between 1:1 mapping & vmemmap array */ 312 pages = VMALLOC_START / (PAGE_SIZE + sizeof(struct page)); 313 pages = SECTION_ALIGN_UP(pages); 314 /* keep vmemmap_start aligned to a top level region table entry */ 315 vmemmap_start = round_down(VMALLOC_START - pages * sizeof(struct page), rte_size); 316 vmemmap_start = min(vmemmap_start, 1UL << MAX_PHYSMEM_BITS); 317 /* maximum mappable address as seen by arch_get_mappable_range() */ 318 max_mappable = vmemmap_start; 319 /* make sure identity map doesn't overlay with vmemmap */ 320 ident_map_size = min(ident_map_size, vmemmap_start); 321 vmemmap_size = SECTION_ALIGN_UP(ident_map_size / PAGE_SIZE) * sizeof(struct page); 322 /* make sure vmemmap doesn't overlay with vmalloc area */ 323 VMALLOC_START = max(vmemmap_start + vmemmap_size, VMALLOC_START); 324 vmemmap = (struct page *)vmemmap_start; 325 326 return asce_limit; 327} 328 329/* 330 * This function clears the BSS section of the decompressed Linux kernel and NOT the decompressor's. 331 */ 332static void clear_bss_section(unsigned long vmlinux_lma) 333{ 334 memset((void *)vmlinux_lma + vmlinux.image_size, 0, vmlinux.bss_size); 335} 336 337/* 338 * Set vmalloc area size to an 8th of (potential) physical memory 339 * size, unless size has been set by kernel command line parameter. 340 */ 341static void setup_vmalloc_size(void) 342{ 343 unsigned long size; 344 345 if (vmalloc_size_set) 346 return; 347 size = round_up(ident_map_size / 8, _SEGMENT_SIZE); 348 vmalloc_size = max(size, vmalloc_size); 349} 350 351static void kaslr_adjust_vmlinux_info(unsigned long offset) 352{ 353 *(unsigned long *)(&vmlinux.entry) += offset; 354 vmlinux.bootdata_off += offset; 355 vmlinux.bootdata_preserved_off += offset; 356#ifdef CONFIG_PIE_BUILD 357 vmlinux.rela_dyn_start += offset; 358 vmlinux.rela_dyn_end += offset; 359 vmlinux.dynsym_start += offset; 360#else 361 vmlinux.got_start += offset; 362 vmlinux.got_end += offset; 363#endif 364 vmlinux.init_mm_off += offset; 365 vmlinux.swapper_pg_dir_off += offset; 366 vmlinux.invalid_pg_dir_off += offset; 367#ifdef CONFIG_KASAN 368 vmlinux.kasan_early_shadow_page_off += offset; 369 vmlinux.kasan_early_shadow_pte_off += offset; 370 vmlinux.kasan_early_shadow_pmd_off += offset; 371 vmlinux.kasan_early_shadow_pud_off += offset; 372 vmlinux.kasan_early_shadow_p4d_off += offset; 373#endif 374} 375 376void startup_kernel(void) 377{ 378 unsigned long max_physmem_end; 379 unsigned long vmlinux_lma = 0; 380 unsigned long amode31_lma = 0; 381 unsigned long asce_limit; 382 unsigned long safe_addr; 383 void *img; 384 psw_t psw; 385 386 setup_lpp(); 387 safe_addr = mem_safe_offset(); 388 389 /* 390 * Reserve decompressor memory together with decompression heap, buffer and 391 * memory which might be occupied by uncompressed kernel at default 1Mb 392 * position (if KASLR is off or failed). 393 */ 394 physmem_reserve(RR_DECOMPRESSOR, 0, safe_addr); 395 if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && parmarea.initrd_size) 396 physmem_reserve(RR_INITRD, parmarea.initrd_start, parmarea.initrd_size); 397 oldmem_data.start = parmarea.oldmem_base; 398 oldmem_data.size = parmarea.oldmem_size; 399 400 store_ipl_parmblock(); 401 read_ipl_report(); 402 uv_query_info(); 403 sclp_early_read_info(); 404 setup_boot_command_line(); 405 parse_boot_command_line(); 406 detect_facilities(); 407 cmma_init(); 408 sanitize_prot_virt_host(); 409 max_physmem_end = detect_max_physmem_end(); 410 setup_ident_map_size(max_physmem_end); 411 setup_vmalloc_size(); 412 asce_limit = setup_kernel_memory_layout(); 413 /* got final ident_map_size, physmem allocations could be performed now */ 414 physmem_set_usable_limit(ident_map_size); 415 detect_physmem_online_ranges(max_physmem_end); 416 save_ipl_cert_comp_list(); 417 rescue_initrd(safe_addr, ident_map_size); 418 rescue_relocs(); 419 420 if (kaslr_enabled()) { 421 vmlinux_lma = randomize_within_range(vmlinux.image_size + vmlinux.bss_size, 422 THREAD_SIZE, vmlinux.default_lma, 423 ident_map_size); 424 if (vmlinux_lma) { 425 __kaslr_offset = vmlinux_lma - vmlinux.default_lma; 426 kaslr_adjust_vmlinux_info(__kaslr_offset); 427 } 428 } 429 vmlinux_lma = vmlinux_lma ?: vmlinux.default_lma; 430 physmem_reserve(RR_VMLINUX, vmlinux_lma, vmlinux.image_size + vmlinux.bss_size); 431 432 if (!IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED)) { 433 img = decompress_kernel(); 434 memmove((void *)vmlinux_lma, img, vmlinux.image_size); 435 } else if (__kaslr_offset) { 436 img = (void *)vmlinux.default_lma; 437 memmove((void *)vmlinux_lma, img, vmlinux.image_size); 438 memset(img, 0, vmlinux.image_size); 439 } 440 441 /* vmlinux decompression is done, shrink reserved low memory */ 442 physmem_reserve(RR_DECOMPRESSOR, 0, (unsigned long)_decompressor_end); 443 if (kaslr_enabled()) 444 amode31_lma = randomize_within_range(vmlinux.amode31_size, PAGE_SIZE, 0, SZ_2G); 445 amode31_lma = amode31_lma ?: vmlinux.default_lma - vmlinux.amode31_size; 446 physmem_reserve(RR_AMODE31, amode31_lma, vmlinux.amode31_size); 447 448 /* 449 * The order of the following operations is important: 450 * 451 * - kaslr_adjust_relocs() must follow clear_bss_section() to establish 452 * static memory references to data in .bss to be used by setup_vmem() 453 * (i.e init_mm.pgd) 454 * 455 * - setup_vmem() must follow kaslr_adjust_relocs() to be able using 456 * static memory references to data in .bss (i.e init_mm.pgd) 457 * 458 * - copy_bootdata() must follow setup_vmem() to propagate changes 459 * to bootdata made by setup_vmem() 460 */ 461 clear_bss_section(vmlinux_lma); 462 kaslr_adjust_relocs(vmlinux_lma, vmlinux_lma + vmlinux.image_size, __kaslr_offset); 463 kaslr_adjust_got(__kaslr_offset); 464 free_relocs(); 465 setup_vmem(asce_limit); 466 copy_bootdata(); 467 468 /* 469 * Save KASLR offset for early dumps, before vmcore_info is set. 470 * Mark as uneven to distinguish from real vmcore_info pointer. 471 */ 472 S390_lowcore.vmcore_info = __kaslr_offset ? __kaslr_offset | 0x1UL : 0; 473 474 /* 475 * Jump to the decompressed kernel entry point and switch DAT mode on. 476 */ 477 psw.addr = vmlinux.entry; 478 psw.mask = PSW_KERNEL_BITS; 479 __load_psw(psw); 480} 481