--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Hibernation support for RISCV
+ *
+ * Copyright (C) 2023 StarFive Technology Co., Ltd.
+ *
+ * Author: Jee Heng Sia <jeeheng.sia@starfivetech.com>
+ */
+
+#include <asm/barrier.h>
+#include <asm/cacheflush.h>
+#include <asm/mmu_context.h>
+#include <asm/page.h>
+#include <asm/pgalloc.h>
+#include <asm/pgtable.h>
+#include <asm/sections.h>
+#include <asm/set_memory.h>
+#include <asm/smp.h>
+#include <asm/suspend.h>
+
+#include <linux/cpu.h>
+#include <linux/memblock.h>
+#include <linux/pm.h>
+#include <linux/sched.h>
+#include <linux/suspend.h>
+#include <linux/utsname.h>
+
+/* 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 the 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)
+{
+ WARN_ON(num_online_cpus() != 1);
+}
+
+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);
projects / platform / kernel / linux-starfive.git / commitdiff