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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2019 FORTH-ICS/CARV
* Nick Kossifidis <mick@ics.forth.gr>
*/
#include <linux/kexec.h>
#include <asm/kexec.h> /* For riscv_kexec_* symbol defines */
#include <linux/smp.h> /* For smp_send_stop () */
#include <asm/cacheflush.h> /* For local_flush_icache_all() */
#include <asm/barrier.h> /* For smp_wmb() */
#include <asm/page.h> /* For PAGE_MASK */
#include <linux/libfdt.h> /* For fdt_check_header() */
#include <asm/set_memory.h> /* For set_memory_x() */
#include <linux/compiler.h> /* For unreachable() */
#include <linux/cpu.h> /* For cpu_down() */
#include <linux/reboot.h>
/*
* kexec_image_info - Print received image details
*/
static void
kexec_image_info(const struct kimage *image)
{
unsigned long i;
pr_debug("Kexec image info:\n");
pr_debug("\ttype: %d\n", image->type);
pr_debug("\tstart: %lx\n", image->start);
pr_debug("\thead: %lx\n", image->head);
pr_debug("\tnr_segments: %lu\n", image->nr_segments);
for (i = 0; i < image->nr_segments; i++) {
pr_debug("\t segment[%lu]: %016lx - %016lx", i,
image->segment[i].mem,
image->segment[i].mem + image->segment[i].memsz);
pr_debug("\t\t0x%lx bytes, %lu pages\n",
(unsigned long) image->segment[i].memsz,
(unsigned long) image->segment[i].memsz / PAGE_SIZE);
}
}
/*
* machine_kexec_prepare - Initialize kexec
*
* This function is called from do_kexec_load, when the user has
* provided us with an image to be loaded. Its goal is to validate
* the image and prepare the control code buffer as needed.
* Note that kimage_alloc_init has already been called and the
* control buffer has already been allocated.
*/
int
machine_kexec_prepare(struct kimage *image)
{
struct kimage_arch *internal = &image->arch;
struct fdt_header fdt = {0};
void *control_code_buffer = NULL;
unsigned int control_code_buffer_sz = 0;
int i = 0;
kexec_image_info(image);
/* Find the Flattened Device Tree and save its physical address */
for (i = 0; i < image->nr_segments; i++) {
if (image->segment[i].memsz <= sizeof(fdt))
continue;
if (image->file_mode)
memcpy(&fdt, image->segment[i].buf, sizeof(fdt));
else if (copy_from_user(&fdt, image->segment[i].buf, sizeof(fdt)))
continue;
if (fdt_check_header(&fdt))
continue;
internal->fdt_addr = (unsigned long) image->segment[i].mem;
break;
}
if (!internal->fdt_addr) {
pr_err("Device tree not included in the provided image\n");
return -EINVAL;
}
/* Copy the assembler code for relocation to the control page */
if (image->type != KEXEC_TYPE_CRASH) {
control_code_buffer = page_address(image->control_code_page);
control_code_buffer_sz = page_size(image->control_code_page);
if (unlikely(riscv_kexec_relocate_size > control_code_buffer_sz)) {
pr_err("Relocation code doesn't fit within a control page\n");
return -EINVAL;
}
memcpy(control_code_buffer, riscv_kexec_relocate,
riscv_kexec_relocate_size);
/* Mark the control page executable */
set_memory_x((unsigned long) control_code_buffer, 1);
}
return 0;
}
/*
* machine_kexec_cleanup - Cleanup any leftovers from
* machine_kexec_prepare
*
* This function is called by kimage_free to handle any arch-specific
* allocations done on machine_kexec_prepare. Since we didn't do any
* allocations there, this is just an empty function. Note that the
* control buffer is freed by kimage_free.
*/
void
machine_kexec_cleanup(struct kimage *image)
{
}
/*
* machine_shutdown - Prepare for a kexec reboot
*
* This function is called by kernel_kexec just before machine_kexec
* below. Its goal is to prepare the rest of the system (the other
* harts and possibly devices etc) for a kexec reboot.
*/
void machine_shutdown(void)
{
/*
* No more interrupts on this hart
* until we are back up.
*/
local_irq_disable();
#if defined(CONFIG_HOTPLUG_CPU)
smp_shutdown_nonboot_cpus(smp_processor_id());
#endif
}
/* Override the weak function in kernel/panic.c */
void crash_smp_send_stop(void)
{
static int cpus_stopped;
/*
* This function can be called twice in panic path, but obviously
* we execute this only once.
*/
if (cpus_stopped)
return;
smp_send_stop();
cpus_stopped = 1;
}
/*
* machine_crash_shutdown - Prepare to kexec after a kernel crash
*
* This function is called by crash_kexec just before machine_kexec
* and its goal is to 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();
crash_save_cpu(regs, smp_processor_id());
pr_info("Starting crashdump kernel...\n");
}
/*
* machine_kexec - Jump to the loaded kimage
*
* This function is called by kernel_kexec which is called by the
* reboot system call when the reboot cmd is LINUX_REBOOT_CMD_KEXEC,
* or by crash_kernel which is called by the kernel's arch-specific
* trap handler in case of a kernel panic. It's the final stage of
* the kexec process where the pre-loaded kimage is ready to be
* executed. We assume at this point that all other harts are
* suspended and this hart will be the new boot hart.
*/
void __noreturn
machine_kexec(struct kimage *image)
{
struct kimage_arch *internal = &image->arch;
unsigned long jump_addr = (unsigned long) image->start;
unsigned long first_ind_entry = (unsigned long) &image->head;
unsigned long this_cpu_id = __smp_processor_id();
unsigned long this_hart_id = cpuid_to_hartid_map(this_cpu_id);
unsigned long fdt_addr = internal->fdt_addr;
void *control_code_buffer = page_address(image->control_code_page);
riscv_kexec_method kexec_method = NULL;
if (image->type != KEXEC_TYPE_CRASH)
kexec_method = control_code_buffer;
else
kexec_method = (riscv_kexec_method) &riscv_kexec_norelocate;
pr_notice("Will call new kernel at %08lx from hart id %lx\n",
jump_addr, this_hart_id);
pr_notice("FDT image at %08lx\n", fdt_addr);
/* Make sure the relocation code is visible to the hart */
local_flush_icache_all();
/* Jump to the relocation code */
pr_notice("Bye...\n");
kexec_method(first_ind_entry, jump_addr, fdt_addr,
this_hart_id, kernel_map.va_pa_offset);
unreachable();
}
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