// SPDX-License-Identifier: GPL-2.0-only /* * kexec for arm64 * * Copyright (C) Linaro. * Copyright (C) Huawei Futurewei Technologies. */ #include <linux/interrupt.h> #include <linux/irq.h> #include <linux/kernel.h> #include <linux/kexec.h> #include <linux/page-flags.h> #include <linux/set_memory.h> #include <linux/smp.h> #include <asm/cacheflush.h> #include <asm/cpu_ops.h> #include <asm/daifflags.h> #include <asm/memory.h> #include <asm/mmu.h> #include <asm/mmu_context.h> #include <asm/page.h> #include "cpu-reset.h" /* Global variables for the arm64_relocate_new_kernel routine. */ extern const unsigned char arm64_relocate_new_kernel[]; extern const unsigned long arm64_relocate_new_kernel_size; /** * kexec_image_info - For debugging output. */ #define kexec_image_info(_i) _kexec_image_info(__func__, __LINE__, _i) static void _kexec_image_info(const char *func, int line, const struct kimage *kimage) { unsigned long i; pr_debug("%s:%d:\n", func, line); pr_debug(" kexec kimage info:\n"); pr_debug(" type: %d\n", kimage->type); pr_debug(" start: %lx\n", kimage->start); pr_debug(" head: %lx\n", kimage->head); pr_debug(" nr_segments: %lu\n", kimage->nr_segments); pr_debug(" kern_reloc: %pa\n", &kimage->arch.kern_reloc); for (i = 0; i < kimage->nr_segments; i++) { pr_debug(" segment[%lu]: %016lx - %016lx, 0x%lx bytes, %lu pages\n", i, kimage->segment[i].mem, kimage->segment[i].mem + kimage->segment[i].memsz, kimage->segment[i].memsz, kimage->segment[i].memsz / PAGE_SIZE); } } void machine_kexec_cleanup(struct kimage *kimage) { /* Empty routine needed to avoid build errors. */ } int machine_kexec_post_load(struct kimage *kimage) { void *reloc_code = page_to_virt(kimage->control_code_page); memcpy(reloc_code, arm64_relocate_new_kernel, arm64_relocate_new_kernel_size); kimage->arch.kern_reloc = __pa(reloc_code); kexec_image_info(kimage); /* * For execution with the MMU off, reloc_code needs to be cleaned to the * PoC and invalidated from the I-cache. */ dcache_clean_inval_poc((unsigned long)reloc_code, (unsigned long)reloc_code + arm64_relocate_new_kernel_size); icache_inval_pou((uintptr_t)reloc_code, (uintptr_t)reloc_code + arm64_relocate_new_kernel_size); return 0; } /** * machine_kexec_prepare - Prepare for a kexec reboot. * * Called from the core kexec code when a kernel image is loaded. * Forbid loading a kexec kernel if we have no way of hotplugging cpus or cpus * are stuck in the kernel. This avoids a panic once we hit machine_kexec(). */ int machine_kexec_prepare(struct kimage *kimage) { if (kimage->type != KEXEC_TYPE_CRASH && cpus_are_stuck_in_kernel()) { pr_err("Can't kexec: CPUs are stuck in the kernel.\n"); return -EBUSY; } return 0; } /** * kexec_list_flush - Helper to flush the kimage list and source pages to PoC. */ static void kexec_list_flush(struct kimage *kimage) { kimage_entry_t *entry; for (entry = &kimage->head; ; entry++) { unsigned int flag; unsigned long addr; /* flush the list entries. */ dcache_clean_inval_poc((unsigned long)entry, (unsigned long)entry + sizeof(kimage_entry_t)); flag = *entry & IND_FLAGS; if (flag == IND_DONE) break; addr = (unsigned long)phys_to_virt(*entry & PAGE_MASK); switch (flag) { case IND_INDIRECTION: /* Set entry point just before the new list page. */ entry = (kimage_entry_t *)addr - 1; break; case IND_SOURCE: /* flush the source pages. */ dcache_clean_inval_poc(addr, addr + PAGE_SIZE); break; case IND_DESTINATION: break; default: BUG(); } } } /** * kexec_segment_flush - Helper to flush the kimage segments to PoC. */ static void kexec_segment_flush(const struct kimage *kimage) { unsigned long i; pr_debug("%s:\n", __func__); for (i = 0; i < kimage->nr_segments; i++) { pr_debug(" segment[%lu]: %016lx - %016lx, 0x%lx bytes, %lu pages\n", i, kimage->segment[i].mem, kimage->segment[i].mem + kimage->segment[i].memsz, kimage->segment[i].memsz, kimage->segment[i].memsz / PAGE_SIZE); dcache_clean_inval_poc( (unsigned long)phys_to_virt(kimage->segment[i].mem), (unsigned long)phys_to_virt(kimage->segment[i].mem) + kimage->segment[i].memsz); } } /** * machine_kexec - Do the kexec reboot. * * Called from the core kexec code for a sys_reboot with LINUX_REBOOT_CMD_KEXEC. */ void machine_kexec(struct kimage *kimage) { bool in_kexec_crash = (kimage == kexec_crash_image); bool stuck_cpus = cpus_are_stuck_in_kernel(); /* * New cpus may have become stuck_in_kernel after we loaded the image. */ BUG_ON(!in_kexec_crash && (stuck_cpus || (num_online_cpus() > 1))); WARN(in_kexec_crash && (stuck_cpus || smp_crash_stop_failed()), "Some CPUs may be stale, kdump will be unreliable.\n"); /* Flush the kimage list and its buffers. */ kexec_list_flush(kimage); /* Flush the new image if already in place. */ if ((kimage != kexec_crash_image) && (kimage->head & IND_DONE)) kexec_segment_flush(kimage); pr_info("Bye!\n"); local_daif_mask(); /* * cpu_soft_restart will shutdown the MMU, disable data caches, then * transfer control to the kern_reloc which contains a copy of * the arm64_relocate_new_kernel routine. arm64_relocate_new_kernel * uses physical addressing to relocate the new image to its final * position and transfers control to the image entry point when the * relocation is complete. * In kexec case, kimage->start points to purgatory assuming that * kernel entry and dtb address are embedded in purgatory by * userspace (kexec-tools). * In kexec_file case, the kernel starts directly without purgatory. */ cpu_soft_restart(kimage->arch.kern_reloc, kimage->head, kimage->start, kimage->arch.dtb_mem); BUG(); /* Should never get here. */ } static void machine_kexec_mask_interrupts(void) { unsigned int i; struct irq_desc *desc; for_each_irq_desc(i, desc) { struct irq_chip *chip; int ret; chip = irq_desc_get_chip(desc); if (!chip) continue; /* * First try to remove the active state. If this * fails, try to EOI the interrupt. */ ret = irq_set_irqchip_state(i, IRQCHIP_STATE_ACTIVE, false); if (ret && irqd_irq_inprogress(&desc->irq_data) && chip->irq_eoi) chip->irq_eoi(&desc->irq_data); if (chip->irq_mask) chip->irq_mask(&desc->irq_data); if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data)) chip->irq_disable(&desc->irq_data); } } /** * machine_crash_shutdown - shutdown non-crashing cpus and save registers */ void machine_crash_shutdown(struct pt_regs *regs) { local_irq_disable(); /* shutdown non-crashing cpus */ crash_smp_send_stop(); /* for crashing cpu */ crash_save_cpu(regs, smp_processor_id()); machine_kexec_mask_interrupts(); pr_info("Starting crashdump kernel...\n"); } void arch_kexec_protect_crashkres(void) { int i; kexec_segment_flush(kexec_crash_image); for (i = 0; i < kexec_crash_image->nr_segments; i++) set_memory_valid( __phys_to_virt(kexec_crash_image->segment[i].mem), kexec_crash_image->segment[i].memsz >> PAGE_SHIFT, 0); } void arch_kexec_unprotect_crashkres(void) { int i; for (i = 0; i < kexec_crash_image->nr_segments; i++) set_memory_valid( __phys_to_virt(kexec_crash_image->segment[i].mem), kexec_crash_image->segment[i].memsz >> PAGE_SHIFT, 1); } #ifdef CONFIG_HIBERNATION /* * To preserve the crash dump kernel image, the relevant memory segments * should be mapped again around the hibernation. */ void crash_prepare_suspend(void) { if (kexec_crash_image) arch_kexec_unprotect_crashkres(); } void crash_post_resume(void) { if (kexec_crash_image) arch_kexec_protect_crashkres(); } /* * crash_is_nosave * * Return true only if a page is part of reserved memory for crash dump kernel, * but does not hold any data of loaded kernel image. * * Note that all the pages in crash dump kernel memory have been initially * marked as Reserved as memory was allocated via memblock_reserve(). * * In hibernation, the pages which are Reserved and yet "nosave" are excluded * from the hibernation iamge. crash_is_nosave() does thich check for crash * dump kernel and will reduce the total size of hibernation image. */ bool crash_is_nosave(unsigned long pfn) { int i; phys_addr_t addr; if (!crashk_res.end) return false; /* in reserved memory? */ addr = __pfn_to_phys(pfn); if ((addr < crashk_res.start) || (crashk_res.end < addr)) return false; if (!kexec_crash_image) return true; /* not part of loaded kernel image? */ for (i = 0; i < kexec_crash_image->nr_segments; i++) if (addr >= kexec_crash_image->segment[i].mem && addr < (kexec_crash_image->segment[i].mem + kexec_crash_image->segment[i].memsz)) return false; return true; } void crash_free_reserved_phys_range(unsigned long begin, unsigned long end) { unsigned long addr; struct page *page; for (addr = begin; addr < end; addr += PAGE_SIZE) { page = phys_to_page(addr); free_reserved_page(page); } } #endif /* CONFIG_HIBERNATION */