1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Hibernation support for RISCV 4 * 5 * Copyright (C) 2023 StarFive Technology Co., Ltd. 6 * 7 * Author: Jee Heng Sia <jeeheng.sia@starfivetech.com> 8 */ 9 10 #include <asm/barrier.h> 11 #include <asm/cacheflush.h> 12 #include <asm/mmu_context.h> 13 #include <asm/page.h> 14 #include <asm/pgalloc.h> 15 #include <asm/pgtable.h> 16 #include <asm/sections.h> 17 #include <asm/set_memory.h> 18 #include <asm/smp.h> 19 #include <asm/suspend.h> 20 21 #include <linux/cpu.h> 22 #include <linux/memblock.h> 23 #include <linux/pm.h> 24 #include <linux/sched.h> 25 #include <linux/suspend.h> 26 #include <linux/utsname.h> 27 28 /* The logical cpu number we should resume on, initialised to a non-cpu number. */ 29 static int sleep_cpu = -EINVAL; 30 31 /* Pointer to the temporary resume page table. */ 32 static pgd_t *resume_pg_dir; 33 34 /* CPU context to be saved. */ 35 struct suspend_context *hibernate_cpu_context; 36 EXPORT_SYMBOL_GPL(hibernate_cpu_context); 37 38 unsigned long relocated_restore_code; 39 EXPORT_SYMBOL_GPL(relocated_restore_code); 40 41 /** 42 * struct arch_hibernate_hdr_invariants - container to store kernel build version. 43 * @uts_version: to save the build number and date so that we do not resume with 44 * a different kernel. 45 */ 46 struct arch_hibernate_hdr_invariants { 47 char uts_version[__NEW_UTS_LEN + 1]; 48 }; 49 50 /** 51 * struct arch_hibernate_hdr - helper parameters that help us to restore the image. 52 * @invariants: container to store kernel build version. 53 * @hartid: to make sure same boot_cpu executes the hibernate/restore code. 54 * @saved_satp: original page table used by the hibernated image. 55 * @restore_cpu_addr: the kernel's image address to restore the CPU context. 56 */ 57 static struct arch_hibernate_hdr { 58 struct arch_hibernate_hdr_invariants invariants; 59 unsigned long hartid; 60 unsigned long saved_satp; 61 unsigned long restore_cpu_addr; 62 } resume_hdr; 63 64 static void arch_hdr_invariants(struct arch_hibernate_hdr_invariants *i) 65 { 66 memset(i, 0, sizeof(*i)); 67 memcpy(i->uts_version, init_utsname()->version, sizeof(i->uts_version)); 68 } 69 70 /* 71 * Check if the given pfn is in the 'nosave' section. 72 */ 73 int pfn_is_nosave(unsigned long pfn) 74 { 75 unsigned long nosave_begin_pfn = sym_to_pfn(&__nosave_begin); 76 unsigned long nosave_end_pfn = sym_to_pfn(&__nosave_end - 1); 77 78 return ((pfn >= nosave_begin_pfn) && (pfn <= nosave_end_pfn)); 79 } 80 81 void notrace save_processor_state(void) 82 { 83 WARN_ON(num_online_cpus() != 1); 84 } 85 86 void notrace restore_processor_state(void) 87 { 88 } 89 90 /* 91 * Helper parameters need to be saved to the hibernation image header. 92 */ 93 int arch_hibernation_header_save(void *addr, unsigned int max_size) 94 { 95 struct arch_hibernate_hdr *hdr = addr; 96 97 if (max_size < sizeof(*hdr)) 98 return -EOVERFLOW; 99 100 arch_hdr_invariants(&hdr->invariants); 101 102 hdr->hartid = cpuid_to_hartid_map(sleep_cpu); 103 hdr->saved_satp = csr_read(CSR_SATP); 104 hdr->restore_cpu_addr = (unsigned long)__hibernate_cpu_resume; 105 106 return 0; 107 } 108 EXPORT_SYMBOL_GPL(arch_hibernation_header_save); 109 110 /* 111 * Retrieve the helper parameters from the hibernation image header. 112 */ 113 int arch_hibernation_header_restore(void *addr) 114 { 115 struct arch_hibernate_hdr_invariants invariants; 116 struct arch_hibernate_hdr *hdr = addr; 117 int ret = 0; 118 119 arch_hdr_invariants(&invariants); 120 121 if (memcmp(&hdr->invariants, &invariants, sizeof(invariants))) { 122 pr_crit("Hibernate image not generated by this kernel!\n"); 123 return -EINVAL; 124 } 125 126 sleep_cpu = riscv_hartid_to_cpuid(hdr->hartid); 127 if (sleep_cpu < 0) { 128 pr_crit("Hibernated on a CPU not known to this kernel!\n"); 129 sleep_cpu = -EINVAL; 130 return -EINVAL; 131 } 132 133 #ifdef CONFIG_SMP 134 ret = bringup_hibernate_cpu(sleep_cpu); 135 if (ret) { 136 sleep_cpu = -EINVAL; 137 return ret; 138 } 139 #endif 140 resume_hdr = *hdr; 141 142 return ret; 143 } 144 EXPORT_SYMBOL_GPL(arch_hibernation_header_restore); 145 146 int swsusp_arch_suspend(void) 147 { 148 int ret = 0; 149 150 if (__cpu_suspend_enter(hibernate_cpu_context)) { 151 sleep_cpu = smp_processor_id(); 152 suspend_save_csrs(hibernate_cpu_context); 153 ret = swsusp_save(); 154 } else { 155 suspend_restore_csrs(hibernate_cpu_context); 156 flush_tlb_all(); 157 flush_icache_all(); 158 159 /* 160 * Tell the hibernation core that we've just restored the memory. 161 */ 162 in_suspend = 0; 163 sleep_cpu = -EINVAL; 164 } 165 166 return ret; 167 } 168 169 static int temp_pgtable_map_pte(pmd_t *dst_pmdp, pmd_t *src_pmdp, unsigned long start, 170 unsigned long end, pgprot_t prot) 171 { 172 pte_t *src_ptep; 173 pte_t *dst_ptep; 174 175 if (pmd_none(READ_ONCE(*dst_pmdp))) { 176 dst_ptep = (pte_t *)get_safe_page(GFP_ATOMIC); 177 if (!dst_ptep) 178 return -ENOMEM; 179 180 pmd_populate_kernel(NULL, dst_pmdp, dst_ptep); 181 } 182 183 dst_ptep = pte_offset_kernel(dst_pmdp, start); 184 src_ptep = pte_offset_kernel(src_pmdp, start); 185 186 do { 187 pte_t pte = READ_ONCE(*src_ptep); 188 189 if (pte_present(pte)) 190 set_pte(dst_ptep, __pte(pte_val(pte) | pgprot_val(prot))); 191 } while (dst_ptep++, src_ptep++, start += PAGE_SIZE, start < end); 192 193 return 0; 194 } 195 196 static int temp_pgtable_map_pmd(pud_t *dst_pudp, pud_t *src_pudp, unsigned long start, 197 unsigned long end, pgprot_t prot) 198 { 199 unsigned long next; 200 unsigned long ret; 201 pmd_t *src_pmdp; 202 pmd_t *dst_pmdp; 203 204 if (pud_none(READ_ONCE(*dst_pudp))) { 205 dst_pmdp = (pmd_t *)get_safe_page(GFP_ATOMIC); 206 if (!dst_pmdp) 207 return -ENOMEM; 208 209 pud_populate(NULL, dst_pudp, dst_pmdp); 210 } 211 212 dst_pmdp = pmd_offset(dst_pudp, start); 213 src_pmdp = pmd_offset(src_pudp, start); 214 215 do { 216 pmd_t pmd = READ_ONCE(*src_pmdp); 217 218 next = pmd_addr_end(start, end); 219 220 if (pmd_none(pmd)) 221 continue; 222 223 if (pmd_leaf(pmd)) { 224 set_pmd(dst_pmdp, __pmd(pmd_val(pmd) | pgprot_val(prot))); 225 } else { 226 ret = temp_pgtable_map_pte(dst_pmdp, src_pmdp, start, next, prot); 227 if (ret) 228 return -ENOMEM; 229 } 230 } while (dst_pmdp++, src_pmdp++, start = next, start != end); 231 232 return 0; 233 } 234 235 static int temp_pgtable_map_pud(p4d_t *dst_p4dp, p4d_t *src_p4dp, unsigned long start, 236 unsigned long end, pgprot_t prot) 237 { 238 unsigned long next; 239 unsigned long ret; 240 pud_t *dst_pudp; 241 pud_t *src_pudp; 242 243 if (p4d_none(READ_ONCE(*dst_p4dp))) { 244 dst_pudp = (pud_t *)get_safe_page(GFP_ATOMIC); 245 if (!dst_pudp) 246 return -ENOMEM; 247 248 p4d_populate(NULL, dst_p4dp, dst_pudp); 249 } 250 251 dst_pudp = pud_offset(dst_p4dp, start); 252 src_pudp = pud_offset(src_p4dp, start); 253 254 do { 255 pud_t pud = READ_ONCE(*src_pudp); 256 257 next = pud_addr_end(start, end); 258 259 if (pud_none(pud)) 260 continue; 261 262 if (pud_leaf(pud)) { 263 set_pud(dst_pudp, __pud(pud_val(pud) | pgprot_val(prot))); 264 } else { 265 ret = temp_pgtable_map_pmd(dst_pudp, src_pudp, start, next, prot); 266 if (ret) 267 return -ENOMEM; 268 } 269 } while (dst_pudp++, src_pudp++, start = next, start != end); 270 271 return 0; 272 } 273 274 static int temp_pgtable_map_p4d(pgd_t *dst_pgdp, pgd_t *src_pgdp, unsigned long start, 275 unsigned long end, pgprot_t prot) 276 { 277 unsigned long next; 278 unsigned long ret; 279 p4d_t *dst_p4dp; 280 p4d_t *src_p4dp; 281 282 if (pgd_none(READ_ONCE(*dst_pgdp))) { 283 dst_p4dp = (p4d_t *)get_safe_page(GFP_ATOMIC); 284 if (!dst_p4dp) 285 return -ENOMEM; 286 287 pgd_populate(NULL, dst_pgdp, dst_p4dp); 288 } 289 290 dst_p4dp = p4d_offset(dst_pgdp, start); 291 src_p4dp = p4d_offset(src_pgdp, start); 292 293 do { 294 p4d_t p4d = READ_ONCE(*src_p4dp); 295 296 next = p4d_addr_end(start, end); 297 298 if (p4d_none(p4d)) 299 continue; 300 301 if (p4d_leaf(p4d)) { 302 set_p4d(dst_p4dp, __p4d(p4d_val(p4d) | pgprot_val(prot))); 303 } else { 304 ret = temp_pgtable_map_pud(dst_p4dp, src_p4dp, start, next, prot); 305 if (ret) 306 return -ENOMEM; 307 } 308 } while (dst_p4dp++, src_p4dp++, start = next, start != end); 309 310 return 0; 311 } 312 313 static int temp_pgtable_mapping(pgd_t *pgdp, unsigned long start, unsigned long end, pgprot_t prot) 314 { 315 pgd_t *dst_pgdp = pgd_offset_pgd(pgdp, start); 316 pgd_t *src_pgdp = pgd_offset_k(start); 317 unsigned long next; 318 unsigned long ret; 319 320 do { 321 pgd_t pgd = READ_ONCE(*src_pgdp); 322 323 next = pgd_addr_end(start, end); 324 325 if (pgd_none(pgd)) 326 continue; 327 328 if (pgd_leaf(pgd)) { 329 set_pgd(dst_pgdp, __pgd(pgd_val(pgd) | pgprot_val(prot))); 330 } else { 331 ret = temp_pgtable_map_p4d(dst_pgdp, src_pgdp, start, next, prot); 332 if (ret) 333 return -ENOMEM; 334 } 335 } while (dst_pgdp++, src_pgdp++, start = next, start != end); 336 337 return 0; 338 } 339 340 static unsigned long relocate_restore_code(void) 341 { 342 void *page = (void *)get_safe_page(GFP_ATOMIC); 343 344 if (!page) 345 return -ENOMEM; 346 347 copy_page(page, hibernate_core_restore_code); 348 349 /* Make the page containing the relocated code executable. */ 350 set_memory_x((unsigned long)page, 1); 351 352 return (unsigned long)page; 353 } 354 355 int swsusp_arch_resume(void) 356 { 357 unsigned long end = (unsigned long)pfn_to_virt(max_low_pfn); 358 unsigned long start = PAGE_OFFSET; 359 int ret; 360 361 /* 362 * Memory allocated by get_safe_page() will be dealt with by the hibernation core, 363 * we don't need to free it here. 364 */ 365 resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC); 366 if (!resume_pg_dir) 367 return -ENOMEM; 368 369 /* 370 * Create a temporary page table and map the whole linear region as executable and 371 * writable. 372 */ 373 ret = temp_pgtable_mapping(resume_pg_dir, start, end, __pgprot(_PAGE_WRITE | _PAGE_EXEC)); 374 if (ret) 375 return ret; 376 377 /* Move the restore code to a new page so that it doesn't get overwritten by itself. */ 378 relocated_restore_code = relocate_restore_code(); 379 if (relocated_restore_code == -ENOMEM) 380 return -ENOMEM; 381 382 /* 383 * Map the __hibernate_cpu_resume() address to the temporary page table so that the 384 * restore code can jumps to it after finished restore the image. The next execution 385 * code doesn't find itself in a different address space after switching over to the 386 * original page table used by the hibernated image. 387 * The __hibernate_cpu_resume() mapping is unnecessary for RV32 since the kernel and 388 * linear addresses are identical, but different for RV64. To ensure consistency, we 389 * map it for both RV32 and RV64 kernels. 390 * Additionally, we should ensure that the page is writable before restoring the image. 391 */ 392 start = (unsigned long)resume_hdr.restore_cpu_addr; 393 end = start + PAGE_SIZE; 394 395 ret = temp_pgtable_mapping(resume_pg_dir, start, end, __pgprot(_PAGE_WRITE)); 396 if (ret) 397 return ret; 398 399 hibernate_restore_image(resume_hdr.saved_satp, (PFN_DOWN(__pa(resume_pg_dir)) | satp_mode), 400 resume_hdr.restore_cpu_addr); 401 402 return 0; 403 } 404 405 #ifdef CONFIG_PM_SLEEP_SMP 406 int hibernate_resume_nonboot_cpu_disable(void) 407 { 408 if (sleep_cpu < 0) { 409 pr_err("Failing to resume from hibernate on an unknown CPU\n"); 410 return -ENODEV; 411 } 412 413 return freeze_secondary_cpus(sleep_cpu); 414 } 415 #endif 416 417 static int __init riscv_hibernate_init(void) 418 { 419 hibernate_cpu_context = kzalloc(sizeof(*hibernate_cpu_context), GFP_KERNEL); 420 421 if (WARN_ON(!hibernate_cpu_context)) 422 return -ENOMEM; 423 424 return 0; 425 } 426 427 early_initcall(riscv_hibernate_init); 428