// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Firmware-Assisted Dump support on POWERVM platform.
 *
 * Copyright 2011, Mahesh Salgaonkar, IBM Corporation.
 * Copyright 2019, Hari Bathini, IBM Corporation.
 */

#define pr_fmt(fmt) "rtas fadump: " fmt

#include <linux/string.h>
#include <linux/memblock.h>
#include <linux/delay.h>
#include <linux/seq_file.h>
#include <linux/crash_dump.h>

#include <asm/page.h>
#include <asm/prom.h>
#include <asm/rtas.h>
#include <asm/fadump.h>
#include <asm/fadump-internal.h>

#include "rtas-fadump.h"

static struct rtas_fadump_mem_struct fdm;
static const struct rtas_fadump_mem_struct *fdm_active;

static void rtas_fadump_update_config(struct fw_dump *fadump_conf,
                                      const struct rtas_fadump_mem_struct *fdm)
{
        fadump_conf->boot_mem_dest_addr =
                be64_to_cpu(fdm->rmr_region.destination_address);

        fadump_conf->fadumphdr_addr = (fadump_conf->boot_mem_dest_addr +
                                       fadump_conf->boot_memory_size);
}

/*
 * This function is called in the capture kernel to get configuration details
 * setup in the first kernel and passed to the f/w.
 */
static void rtas_fadump_get_config(struct fw_dump *fadump_conf,
                                   const struct rtas_fadump_mem_struct *fdm)
{
        fadump_conf->boot_mem_addr[0] =
                be64_to_cpu(fdm->rmr_region.source_address);
        fadump_conf->boot_mem_sz[0] = be64_to_cpu(fdm->rmr_region.source_len);
        fadump_conf->boot_memory_size = fadump_conf->boot_mem_sz[0];

        fadump_conf->boot_mem_top = fadump_conf->boot_memory_size;
        fadump_conf->boot_mem_regs_cnt = 1;

        /*
         * Start address of reserve dump area (permanent reservation) for
         * re-registering FADump after dump capture.
         */
        fadump_conf->reserve_dump_area_start =
                be64_to_cpu(fdm->cpu_state_data.destination_address);

        rtas_fadump_update_config(fadump_conf, fdm);
}

static u64 rtas_fadump_init_mem_struct(struct fw_dump *fadump_conf)
{
        u64 addr = fadump_conf->reserve_dump_area_start;

        memset(&fdm, 0, sizeof(struct rtas_fadump_mem_struct));
        addr = addr & PAGE_MASK;

        fdm.header.dump_format_version = cpu_to_be32(0x00000001);
        fdm.header.dump_num_sections = cpu_to_be16(3);
        fdm.header.dump_status_flag = 0;
        fdm.header.offset_first_dump_section =
                cpu_to_be32((u32)offsetof(struct rtas_fadump_mem_struct,
                                          cpu_state_data));

        /*
         * Fields for disk dump option.
         * We are not using disk dump option, hence set these fields to 0.
         */
        fdm.header.dd_block_size = 0;
        fdm.header.dd_block_offset = 0;
        fdm.header.dd_num_blocks = 0;
        fdm.header.dd_offset_disk_path = 0;

        /* set 0 to disable an automatic dump-reboot. */
        fdm.header.max_time_auto = 0;

        /* Kernel dump sections */
        /* cpu state data section. */
        fdm.cpu_state_data.request_flag =
                cpu_to_be32(RTAS_FADUMP_REQUEST_FLAG);
        fdm.cpu_state_data.source_data_type =
                cpu_to_be16(RTAS_FADUMP_CPU_STATE_DATA);
        fdm.cpu_state_data.source_address = 0;
        fdm.cpu_state_data.source_len =
                cpu_to_be64(fadump_conf->cpu_state_data_size);
        fdm.cpu_state_data.destination_address = cpu_to_be64(addr);
        addr += fadump_conf->cpu_state_data_size;

        /* hpte region section */
        fdm.hpte_region.request_flag = cpu_to_be32(RTAS_FADUMP_REQUEST_FLAG);
        fdm.hpte_region.source_data_type =
                cpu_to_be16(RTAS_FADUMP_HPTE_REGION);
        fdm.hpte_region.source_address = 0;
        fdm.hpte_region.source_len =
                cpu_to_be64(fadump_conf->hpte_region_size);
        fdm.hpte_region.destination_address = cpu_to_be64(addr);
        addr += fadump_conf->hpte_region_size;

        /* RMA region section */
        fdm.rmr_region.request_flag = cpu_to_be32(RTAS_FADUMP_REQUEST_FLAG);
        fdm.rmr_region.source_data_type =
                cpu_to_be16(RTAS_FADUMP_REAL_MODE_REGION);
        fdm.rmr_region.source_address = cpu_to_be64(0);
        fdm.rmr_region.source_len = cpu_to_be64(fadump_conf->boot_memory_size);
        fdm.rmr_region.destination_address = cpu_to_be64(addr);
        addr += fadump_conf->boot_memory_size;

        rtas_fadump_update_config(fadump_conf, &fdm);

        return addr;
}

static u64 rtas_fadump_get_bootmem_min(void)
{
        return RTAS_FADUMP_MIN_BOOT_MEM;
}

static int rtas_fadump_register(struct fw_dump *fadump_conf)
{
        unsigned int wait_time;
        int rc, err = -EIO;

        /* TODO: Add upper time limit for the delay */
        do {
                rc =  rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1,
                                NULL, FADUMP_REGISTER, &fdm,
                                sizeof(struct rtas_fadump_mem_struct));

                wait_time = rtas_busy_delay_time(rc);
                if (wait_time)
                        mdelay(wait_time);

        } while (wait_time);

        switch (rc) {
        case 0:
                pr_info("Registration is successful!\n");
                fadump_conf->dump_registered = 1;
                err = 0;
                break;
        case -1:
                pr_err("Failed to register. Hardware Error(%d).\n", rc);
                break;
        case -3:
                if (!is_fadump_boot_mem_contiguous())
                        pr_err("Can't have holes in boot memory area.\n");
                else if (!is_fadump_reserved_mem_contiguous())
                        pr_err("Can't have holes in reserved memory area.\n");

                pr_err("Failed to register. Parameter Error(%d).\n", rc);
                err = -EINVAL;
                break;
        case -9:
                pr_err("Already registered!\n");
                fadump_conf->dump_registered = 1;
                err = -EEXIST;
                break;
        default:
                pr_err("Failed to register. Unknown Error(%d).\n", rc);
                break;
        }

        return err;
}

static int rtas_fadump_unregister(struct fw_dump *fadump_conf)
{
        unsigned int wait_time;
        int rc;

        /* TODO: Add upper time limit for the delay */
        do {
                rc =  rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1,
                                NULL, FADUMP_UNREGISTER, &fdm,
                                sizeof(struct rtas_fadump_mem_struct));

                wait_time = rtas_busy_delay_time(rc);
                if (wait_time)
                        mdelay(wait_time);
        } while (wait_time);

        if (rc) {
                pr_err("Failed to un-register - unexpected error(%d).\n", rc);
                return -EIO;
        }

        fadump_conf->dump_registered = 0;
        return 0;
}

static int rtas_fadump_invalidate(struct fw_dump *fadump_conf)
{
        unsigned int wait_time;
        int rc;

        /* TODO: Add upper time limit for the delay */
        do {
                rc =  rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1,
                                NULL, FADUMP_INVALIDATE, fdm_active,
                                sizeof(struct rtas_fadump_mem_struct));

                wait_time = rtas_busy_delay_time(rc);
                if (wait_time)
                        mdelay(wait_time);
        } while (wait_time);

        if (rc) {
                pr_err("Failed to invalidate - unexpected error (%d).\n", rc);
                return -EIO;
        }

        fadump_conf->dump_active = 0;
        fdm_active = NULL;
        return 0;
}

#define RTAS_FADUMP_GPR_MASK            0xffffff0000000000
static inline int rtas_fadump_gpr_index(u64 id)
{
        char str[3];
        int i = -1;

        if ((id & RTAS_FADUMP_GPR_MASK) == fadump_str_to_u64("GPR")) {
                /* get the digits at the end */
                id &= ~RTAS_FADUMP_GPR_MASK;
                id >>= 24;
                str[2] = '\0';
                str[1] = id & 0xff;
                str[0] = (id >> 8) & 0xff;
                if (kstrtoint(str, 10, &i))
                        i = -EINVAL;
                if (i > 31)
                        i = -1;
        }
        return i;
}

static void rtas_fadump_set_regval(struct pt_regs *regs, u64 reg_id, u64 reg_val)
{
        int i;

        i = rtas_fadump_gpr_index(reg_id);
        if (i >= 0)
                regs->gpr[i] = (unsigned long)reg_val;
        else if (reg_id == fadump_str_to_u64("NIA"))
                regs->nip = (unsigned long)reg_val;
        else if (reg_id == fadump_str_to_u64("MSR"))
                regs->msr = (unsigned long)reg_val;
        else if (reg_id == fadump_str_to_u64("CTR"))
                regs->ctr = (unsigned long)reg_val;
        else if (reg_id == fadump_str_to_u64("LR"))
                regs->link = (unsigned long)reg_val;
        else if (reg_id == fadump_str_to_u64("XER"))
                regs->xer = (unsigned long)reg_val;
        else if (reg_id == fadump_str_to_u64("CR"))
                regs->ccr = (unsigned long)reg_val;
        else if (reg_id == fadump_str_to_u64("DAR"))
                regs->dar = (unsigned long)reg_val;
        else if (reg_id == fadump_str_to_u64("DSISR"))
                regs->dsisr = (unsigned long)reg_val;
}

static struct rtas_fadump_reg_entry*
rtas_fadump_read_regs(struct rtas_fadump_reg_entry *reg_entry,
                      struct pt_regs *regs)
{
        memset(regs, 0, sizeof(struct pt_regs));

        while (be64_to_cpu(reg_entry->reg_id) != fadump_str_to_u64("CPUEND")) {
                rtas_fadump_set_regval(regs, be64_to_cpu(reg_entry->reg_id),
                                       be64_to_cpu(reg_entry->reg_value));
                reg_entry++;
        }
        reg_entry++;
        return reg_entry;
}

/*
 * Read CPU state dump data and convert it into ELF notes.
 * The CPU dump starts with magic number "REGSAVE". NumCpusOffset should be
 * used to access the data to allow for additional fields to be added without
 * affecting compatibility. Each list of registers for a CPU starts with
 * "CPUSTRT" and ends with "CPUEND". Each register entry is of 16 bytes,
 * 8 Byte ASCII identifier and 8 Byte register value. The register entry
 * with identifier "CPUSTRT" and "CPUEND" contains 4 byte cpu id as part
 * of register value. For more details refer to PAPR document.
 *
 * Only for the crashing cpu we ignore the CPU dump data and get exact
 * state from fadump crash info structure populated by first kernel at the
 * time of crash.
 */
static int __init rtas_fadump_build_cpu_notes(struct fw_dump *fadump_conf)
{
        struct rtas_fadump_reg_save_area_header *reg_header;
        struct fadump_crash_info_header *fdh = NULL;
        struct rtas_fadump_reg_entry *reg_entry;
        u32 num_cpus, *note_buf;
        int i, rc = 0, cpu = 0;
        struct pt_regs regs;
        unsigned long addr;
        void *vaddr;

        addr = be64_to_cpu(fdm_active->cpu_state_data.destination_address);
        vaddr = __va(addr);

        reg_header = vaddr;
        if (be64_to_cpu(reg_header->magic_number) !=
            fadump_str_to_u64("REGSAVE")) {
                pr_err("Unable to read register save area.\n");
                return -ENOENT;
        }

        pr_debug("--------CPU State Data------------\n");
        pr_debug("Magic Number: %llx\n", be64_to_cpu(reg_header->magic_number));
        pr_debug("NumCpuOffset: %x\n", be32_to_cpu(reg_header->num_cpu_offset));

        vaddr += be32_to_cpu(reg_header->num_cpu_offset);
        num_cpus = be32_to_cpu(*((__be32 *)(vaddr)));
        pr_debug("NumCpus     : %u\n", num_cpus);
        vaddr += sizeof(u32);
        reg_entry = (struct rtas_fadump_reg_entry *)vaddr;

        rc = fadump_setup_cpu_notes_buf(num_cpus);
        if (rc != 0)
                return rc;

        note_buf = (u32 *)fadump_conf->cpu_notes_buf_vaddr;

        if (fadump_conf->fadumphdr_addr)
                fdh = __va(fadump_conf->fadumphdr_addr);

        for (i = 0; i < num_cpus; i++) {
                if (be64_to_cpu(reg_entry->reg_id) !=
                    fadump_str_to_u64("CPUSTRT")) {
                        pr_err("Unable to read CPU state data\n");
                        rc = -ENOENT;
                        goto error_out;
                }
                /* Lower 4 bytes of reg_value contains logical cpu id */
                cpu = (be64_to_cpu(reg_entry->reg_value) &
                       RTAS_FADUMP_CPU_ID_MASK);
                if (fdh && !cpumask_test_cpu(cpu, &fdh->online_mask)) {
                        RTAS_FADUMP_SKIP_TO_NEXT_CPU(reg_entry);
                        continue;
                }
                pr_debug("Reading register data for cpu %d...\n", cpu);
                if (fdh && fdh->crashing_cpu == cpu) {
                        regs = fdh->regs;
                        note_buf = fadump_regs_to_elf_notes(note_buf, &regs);
                        RTAS_FADUMP_SKIP_TO_NEXT_CPU(reg_entry);
                } else {
                        reg_entry++;
                        reg_entry = rtas_fadump_read_regs(reg_entry, &regs);
                        note_buf = fadump_regs_to_elf_notes(note_buf, &regs);
                }
        }
        final_note(note_buf);

        if (fdh) {
                pr_debug("Updating elfcore header (%llx) with cpu notes\n",
                         fdh->elfcorehdr_addr);
                fadump_update_elfcore_header(__va(fdh->elfcorehdr_addr));
        }
        return 0;

error_out:
        fadump_free_cpu_notes_buf();
        return rc;

}

/*
 * Validate and process the dump data stored by firmware before exporting
 * it through '/proc/vmcore'.
 */
static int __init rtas_fadump_process(struct fw_dump *fadump_conf)
{
        struct fadump_crash_info_header *fdh;
        int rc = 0;

        if (!fdm_active || !fadump_conf->fadumphdr_addr)
                return -EINVAL;

        /* Check if the dump data is valid. */
        if ((be16_to_cpu(fdm_active->header.dump_status_flag) ==
                        RTAS_FADUMP_ERROR_FLAG) ||
                        (fdm_active->cpu_state_data.error_flags != 0) ||
                        (fdm_active->rmr_region.error_flags != 0)) {
                pr_err("Dump taken by platform is not valid\n");
                return -EINVAL;
        }
        if ((fdm_active->rmr_region.bytes_dumped !=
                        fdm_active->rmr_region.source_len) ||
                        !fdm_active->cpu_state_data.bytes_dumped) {
                pr_err("Dump taken by platform is incomplete\n");
                return -EINVAL;
        }

        /* Validate the fadump crash info header */
        fdh = __va(fadump_conf->fadumphdr_addr);
        if (fdh->magic_number != FADUMP_CRASH_INFO_MAGIC) {
                pr_err("Crash info header is not valid.\n");
                return -EINVAL;
        }

        rc = rtas_fadump_build_cpu_notes(fadump_conf);
        if (rc)
                return rc;

        /*
         * We are done validating dump info and elfcore header is now ready
         * to be exported. set elfcorehdr_addr so that vmcore module will
         * export the elfcore header through '/proc/vmcore'.
         */
        elfcorehdr_addr = fdh->elfcorehdr_addr;

        return 0;
}

static void rtas_fadump_region_show(struct fw_dump *fadump_conf,
                                    struct seq_file *m)
{
        const struct rtas_fadump_section *cpu_data_section;
        const struct rtas_fadump_mem_struct *fdm_ptr;

        if (fdm_active)
                fdm_ptr = fdm_active;
        else
                fdm_ptr = &fdm;

        cpu_data_section = &(fdm_ptr->cpu_state_data);
        seq_printf(m, "CPU :[%#016llx-%#016llx] %#llx bytes, Dumped: %#llx\n",
                   be64_to_cpu(cpu_data_section->destination_address),
                   be64_to_cpu(cpu_data_section->destination_address) +
                   be64_to_cpu(cpu_data_section->source_len) - 1,
                   be64_to_cpu(cpu_data_section->source_len),
                   be64_to_cpu(cpu_data_section->bytes_dumped));

        seq_printf(m, "HPTE:[%#016llx-%#016llx] %#llx bytes, Dumped: %#llx\n",
                   be64_to_cpu(fdm_ptr->hpte_region.destination_address),
                   be64_to_cpu(fdm_ptr->hpte_region.destination_address) +
                   be64_to_cpu(fdm_ptr->hpte_region.source_len) - 1,
                   be64_to_cpu(fdm_ptr->hpte_region.source_len),
                   be64_to_cpu(fdm_ptr->hpte_region.bytes_dumped));

        seq_printf(m, "DUMP: Src: %#016llx, Dest: %#016llx, ",
                   be64_to_cpu(fdm_ptr->rmr_region.source_address),
                   be64_to_cpu(fdm_ptr->rmr_region.destination_address));
        seq_printf(m, "Size: %#llx, Dumped: %#llx bytes\n",
                   be64_to_cpu(fdm_ptr->rmr_region.source_len),
                   be64_to_cpu(fdm_ptr->rmr_region.bytes_dumped));

        /* Dump is active. Show reserved area start address. */
        if (fdm_active) {
                seq_printf(m, "\nMemory above %#016lx is reserved for saving crash dump\n",
                           fadump_conf->reserve_dump_area_start);
        }
}

static void rtas_fadump_trigger(struct fadump_crash_info_header *fdh,
                                const char *msg)
{
        /* Call ibm,os-term rtas call to trigger firmware assisted dump */
        rtas_os_term((char *)msg);
}

static struct fadump_ops rtas_fadump_ops = {
        .fadump_init_mem_struct         = rtas_fadump_init_mem_struct,
        .fadump_get_bootmem_min         = rtas_fadump_get_bootmem_min,
        .fadump_register                = rtas_fadump_register,
        .fadump_unregister              = rtas_fadump_unregister,
        .fadump_invalidate              = rtas_fadump_invalidate,
        .fadump_process                 = rtas_fadump_process,
        .fadump_region_show             = rtas_fadump_region_show,
        .fadump_trigger                 = rtas_fadump_trigger,
};

void __init rtas_fadump_dt_scan(struct fw_dump *fadump_conf, u64 node)
{
        int i, size, num_sections;
        const __be32 *sections;
        const __be32 *token;

        /*
         * Check if Firmware Assisted dump is supported. if yes, check
         * if dump has been initiated on last reboot.
         */
        token = of_get_flat_dt_prop(node, "ibm,configure-kernel-dump", NULL);
        if (!token)
                return;

        fadump_conf->ibm_configure_kernel_dump = be32_to_cpu(*token);
        fadump_conf->ops                = &rtas_fadump_ops;
        fadump_conf->fadump_supported   = 1;

        /* Firmware supports 64-bit value for size, align it to pagesize. */
        fadump_conf->max_copy_size = ALIGN_DOWN(U64_MAX, PAGE_SIZE);

        /*
         * The 'ibm,kernel-dump' rtas node is present only if there is
         * dump data waiting for us.
         */
        fdm_active = of_get_flat_dt_prop(node, "ibm,kernel-dump", NULL);
        if (fdm_active) {
                pr_info("Firmware-assisted dump is active.\n");
                fadump_conf->dump_active = 1;
                rtas_fadump_get_config(fadump_conf, (void *)__pa(fdm_active));
        }

        /* Get the sizes required to store dump data for the firmware provided
         * dump sections.
         * For each dump section type supported, a 32bit cell which defines
         * the ID of a supported section followed by two 32 bit cells which
         * gives the size of the section in bytes.
         */
        sections = of_get_flat_dt_prop(node, "ibm,configure-kernel-dump-sizes",
                                        &size);

        if (!sections)
                return;

        num_sections = size / (3 * sizeof(u32));

        for (i = 0; i < num_sections; i++, sections += 3) {
                u32 type = (u32)of_read_number(sections, 1);

                switch (type) {
                case RTAS_FADUMP_CPU_STATE_DATA:
                        fadump_conf->cpu_state_data_size =
                                        of_read_ulong(&sections[1], 2);
                        break;
                case RTAS_FADUMP_HPTE_REGION:
                        fadump_conf->hpte_region_size =
                                        of_read_ulong(&sections[1], 2);
                        break;
                }
        }
}