Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input

[linux-btrfs-devel.git] / drivers / acpi / apei / ghes.c

/*
 * APEI Generic Hardware Error Source support
 *
 * Generic Hardware Error Source provides a way to report platform
 * hardware errors (such as that from chipset). It works in so called
 * "Firmware First" mode, that is, hardware errors are reported to
 * firmware firstly, then reported to Linux by firmware. This way,
 * some non-standard hardware error registers or non-standard hardware
 * link can be checked by firmware to produce more hardware error
 * information for Linux.
 *
 * For more information about Generic Hardware Error Source, please
 * refer to ACPI Specification version 4.0, section 17.3.2.6
 *
 * Copyright 2010,2011 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/io.h>
#include <linux/interrupt.h>
#include <linux/timer.h>
#include <linux/cper.h>
#include <linux/kdebug.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/ratelimit.h>
#include <linux/vmalloc.h>
#include <linux/irq_work.h>
#include <linux/llist.h>
#include <linux/genalloc.h>
#include <acpi/apei.h>
#include <acpi/atomicio.h>
#include <acpi/hed.h>
#include <asm/mce.h>
#include <asm/tlbflush.h>
#include <asm/nmi.h>

#include "apei-internal.h"

#define GHES_PFX        "GHES: "

#define GHES_ESTATUS_MAX_SIZE           65536
#define GHES_ESOURCE_PREALLOC_MAX_SIZE  65536

#define GHES_ESTATUS_POOL_MIN_ALLOC_ORDER 3

/* This is just an estimation for memory pool allocation */
#define GHES_ESTATUS_CACHE_AVG_SIZE     512

#define GHES_ESTATUS_CACHES_SIZE        4

#define GHES_ESTATUS_IN_CACHE_MAX_NSEC  10000000000ULL
/* Prevent too many caches are allocated because of RCU */
#define GHES_ESTATUS_CACHE_ALLOCED_MAX  (GHES_ESTATUS_CACHES_SIZE * 3 / 2)

#define GHES_ESTATUS_CACHE_LEN(estatus_len)                     \
        (sizeof(struct ghes_estatus_cache) + (estatus_len))
#define GHES_ESTATUS_FROM_CACHE(estatus_cache)                  \
        ((struct acpi_hest_generic_status *)                    \
         ((struct ghes_estatus_cache *)(estatus_cache) + 1))

#define GHES_ESTATUS_NODE_LEN(estatus_len)                      \
        (sizeof(struct ghes_estatus_node) + (estatus_len))
#define GHES_ESTATUS_FROM_NODE(estatus_node)                            \
        ((struct acpi_hest_generic_status *)                            \
         ((struct ghes_estatus_node *)(estatus_node) + 1))

/*
 * One struct ghes is created for each generic hardware error source.
 * It provides the context for APEI hardware error timer/IRQ/SCI/NMI
 * handler.
 *
 * estatus: memory buffer for error status block, allocated during
 * HEST parsing.
 */
#define GHES_TO_CLEAR           0x0001
#define GHES_EXITING            0x0002

struct ghes {
        struct acpi_hest_generic *generic;
        struct acpi_hest_generic_status *estatus;
        u64 buffer_paddr;
        unsigned long flags;
        union {
                struct list_head list;
                struct timer_list timer;
                unsigned int irq;
        };
};

struct ghes_estatus_node {
        struct llist_node llnode;
        struct acpi_hest_generic *generic;
};

struct ghes_estatus_cache {
        u32 estatus_len;
        atomic_t count;
        struct acpi_hest_generic *generic;
        unsigned long long time_in;
        struct rcu_head rcu;
};

int ghes_disable;
module_param_named(disable, ghes_disable, bool, 0);

static int ghes_panic_timeout   __read_mostly = 30;

/*
 * All error sources notified with SCI shares one notifier function,
 * so they need to be linked and checked one by one.  This is applied
 * to NMI too.
 *
 * RCU is used for these lists, so ghes_list_mutex is only used for
 * list changing, not for traversing.
 */
static LIST_HEAD(ghes_sci);
static LIST_HEAD(ghes_nmi);
static DEFINE_MUTEX(ghes_list_mutex);

/*
 * NMI may be triggered on any CPU, so ghes_nmi_lock is used for
 * mutual exclusion.
 */
static DEFINE_RAW_SPINLOCK(ghes_nmi_lock);

/*
 * Because the memory area used to transfer hardware error information
 * from BIOS to Linux can be determined only in NMI, IRQ or timer
 * handler, but general ioremap can not be used in atomic context, so
 * a special version of atomic ioremap is implemented for that.
 */

/*
 * Two virtual pages are used, one for NMI context, the other for
 * IRQ/PROCESS context
 */
#define GHES_IOREMAP_PAGES              2
#define GHES_IOREMAP_NMI_PAGE(base)     (base)
#define GHES_IOREMAP_IRQ_PAGE(base)     ((base) + PAGE_SIZE)

/* virtual memory area for atomic ioremap */
static struct vm_struct *ghes_ioremap_area;
/*
 * These 2 spinlock is used to prevent atomic ioremap virtual memory
 * area from being mapped simultaneously.
 */
static DEFINE_RAW_SPINLOCK(ghes_ioremap_lock_nmi);
static DEFINE_SPINLOCK(ghes_ioremap_lock_irq);

/*
 * printk is not safe in NMI context.  So in NMI handler, we allocate
 * required memory from lock-less memory allocator
 * (ghes_estatus_pool), save estatus into it, put them into lock-less
 * list (ghes_estatus_llist), then delay printk into IRQ context via
 * irq_work (ghes_proc_irq_work).  ghes_estatus_size_request record
 * required pool size by all NMI error source.
 */
static struct gen_pool *ghes_estatus_pool;
static unsigned long ghes_estatus_pool_size_request;
static struct llist_head ghes_estatus_llist;
static struct irq_work ghes_proc_irq_work;

struct ghes_estatus_cache *ghes_estatus_caches[GHES_ESTATUS_CACHES_SIZE];
static atomic_t ghes_estatus_cache_alloced;

static int ghes_ioremap_init(void)
{
        ghes_ioremap_area = __get_vm_area(PAGE_SIZE * GHES_IOREMAP_PAGES,
                VM_IOREMAP, VMALLOC_START, VMALLOC_END);
        if (!ghes_ioremap_area) {
                pr_err(GHES_PFX "Failed to allocate virtual memory area for atomic ioremap.\n");
                return -ENOMEM;
        }

        return 0;
}

static void ghes_ioremap_exit(void)
{
        free_vm_area(ghes_ioremap_area);
}

static void __iomem *ghes_ioremap_pfn_nmi(u64 pfn)
{
        unsigned long vaddr;

        vaddr = (unsigned long)GHES_IOREMAP_NMI_PAGE(ghes_ioremap_area->addr);
        ioremap_page_range(vaddr, vaddr + PAGE_SIZE,
                           pfn << PAGE_SHIFT, PAGE_KERNEL);

        return (void __iomem *)vaddr;
}

static void __iomem *ghes_ioremap_pfn_irq(u64 pfn)
{
        unsigned long vaddr;

        vaddr = (unsigned long)GHES_IOREMAP_IRQ_PAGE(ghes_ioremap_area->addr);
        ioremap_page_range(vaddr, vaddr + PAGE_SIZE,
                           pfn << PAGE_SHIFT, PAGE_KERNEL);

        return (void __iomem *)vaddr;
}

static void ghes_iounmap_nmi(void __iomem *vaddr_ptr)
{
        unsigned long vaddr = (unsigned long __force)vaddr_ptr;
        void *base = ghes_ioremap_area->addr;

        BUG_ON(vaddr != (unsigned long)GHES_IOREMAP_NMI_PAGE(base));
        unmap_kernel_range_noflush(vaddr, PAGE_SIZE);
        __flush_tlb_one(vaddr);
}

static void ghes_iounmap_irq(void __iomem *vaddr_ptr)
{
        unsigned long vaddr = (unsigned long __force)vaddr_ptr;
        void *base = ghes_ioremap_area->addr;

        BUG_ON(vaddr != (unsigned long)GHES_IOREMAP_IRQ_PAGE(base));
        unmap_kernel_range_noflush(vaddr, PAGE_SIZE);
        __flush_tlb_one(vaddr);
}

static int ghes_estatus_pool_init(void)
{
        ghes_estatus_pool = gen_pool_create(GHES_ESTATUS_POOL_MIN_ALLOC_ORDER, -1);
        if (!ghes_estatus_pool)
                return -ENOMEM;
        return 0;
}

static void ghes_estatus_pool_free_chunk_page(struct gen_pool *pool,
                                              struct gen_pool_chunk *chunk,
                                              void *data)
{
        free_page(chunk->start_addr);
}

static void ghes_estatus_pool_exit(void)
{
        gen_pool_for_each_chunk(ghes_estatus_pool,
                                ghes_estatus_pool_free_chunk_page, NULL);
        gen_pool_destroy(ghes_estatus_pool);
}

static int ghes_estatus_pool_expand(unsigned long len)
{
        unsigned long i, pages, size, addr;
        int ret;

        ghes_estatus_pool_size_request += PAGE_ALIGN(len);
        size = gen_pool_size(ghes_estatus_pool);
        if (size >= ghes_estatus_pool_size_request)
                return 0;
        pages = (ghes_estatus_pool_size_request - size) / PAGE_SIZE;
        for (i = 0; i < pages; i++) {
                addr = __get_free_page(GFP_KERNEL);
                if (!addr)
                        return -ENOMEM;
                ret = gen_pool_add(ghes_estatus_pool, addr, PAGE_SIZE, -1);
                if (ret)
                        return ret;
        }

        return 0;
}

static void ghes_estatus_pool_shrink(unsigned long len)
{
        ghes_estatus_pool_size_request -= PAGE_ALIGN(len);
}

static struct ghes *ghes_new(struct acpi_hest_generic *generic)
{
        struct ghes *ghes;
        unsigned int error_block_length;
        int rc;

        ghes = kzalloc(sizeof(*ghes), GFP_KERNEL);
        if (!ghes)
                return ERR_PTR(-ENOMEM);
        ghes->generic = generic;
        rc = acpi_pre_map_gar(&generic->error_status_address);
        if (rc)
                goto err_free;
        error_block_length = generic->error_block_length;
        if (error_block_length > GHES_ESTATUS_MAX_SIZE) {
                pr_warning(FW_WARN GHES_PFX
                           "Error status block length is too long: %u for "
                           "generic hardware error source: %d.\n",
                           error_block_length, generic->header.source_id);
                error_block_length = GHES_ESTATUS_MAX_SIZE;
        }
        ghes->estatus = kmalloc(error_block_length, GFP_KERNEL);
        if (!ghes->estatus) {
                rc = -ENOMEM;
                goto err_unmap;
        }

        return ghes;

err_unmap:
        acpi_post_unmap_gar(&generic->error_status_address);
err_free:
        kfree(ghes);
        return ERR_PTR(rc);
}

static void ghes_fini(struct ghes *ghes)
{
        kfree(ghes->estatus);
        acpi_post_unmap_gar(&ghes->generic->error_status_address);
}

enum {
        GHES_SEV_NO = 0x0,
        GHES_SEV_CORRECTED = 0x1,
        GHES_SEV_RECOVERABLE = 0x2,
        GHES_SEV_PANIC = 0x3,
};

static inline int ghes_severity(int severity)
{
        switch (severity) {
        case CPER_SEV_INFORMATIONAL:
                return GHES_SEV_NO;
        case CPER_SEV_CORRECTED:
                return GHES_SEV_CORRECTED;
        case CPER_SEV_RECOVERABLE:
                return GHES_SEV_RECOVERABLE;
        case CPER_SEV_FATAL:
                return GHES_SEV_PANIC;
        default:
                /* Unknown, go panic */
                return GHES_SEV_PANIC;
        }
}

static void ghes_copy_tofrom_phys(void *buffer, u64 paddr, u32 len,
                                  int from_phys)
{
        void __iomem *vaddr;
        unsigned long flags = 0;
        int in_nmi = in_nmi();
        u64 offset;
        u32 trunk;

        while (len > 0) {
                offset = paddr - (paddr & PAGE_MASK);
                if (in_nmi) {
                        raw_spin_lock(&ghes_ioremap_lock_nmi);
                        vaddr = ghes_ioremap_pfn_nmi(paddr >> PAGE_SHIFT);
                } else {
                        spin_lock_irqsave(&ghes_ioremap_lock_irq, flags);
                        vaddr = ghes_ioremap_pfn_irq(paddr >> PAGE_SHIFT);
                }
                trunk = PAGE_SIZE - offset;
                trunk = min(trunk, len);
                if (from_phys)
                        memcpy_fromio(buffer, vaddr + offset, trunk);
                else
                        memcpy_toio(vaddr + offset, buffer, trunk);
                len -= trunk;
                paddr += trunk;
                buffer += trunk;
                if (in_nmi) {
                        ghes_iounmap_nmi(vaddr);
                        raw_spin_unlock(&ghes_ioremap_lock_nmi);
                } else {
                        ghes_iounmap_irq(vaddr);
                        spin_unlock_irqrestore(&ghes_ioremap_lock_irq, flags);
                }
        }
}

static int ghes_read_estatus(struct ghes *ghes, int silent)
{
        struct acpi_hest_generic *g = ghes->generic;
        u64 buf_paddr;
        u32 len;
        int rc;

        rc = acpi_atomic_read(&buf_paddr, &g->error_status_address);
        if (rc) {
                if (!silent && printk_ratelimit())
                        pr_warning(FW_WARN GHES_PFX
"Failed to read error status block address for hardware error source: %d.\n",
                                   g->header.source_id);
                return -EIO;
        }
        if (!buf_paddr)
                return -ENOENT;

        ghes_copy_tofrom_phys(ghes->estatus, buf_paddr,
                              sizeof(*ghes->estatus), 1);
        if (!ghes->estatus->block_status)
                return -ENOENT;

        ghes->buffer_paddr = buf_paddr;
        ghes->flags |= GHES_TO_CLEAR;

        rc = -EIO;
        len = apei_estatus_len(ghes->estatus);
        if (len < sizeof(*ghes->estatus))
                goto err_read_block;
        if (len > ghes->generic->error_block_length)
                goto err_read_block;
        if (apei_estatus_check_header(ghes->estatus))
                goto err_read_block;
        ghes_copy_tofrom_phys(ghes->estatus + 1,
                              buf_paddr + sizeof(*ghes->estatus),
                              len - sizeof(*ghes->estatus), 1);
        if (apei_estatus_check(ghes->estatus))
                goto err_read_block;
        rc = 0;

err_read_block:
        if (rc && !silent && printk_ratelimit())
                pr_warning(FW_WARN GHES_PFX
                           "Failed to read error status block!\n");
        return rc;
}

static void ghes_clear_estatus(struct ghes *ghes)
{
        ghes->estatus->block_status = 0;
        if (!(ghes->flags & GHES_TO_CLEAR))
                return;
        ghes_copy_tofrom_phys(ghes->estatus, ghes->buffer_paddr,
                              sizeof(ghes->estatus->block_status), 0);
        ghes->flags &= ~GHES_TO_CLEAR;
}

static void ghes_do_proc(const struct acpi_hest_generic_status *estatus)
{
        int sev, sec_sev;
        struct acpi_hest_generic_data *gdata;

        sev = ghes_severity(estatus->error_severity);
        apei_estatus_for_each_section(estatus, gdata) {
                sec_sev = ghes_severity(gdata->error_severity);
                if (!uuid_le_cmp(*(uuid_le *)gdata->section_type,
                                 CPER_SEC_PLATFORM_MEM)) {
                        struct cper_sec_mem_err *mem_err;
                        mem_err = (struct cper_sec_mem_err *)(gdata+1);
#ifdef CONFIG_X86_MCE
                        apei_mce_report_mem_error(sev == GHES_SEV_CORRECTED,
                                                  mem_err);
#endif
#ifdef CONFIG_ACPI_APEI_MEMORY_FAILURE
                        if (sev == GHES_SEV_RECOVERABLE &&
                            sec_sev == GHES_SEV_RECOVERABLE &&
                            mem_err->validation_bits & CPER_MEM_VALID_PHYSICAL_ADDRESS) {
                                unsigned long pfn;
                                pfn = mem_err->physical_addr >> PAGE_SHIFT;
                                memory_failure_queue(pfn, 0, 0);
                        }
#endif
                }
        }
}

static void __ghes_print_estatus(const char *pfx,
                                 const struct acpi_hest_generic *generic,
                                 const struct acpi_hest_generic_status *estatus)
{
        if (pfx == NULL) {
                if (ghes_severity(estatus->error_severity) <=
                    GHES_SEV_CORRECTED)
                        pfx = KERN_WARNING HW_ERR;
                else
                        pfx = KERN_ERR HW_ERR;
        }
        printk("%s""Hardware error from APEI Generic Hardware Error Source: %d\n",
               pfx, generic->header.source_id);
        apei_estatus_print(pfx, estatus);
}

static int ghes_print_estatus(const char *pfx,
                              const struct acpi_hest_generic *generic,
                              const struct acpi_hest_generic_status *estatus)
{
        /* Not more than 2 messages every 5 seconds */
        static DEFINE_RATELIMIT_STATE(ratelimit_corrected, 5*HZ, 2);
        static DEFINE_RATELIMIT_STATE(ratelimit_uncorrected, 5*HZ, 2);
        struct ratelimit_state *ratelimit;

        if (ghes_severity(estatus->error_severity) <= GHES_SEV_CORRECTED)
                ratelimit = &ratelimit_corrected;
        else
                ratelimit = &ratelimit_uncorrected;
        if (__ratelimit(ratelimit)) {
                __ghes_print_estatus(pfx, generic, estatus);
                return 1;
        }
        return 0;
}

/*
 * GHES error status reporting throttle, to report more kinds of
 * errors, instead of just most frequently occurred errors.
 */
static int ghes_estatus_cached(struct acpi_hest_generic_status *estatus)
{
        u32 len;
        int i, cached = 0;
        unsigned long long now;
        struct ghes_estatus_cache *cache;
        struct acpi_hest_generic_status *cache_estatus;

        len = apei_estatus_len(estatus);
        rcu_read_lock();
        for (i = 0; i < GHES_ESTATUS_CACHES_SIZE; i++) {
                cache = rcu_dereference(ghes_estatus_caches[i]);
                if (cache == NULL)
                        continue;
                if (len != cache->estatus_len)
                        continue;
                cache_estatus = GHES_ESTATUS_FROM_CACHE(cache);
                if (memcmp(estatus, cache_estatus, len))
                        continue;
                atomic_inc(&cache->count);
                now = sched_clock();
                if (now - cache->time_in < GHES_ESTATUS_IN_CACHE_MAX_NSEC)
                        cached = 1;
                break;
        }
        rcu_read_unlock();
        return cached;
}

static struct ghes_estatus_cache *ghes_estatus_cache_alloc(
        struct acpi_hest_generic *generic,
        struct acpi_hest_generic_status *estatus)
{
        int alloced;
        u32 len, cache_len;
        struct ghes_estatus_cache *cache;
        struct acpi_hest_generic_status *cache_estatus;

        alloced = atomic_add_return(1, &ghes_estatus_cache_alloced);
        if (alloced > GHES_ESTATUS_CACHE_ALLOCED_MAX) {
                atomic_dec(&ghes_estatus_cache_alloced);
                return NULL;
        }
        len = apei_estatus_len(estatus);
        cache_len = GHES_ESTATUS_CACHE_LEN(len);
        cache = (void *)gen_pool_alloc(ghes_estatus_pool, cache_len);
        if (!cache) {
                atomic_dec(&ghes_estatus_cache_alloced);
                return NULL;
        }
        cache_estatus = GHES_ESTATUS_FROM_CACHE(cache);
        memcpy(cache_estatus, estatus, len);
        cache->estatus_len = len;
        atomic_set(&cache->count, 0);
        cache->generic = generic;
        cache->time_in = sched_clock();
        return cache;
}

static void ghes_estatus_cache_free(struct ghes_estatus_cache *cache)
{
        u32 len;

        len = apei_estatus_len(GHES_ESTATUS_FROM_CACHE(cache));
        len = GHES_ESTATUS_CACHE_LEN(len);
        gen_pool_free(ghes_estatus_pool, (unsigned long)cache, len);
        atomic_dec(&ghes_estatus_cache_alloced);
}

static void ghes_estatus_cache_rcu_free(struct rcu_head *head)
{
        struct ghes_estatus_cache *cache;

        cache = container_of(head, struct ghes_estatus_cache, rcu);
        ghes_estatus_cache_free(cache);
}

static void ghes_estatus_cache_add(
        struct acpi_hest_generic *generic,
        struct acpi_hest_generic_status *estatus)
{
        int i, slot = -1, count;
        unsigned long long now, duration, period, max_period = 0;
        struct ghes_estatus_cache *cache, *slot_cache = NULL, *new_cache;

        new_cache = ghes_estatus_cache_alloc(generic, estatus);
        if (new_cache == NULL)
                return;
        rcu_read_lock();
        now = sched_clock();
        for (i = 0; i < GHES_ESTATUS_CACHES_SIZE; i++) {
                cache = rcu_dereference(ghes_estatus_caches[i]);
                if (cache == NULL) {
                        slot = i;
                        slot_cache = NULL;
                        break;
                }
                duration = now - cache->time_in;
                if (duration >= GHES_ESTATUS_IN_CACHE_MAX_NSEC) {
                        slot = i;
                        slot_cache = cache;
                        break;
                }
                count = atomic_read(&cache->count);
                period = duration;
                do_div(period, (count + 1));
                if (period > max_period) {
                        max_period = period;
                        slot = i;
                        slot_cache = cache;
                }
        }
        /* new_cache must be put into array after its contents are written */
        smp_wmb();
        if (slot != -1 && cmpxchg(ghes_estatus_caches + slot,
                                  slot_cache, new_cache) == slot_cache) {
                if (slot_cache)
                        call_rcu(&slot_cache->rcu, ghes_estatus_cache_rcu_free);
        } else
                ghes_estatus_cache_free(new_cache);
        rcu_read_unlock();
}

static int ghes_proc(struct ghes *ghes)
{
        int rc;

        rc = ghes_read_estatus(ghes, 0);
        if (rc)
                goto out;
        if (!ghes_estatus_cached(ghes->estatus)) {
                if (ghes_print_estatus(NULL, ghes->generic, ghes->estatus))
                        ghes_estatus_cache_add(ghes->generic, ghes->estatus);
        }
        ghes_do_proc(ghes->estatus);
out:
        ghes_clear_estatus(ghes);
        return 0;
}

static void ghes_add_timer(struct ghes *ghes)
{
        struct acpi_hest_generic *g = ghes->generic;
        unsigned long expire;

        if (!g->notify.poll_interval) {
                pr_warning(FW_WARN GHES_PFX "Poll interval is 0 for generic hardware error source: %d, disabled.\n",
                           g->header.source_id);
                return;
        }
        expire = jiffies + msecs_to_jiffies(g->notify.poll_interval);
        ghes->timer.expires = round_jiffies_relative(expire);
        add_timer(&ghes->timer);
}

static void ghes_poll_func(unsigned long data)
{
        struct ghes *ghes = (void *)data;

        ghes_proc(ghes);
        if (!(ghes->flags & GHES_EXITING))
                ghes_add_timer(ghes);
}

static irqreturn_t ghes_irq_func(int irq, void *data)
{
        struct ghes *ghes = data;
        int rc;

        rc = ghes_proc(ghes);
        if (rc)
                return IRQ_NONE;

        return IRQ_HANDLED;
}

static int ghes_notify_sci(struct notifier_block *this,
                                  unsigned long event, void *data)
{
        struct ghes *ghes;
        int ret = NOTIFY_DONE;

        rcu_read_lock();
        list_for_each_entry_rcu(ghes, &ghes_sci, list) {
                if (!ghes_proc(ghes))
                        ret = NOTIFY_OK;
        }
        rcu_read_unlock();

        return ret;
}

static void ghes_proc_in_irq(struct irq_work *irq_work)
{
        struct llist_node *llnode, *next, *tail = NULL;
        struct ghes_estatus_node *estatus_node;
        struct acpi_hest_generic *generic;
        struct acpi_hest_generic_status *estatus;
        u32 len, node_len;

        /*
         * Because the time order of estatus in list is reversed,
         * revert it back to proper order.
         */
        llnode = llist_del_all(&ghes_estatus_llist);
        while (llnode) {
                next = llnode->next;
                llnode->next = tail;
                tail = llnode;
                llnode = next;
        }
        llnode = tail;
        while (llnode) {
                next = llnode->next;
                estatus_node = llist_entry(llnode, struct ghes_estatus_node,
                                           llnode);
                estatus = GHES_ESTATUS_FROM_NODE(estatus_node);
                len = apei_estatus_len(estatus);
                node_len = GHES_ESTATUS_NODE_LEN(len);
                ghes_do_proc(estatus);
                if (!ghes_estatus_cached(estatus)) {
                        generic = estatus_node->generic;
                        if (ghes_print_estatus(NULL, generic, estatus))
                                ghes_estatus_cache_add(generic, estatus);
                }
                gen_pool_free(ghes_estatus_pool, (unsigned long)estatus_node,
                              node_len);
                llnode = next;
        }
}

static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
{
        struct ghes *ghes, *ghes_global = NULL;
        int sev, sev_global = -1;
        int ret = NMI_DONE;

        raw_spin_lock(&ghes_nmi_lock);
        list_for_each_entry_rcu(ghes, &ghes_nmi, list) {
                if (ghes_read_estatus(ghes, 1)) {
                        ghes_clear_estatus(ghes);
                        continue;
                }
                sev = ghes_severity(ghes->estatus->error_severity);
                if (sev > sev_global) {
                        sev_global = sev;
                        ghes_global = ghes;
                }
                ret = NMI_HANDLED;
        }

        if (ret == NMI_DONE)
                goto out;

        if (sev_global >= GHES_SEV_PANIC) {
                oops_begin();
                __ghes_print_estatus(KERN_EMERG HW_ERR, ghes_global->generic,
                                     ghes_global->estatus);
                /* reboot to log the error! */
                if (panic_timeout == 0)
                        panic_timeout = ghes_panic_timeout;
                panic("Fatal hardware error!");
        }

        list_for_each_entry_rcu(ghes, &ghes_nmi, list) {
#ifdef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
                u32 len, node_len;
                struct ghes_estatus_node *estatus_node;
                struct acpi_hest_generic_status *estatus;
#endif
                if (!(ghes->flags & GHES_TO_CLEAR))
                        continue;
#ifdef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
                if (ghes_estatus_cached(ghes->estatus))
                        goto next;
                /* Save estatus for further processing in IRQ context */
                len = apei_estatus_len(ghes->estatus);
                node_len = GHES_ESTATUS_NODE_LEN(len);
                estatus_node = (void *)gen_pool_alloc(ghes_estatus_pool,
                                                      node_len);
                if (estatus_node) {
                        estatus_node->generic = ghes->generic;
                        estatus = GHES_ESTATUS_FROM_NODE(estatus_node);
                        memcpy(estatus, ghes->estatus, len);
                        llist_add(&estatus_node->llnode, &ghes_estatus_llist);
                }
next:
#endif
                ghes_clear_estatus(ghes);
        }
#ifdef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
        irq_work_queue(&ghes_proc_irq_work);
#endif

out:
        raw_spin_unlock(&ghes_nmi_lock);
        return ret;
}

static struct notifier_block ghes_notifier_sci = {
        .notifier_call = ghes_notify_sci,
};

static unsigned long ghes_esource_prealloc_size(
        const struct acpi_hest_generic *generic)
{
        unsigned long block_length, prealloc_records, prealloc_size;

        block_length = min_t(unsigned long, generic->error_block_length,
                             GHES_ESTATUS_MAX_SIZE);
        prealloc_records = max_t(unsigned long,
                                 generic->records_to_preallocate, 1);
        prealloc_size = min_t(unsigned long, block_length * prealloc_records,
                              GHES_ESOURCE_PREALLOC_MAX_SIZE);

        return prealloc_size;
}

static int __devinit ghes_probe(struct platform_device *ghes_dev)
{
        struct acpi_hest_generic *generic;
        struct ghes *ghes = NULL;
        unsigned long len;
        int rc = -EINVAL;

        generic = *(struct acpi_hest_generic **)ghes_dev->dev.platform_data;
        if (!generic->enabled)
                return -ENODEV;

        switch (generic->notify.type) {
        case ACPI_HEST_NOTIFY_POLLED:
        case ACPI_HEST_NOTIFY_EXTERNAL:
        case ACPI_HEST_NOTIFY_SCI:
        case ACPI_HEST_NOTIFY_NMI:
                break;
        case ACPI_HEST_NOTIFY_LOCAL:
                pr_warning(GHES_PFX "Generic hardware error source: %d notified via local interrupt is not supported!\n",
                           generic->header.source_id);
                goto err;
        default:
                pr_warning(FW_WARN GHES_PFX "Unknown notification type: %u for generic hardware error source: %d\n",
                           generic->notify.type, generic->header.source_id);
                goto err;
        }

        rc = -EIO;
        if (generic->error_block_length <
            sizeof(struct acpi_hest_generic_status)) {
                pr_warning(FW_BUG GHES_PFX "Invalid error block length: %u for generic hardware error source: %d\n",
                           generic->error_block_length,
                           generic->header.source_id);
                goto err;
        }
        ghes = ghes_new(generic);
        if (IS_ERR(ghes)) {
                rc = PTR_ERR(ghes);
                ghes = NULL;
                goto err;
        }
        switch (generic->notify.type) {
        case ACPI_HEST_NOTIFY_POLLED:
                ghes->timer.function = ghes_poll_func;
                ghes->timer.data = (unsigned long)ghes;
                init_timer_deferrable(&ghes->timer);
                ghes_add_timer(ghes);
                break;
        case ACPI_HEST_NOTIFY_EXTERNAL:
                /* External interrupt vector is GSI */
                if (acpi_gsi_to_irq(generic->notify.vector, &ghes->irq)) {
                        pr_err(GHES_PFX "Failed to map GSI to IRQ for generic hardware error source: %d\n",
                               generic->header.source_id);
                        goto err;
                }
                if (request_irq(ghes->irq, ghes_irq_func,
                                0, "GHES IRQ", ghes)) {
                        pr_err(GHES_PFX "Failed to register IRQ for generic hardware error source: %d\n",
                               generic->header.source_id);
                        goto err;
                }
                break;
        case ACPI_HEST_NOTIFY_SCI:
                mutex_lock(&ghes_list_mutex);
                if (list_empty(&ghes_sci))
                        register_acpi_hed_notifier(&ghes_notifier_sci);
                list_add_rcu(&ghes->list, &ghes_sci);
                mutex_unlock(&ghes_list_mutex);
                break;
        case ACPI_HEST_NOTIFY_NMI:
                len = ghes_esource_prealloc_size(generic);
                ghes_estatus_pool_expand(len);
                mutex_lock(&ghes_list_mutex);
                if (list_empty(&ghes_nmi))
                        register_nmi_handler(NMI_LOCAL, ghes_notify_nmi, 0,
                                                "ghes");
                list_add_rcu(&ghes->list, &ghes_nmi);
                mutex_unlock(&ghes_list_mutex);
                break;
        default:
                BUG();
        }
        platform_set_drvdata(ghes_dev, ghes);

        return 0;
err:
        if (ghes) {
                ghes_fini(ghes);
                kfree(ghes);
        }
        return rc;
}

static int __devexit ghes_remove(struct platform_device *ghes_dev)
{
        struct ghes *ghes;
        struct acpi_hest_generic *generic;
        unsigned long len;

        ghes = platform_get_drvdata(ghes_dev);
        generic = ghes->generic;

        ghes->flags |= GHES_EXITING;
        switch (generic->notify.type) {
        case ACPI_HEST_NOTIFY_POLLED:
                del_timer_sync(&ghes->timer);
                break;
        case ACPI_HEST_NOTIFY_EXTERNAL:
                free_irq(ghes->irq, ghes);
                break;
        case ACPI_HEST_NOTIFY_SCI:
                mutex_lock(&ghes_list_mutex);
                list_del_rcu(&ghes->list);
                if (list_empty(&ghes_sci))
                        unregister_acpi_hed_notifier(&ghes_notifier_sci);
                mutex_unlock(&ghes_list_mutex);
                break;
        case ACPI_HEST_NOTIFY_NMI:
                mutex_lock(&ghes_list_mutex);
                list_del_rcu(&ghes->list);
                if (list_empty(&ghes_nmi))
                        unregister_nmi_handler(NMI_LOCAL, "ghes");
                mutex_unlock(&ghes_list_mutex);
                /*
                 * To synchronize with NMI handler, ghes can only be
                 * freed after NMI handler finishes.
                 */
                synchronize_rcu();
                len = ghes_esource_prealloc_size(generic);
                ghes_estatus_pool_shrink(len);
                break;
        default:
                BUG();
                break;
        }

        ghes_fini(ghes);
        kfree(ghes);

        platform_set_drvdata(ghes_dev, NULL);

        return 0;
}

static struct platform_driver ghes_platform_driver = {
        .driver         = {
                .name   = "GHES",
                .owner  = THIS_MODULE,
        },
        .probe          = ghes_probe,
        .remove         = ghes_remove,
};

static int __init ghes_init(void)
{
        int rc;

        if (acpi_disabled)
                return -ENODEV;

        if (hest_disable) {
                pr_info(GHES_PFX "HEST is not enabled!\n");
                return -EINVAL;
        }

        if (ghes_disable) {
                pr_info(GHES_PFX "GHES is not enabled!\n");
                return -EINVAL;
        }

        init_irq_work(&ghes_proc_irq_work, ghes_proc_in_irq);

        rc = ghes_ioremap_init();
        if (rc)
                goto err;

        rc = ghes_estatus_pool_init();
        if (rc)
                goto err_ioremap_exit;

        rc = ghes_estatus_pool_expand(GHES_ESTATUS_CACHE_AVG_SIZE *
                                      GHES_ESTATUS_CACHE_ALLOCED_MAX);
        if (rc)
                goto err_pool_exit;

        rc = platform_driver_register(&ghes_platform_driver);
        if (rc)
                goto err_pool_exit;

        rc = apei_osc_setup();
        if (rc == 0 && osc_sb_apei_support_acked)
                pr_info(GHES_PFX "APEI firmware first mode is enabled by APEI bit and WHEA _OSC.\n");
        else if (rc == 0 && !osc_sb_apei_support_acked)
                pr_info(GHES_PFX "APEI firmware first mode is enabled by WHEA _OSC.\n");
        else if (rc && osc_sb_apei_support_acked)
                pr_info(GHES_PFX "APEI firmware first mode is enabled by APEI bit.\n");
        else
                pr_info(GHES_PFX "Failed to enable APEI firmware first mode.\n");

        return 0;
err_pool_exit:
        ghes_estatus_pool_exit();
err_ioremap_exit:
        ghes_ioremap_exit();
err:
        return rc;
}

static void __exit ghes_exit(void)
{
        platform_driver_unregister(&ghes_platform_driver);
        ghes_estatus_pool_exit();
        ghes_ioremap_exit();
}

module_init(ghes_init);
module_exit(ghes_exit);

MODULE_AUTHOR("Huang Ying");
MODULE_DESCRIPTION("APEI Generic Hardware Error Source support");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:GHES");