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 } 84 85 void notrace restore_processor_state(void) 86 { 87 } 88 89 /* 90 * Helper parameters need to be saved to the hibernation image header. 91 */ 92 int arch_hibernation_header_save(void *addr, unsigned int max_size) 93 { 94 struct arch_hibernate_hdr *hdr = addr; 95 96 if (max_size < sizeof(*hdr)) 97 return -EOVERFLOW; 98 99 arch_hdr_invariants(&hdr->invariants); 100 101 hdr->hartid = cpuid_to_hartid_map(sleep_cpu); 102 hdr->saved_satp = csr_read(CSR_SATP); 103 hdr->restore_cpu_addr = (unsigned long)__hibernate_cpu_resume; 104 105 return 0; 106 } 107 EXPORT_SYMBOL_GPL(arch_hibernation_header_save); 108 109 /* 110 * Retrieve the helper parameters from the hibernation image header. 111 */ 112 int arch_hibernation_header_restore(void *addr) 113 { 114 struct arch_hibernate_hdr_invariants invariants; 115 struct arch_hibernate_hdr *hdr = addr; 116 int ret = 0; 117 118 arch_hdr_invariants(&invariants); 119 120 if (memcmp(&hdr->invariants, &invariants, sizeof(invariants))) { 121 pr_crit("Hibernate image not generated by this kernel!\n"); 122 return -EINVAL; 123 } 124 125 sleep_cpu = riscv_hartid_to_cpuid(hdr->hartid); 126 if (sleep_cpu < 0) { 127 pr_crit("Hibernated on a CPU not known to this kernel!\n"); 128 sleep_cpu = -EINVAL; 129 return -EINVAL; 130 } 131 132 #ifdef CONFIG_SMP 133 ret = bringup_hibernate_cpu(sleep_cpu); 134 if (ret) { 135 sleep_cpu = -EINVAL; 136 return ret; 137 } 138 #endif 139 resume_hdr = *hdr; 140 141 return ret; 142 } 143 EXPORT_SYMBOL_GPL(arch_hibernation_header_restore); 144 145 int swsusp_arch_suspend(void) 146 { 147 int ret = 0; 148 149 if (__cpu_suspend_enter(hibernate_cpu_context)) { 150 sleep_cpu = smp_processor_id(); 151 suspend_save_csrs(hibernate_cpu_context); 152 ret = swsusp_save(); 153 } else { 154 suspend_restore_csrs(hibernate_cpu_context); 155 flush_tlb_all(); 156 flush_icache_all(); 157 158 /* 159 * Tell the hibernation core that we've just restored the memory. 160 */ 161 in_suspend = 0; 162 sleep_cpu = -EINVAL; 163 } 164 165 return ret; 166 } 167 168 static int temp_pgtable_map_pte(pmd_t *dst_pmdp, pmd_t *src_pmdp, unsigned long start, 169 unsigned long end, pgprot_t prot) 170 { 171 pte_t *src_ptep; 172 pte_t *dst_ptep; 173 174 if (pmd_none(READ_ONCE(*dst_pmdp))) { 175 dst_ptep = (pte_t *)get_safe_page(GFP_ATOMIC); 176 if (!dst_ptep) 177 return -ENOMEM; 178 179 pmd_populate_kernel(NULL, dst_pmdp, dst_ptep); 180 } 181 182 dst_ptep = pte_offset_kernel(dst_pmdp, start); 183 src_ptep = pte_offset_kernel(src_pmdp, start); 184 185 do { 186 pte_t pte = READ_ONCE(*src_ptep); 187 188 if (pte_present(pte)) 189 set_pte(dst_ptep, __pte(pte_val(pte) | pgprot_val(prot))); 190 } while (dst_ptep++, src_ptep++, start += PAGE_SIZE, start < end); 191 192 return 0; 193 } 194 195 static int temp_pgtable_map_pmd(pud_t *dst_pudp, pud_t *src_pudp, unsigned long start, 196 unsigned long end, pgprot_t prot) 197 { 198 unsigned long next; 199 unsigned long ret; 200 pmd_t *src_pmdp; 201 pmd_t *dst_pmdp; 202 203 if (pud_none(READ_ONCE(*dst_pudp))) { 204 dst_pmdp = (pmd_t *)get_safe_page(GFP_ATOMIC); 205 if (!dst_pmdp) 206 return -ENOMEM; 207 208 pud_populate(NULL, dst_pudp, dst_pmdp); 209 } 210 211 dst_pmdp = pmd_offset(dst_pudp, start); 212 src_pmdp = pmd_offset(src_pudp, start); 213 214 do { 215 pmd_t pmd = READ_ONCE(*src_pmdp); 216 217 next = pmd_addr_end(start, end); 218 219 if (pmd_none(pmd)) 220 continue; 221 222 if (pmd_leaf(pmd)) { 223 set_pmd(dst_pmdp, __pmd(pmd_val(pmd) | pgprot_val(prot))); 224 } else { 225 ret = temp_pgtable_map_pte(dst_pmdp, src_pmdp, start, next, prot); 226 if (ret) 227 return -ENOMEM; 228 } 229 } while (dst_pmdp++, src_pmdp++, start = next, start != end); 230 231 return 0; 232 } 233 234 static int temp_pgtable_map_pud(p4d_t *dst_p4dp, p4d_t *src_p4dp, unsigned long start, 235 unsigned long end, pgprot_t prot) 236 { 237 unsigned long next; 238 unsigned long ret; 239 pud_t *dst_pudp; 240 pud_t *src_pudp; 241 242 if (p4d_none(READ_ONCE(*dst_p4dp))) { 243 dst_pudp = (pud_t *)get_safe_page(GFP_ATOMIC); 244 if (!dst_pudp) 245 return -ENOMEM; 246 247 p4d_populate(NULL, dst_p4dp, dst_pudp); 248 } 249 250 dst_pudp = pud_offset(dst_p4dp, start); 251 src_pudp = pud_offset(src_p4dp, start); 252 253 do { 254 pud_t pud = READ_ONCE(*src_pudp); 255 256 next = pud_addr_end(start, end); 257 258 if (pud_none(pud)) 259 continue; 260 261 if (pud_leaf(pud)) { 262 set_pud(dst_pudp, __pud(pud_val(pud) | pgprot_val(prot))); 263 } else { 264 ret = temp_pgtable_map_pmd(dst_pudp, src_pudp, start, next, prot); 265 if (ret) 266 return -ENOMEM; 267 } 268 } while (dst_pudp++, src_pudp++, start = next, start != end); 269 270 return 0; 271 } 272 273 static int temp_pgtable_map_p4d(pgd_t *dst_pgdp, pgd_t *src_pgdp, unsigned long start, 274 unsigned long end, pgprot_t prot) 275 { 276 unsigned long next; 277 unsigned long ret; 278 p4d_t *dst_p4dp; 279 p4d_t *src_p4dp; 280 281 if (pgd_none(READ_ONCE(*dst_pgdp))) { 282 dst_p4dp = (p4d_t *)get_safe_page(GFP_ATOMIC); 283 if (!dst_p4dp) 284 return -ENOMEM; 285 286 pgd_populate(NULL, dst_pgdp, dst_p4dp); 287 } 288 289 dst_p4dp = p4d_offset(dst_pgdp, start); 290 src_p4dp = p4d_offset(src_pgdp, start); 291 292 do { 293 p4d_t p4d = READ_ONCE(*src_p4dp); 294 295 next = p4d_addr_end(start, end); 296 297 if (p4d_none(p4d)) 298 continue; 299 300 if (p4d_leaf(p4d)) { 301 set_p4d(dst_p4dp, __p4d(p4d_val(p4d) | pgprot_val(prot))); 302 } else { 303 ret = temp_pgtable_map_pud(dst_p4dp, src_p4dp, start, next, prot); 304 if (ret) 305 return -ENOMEM; 306 } 307 } while (dst_p4dp++, src_p4dp++, start = next, start != end); 308 309 return 0; 310 } 311 312 static int temp_pgtable_mapping(pgd_t *pgdp, unsigned long start, unsigned long end, pgprot_t prot) 313 { 314 pgd_t *dst_pgdp = pgd_offset_pgd(pgdp, start); 315 pgd_t *src_pgdp = pgd_offset_k(start); 316 unsigned long next; 317 unsigned long ret; 318 319 do { 320 pgd_t pgd = READ_ONCE(*src_pgdp); 321 322 next = pgd_addr_end(start, end); 323 324 if (pgd_none(pgd)) 325 continue; 326 327 if (pgd_leaf(pgd)) { 328 set_pgd(dst_pgdp, __pgd(pgd_val(pgd) | pgprot_val(prot))); 329 } else { 330 ret = temp_pgtable_map_p4d(dst_pgdp, src_pgdp, start, next, prot); 331 if (ret) 332 return -ENOMEM; 333 } 334 } while (dst_pgdp++, src_pgdp++, start = next, start != end); 335 336 return 0; 337 } 338 339 static unsigned long relocate_restore_code(void) 340 { 341 void *page = (void *)get_safe_page(GFP_ATOMIC); 342 343 if (!page) 344 return -ENOMEM; 345 346 copy_page(page, hibernate_core_restore_code); 347 348 /* Make the page containing the relocated code executable. */ 349 set_memory_x((unsigned long)page, 1); 350 351 return (unsigned long)page; 352 } 353 354 int swsusp_arch_resume(void) 355 { 356 unsigned long end = (unsigned long)pfn_to_virt(max_low_pfn); 357 unsigned long start = PAGE_OFFSET; 358 int ret; 359 360 /* 361 * Memory allocated by get_safe_page() will be dealt with by the hibernation core, 362 * we don't need to free it here. 363 */ 364 resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC); 365 if (!resume_pg_dir) 366 return -ENOMEM; 367 368 /* 369 * Create a temporary page table and map the whole linear region as executable and 370 * writable. 371 */ 372 ret = temp_pgtable_mapping(resume_pg_dir, start, end, __pgprot(_PAGE_WRITE | _PAGE_EXEC)); 373 if (ret) 374 return ret; 375 376 /* Move the restore code to a new page so that it doesn't get overwritten by itself. */ 377 relocated_restore_code = relocate_restore_code(); 378 if (relocated_restore_code == -ENOMEM) 379 return -ENOMEM; 380 381 /* 382 * Map the __hibernate_cpu_resume() address to the temporary page table so that the 383 * restore code can jumps to it after finished restore the image. The next execution 384 * code doesn't find itself in a different address space after switching over to the 385 * original page table used by the hibernated image. 386 * The __hibernate_cpu_resume() mapping is unnecessary for RV32 since the kernel and 387 * linear addresses are identical, but different for RV64. To ensure consistency, we 388 * map it for both RV32 and RV64 kernels. 389 * Additionally, we should ensure that the page is writable before restoring the image. 390 */ 391 start = (unsigned long)resume_hdr.restore_cpu_addr; 392 end = start + PAGE_SIZE; 393 394 ret = temp_pgtable_mapping(resume_pg_dir, start, end, __pgprot(_PAGE_WRITE)); 395 if (ret) 396 return ret; 397 398 hibernate_restore_image(resume_hdr.saved_satp, (PFN_DOWN(__pa(resume_pg_dir)) | satp_mode), 399 resume_hdr.restore_cpu_addr); 400 401 return 0; 402 } 403 404 #ifdef CONFIG_PM_SLEEP_SMP 405 int hibernate_resume_nonboot_cpu_disable(void) 406 { 407 if (sleep_cpu < 0) { 408 pr_err("Failing to resume from hibernate on an unknown CPU\n"); 409 return -ENODEV; 410 } 411 412 return freeze_secondary_cpus(sleep_cpu); 413 } 414 #endif 415 416 static int __init riscv_hibernate_init(void) 417 { 418 hibernate_cpu_context = kzalloc(sizeof(*hibernate_cpu_context), GFP_KERNEL); 419 420 if (WARN_ON(!hibernate_cpu_context)) 421 return -ENOMEM; 422 423 return 0; 424 } 425 426 early_initcall(riscv_hibernate_init); 427