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/*
* kexec for arm64
*
* Copyright (C) Linaro.
* Copyright (C) Huawei Futurewei Technologies.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kexec.h>
#include <linux/smp.h>
#include <asm/cacheflush.h>
#include <asm/cpu_ops.h>
#include <asm/mmu_context.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;
static unsigned long kimage_start;
/**
* 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);
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. */
}
/**
* 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)
{
kimage_start = kimage->start;
kexec_image_info(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;
void *addr;
/* flush the list entries. */
__flush_dcache_area(entry, sizeof(kimage_entry_t));
flag = *entry & IND_FLAGS;
if (flag == IND_DONE)
break;
addr = 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. */
__flush_dcache_area(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);
__flush_dcache_area(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)
{
phys_addr_t reboot_code_buffer_phys;
void *reboot_code_buffer;
/*
* New cpus may have become stuck_in_kernel after we loaded the image.
*/
BUG_ON(cpus_are_stuck_in_kernel() || (num_online_cpus() > 1));
reboot_code_buffer_phys = page_to_phys(kimage->control_code_page);
reboot_code_buffer = phys_to_virt(reboot_code_buffer_phys);
kexec_image_info(kimage);
pr_debug("%s:%d: control_code_page: %p\n", __func__, __LINE__,
kimage->control_code_page);
pr_debug("%s:%d: reboot_code_buffer_phys: %pa\n", __func__, __LINE__,
&reboot_code_buffer_phys);
pr_debug("%s:%d: reboot_code_buffer: %p\n", __func__, __LINE__,
reboot_code_buffer);
pr_debug("%s:%d: relocate_new_kernel: %p\n", __func__, __LINE__,
arm64_relocate_new_kernel);
pr_debug("%s:%d: relocate_new_kernel_size: 0x%lx(%lu) bytes\n",
__func__, __LINE__, arm64_relocate_new_kernel_size,
arm64_relocate_new_kernel_size);
/*
* Copy arm64_relocate_new_kernel to the reboot_code_buffer for use
* after the kernel is shut down.
*/
memcpy(reboot_code_buffer, arm64_relocate_new_kernel,
arm64_relocate_new_kernel_size);
/* Flush the reboot_code_buffer in preparation for its execution. */
__flush_dcache_area(reboot_code_buffer, arm64_relocate_new_kernel_size);
flush_icache_range((uintptr_t)reboot_code_buffer,
arm64_relocate_new_kernel_size);
/* Flush the kimage list and its buffers. */
kexec_list_flush(kimage);
/* Flush the new image if already in place. */
if (kimage->head & IND_DONE)
kexec_segment_flush(kimage);
pr_info("Bye!\n");
/* Disable all DAIF exceptions. */
asm volatile ("msr daifset, #0xf" : : : "memory");
/*
* cpu_soft_restart will shutdown the MMU, disable data caches, then
* transfer control to the reboot_code_buffer 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.
*/
cpu_soft_restart(1, reboot_code_buffer_phys, kimage->head,
kimage_start, 0);
BUG(); /* Should never get here. */
}
void machine_crash_shutdown(struct pt_regs *regs)
{
/* Empty routine needed to avoid build errors. */
}
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