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