// SPDX-License-Identifier: GPL-2.0-only /* * Hibernation support for RISCV * * Copyright (C) 2023 StarFive Technology Co., Ltd. * * Author: Jee Heng Sia */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* The logical cpu number we should resume on, initialised to a non-cpu number. */ static int sleep_cpu = -EINVAL; /* Pointer to the temporary resume page table. */ static pgd_t *resume_pg_dir; /* CPU context to be saved. */ struct suspend_context *hibernate_cpu_context; EXPORT_SYMBOL_GPL(hibernate_cpu_context); unsigned long relocated_restore_code; EXPORT_SYMBOL_GPL(relocated_restore_code); /** * struct arch_hibernate_hdr_invariants - container to store kernel build version. * @uts_version: to save the build number and date so that we do not resume with * a different kernel. */ struct arch_hibernate_hdr_invariants { char uts_version[__NEW_UTS_LEN + 1]; }; /** * struct arch_hibernate_hdr - helper parameters that help us to restore the image. * @invariants: container to store kernel build version. * @hartid: to make sure same boot_cpu executes the hibernate/restore code. * @saved_satp: original page table used by the hibernated image. * @restore_cpu_addr: the kernel's image address to restore the CPU context. */ static struct arch_hibernate_hdr { struct arch_hibernate_hdr_invariants invariants; unsigned long hartid; unsigned long saved_satp; unsigned long restore_cpu_addr; } resume_hdr; static void arch_hdr_invariants(struct arch_hibernate_hdr_invariants *i) { memset(i, 0, sizeof(*i)); memcpy(i->uts_version, init_utsname()->version, sizeof(i->uts_version)); } /* * Check if the given pfn is in the 'nosave' section. */ int pfn_is_nosave(unsigned long pfn) { unsigned long nosave_begin_pfn = sym_to_pfn(&__nosave_begin); unsigned long nosave_end_pfn = sym_to_pfn(&__nosave_end - 1); return ((pfn >= nosave_begin_pfn) && (pfn <= nosave_end_pfn)); } void notrace save_processor_state(void) { } void notrace restore_processor_state(void) { } /* * Helper parameters need to be saved to the hibernation image header. */ int arch_hibernation_header_save(void *addr, unsigned int max_size) { struct arch_hibernate_hdr *hdr = addr; if (max_size < sizeof(*hdr)) return -EOVERFLOW; arch_hdr_invariants(&hdr->invariants); hdr->hartid = cpuid_to_hartid_map(sleep_cpu); hdr->saved_satp = csr_read(CSR_SATP); hdr->restore_cpu_addr = (unsigned long)__hibernate_cpu_resume; return 0; } EXPORT_SYMBOL_GPL(arch_hibernation_header_save); /* * Retrieve the helper parameters from the hibernation image header. */ int arch_hibernation_header_restore(void *addr) { struct arch_hibernate_hdr_invariants invariants; struct arch_hibernate_hdr *hdr = addr; int ret = 0; arch_hdr_invariants(&invariants); if (memcmp(&hdr->invariants, &invariants, sizeof(invariants))) { pr_crit("Hibernate image not generated by this kernel!\n"); return -EINVAL; } sleep_cpu = riscv_hartid_to_cpuid(hdr->hartid); if (sleep_cpu < 0) { pr_crit("Hibernated on a CPU not known to this kernel!\n"); sleep_cpu = -EINVAL; return -EINVAL; } #ifdef CONFIG_SMP ret = bringup_hibernate_cpu(sleep_cpu); if (ret) { sleep_cpu = -EINVAL; return ret; } #endif resume_hdr = *hdr; return ret; } EXPORT_SYMBOL_GPL(arch_hibernation_header_restore); int swsusp_arch_suspend(void) { int ret = 0; if (__cpu_suspend_enter(hibernate_cpu_context)) { sleep_cpu = smp_processor_id(); suspend_save_csrs(hibernate_cpu_context); ret = swsusp_save(); } else { suspend_restore_csrs(hibernate_cpu_context); flush_tlb_all(); flush_icache_all(); /* * Tell the hibernation core that we've just restored the memory. */ in_suspend = 0; sleep_cpu = -EINVAL; } return ret; } static int temp_pgtable_map_pte(pmd_t *dst_pmdp, pmd_t *src_pmdp, unsigned long start, unsigned long end, pgprot_t prot) { pte_t *src_ptep; pte_t *dst_ptep; if (pmd_none(READ_ONCE(*dst_pmdp))) { dst_ptep = (pte_t *)get_safe_page(GFP_ATOMIC); if (!dst_ptep) return -ENOMEM; pmd_populate_kernel(NULL, dst_pmdp, dst_ptep); } dst_ptep = pte_offset_kernel(dst_pmdp, start); src_ptep = pte_offset_kernel(src_pmdp, start); do { pte_t pte = READ_ONCE(*src_ptep); if (pte_present(pte)) set_pte(dst_ptep, __pte(pte_val(pte) | pgprot_val(prot))); } while (dst_ptep++, src_ptep++, start += PAGE_SIZE, start < end); return 0; } static int temp_pgtable_map_pmd(pud_t *dst_pudp, pud_t *src_pudp, unsigned long start, unsigned long end, pgprot_t prot) { unsigned long next; unsigned long ret; pmd_t *src_pmdp; pmd_t *dst_pmdp; if (pud_none(READ_ONCE(*dst_pudp))) { dst_pmdp = (pmd_t *)get_safe_page(GFP_ATOMIC); if (!dst_pmdp) return -ENOMEM; pud_populate(NULL, dst_pudp, dst_pmdp); } dst_pmdp = pmd_offset(dst_pudp, start); src_pmdp = pmd_offset(src_pudp, start); do { pmd_t pmd = READ_ONCE(*src_pmdp); next = pmd_addr_end(start, end); if (pmd_none(pmd)) continue; if (pmd_leaf(pmd)) { set_pmd(dst_pmdp, __pmd(pmd_val(pmd) | pgprot_val(prot))); } else { ret = temp_pgtable_map_pte(dst_pmdp, src_pmdp, start, next, prot); if (ret) return -ENOMEM; } } while (dst_pmdp++, src_pmdp++, start = next, start != end); return 0; } static int temp_pgtable_map_pud(p4d_t *dst_p4dp, p4d_t *src_p4dp, unsigned long start, unsigned long end, pgprot_t prot) { unsigned long next; unsigned long ret; pud_t *dst_pudp; pud_t *src_pudp; if (p4d_none(READ_ONCE(*dst_p4dp))) { dst_pudp = (pud_t *)get_safe_page(GFP_ATOMIC); if (!dst_pudp) return -ENOMEM; p4d_populate(NULL, dst_p4dp, dst_pudp); } dst_pudp = pud_offset(dst_p4dp, start); src_pudp = pud_offset(src_p4dp, start); do { pud_t pud = READ_ONCE(*src_pudp); next = pud_addr_end(start, end); if (pud_none(pud)) continue; if (pud_leaf(pud)) { set_pud(dst_pudp, __pud(pud_val(pud) | pgprot_val(prot))); } else { ret = temp_pgtable_map_pmd(dst_pudp, src_pudp, start, next, prot); if (ret) return -ENOMEM; } } while (dst_pudp++, src_pudp++, start = next, start != end); return 0; } static int temp_pgtable_map_p4d(pgd_t *dst_pgdp, pgd_t *src_pgdp, unsigned long start, unsigned long end, pgprot_t prot) { unsigned long next; unsigned long ret; p4d_t *dst_p4dp; p4d_t *src_p4dp; if (pgd_none(READ_ONCE(*dst_pgdp))) { dst_p4dp = (p4d_t *)get_safe_page(GFP_ATOMIC); if (!dst_p4dp) return -ENOMEM; pgd_populate(NULL, dst_pgdp, dst_p4dp); } dst_p4dp = p4d_offset(dst_pgdp, start); src_p4dp = p4d_offset(src_pgdp, start); do { p4d_t p4d = READ_ONCE(*src_p4dp); next = p4d_addr_end(start, end); if (p4d_none(p4d)) continue; if (p4d_leaf(p4d)) { set_p4d(dst_p4dp, __p4d(p4d_val(p4d) | pgprot_val(prot))); } else { ret = temp_pgtable_map_pud(dst_p4dp, src_p4dp, start, next, prot); if (ret) return -ENOMEM; } } while (dst_p4dp++, src_p4dp++, start = next, start != end); return 0; } static int temp_pgtable_mapping(pgd_t *pgdp, unsigned long start, unsigned long end, pgprot_t prot) { pgd_t *dst_pgdp = pgd_offset_pgd(pgdp, start); pgd_t *src_pgdp = pgd_offset_k(start); unsigned long next; unsigned long ret; do { pgd_t pgd = READ_ONCE(*src_pgdp); next = pgd_addr_end(start, end); if (pgd_none(pgd)) continue; if (pgd_leaf(pgd)) { set_pgd(dst_pgdp, __pgd(pgd_val(pgd) | pgprot_val(prot))); } else { ret = temp_pgtable_map_p4d(dst_pgdp, src_pgdp, start, next, prot); if (ret) return -ENOMEM; } } while (dst_pgdp++, src_pgdp++, start = next, start != end); return 0; } static unsigned long relocate_restore_code(void) { void *page = (void *)get_safe_page(GFP_ATOMIC); if (!page) return -ENOMEM; copy_page(page, hibernate_core_restore_code); /* Make the page containing the relocated code executable. */ set_memory_x((unsigned long)page, 1); return (unsigned long)page; } int swsusp_arch_resume(void) { unsigned long end = (unsigned long)pfn_to_virt(max_low_pfn); unsigned long start = PAGE_OFFSET; int ret; /* * Memory allocated by get_safe_page() will be dealt with by the hibernation core, * we don't need to free it here. */ resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC); if (!resume_pg_dir) return -ENOMEM; /* * Create a temporary page table and map the whole linear region as executable and * writable. */ ret = temp_pgtable_mapping(resume_pg_dir, start, end, __pgprot(_PAGE_WRITE | _PAGE_EXEC)); if (ret) return ret; /* Move the restore code to a new page so that it doesn't get overwritten by itself. */ relocated_restore_code = relocate_restore_code(); if (relocated_restore_code == -ENOMEM) return -ENOMEM; /* * Map the __hibernate_cpu_resume() address to the temporary page table so that the * restore code can jumps to it after finished restore the image. The next execution * code doesn't find itself in a different address space after switching over to the * original page table used by the hibernated image. * The __hibernate_cpu_resume() mapping is unnecessary for RV32 since the kernel and * linear addresses are identical, but different for RV64. To ensure consistency, we * map it for both RV32 and RV64 kernels. * Additionally, we should ensure that the page is writable before restoring the image. */ start = (unsigned long)resume_hdr.restore_cpu_addr; end = start + PAGE_SIZE; ret = temp_pgtable_mapping(resume_pg_dir, start, end, __pgprot(_PAGE_WRITE)); if (ret) return ret; hibernate_restore_image(resume_hdr.saved_satp, (PFN_DOWN(__pa(resume_pg_dir)) | satp_mode), resume_hdr.restore_cpu_addr); return 0; } #ifdef CONFIG_PM_SLEEP_SMP int hibernate_resume_nonboot_cpu_disable(void) { if (sleep_cpu < 0) { pr_err("Failing to resume from hibernate on an unknown CPU\n"); return -ENODEV; } return freeze_secondary_cpus(sleep_cpu); } #endif static int __init riscv_hibernate_init(void) { hibernate_cpu_context = kzalloc(sizeof(*hibernate_cpu_context), GFP_KERNEL); if (WARN_ON(!hibernate_cpu_context)) return -ENOMEM; return 0; } early_initcall(riscv_hibernate_init);