![Geoff Levand](/assets/img/avatar_default.png)
To aid in debugging kexec problems or when adding new functionality to kexec add a new routine kexec_image_info() and several inline pr_debug statements. Signed-off-by: Geoff Levand <geoff@infradead.org> Reviewed-by: James Morse <james.morse@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
213 lines
5.8 KiB
C
213 lines
5.8 KiB
C
/*
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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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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kexec.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/mmu_context.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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static unsigned long kimage_start;
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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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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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/**
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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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kimage_start = kimage->start;
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kexec_image_info(kimage);
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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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phys_addr_t reboot_code_buffer_phys;
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void *reboot_code_buffer;
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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(cpus_are_stuck_in_kernel() || (num_online_cpus() > 1));
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reboot_code_buffer_phys = page_to_phys(kimage->control_code_page);
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reboot_code_buffer = phys_to_virt(reboot_code_buffer_phys);
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kexec_image_info(kimage);
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pr_debug("%s:%d: control_code_page: %p\n", __func__, __LINE__,
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kimage->control_code_page);
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pr_debug("%s:%d: reboot_code_buffer_phys: %pa\n", __func__, __LINE__,
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&reboot_code_buffer_phys);
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pr_debug("%s:%d: reboot_code_buffer: %p\n", __func__, __LINE__,
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reboot_code_buffer);
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pr_debug("%s:%d: relocate_new_kernel: %p\n", __func__, __LINE__,
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arm64_relocate_new_kernel);
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pr_debug("%s:%d: relocate_new_kernel_size: 0x%lx(%lu) bytes\n",
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__func__, __LINE__, arm64_relocate_new_kernel_size,
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arm64_relocate_new_kernel_size);
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/*
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* Copy arm64_relocate_new_kernel to the reboot_code_buffer for use
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* after the kernel is shut down.
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*/
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memcpy(reboot_code_buffer, arm64_relocate_new_kernel,
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arm64_relocate_new_kernel_size);
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/* Flush the reboot_code_buffer in preparation for its execution. */
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__flush_dcache_area(reboot_code_buffer, arm64_relocate_new_kernel_size);
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flush_icache_range((uintptr_t)reboot_code_buffer,
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arm64_relocate_new_kernel_size);
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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->head & IND_DONE)
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kexec_segment_flush(kimage);
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pr_info("Bye!\n");
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/* Disable all DAIF exceptions. */
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asm volatile ("msr daifset, #0xf" : : : "memory");
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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 reboot_code_buffer 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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*/
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cpu_soft_restart(1, reboot_code_buffer_phys, kimage->head,
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kimage_start, 0);
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BUG(); /* Should never get here. */
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}
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void machine_crash_shutdown(struct pt_regs *regs)
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{
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/* Empty routine needed to avoid build errors. */
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}
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