/*
 * apei-base.c - ACPI Platform Error Interface (APEI) supporting
 * infrastructure
 *
 * APEI allows to report errors (for example from the chipset) to the
 * the operating system. This improves NMI handling especially. In
 * addition it supports error serialization and error injection.
 *
 * For more information about APEI, please refer to ACPI Specification
 * version 4.0, chapter 17.
 *
 * This file has Common functions used by more than one APEI table,
 * including framework of interpreter for ERST and EINJ; resource
 * management for APEI registers.
 *
 * Copyright (C) 2009, Intel Corp.
 *      Author: Huang Ying <ying.huang@intel.com>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/acpi.h>
#include <linux/acpi_io.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/kref.h>
#include <linux/rculist.h>
#include <linux/interrupt.h>
#include <linux/debugfs.h>

#include "apei-internal.h"

#define APEI_PFX "APEI: "

/*
 * APEI ERST (Error Record Serialization Table) and EINJ (Error
 * INJection) interpreter framework.
 */

#define APEI_EXEC_PRESERVE_REGISTER     0x1

void apei_exec_ctx_init(struct apei_exec_context *ctx,
                        struct apei_exec_ins_type *ins_table,
                        u32 instructions,
                        struct acpi_whea_header *action_table,
                        u32 entries)
{
        ctx->ins_table = ins_table;
        ctx->instructions = instructions;
        ctx->action_table = action_table;
        ctx->entries = entries;
}
EXPORT_SYMBOL_GPL(apei_exec_ctx_init);

int __apei_exec_read_register(struct acpi_whea_header *entry, u64 *val)
{
        int rc;

        rc = apei_read(val, &entry->register_region);
        if (rc)
                return rc;
        *val >>= entry->register_region.bit_offset;
        *val &= entry->mask;

        return 0;
}

int apei_exec_read_register(struct apei_exec_context *ctx,
                            struct acpi_whea_header *entry)
{
        int rc;
        u64 val = 0;

        rc = __apei_exec_read_register(entry, &val);
        if (rc)
                return rc;
        ctx->value = val;

        return 0;
}
EXPORT_SYMBOL_GPL(apei_exec_read_register);

int apei_exec_read_register_value(struct apei_exec_context *ctx,
                                  struct acpi_whea_header *entry)
{
        int rc;

        rc = apei_exec_read_register(ctx, entry);
        if (rc)
                return rc;
        ctx->value = (ctx->value == entry->value);

        return 0;
}
EXPORT_SYMBOL_GPL(apei_exec_read_register_value);

int __apei_exec_write_register(struct acpi_whea_header *entry, u64 val)
{
        int rc;

        val &= entry->mask;
        val <<= entry->register_region.bit_offset;
        if (entry->flags & APEI_EXEC_PRESERVE_REGISTER) {
                u64 valr = 0;
                rc = apei_read(&valr, &entry->register_region);
                if (rc)
                        return rc;
                valr &= ~(entry->mask << entry->register_region.bit_offset);
                val |= valr;
        }
        rc = apei_write(val, &entry->register_region);

        return rc;
}

int apei_exec_write_register(struct apei_exec_context *ctx,
                             struct acpi_whea_header *entry)
{
        return __apei_exec_write_register(entry, ctx->value);
}
EXPORT_SYMBOL_GPL(apei_exec_write_register);

int apei_exec_write_register_value(struct apei_exec_context *ctx,
                                   struct acpi_whea_header *entry)
{
        int rc;

        ctx->value = entry->value;
        rc = apei_exec_write_register(ctx, entry);

        return rc;
}
EXPORT_SYMBOL_GPL(apei_exec_write_register_value);

int apei_exec_noop(struct apei_exec_context *ctx,
                   struct acpi_whea_header *entry)
{
        return 0;
}
EXPORT_SYMBOL_GPL(apei_exec_noop);

/*
 * Interpret the specified action. Go through whole action table,
 * execute all instructions belong to the action.
 */
int __apei_exec_run(struct apei_exec_context *ctx, u8 action,
                    bool optional)
{
        int rc = -ENOENT;
        u32 i, ip;
        struct acpi_whea_header *entry;
        apei_exec_ins_func_t run;

        ctx->ip = 0;

        /*
         * "ip" is the instruction pointer of current instruction,
         * "ctx->ip" specifies the next instruction to executed,
         * instruction "run" function may change the "ctx->ip" to
         * implement "goto" semantics.
         */
rewind:
        ip = 0;
        for (i = 0; i < ctx->entries; i++) {
                entry = &ctx->action_table[i];
                if (entry->action != action)
                        continue;
                if (ip == ctx->ip) {
                        if (entry->instruction >= ctx->instructions ||
                            !ctx->ins_table[entry->instruction].run) {
                                pr_warning(FW_WARN APEI_PFX
                        "Invalid action table, unknown instruction type: %d\n",
                                           entry->instruction);
                                return -EINVAL;
                        }
                        run = ctx->ins_table[entry->instruction].run;
                        rc = run(ctx, entry);
                        if (rc < 0)
                                return rc;
                        else if (rc != APEI_EXEC_SET_IP)
                                ctx->ip++;
                }
                ip++;
                if (ctx->ip < ip)
                        goto rewind;
        }

        return !optional && rc < 0 ? rc : 0;
}
EXPORT_SYMBOL_GPL(__apei_exec_run);

typedef int (*apei_exec_entry_func_t)(struct apei_exec_context *ctx,
                                      struct acpi_whea_header *entry,
                                      void *data);

static int apei_exec_for_each_entry(struct apei_exec_context *ctx,
                                    apei_exec_entry_func_t func,
                                    void *data,
                                    int *end)
{
        u8 ins;
        int i, rc;
        struct acpi_whea_header *entry;
        struct apei_exec_ins_type *ins_table = ctx->ins_table;

        for (i = 0; i < ctx->entries; i++) {
                entry = ctx->action_table + i;
                ins = entry->instruction;
                if (end)
                        *end = i;
                if (ins >= ctx->instructions || !ins_table[ins].run) {
                        pr_warning(FW_WARN APEI_PFX
                        "Invalid action table, unknown instruction type: %d\n",
                                   ins);
                        return -EINVAL;
                }
                rc = func(ctx, entry, data);
                if (rc)
                        return rc;
        }

        return 0;
}

static int pre_map_gar_callback(struct apei_exec_context *ctx,
                                struct acpi_whea_header *entry,
                                void *data)
{
        u8 ins = entry->instruction;

        if (ctx->ins_table[ins].flags & APEI_EXEC_INS_ACCESS_REGISTER)
                return apei_map_generic_address(&entry->register_region);

        return 0;
}

/*
 * Pre-map all GARs in action table to make it possible to access them
 * in NMI handler.
 */
int apei_exec_pre_map_gars(struct apei_exec_context *ctx)
{
        int rc, end;

        rc = apei_exec_for_each_entry(ctx, pre_map_gar_callback,
                                      NULL, &end);
        if (rc) {
                struct apei_exec_context ctx_unmap;
                memcpy(&ctx_unmap, ctx, sizeof(*ctx));
                ctx_unmap.entries = end;
                apei_exec_post_unmap_gars(&ctx_unmap);
        }

        return rc;
}
EXPORT_SYMBOL_GPL(apei_exec_pre_map_gars);

static int post_unmap_gar_callback(struct apei_exec_context *ctx,
                                   struct acpi_whea_header *entry,
                                   void *data)
{
        u8 ins = entry->instruction;

        if (ctx->ins_table[ins].flags & APEI_EXEC_INS_ACCESS_REGISTER)
                apei_unmap_generic_address(&entry->register_region);

        return 0;
}

/* Post-unmap all GAR in action table. */
int apei_exec_post_unmap_gars(struct apei_exec_context *ctx)
{
        return apei_exec_for_each_entry(ctx, post_unmap_gar_callback,
                                        NULL, NULL);
}
EXPORT_SYMBOL_GPL(apei_exec_post_unmap_gars);

/*
 * Resource management for GARs in APEI
 */
struct apei_res {
        struct list_head list;
        unsigned long start;
        unsigned long end;
};

/* Collect all resources requested, to avoid conflict */
struct apei_resources apei_resources_all = {
        .iomem = LIST_HEAD_INIT(apei_resources_all.iomem),
        .ioport = LIST_HEAD_INIT(apei_resources_all.ioport),
};

static int apei_res_add(struct list_head *res_list,
                        unsigned long start, unsigned long size)
{
        struct apei_res *res, *resn, *res_ins = NULL;
        unsigned long end = start + size;

        if (end <= start)
                return 0;
repeat:
        list_for_each_entry_safe(res, resn, res_list, list) {
                if (res->start > end || res->end < start)
                        continue;
                else if (end <= res->end && start >= res->start) {
                        kfree(res_ins);
                        return 0;
                }
                list_del(&res->list);
                res->start = start = min(res->start, start);
                res->end = end = max(res->end, end);
                kfree(res_ins);
                res_ins = res;
                goto repeat;
        }

        if (res_ins)
                list_add(&res_ins->list, res_list);
        else {
                res_ins = kmalloc(sizeof(*res), GFP_KERNEL);
                if (!res_ins)
                        return -ENOMEM;
                res_ins->start = start;
                res_ins->end = end;
                list_add(&res_ins->list, res_list);
        }

        return 0;
}

static int apei_res_sub(struct list_head *res_list1,
                        struct list_head *res_list2)
{
        struct apei_res *res1, *resn1, *res2, *res;
        res1 = list_entry(res_list1->next, struct apei_res, list);
        resn1 = list_entry(res1->list.next, struct apei_res, list);
        while (&res1->list != res_list1) {
                list_for_each_entry(res2, res_list2, list) {
                        if (res1->start >= res2->end ||
                            res1->end <= res2->start)
                                continue;
                        else if (res1->end <= res2->end &&
                                 res1->start >= res2->start) {
                                list_del(&res1->list);
                                kfree(res1);
                                break;
                        } else if (res1->end > res2->end &&
                                   res1->start < res2->start) {
                                res = kmalloc(sizeof(*res), GFP_KERNEL);
                                if (!res)
                                        return -ENOMEM;
                                res->start = res2->end;
                                res->end = res1->end;
                                res1->end = res2->start;
                                list_add(&res->list, &res1->list);
                                resn1 = res;
                        } else {
                                if (res1->start < res2->start)
                                        res1->end = res2->start;
                                else
                                        res1->start = res2->end;
                        }
                }
                res1 = resn1;
                resn1 = list_entry(resn1->list.next, struct apei_res, list);
        }

        return 0;
}

static void apei_res_clean(struct list_head *res_list)
{
        struct apei_res *res, *resn;

        list_for_each_entry_safe(res, resn, res_list, list) {
                list_del(&res->list);
                kfree(res);
        }
}

void apei_resources_fini(struct apei_resources *resources)
{
        apei_res_clean(&resources->iomem);
        apei_res_clean(&resources->ioport);
}
EXPORT_SYMBOL_GPL(apei_resources_fini);

static int apei_resources_merge(struct apei_resources *resources1,
                                struct apei_resources *resources2)
{
        int rc;
        struct apei_res *res;

        list_for_each_entry(res, &resources2->iomem, list) {
                rc = apei_res_add(&resources1->iomem, res->start,
                                  res->end - res->start);
                if (rc)
                        return rc;
        }
        list_for_each_entry(res, &resources2->ioport, list) {
                rc = apei_res_add(&resources1->ioport, res->start,
                                  res->end - res->start);
                if (rc)
                        return rc;
        }

        return 0;
}

int apei_resources_add(struct apei_resources *resources,
                       unsigned long start, unsigned long size,
                       bool iomem)
{
        if (iomem)
                return apei_res_add(&resources->iomem, start, size);
        else
                return apei_res_add(&resources->ioport, start, size);
}
EXPORT_SYMBOL_GPL(apei_resources_add);

/*
 * EINJ has two groups of GARs (EINJ table entry and trigger table
 * entry), so common resources are subtracted from the trigger table
 * resources before the second requesting.
 */
int apei_resources_sub(struct apei_resources *resources1,
                       struct apei_resources *resources2)
{
        int rc;

        rc = apei_res_sub(&resources1->iomem, &resources2->iomem);
        if (rc)
                return rc;
        return apei_res_sub(&resources1->ioport, &resources2->ioport);
}
EXPORT_SYMBOL_GPL(apei_resources_sub);

static int apei_get_nvs_callback(__u64 start, __u64 size, void *data)
{
        struct apei_resources *resources = data;
        return apei_res_add(&resources->iomem, start, size);
}

static int apei_get_nvs_resources(struct apei_resources *resources)
{
        return acpi_nvs_for_each_region(apei_get_nvs_callback, resources);
}

/*
 * IO memory/port resource management mechanism is used to check
 * whether memory/port area used by GARs conflicts with normal memory
 * or IO memory/port of devices.
 */
int apei_resources_request(struct apei_resources *resources,
                           const char *desc)
{
        struct apei_res *res, *res_bak = NULL;
        struct resource *r;
        struct apei_resources nvs_resources;
        int rc;

        rc = apei_resources_sub(resources, &apei_resources_all);
        if (rc)
                return rc;

        /*
         * Some firmware uses ACPI NVS region, that has been marked as
         * busy, so exclude it from APEI resources to avoid false
         * conflict.
         */
        apei_resources_init(&nvs_resources);
        rc = apei_get_nvs_resources(&nvs_resources);
        if (rc)
                goto res_fini;
        rc = apei_resources_sub(resources, &nvs_resources);
        if (rc)
                goto res_fini;

        rc = -EINVAL;
        list_for_each_entry(res, &resources->iomem, list) {
                r = request_mem_region(res->start, res->end - res->start,
                                       desc);
                if (!r) {
                        pr_err(APEI_PFX
                "Can not request [mem %#010llx-%#010llx] for %s registers\n",
                               (unsigned long long)res->start,
                               (unsigned long long)res->end - 1, desc);
                        res_bak = res;
                        goto err_unmap_iomem;
                }
        }

        list_for_each_entry(res, &resources->ioport, list) {
                r = request_region(res->start, res->end - res->start, desc);
                if (!r) {
                        pr_err(APEI_PFX
                "Can not request [io  %#06llx-%#06llx] for %s registers\n",
                               (unsigned long long)res->start,
                               (unsigned long long)res->end - 1, desc);
                        res_bak = res;
                        goto err_unmap_ioport;
                }
        }

        rc = apei_resources_merge(&apei_resources_all, resources);
        if (rc) {
                pr_err(APEI_PFX "Fail to merge resources!\n");
                goto err_unmap_ioport;
        }

        return 0;
err_unmap_ioport:
        list_for_each_entry(res, &resources->ioport, list) {
                if (res == res_bak)
                        break;
                release_region(res->start, res->end - res->start);
        }
        res_bak = NULL;
err_unmap_iomem:
        list_for_each_entry(res, &resources->iomem, list) {
                if (res == res_bak)
                        break;
                release_mem_region(res->start, res->end - res->start);
        }
res_fini:
        apei_resources_fini(&nvs_resources);
        return rc;
}
EXPORT_SYMBOL_GPL(apei_resources_request);

void apei_resources_release(struct apei_resources *resources)
{
        int rc;
        struct apei_res *res;

        list_for_each_entry(res, &resources->iomem, list)
                release_mem_region(res->start, res->end - res->start);
        list_for_each_entry(res, &resources->ioport, list)
                release_region(res->start, res->end - res->start);

        rc = apei_resources_sub(&apei_resources_all, resources);
        if (rc)
                pr_err(APEI_PFX "Fail to sub resources!\n");
}
EXPORT_SYMBOL_GPL(apei_resources_release);

static int apei_check_gar(struct acpi_generic_address *reg, u64 *paddr,
                                u32 *access_bit_width)
{
        u32 bit_width, bit_offset, access_size_code, space_id;

        bit_width = reg->bit_width;
        bit_offset = reg->bit_offset;
        access_size_code = reg->access_width;
        space_id = reg->space_id;
        /* Handle possible alignment issues */
        memcpy(paddr, &reg->address, sizeof(*paddr));
        if (!*paddr) {
                pr_warning(FW_BUG APEI_PFX
                           "Invalid physical address in GAR [0x%llx/%u/%u/%u/%u]\n",
                           *paddr, bit_width, bit_offset, access_size_code,
                           space_id);
                return -EINVAL;
        }

        if (access_size_code < 1 || access_size_code > 4) {
                pr_warning(FW_BUG APEI_PFX
                           "Invalid access size code in GAR [0x%llx/%u/%u/%u/%u]\n",
                           *paddr, bit_width, bit_offset, access_size_code,
                           space_id);
                return -EINVAL;
        }
        *access_bit_width = 1UL << (access_size_code + 2);

        /* Fixup common BIOS bug */
        if (bit_width == 32 && bit_offset == 0 && (*paddr & 0x03) == 0 &&
            *access_bit_width < 32)
                *access_bit_width = 32;
        else if (bit_width == 64 && bit_offset == 0 && (*paddr & 0x07) == 0 &&
            *access_bit_width < 64)
                *access_bit_width = 64;

        if ((bit_width + bit_offset) > *access_bit_width) {
                pr_warning(FW_BUG APEI_PFX
                           "Invalid bit width + offset in GAR [0x%llx/%u/%u/%u/%u]\n",
                           *paddr, bit_width, bit_offset, access_size_code,
                           space_id);
                return -EINVAL;
        }

        if (space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY &&
            space_id != ACPI_ADR_SPACE_SYSTEM_IO) {
                pr_warning(FW_BUG APEI_PFX
                           "Invalid address space type in GAR [0x%llx/%u/%u/%u/%u]\n",
                           *paddr, bit_width, bit_offset, access_size_code,
                           space_id);
                return -EINVAL;
        }

        return 0;
}

int apei_map_generic_address(struct acpi_generic_address *reg)
{
        int rc;
        u32 access_bit_width;
        u64 address;

        rc = apei_check_gar(reg, &address, &access_bit_width);
        if (rc)
                return rc;
        return acpi_os_map_generic_address(reg);
}
EXPORT_SYMBOL_GPL(apei_map_generic_address);

/* read GAR in interrupt (including NMI) or process context */
int apei_read(u64 *val, struct acpi_generic_address *reg)
{
        int rc;
        u32 access_bit_width;
        u64 address;
        acpi_status status;

        rc = apei_check_gar(reg, &address, &access_bit_width);
        if (rc)
                return rc;

        *val = 0;
        switch(reg->space_id) {
        case ACPI_ADR_SPACE_SYSTEM_MEMORY:
                status = acpi_os_read_memory((acpi_physical_address) address,
                                               val, access_bit_width);
                if (ACPI_FAILURE(status))
                        return -EIO;
                break;
        case ACPI_ADR_SPACE_SYSTEM_IO:
                status = acpi_os_read_port(address, (u32 *)val,
                                           access_bit_width);
                if (ACPI_FAILURE(status))
                        return -EIO;
                break;
        default:
                return -EINVAL;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(apei_read);

/* write GAR in interrupt (including NMI) or process context */
int apei_write(u64 val, struct acpi_generic_address *reg)
{
        int rc;
        u32 access_bit_width;
        u64 address;
        acpi_status status;

        rc = apei_check_gar(reg, &address, &access_bit_width);
        if (rc)
                return rc;

        switch (reg->space_id) {
        case ACPI_ADR_SPACE_SYSTEM_MEMORY:
                status = acpi_os_write_memory((acpi_physical_address) address,
                                                val, access_bit_width);
                if (ACPI_FAILURE(status))
                        return -EIO;
                break;
        case ACPI_ADR_SPACE_SYSTEM_IO:
                status = acpi_os_write_port(address, val, access_bit_width);
                if (ACPI_FAILURE(status))
                        return -EIO;
                break;
        default:
                return -EINVAL;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(apei_write);

static int collect_res_callback(struct apei_exec_context *ctx,
                                struct acpi_whea_header *entry,
                                void *data)
{
        struct apei_resources *resources = data;
        struct acpi_generic_address *reg = &entry->register_region;
        u8 ins = entry->instruction;
        u32 access_bit_width;
        u64 paddr;
        int rc;

        if (!(ctx->ins_table[ins].flags & APEI_EXEC_INS_ACCESS_REGISTER))
                return 0;

        rc = apei_check_gar(reg, &paddr, &access_bit_width);
        if (rc)
                return rc;

        switch (reg->space_id) {
        case ACPI_ADR_SPACE_SYSTEM_MEMORY:
                return apei_res_add(&resources->iomem, paddr,
                                    access_bit_width / 8);
        case ACPI_ADR_SPACE_SYSTEM_IO:
                return apei_res_add(&resources->ioport, paddr,
                                    access_bit_width / 8);
        default:
                return -EINVAL;
        }
}

/*
 * Same register may be used by multiple instructions in GARs, so
 * resources are collected before requesting.
 */
int apei_exec_collect_resources(struct apei_exec_context *ctx,
                                struct apei_resources *resources)
{
        return apei_exec_for_each_entry(ctx, collect_res_callback,
                                        resources, NULL);
}
EXPORT_SYMBOL_GPL(apei_exec_collect_resources);

struct dentry *apei_get_debugfs_dir(void)
{
        static struct dentry *dapei;

        if (!dapei)
                dapei = debugfs_create_dir("apei", NULL);

        return dapei;
}
EXPORT_SYMBOL_GPL(apei_get_debugfs_dir);

int apei_osc_setup(void)
{
        static u8 whea_uuid_str[] = "ed855e0c-6c90-47bf-a62a-26de0fc5ad5c";
        acpi_handle handle;
        u32 capbuf[3];
        struct acpi_osc_context context = {
                .uuid_str       = whea_uuid_str,
                .rev            = 1,
                .cap.length     = sizeof(capbuf),
                .cap.pointer    = capbuf,
        };

        capbuf[OSC_QUERY_TYPE] = OSC_QUERY_ENABLE;
        capbuf[OSC_SUPPORT_TYPE] = 1;
        capbuf[OSC_CONTROL_TYPE] = 0;

        if (ACPI_FAILURE(acpi_get_handle(NULL, "\\_SB", &handle))
            || ACPI_FAILURE(acpi_run_osc(handle, &context)))
                return -EIO;
        else {
                kfree(context.ret.pointer);
                return 0;
        }
}
EXPORT_SYMBOL_GPL(apei_osc_setup);