// SPDX-License-Identifier: GPL-2.0
/*
 * machine_kexec.c - handle transition of Linux booting another kernel
 * Copyright (C) 2002-2003 Eric Biederman  <ebiederm@xmission.com>
 *
 * GameCube/ppc32 port Copyright (C) 2004 Albert Herranz
 * LANDISK/sh4 supported by kogiidena
 */
#include <linux/mm.h>
#include <linux/kexec.h>
#include <linux/delay.h>
#include <linux/reboot.h>
#include <linux/numa.h>
#include <linux/ftrace.h>
#include <linux/suspend.h>
#include <linux/memblock.h>
#include <asm/mmu_context.h>
#include <asm/io.h>
#include <asm/cacheflush.h>
#include <asm/sh_bios.h>
#include <asm/reboot.h>

typedef void (*relocate_new_kernel_t)(unsigned long indirection_page,
                                      unsigned long reboot_code_buffer,
                                      unsigned long start_address);

extern const unsigned char relocate_new_kernel[];
extern const unsigned int relocate_new_kernel_size;
extern void *vbr_base;

void native_machine_crash_shutdown(struct pt_regs *regs)
{
        /* Nothing to do for UP, but definitely broken for SMP.. */
}

/*
 * Do what every setup is needed on image and the
 * reboot code buffer to allow us to avoid allocations
 * later.
 */
int machine_kexec_prepare(struct kimage *image)
{
        return 0;
}

void machine_kexec_cleanup(struct kimage *image)
{
}

static void kexec_info(struct kimage *image)
{
        int i;
        printk("kexec information\n");
        for (i = 0; i < image->nr_segments; i++) {
                printk("  segment[%d]: 0x%08x - 0x%08x (0x%08x)\n",
                       i,
                       (unsigned int)image->segment[i].mem,
                       (unsigned int)image->segment[i].mem +
                                     image->segment[i].memsz,
                       (unsigned int)image->segment[i].memsz);
        }
        printk("  start     : 0x%08x\n\n", (unsigned int)image->start);
}

/*
 * Do not allocate memory (or fail in any way) in machine_kexec().
 * We are past the point of no return, committed to rebooting now.
 */
void machine_kexec(struct kimage *image)
{
        unsigned long page_list;
        unsigned long reboot_code_buffer;
        relocate_new_kernel_t rnk;
        unsigned long entry;
        unsigned long *ptr;
        int save_ftrace_enabled;

        /*
         * Nicked from the mips version of machine_kexec():
         * The generic kexec code builds a page list with physical
         * addresses. Use phys_to_virt() to convert them to virtual.
         */
        for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE);
             ptr = (entry & IND_INDIRECTION) ?
               phys_to_virt(entry & PAGE_MASK) : ptr + 1) {
                if (*ptr & IND_SOURCE || *ptr & IND_INDIRECTION ||
                    *ptr & IND_DESTINATION)
                        *ptr = (unsigned long) phys_to_virt(*ptr);
        }

#ifdef CONFIG_KEXEC_JUMP
        if (image->preserve_context)
                save_processor_state();
#endif

        save_ftrace_enabled = __ftrace_enabled_save();

        /* Interrupts aren't acceptable while we reboot */
        local_irq_disable();

        page_list = image->head;

        /* we need both effective and real address here */
        reboot_code_buffer =
                        (unsigned long)page_address(image->control_code_page);

        /* copy our kernel relocation code to the control code page */
        memcpy((void *)reboot_code_buffer, relocate_new_kernel,
                                                relocate_new_kernel_size);

        kexec_info(image);
        flush_cache_all();

        sh_bios_vbr_reload();

        /* now call it */
        rnk = (relocate_new_kernel_t) reboot_code_buffer;
        (*rnk)(page_list, reboot_code_buffer,
               (unsigned long)phys_to_virt(image->start));

#ifdef CONFIG_KEXEC_JUMP
        asm volatile("ldc %0, vbr" : : "r" (&vbr_base) : "memory");

        if (image->preserve_context)
                restore_processor_state();

        /* Convert page list back to physical addresses, what a mess. */
        for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE);
             ptr = (*ptr & IND_INDIRECTION) ?
               phys_to_virt(*ptr & PAGE_MASK) : ptr + 1) {
                if (*ptr & IND_SOURCE || *ptr & IND_INDIRECTION ||
                    *ptr & IND_DESTINATION)
                        *ptr = virt_to_phys(*ptr);
        }
#endif

        __ftrace_enabled_restore(save_ftrace_enabled);
}

void __init reserve_crashkernel(void)
{
        unsigned long long crash_size, crash_base;
        int ret;

        if (!IS_ENABLED(CONFIG_CRASH_RESERVE))
                return;

        ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
                        &crash_size, &crash_base, NULL, NULL, NULL);
        if (ret == 0 && crash_size > 0) {
                crashk_res.start = crash_base;
                crashk_res.end = crash_base + crash_size - 1;
        }

        if (crashk_res.end == crashk_res.start)
                goto disable;

        crash_size = PAGE_ALIGN(resource_size(&crashk_res));
        if (!crashk_res.start) {
                unsigned long max = memblock_end_of_DRAM() - memory_limit;
                crashk_res.start = memblock_phys_alloc_range(crash_size,
                                                             PAGE_SIZE, 0, max);
                if (!crashk_res.start) {
                        pr_err("crashkernel allocation failed\n");
                        goto disable;
                }
        } else {
                ret = memblock_reserve(crashk_res.start, crash_size);
                if (unlikely(ret < 0)) {
                        pr_err("crashkernel reservation failed - "
                               "memory is in use\n");
                        goto disable;
                }
        }

        crashk_res.end = crashk_res.start + crash_size - 1;

        /*
         * Crash kernel trumps memory limit
         */
        if ((memblock_end_of_DRAM() - memory_limit) <= crashk_res.end) {
                memory_limit = 0;
                pr_info("Disabled memory limit for crashkernel\n");
        }

        pr_info("Reserving %ldMB of memory at 0x%08lx "
                "for crashkernel (System RAM: %ldMB)\n",
                (unsigned long)(crash_size >> 20),
                (unsigned long)(crashk_res.start),
                (unsigned long)(memblock_phys_mem_size() >> 20));

        return;

disable:
        crashk_res.start = crashk_res.end = 0;
}