zcore.c

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/*
 * zcore module to export memory content and register sets for creating system
 * dumps on SCSI disks (zfcpdump). The "zcore/mem" debugfs file shows the same
 * dump format as s390 standalone dumps.
 *
 * For more information please refer to Documentation/s390/zfcpdump.txt
 *
 * Copyright IBM Corp. 2003, 2008
 * Author(s): Michael Holzheu
 */

#define KMSG_COMPONENT "zdump"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/init.h>
#include <linux/slab.h>
#include <linux/miscdevice.h>
#include <linux/debugfs.h>
#include <linux/module.h>
#include <asm/asm-offsets.h>
#include <asm/ipl.h>
#include <asm/sclp.h>
#include <asm/setup.h>
#include <asm/uaccess.h>
#include <asm/debug.h>
#include <asm/processor.h>
#include <asm/irqflags.h>
#include <asm/checksum.h>
#include "sclp.h"

#define TRACE(x...) debug_sprintf_event(zcore_dbf, 1, x)

#define TO_USER     0
#define TO_KERNEL   1
#define CHUNK_INFO_SIZE 34 /* 2 16-byte char, each followed by blank */

enum arch_id {
    ARCH_S390   = 0,
    ARCH_S390X  = 1,
};

/* dump system info */

struct sys_info {
    enum arch_id     arch;
    unsigned long    sa_base;
    u32      sa_size;
    int      cpu_map[NR_CPUS];
    unsigned long    mem_size;
    struct save_area lc_mask;
};

struct ipib_info {
    unsigned long   ipib;
    u32     checksum;
}  __attribute__((packed));

static struct sys_info sys_info;
static struct debug_info *zcore_dbf;
static int hsa_available;
static struct dentry *zcore_dir;
static struct dentry *zcore_file;
static struct dentry *zcore_memmap_file;
static struct dentry *zcore_reipl_file;
static struct ipl_parameter_block *ipl_block;

/*
 * Copy memory from HSA to kernel or user memory (not reentrant):
 *
 * @dest:  Kernel or user buffer where memory should be copied to
 * @src:   Start address within HSA where data should be copied
 * @count: Size of buffer, which should be copied
 * @mode:  Either TO_KERNEL or TO_USER
 */
static int memcpy_hsa(void *dest, unsigned long src, size_t count, int mode)
{
    int offs, blk_num;
    static char buf[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));

    if (count == 0)
        return 0;

    /* copy first block */
    offs = 0;
    if ((src % PAGE_SIZE) != 0) {
        blk_num = src / PAGE_SIZE + 2;
        if (sclp_sdias_copy(buf, blk_num, 1)) {
            TRACE("sclp_sdias_copy() failed\n");
            return -EIO;
        }
        offs = min((PAGE_SIZE - (src % PAGE_SIZE)), count);
        if (mode == TO_USER) {
            if (copy_to_user((__force __user void*) dest,
                     buf + (src % PAGE_SIZE), offs))
                return -EFAULT;
        } else
            memcpy(dest, buf + (src % PAGE_SIZE), offs);
    }
    if (offs == count)
        goto out;

    /* copy middle */
    for (; (offs + PAGE_SIZE) <= count; offs += PAGE_SIZE) {
        blk_num = (src + offs) / PAGE_SIZE + 2;
        if (sclp_sdias_copy(buf, blk_num, 1)) {
            TRACE("sclp_sdias_copy() failed\n");
            return -EIO;
        }
        if (mode == TO_USER) {
            if (copy_to_user((__force __user void*) dest + offs,
                     buf, PAGE_SIZE))
                return -EFAULT;
        } else
            memcpy(dest + offs, buf, PAGE_SIZE);
    }
    if (offs == count)
        goto out;

    /* copy last block */
    blk_num = (src + offs) / PAGE_SIZE + 2;
    if (sclp_sdias_copy(buf, blk_num, 1)) {
        TRACE("sclp_sdias_copy() failed\n");
        return -EIO;
    }
    if (mode == TO_USER) {
        if (copy_to_user((__force __user void*) dest + offs, buf,
                 PAGE_SIZE))
            return -EFAULT;
    } else
        memcpy(dest + offs, buf, count - offs);
out:
    return 0;
}

static int memcpy_hsa_user(void __user *dest, unsigned long src, size_t count)
{
    return memcpy_hsa((void __force *) dest, src, count, TO_USER);
}

static int memcpy_hsa_kernel(void *dest, unsigned long src, size_t count)
{
    return memcpy_hsa(dest, src, count, TO_KERNEL);
}

static int __init init_cpu_info(enum arch_id arch)
{
    struct save_area *sa;

    /* get info for boot cpu from lowcore, stored in the HSA */

    sa = kmalloc(sizeof(*sa), GFP_KERNEL);
    if (!sa)
        return -ENOMEM;
    if (memcpy_hsa_kernel(sa, sys_info.sa_base, sys_info.sa_size) < 0) {
        TRACE("could not copy from HSA\n");
        kfree(sa);
        return -EIO;
    }
    zfcpdump_save_areas[0] = sa;
    return 0;
}

static DEFINE_MUTEX(zcore_mutex);

#define DUMP_VERSION    0x5
#define DUMP_MAGIC  0xa8190173618f23fdULL
#define DUMP_ARCH_S390X 2
#define DUMP_ARCH_S390  1
#define HEADER_SIZE 4096

/* dump header dumped according to s390 crash dump format */

struct zcore_header {
    u64 magic;
    u32 version;
    u32 header_size;
    u32 dump_level;
    u32 page_size;
    u64 mem_size;
    u64 mem_start;
    u64 mem_end;
    u32 num_pages;
    u32 pad1;
    u64 tod;
    struct cpuid cpu_id;
    u32 arch_id;
    u32 volnr;
    u32 build_arch;
    u64 rmem_size;
    u8 mvdump;
    u16 cpu_cnt;
    u16 real_cpu_cnt;
    u8 end_pad1[0x200-0x061];
    u64 mvdump_sign;
    u64 mvdump_zipl_time;
    u8 end_pad2[0x800-0x210];
    u32 lc_vec[512];
} __attribute__((packed,__aligned__(16)));

static struct zcore_header zcore_header = {
    .magic      = DUMP_MAGIC,
    .version    = DUMP_VERSION,
    .header_size    = 4096,
    .dump_level = 0,
    .page_size  = PAGE_SIZE,
    .mem_start  = 0,
#ifdef CONFIG_64BIT
    .build_arch = DUMP_ARCH_S390X,
#else
    .build_arch = DUMP_ARCH_S390,
#endif
};

/*
 * Copy lowcore info to buffer. Use map in order to copy only register parts.
 *
 * @buf:    User buffer
 * @sa:     Pointer to save area
 * @sa_off: Offset in save area to copy
 * @len:    Number of bytes to copy
 */
static int copy_lc(void __user *buf, void *sa, int sa_off, int len)
{
    int i;
    char *lc_mask = (char*)&sys_info.lc_mask;

    for (i = 0; i < len; i++) {
        if (!lc_mask[i + sa_off])
            continue;
        if (copy_to_user(buf + i, sa + sa_off + i, 1))
            return -EFAULT;
    }
    return 0;
}

/*
 * Copy lowcores info to memory, if necessary
 *
 * @buf:   User buffer
 * @addr:  Start address of buffer in dump memory
 * @count: Size of buffer
 */
static int zcore_add_lc(char __user *buf, unsigned long start, size_t count)
{
    unsigned long end;
    int i = 0;

    if (count == 0)
        return 0;

    end = start + count;
    while (zfcpdump_save_areas[i]) {
        unsigned long cp_start, cp_end; /* copy range */
        unsigned long sa_start, sa_end; /* save area range */
        unsigned long prefix;
        unsigned long sa_off, len, buf_off;

        prefix = zfcpdump_save_areas[i]->pref_reg;
        sa_start = prefix + sys_info.sa_base;
        sa_end = prefix + sys_info.sa_base + sys_info.sa_size;

        if ((end < sa_start) || (start > sa_end))
            goto next;
        cp_start = max(start, sa_start);
        cp_end = min(end, sa_end);

        buf_off = cp_start - start;
        sa_off = cp_start - sa_start;
        len = cp_end - cp_start;

        TRACE("copy_lc for: %lx\n", start);
        if (copy_lc(buf + buf_off, zfcpdump_save_areas[i], sa_off, len))
            return -EFAULT;
next:
        i++;
    }
    return 0;
}

/*
 * Read routine for zcore character device
 * First 4K are dump header
 * Next 32MB are HSA Memory
 * Rest is read from absolute Memory
 */
static ssize_t zcore_read(struct file *file, char __user *buf, size_t count,
              loff_t *ppos)
{
    unsigned long mem_start; /* Start address in memory */
    size_t mem_offs;     /* Offset in dump memory */
    size_t hdr_count;    /* Size of header part of output buffer */
    size_t size;
    int rc;

    mutex_lock(&zcore_mutex);

    if (*ppos > (sys_info.mem_size + HEADER_SIZE)) {
        rc = -EINVAL;
        goto fail;
    }

    count = min(count, (size_t) (sys_info.mem_size + HEADER_SIZE - *ppos));

    /* Copy dump header */
    if (*ppos < HEADER_SIZE) {
        size = min(count, (size_t) (HEADER_SIZE - *ppos));
        if (copy_to_user(buf, &zcore_header + *ppos, size)) {
            rc = -EFAULT;
            goto fail;
        }
        hdr_count = size;
        mem_start = 0;
    } else {
        hdr_count = 0;
        mem_start = *ppos - HEADER_SIZE;
    }

    mem_offs = 0;

    /* Copy from HSA data */
    if (*ppos < (ZFCPDUMP_HSA_SIZE + HEADER_SIZE)) {
        size = min((count - hdr_count), (size_t) (ZFCPDUMP_HSA_SIZE
               - mem_start));
        rc = memcpy_hsa_user(buf + hdr_count, mem_start, size);
        if (rc)
            goto fail;

        mem_offs += size;
    }

    /* Copy from real mem */
    size = count - mem_offs - hdr_count;
    rc = copy_to_user_real(buf + hdr_count + mem_offs,
                   (void *) mem_start + mem_offs, size);
    if (rc)
        goto fail;

    /*
     * Since s390 dump analysis tools like lcrash or crash
     * expect register sets in the prefix pages of the cpus,
     * we copy them into the read buffer, if necessary.
     * buf + hdr_count: Start of memory part of output buffer
     * mem_start: Start memory address to copy from
     * count - hdr_count: Size of memory area to copy
     */
    if (zcore_add_lc(buf + hdr_count, mem_start, count - hdr_count)) {
        rc = -EFAULT;
        goto fail;
    }
    *ppos += count;
fail:
    mutex_unlock(&zcore_mutex);
    return (rc < 0) ? rc : count;
}

static int zcore_open(struct inode *inode, struct file *filp)
{
    if (!hsa_available)
        return -ENODATA;
    else
        return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
}

static int zcore_release(struct inode *inode, struct file *filep)
{
    diag308(DIAG308_REL_HSA, NULL);
    hsa_available = 0;
    return 0;
}

static loff_t zcore_lseek(struct file *file, loff_t offset, int orig)
{
    loff_t rc;

    mutex_lock(&zcore_mutex);
    switch (orig) {
    case 0:
        file->f_pos = offset;
        rc = file->f_pos;
        break;
    case 1:
        file->f_pos += offset;
        rc = file->f_pos;
        break;
    default:
        rc = -EINVAL;
    }
    mutex_unlock(&zcore_mutex);
    return rc;
}

static const struct file_operations zcore_fops = {
    .owner      = THIS_MODULE,
    .llseek     = zcore_lseek,
    .read       = zcore_read,
    .open       = zcore_open,
    .release    = zcore_release,
};

static ssize_t zcore_memmap_read(struct file *filp, char __user *buf,
                 size_t count, loff_t *ppos)
{
    return simple_read_from_buffer(buf, count, ppos, filp->private_data,
                       MEMORY_CHUNKS * CHUNK_INFO_SIZE);
}

static int zcore_memmap_open(struct inode *inode, struct file *filp)
{
    int i;
    char *buf;
    struct mem_chunk *chunk_array;

    chunk_array = kzalloc(MEMORY_CHUNKS * sizeof(struct mem_chunk),
                  GFP_KERNEL);
    if (!chunk_array)
        return -ENOMEM;
    detect_memory_layout(chunk_array);
    buf = kzalloc(MEMORY_CHUNKS * CHUNK_INFO_SIZE, GFP_KERNEL);
    if (!buf) {
        kfree(chunk_array);
        return -ENOMEM;
    }
    for (i = 0; i < MEMORY_CHUNKS; i++) {
        sprintf(buf + (i * CHUNK_INFO_SIZE), "%016llx %016llx ",
            (unsigned long long) chunk_array[i].addr,
            (unsigned long long) chunk_array[i].size);
        if (chunk_array[i].size == 0)
            break;
    }
    kfree(chunk_array);
    filp->private_data = buf;
    return nonseekable_open(inode, filp);
}

static int zcore_memmap_release(struct inode *inode, struct file *filp)
{
    kfree(filp->private_data);
    return 0;
}

static const struct file_operations zcore_memmap_fops = {
    .owner      = THIS_MODULE,
    .read       = zcore_memmap_read,
    .open       = zcore_memmap_open,
    .release    = zcore_memmap_release,
    .llseek     = no_llseek,
};

static ssize_t zcore_reipl_write(struct file *filp, const char __user *buf,
                 size_t count, loff_t *ppos)
{
    if (ipl_block) {
        diag308(DIAG308_SET, ipl_block);
        diag308(DIAG308_IPL, NULL);
    }
    return count;
}

static int zcore_reipl_open(struct inode *inode, struct file *filp)
{
    return nonseekable_open(inode, filp);
}

static int zcore_reipl_release(struct inode *inode, struct file *filp)
{
    return 0;
}

static const struct file_operations zcore_reipl_fops = {
    .owner      = THIS_MODULE,
    .write      = zcore_reipl_write,
    .open       = zcore_reipl_open,
    .release    = zcore_reipl_release,
    .llseek     = no_llseek,
};

#ifdef CONFIG_32BIT

static void __init set_lc_mask(struct save_area *map)
{
    memset(&map->ext_save, 0xff, sizeof(map->ext_save));
    memset(&map->timer, 0xff, sizeof(map->timer));
    memset(&map->clk_cmp, 0xff, sizeof(map->clk_cmp));
    memset(&map->psw, 0xff, sizeof(map->psw));
    memset(&map->pref_reg, 0xff, sizeof(map->pref_reg));
    memset(&map->acc_regs, 0xff, sizeof(map->acc_regs));
    memset(&map->fp_regs, 0xff, sizeof(map->fp_regs));
    memset(&map->gp_regs, 0xff, sizeof(map->gp_regs));
    memset(&map->ctrl_regs, 0xff, sizeof(map->ctrl_regs));
}

#else /* CONFIG_32BIT */

static void __init set_lc_mask(struct save_area *map)
{
    memset(&map->fp_regs, 0xff, sizeof(map->fp_regs));
    memset(&map->gp_regs, 0xff, sizeof(map->gp_regs));
    memset(&map->psw, 0xff, sizeof(map->psw));
    memset(&map->pref_reg, 0xff, sizeof(map->pref_reg));
    memset(&map->fp_ctrl_reg, 0xff, sizeof(map->fp_ctrl_reg));
    memset(&map->tod_reg, 0xff, sizeof(map->tod_reg));
    memset(&map->timer, 0xff, sizeof(map->timer));
    memset(&map->clk_cmp, 0xff, sizeof(map->clk_cmp));
    memset(&map->acc_regs, 0xff, sizeof(map->acc_regs));
    memset(&map->ctrl_regs, 0xff, sizeof(map->ctrl_regs));
}

#endif /* CONFIG_32BIT */

/*
 * Initialize dump globals for a given architecture
 */
static int __init sys_info_init(enum arch_id arch)
{
    int rc;

    switch (arch) {
    case ARCH_S390X:
        pr_alert("DETECTED 'S390X (64 bit) OS'\n");
        break;
    case ARCH_S390:
        pr_alert("DETECTED 'S390 (32 bit) OS'\n");
        break;
    default:
        pr_alert("0x%x is an unknown architecture.\n",arch);
        return -EINVAL;
    }
    sys_info.sa_base = SAVE_AREA_BASE;
    sys_info.sa_size = sizeof(struct save_area);
    sys_info.arch = arch;
    set_lc_mask(&sys_info.lc_mask);
    rc = init_cpu_info(arch);
    if (rc)
        return rc;
    sys_info.mem_size = real_memory_size;

    return 0;
}

static int __init check_sdias(void)
{
    int rc, act_hsa_size;

    rc = sclp_sdias_blk_count();
    if (rc < 0) {
        TRACE("Could not determine HSA size\n");
        return rc;
    }
    act_hsa_size = (rc - 1) * PAGE_SIZE;
    if (act_hsa_size < ZFCPDUMP_HSA_SIZE) {
        TRACE("HSA size too small: %i\n", act_hsa_size);
        return -EINVAL;
    }
    return 0;
}

static int __init get_mem_size(unsigned long *mem)
{
    int i;
    struct mem_chunk *chunk_array;

    chunk_array = kzalloc(MEMORY_CHUNKS * sizeof(struct mem_chunk),
                  GFP_KERNEL);
    if (!chunk_array)
        return -ENOMEM;
    detect_memory_layout(chunk_array);
    for (i = 0; i < MEMORY_CHUNKS; i++) {
        if (chunk_array[i].size == 0)
            break;
        *mem += chunk_array[i].size;
    }
    kfree(chunk_array);
    return 0;
}

static int __init zcore_header_init(int arch, struct zcore_header *hdr)
{
    int rc, i;
    unsigned long memory = 0;
    u32 prefix;

    if (arch == ARCH_S390X)
        hdr->arch_id = DUMP_ARCH_S390X;
    else
        hdr->arch_id = DUMP_ARCH_S390;
    rc = get_mem_size(&memory);
    if (rc)
        return rc;
    hdr->mem_size = memory;
    hdr->rmem_size = memory;
    hdr->mem_end = sys_info.mem_size;
    hdr->num_pages = memory / PAGE_SIZE;
    hdr->tod = get_clock();
    get_cpu_id(&hdr->cpu_id);
    for (i = 0; zfcpdump_save_areas[i]; i++) {
        prefix = zfcpdump_save_areas[i]->pref_reg;
        hdr->real_cpu_cnt++;
        if (!prefix)
            continue;
        hdr->lc_vec[hdr->cpu_cnt] = prefix;
        hdr->cpu_cnt++;
    }
    return 0;
}

/*
 * Provide IPL parameter information block from either HSA or memory
 * for future reipl
 */
static int __init zcore_reipl_init(void)
{
    struct ipib_info ipib_info;
    int rc;

    rc = memcpy_hsa_kernel(&ipib_info, __LC_DUMP_REIPL, sizeof(ipib_info));
    if (rc)
        return rc;
    if (ipib_info.ipib == 0)
        return 0;
    ipl_block = (void *) __get_free_page(GFP_KERNEL);
    if (!ipl_block)
        return -ENOMEM;
    if (ipib_info.ipib < ZFCPDUMP_HSA_SIZE)
        rc = memcpy_hsa_kernel(ipl_block, ipib_info.ipib, PAGE_SIZE);
    else
        rc = memcpy_real(ipl_block, (void *) ipib_info.ipib, PAGE_SIZE);
    if (rc || csum_partial(ipl_block, ipl_block->hdr.len, 0) !=
        ipib_info.checksum) {
        TRACE("Checksum does not match\n");
        free_page((unsigned long) ipl_block);
        ipl_block = NULL;
    }
    return 0;
}

static int __init zcore_init(void)
{
    unsigned char arch;
    int rc;

    if (ipl_info.type != IPL_TYPE_FCP_DUMP)
        return -ENODATA;
    if (OLDMEM_BASE)
        return -ENODATA;

    zcore_dbf = debug_register("zcore", 4, 1, 4 * sizeof(long));
    debug_register_view(zcore_dbf, &debug_sprintf_view);
    debug_set_level(zcore_dbf, 6);

    TRACE("devno:  %x\n", ipl_info.data.fcp.dev_id.devno);
    TRACE("wwpn:   %llx\n", (unsigned long long) ipl_info.data.fcp.wwpn);
    TRACE("lun:    %llx\n", (unsigned long long) ipl_info.data.fcp.lun);

    rc = sclp_sdias_init();
    if (rc)
        goto fail;

    rc = check_sdias();
    if (rc)
        goto fail;

    rc = memcpy_hsa_kernel(&arch, __LC_AR_MODE_ID, 1);
    if (rc)
        goto fail;

#ifdef CONFIG_64BIT
    if (arch == ARCH_S390) {
        pr_alert("The 64-bit dump tool cannot be used for a "
             "32-bit system\n");
        rc = -EINVAL;
        goto fail;
    }
#else /* CONFIG_64BIT */
    if (arch == ARCH_S390X) {
        pr_alert("The 32-bit dump tool cannot be used for a "
             "64-bit system\n");
        rc = -EINVAL;
        goto fail;
    }
#endif /* CONFIG_64BIT */

    rc = sys_info_init(arch);
    if (rc)
        goto fail;

    rc = zcore_header_init(arch, &zcore_header);
    if (rc)
        goto fail;

    rc = zcore_reipl_init();
    if (rc)
        goto fail;

    zcore_dir = debugfs_create_dir("zcore" , NULL);
    if (!zcore_dir) {
        rc = -ENOMEM;
        goto fail;
    }
    zcore_file = debugfs_create_file("mem", S_IRUSR, zcore_dir, NULL,
                     &zcore_fops);
    if (!zcore_file) {
        rc = -ENOMEM;
        goto fail_dir;
    }
    zcore_memmap_file = debugfs_create_file("memmap", S_IRUSR, zcore_dir,
                        NULL, &zcore_memmap_fops);
    if (!zcore_memmap_file) {
        rc = -ENOMEM;
        goto fail_file;
    }
    zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir,
                        NULL, &zcore_reipl_fops);
    if (!zcore_reipl_file) {
        rc = -ENOMEM;
        goto fail_memmap_file;
    }
    hsa_available = 1;
    return 0;

fail_memmap_file:
    debugfs_remove(zcore_memmap_file);
fail_file:
    debugfs_remove(zcore_file);
fail_dir:
    debugfs_remove(zcore_dir);
fail:
    diag308(DIAG308_REL_HSA, NULL);
    return rc;
}

static void __exit zcore_exit(void)
{
    debug_unregister(zcore_dbf);
    sclp_sdias_exit();
    free_page((unsigned long) ipl_block);
    debugfs_remove(zcore_reipl_file);
    debugfs_remove(zcore_memmap_file);
    debugfs_remove(zcore_file);
    debugfs_remove(zcore_dir);
    diag308(DIAG308_REL_HSA, NULL);
}

MODULE_AUTHOR("Copyright IBM Corp. 2003,2008");
MODULE_DESCRIPTION("zcore module for zfcpdump support");
MODULE_LICENSE("GPL");

subsys_initcall(zcore_init);
module_exit(zcore_exit);