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 21 unsigned long __bootdata_preserved(__kaslr_offset); 22 unsigned long __bootdata_preserved(__abs_lowcore); 23 unsigned long __bootdata_preserved(__memcpy_real_area); 24 pte_t *__bootdata_preserved(memcpy_real_ptep); 25 unsigned long __bootdata_preserved(VMALLOC_START); 26 unsigned long __bootdata_preserved(VMALLOC_END); 27 struct page *__bootdata_preserved(vmemmap); 28 unsigned long __bootdata_preserved(vmemmap_size); 29 unsigned long __bootdata_preserved(MODULES_VADDR); 30 unsigned long __bootdata_preserved(MODULES_END); 31 unsigned long __bootdata_preserved(max_mappable); 32 unsigned long __bootdata(ident_map_size); 33 34 u64 __bootdata_preserved(stfle_fac_list[16]); 35 u64 __bootdata_preserved(alt_stfle_fac_list[16]); 36 struct oldmem_data __bootdata_preserved(oldmem_data); 37 38 struct machine_info machine; 39 40 void 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 49 static 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 61 static 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 91 static 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 } 102 103 static 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 112 unsigned long mem_safe_offset(void) 113 { 114 return vmlinux.default_lma + vmlinux.image_size + vmlinux.bss_size; 115 } 116 #endif 117 118 static 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 } 133 134 static 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 static 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 */ 194 static 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 } 214 215 static 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 vmalloc_size = min(vmalloc_size, round_down(VMALLOC_END / 2, _REGION3_SIZE)); 259 VMALLOC_START = VMALLOC_END - vmalloc_size; 260 261 /* split remaining virtual space between 1:1 mapping & vmemmap array */ 262 pages = VMALLOC_START / (PAGE_SIZE + sizeof(struct page)); 263 pages = SECTION_ALIGN_UP(pages); 264 /* keep vmemmap_start aligned to a top level region table entry */ 265 vmemmap_start = round_down(VMALLOC_START - pages * sizeof(struct page), rte_size); 266 vmemmap_start = min(vmemmap_start, 1UL << MAX_PHYSMEM_BITS); 267 /* maximum mappable address as seen by arch_get_mappable_range() */ 268 max_mappable = vmemmap_start; 269 /* make sure identity map doesn't overlay with vmemmap */ 270 ident_map_size = min(ident_map_size, vmemmap_start); 271 vmemmap_size = SECTION_ALIGN_UP(ident_map_size / PAGE_SIZE) * sizeof(struct page); 272 /* make sure vmemmap doesn't overlay with vmalloc area */ 273 VMALLOC_START = max(vmemmap_start + vmemmap_size, VMALLOC_START); 274 vmemmap = (struct page *)vmemmap_start; 275 276 return asce_limit; 277 } 278 279 /* 280 * This function clears the BSS section of the decompressed Linux kernel and NOT the decompressor's. 281 */ 282 static void clear_bss_section(unsigned long vmlinux_lma) 283 { 284 memset((void *)vmlinux_lma + vmlinux.image_size, 0, vmlinux.bss_size); 285 } 286 287 /* 288 * Set vmalloc area size to an 8th of (potential) physical memory 289 * size, unless size has been set by kernel command line parameter. 290 */ 291 static void setup_vmalloc_size(void) 292 { 293 unsigned long size; 294 295 if (vmalloc_size_set) 296 return; 297 size = round_up(ident_map_size / 8, _SEGMENT_SIZE); 298 vmalloc_size = max(size, vmalloc_size); 299 } 300 301 static void offset_vmlinux_info(unsigned long offset) 302 { 303 *(unsigned long *)(&vmlinux.entry) += offset; 304 vmlinux.bootdata_off += offset; 305 vmlinux.bootdata_preserved_off += offset; 306 vmlinux.rela_dyn_start += offset; 307 vmlinux.rela_dyn_end += offset; 308 vmlinux.dynsym_start += offset; 309 vmlinux.init_mm_off += offset; 310 vmlinux.swapper_pg_dir_off += offset; 311 vmlinux.invalid_pg_dir_off += offset; 312 #ifdef CONFIG_KASAN 313 vmlinux.kasan_early_shadow_page_off += offset; 314 vmlinux.kasan_early_shadow_pte_off += offset; 315 vmlinux.kasan_early_shadow_pmd_off += offset; 316 vmlinux.kasan_early_shadow_pud_off += offset; 317 vmlinux.kasan_early_shadow_p4d_off += offset; 318 #endif 319 } 320 321 void startup_kernel(void) 322 { 323 unsigned long max_physmem_end; 324 unsigned long vmlinux_lma = 0; 325 unsigned long amode31_lma = 0; 326 unsigned long asce_limit; 327 unsigned long safe_addr; 328 void *img; 329 psw_t psw; 330 331 setup_lpp(); 332 safe_addr = mem_safe_offset(); 333 334 /* 335 * Reserve decompressor memory together with decompression heap, buffer and 336 * memory which might be occupied by uncompressed kernel at default 1Mb 337 * position (if KASLR is off or failed). 338 */ 339 physmem_reserve(RR_DECOMPRESSOR, 0, safe_addr); 340 if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && parmarea.initrd_size) 341 physmem_reserve(RR_INITRD, parmarea.initrd_start, parmarea.initrd_size); 342 oldmem_data.start = parmarea.oldmem_base; 343 oldmem_data.size = parmarea.oldmem_size; 344 345 store_ipl_parmblock(); 346 read_ipl_report(); 347 uv_query_info(); 348 sclp_early_read_info(); 349 setup_boot_command_line(); 350 parse_boot_command_line(); 351 detect_facilities(); 352 cmma_init(); 353 sanitize_prot_virt_host(); 354 max_physmem_end = detect_max_physmem_end(); 355 setup_ident_map_size(max_physmem_end); 356 setup_vmalloc_size(); 357 asce_limit = setup_kernel_memory_layout(); 358 /* got final ident_map_size, physmem allocations could be performed now */ 359 physmem_set_usable_limit(ident_map_size); 360 detect_physmem_online_ranges(max_physmem_end); 361 save_ipl_cert_comp_list(); 362 rescue_initrd(safe_addr, ident_map_size); 363 364 if (kaslr_enabled()) { 365 vmlinux_lma = randomize_within_range(vmlinux.image_size + vmlinux.bss_size, 366 THREAD_SIZE, vmlinux.default_lma, 367 ident_map_size); 368 if (vmlinux_lma) { 369 __kaslr_offset = vmlinux_lma - vmlinux.default_lma; 370 offset_vmlinux_info(__kaslr_offset); 371 } 372 } 373 vmlinux_lma = vmlinux_lma ?: vmlinux.default_lma; 374 physmem_reserve(RR_VMLINUX, vmlinux_lma, vmlinux.image_size + vmlinux.bss_size); 375 376 if (!IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED)) { 377 img = decompress_kernel(); 378 memmove((void *)vmlinux_lma, img, vmlinux.image_size); 379 } else if (__kaslr_offset) { 380 img = (void *)vmlinux.default_lma; 381 memmove((void *)vmlinux_lma, img, vmlinux.image_size); 382 memset(img, 0, vmlinux.image_size); 383 } 384 385 /* vmlinux decompression is done, shrink reserved low memory */ 386 physmem_reserve(RR_DECOMPRESSOR, 0, (unsigned long)_decompressor_end); 387 if (kaslr_enabled()) 388 amode31_lma = randomize_within_range(vmlinux.amode31_size, PAGE_SIZE, 0, SZ_2G); 389 amode31_lma = amode31_lma ?: vmlinux.default_lma - vmlinux.amode31_size; 390 physmem_reserve(RR_AMODE31, amode31_lma, vmlinux.amode31_size); 391 392 /* 393 * The order of the following operations is important: 394 * 395 * - handle_relocs() must follow clear_bss_section() to establish static 396 * memory references to data in .bss to be used by setup_vmem() 397 * (i.e init_mm.pgd) 398 * 399 * - setup_vmem() must follow handle_relocs() to be able using 400 * static memory references to data in .bss (i.e init_mm.pgd) 401 * 402 * - copy_bootdata() must follow setup_vmem() to propagate changes to 403 * bootdata made by setup_vmem() 404 */ 405 clear_bss_section(vmlinux_lma); 406 handle_relocs(__kaslr_offset); 407 setup_vmem(asce_limit); 408 copy_bootdata(); 409 410 /* 411 * Save KASLR offset for early dumps, before vmcore_info is set. 412 * Mark as uneven to distinguish from real vmcore_info pointer. 413 */ 414 S390_lowcore.vmcore_info = __kaslr_offset ? __kaslr_offset | 0x1UL : 0; 415 416 /* 417 * Jump to the decompressed kernel entry point and switch DAT mode on. 418 */ 419 psw.addr = vmlinux.entry; 420 psw.mask = PSW_KERNEL_BITS; 421 __load_psw(psw); 422 } 423