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