extmem.c

Go to the documentation of this file.

/*
 * Author(s)......: Carsten Otte <[email protected]>
 *          Rob M van der Heij <[email protected]>
 *          Steven Shultz <[email protected]>
 * Bugreports.to..: <[email protected]>
 * Copyright IBM Corp. 2002, 2004
 */

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

#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/bootmem.h>
#include <linux/ctype.h>
#include <linux/ioport.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/ebcdic.h>
#include <asm/errno.h>
#include <asm/extmem.h>
#include <asm/cpcmd.h>
#include <asm/setup.h>

#define DCSS_LOADSHR    0x00
#define DCSS_LOADNSR    0x04
#define DCSS_PURGESEG   0x08
#define DCSS_FINDSEG    0x0c
#define DCSS_LOADNOLY   0x10
#define DCSS_SEGEXT     0x18
#define DCSS_LOADSHRX   0x20
#define DCSS_LOADNSRX   0x24
#define DCSS_FINDSEGX   0x2c
#define DCSS_SEGEXTX    0x38
#define DCSS_FINDSEGA   0x0c

struct qrange {
    unsigned long  start; /* last byte type */
    unsigned long  end;   /* last byte reserved */
};

struct qout64 {
    unsigned long segstart;
    unsigned long segend;
    int segcnt;
    int segrcnt;
    struct qrange range[6];
};

#ifdef CONFIG_64BIT
struct qrange_old {
    unsigned int start; /* last byte type */
    unsigned int end;   /* last byte reserved */
};

/* output area format for the Diag x'64' old subcode x'18' */
struct qout64_old {
    int segstart;
    int segend;
    int segcnt;
    int segrcnt;
    struct qrange_old range[6];
};
#endif

struct qin64 {
    char qopcode;
    char rsrv1[3];
    char qrcode;
    char rsrv2[3];
    char qname[8];
    unsigned int qoutptr;
    short int qoutlen;
};

struct dcss_segment {
    struct list_head list;
    char dcss_name[8];
    char res_name[15];
    unsigned long start_addr;
    unsigned long end;
    atomic_t ref_count;
    int do_nonshared;
    unsigned int vm_segtype;
    struct qrange range[6];
    int segcnt;
    struct resource *res;
};

static DEFINE_MUTEX(dcss_lock);
static LIST_HEAD(dcss_list);
static char *segtype_string[] = { "SW", "EW", "SR", "ER", "SN", "EN", "SC",
                    "EW/EN-MIXED" };
static int loadshr_scode, loadnsr_scode, findseg_scode;
static int segext_scode, purgeseg_scode;
static int scode_set;

/* set correct Diag x'64' subcodes. */
static int
dcss_set_subcodes(void)
{
#ifdef CONFIG_64BIT
    char *name = kmalloc(8 * sizeof(char), GFP_KERNEL | GFP_DMA);
    unsigned long rx, ry;
    int rc;

    if (name == NULL)
        return -ENOMEM;

    rx = (unsigned long) name;
    ry = DCSS_FINDSEGX;

    strcpy(name, "dummy");
    asm volatile(
        "   diag    %0,%1,0x64\n"
        "0: ipm %2\n"
        "   srl %2,28\n"
        "   j   2f\n"
        "1: la  %2,3\n"
        "2:\n"
        EX_TABLE(0b, 1b)
        : "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");

    kfree(name);
    /* Diag x'64' new subcodes are supported, set to new subcodes */
    if (rc != 3) {
        loadshr_scode = DCSS_LOADSHRX;
        loadnsr_scode = DCSS_LOADNSRX;
        purgeseg_scode = DCSS_PURGESEG;
        findseg_scode = DCSS_FINDSEGX;
        segext_scode = DCSS_SEGEXTX;
        return 0;
    }
#endif
    /* Diag x'64' new subcodes are not supported, set to old subcodes */
    loadshr_scode = DCSS_LOADNOLY;
    loadnsr_scode = DCSS_LOADNSR;
    purgeseg_scode = DCSS_PURGESEG;
    findseg_scode = DCSS_FINDSEG;
    segext_scode = DCSS_SEGEXT;
    return 0;
}

/*
 * Create the 8 bytes, ebcdic VM segment name from
 * an ascii name.
 */
static void
dcss_mkname(char *name, char *dcss_name)
{
    int i;

    for (i = 0; i < 8; i++) {
        if (name[i] == '\0')
            break;
        dcss_name[i] = toupper(name[i]);
    };
    for (; i < 8; i++)
        dcss_name[i] = ' ';
    ASCEBC(dcss_name, 8);
}


/*
 * search all segments in dcss_list, and return the one
 * namend *name. If not found, return NULL.
 */
static struct dcss_segment *
segment_by_name (char *name)
{
    char dcss_name[9];
    struct list_head *l;
    struct dcss_segment *tmp, *retval = NULL;

    BUG_ON(!mutex_is_locked(&dcss_lock));
    dcss_mkname (name, dcss_name);
    list_for_each (l, &dcss_list) {
        tmp = list_entry (l, struct dcss_segment, list);
        if (memcmp(tmp->dcss_name, dcss_name, 8) == 0) {
            retval = tmp;
            break;
        }
    }
    return retval;
}


/*
 * Perform a function on a dcss segment.
 */
static inline int
dcss_diag(int *func, void *parameter,
           unsigned long *ret1, unsigned long *ret2)
{
    unsigned long rx, ry;
    int rc;

    if (scode_set == 0) {
        rc = dcss_set_subcodes();
        if (rc < 0)
            return rc;
        scode_set = 1;
    }
    rx = (unsigned long) parameter;
    ry = (unsigned long) *func;

#ifdef CONFIG_64BIT
    /* 64-bit Diag x'64' new subcode, keep in 64-bit addressing mode */
    if (*func > DCSS_SEGEXT)
        asm volatile(
            "   diag    %0,%1,0x64\n"
            "   ipm %2\n"
            "   srl %2,28\n"
            : "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");
    /* 31-bit Diag x'64' old subcode, switch to 31-bit addressing mode */
    else
        asm volatile(
            "   sam31\n"
            "   diag    %0,%1,0x64\n"
            "   sam64\n"
            "   ipm %2\n"
            "   srl %2,28\n"
            : "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");
#else
    asm volatile(
        "   diag    %0,%1,0x64\n"
        "   ipm %2\n"
        "   srl %2,28\n"
        : "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");
#endif
    *ret1 = rx;
    *ret2 = ry;
    return rc;
}

static inline int
dcss_diag_translate_rc (int vm_rc) {
    if (vm_rc == 44)
        return -ENOENT;
    return -EIO;
}


/* do a diag to get info about a segment.
 * fills start_address, end and vm_segtype fields
 */
static int
query_segment_type (struct dcss_segment *seg)
{
    unsigned long dummy, vmrc;
    int diag_cc, rc, i;
    struct qout64 *qout;
    struct qin64 *qin;

    qin = kmalloc(sizeof(*qin), GFP_KERNEL | GFP_DMA);
    qout = kmalloc(sizeof(*qout), GFP_KERNEL | GFP_DMA);
    if ((qin == NULL) || (qout == NULL)) {
        rc = -ENOMEM;
        goto out_free;
    }

    /* initialize diag input parameters */
    qin->qopcode = DCSS_FINDSEGA;
    qin->qoutptr = (unsigned long) qout;
    qin->qoutlen = sizeof(struct qout64);
    memcpy (qin->qname, seg->dcss_name, 8);

    diag_cc = dcss_diag(&segext_scode, qin, &dummy, &vmrc);

    if (diag_cc < 0) {
        rc = diag_cc;
        goto out_free;
    }
    if (diag_cc > 1) {
        pr_warning("Querying a DCSS type failed with rc=%ld\n", vmrc);
        rc = dcss_diag_translate_rc (vmrc);
        goto out_free;
    }

#ifdef CONFIG_64BIT
    /* Only old format of output area of Diagnose x'64' is supported,
       copy data for the new format. */
    if (segext_scode == DCSS_SEGEXT) {
        struct qout64_old *qout_old;
        qout_old = kzalloc(sizeof(*qout_old), GFP_KERNEL | GFP_DMA);
        if (qout_old == NULL) {
            rc = -ENOMEM;
            goto out_free;
        }
        memcpy(qout_old, qout, sizeof(struct qout64_old));
        qout->segstart = (unsigned long) qout_old->segstart;
        qout->segend = (unsigned long) qout_old->segend;
        qout->segcnt = qout_old->segcnt;
        qout->segrcnt = qout_old->segrcnt;

        if (qout->segcnt > 6)
            qout->segrcnt = 6;
        for (i = 0; i < qout->segrcnt; i++) {
            qout->range[i].start =
                (unsigned long) qout_old->range[i].start;
            qout->range[i].end =
                (unsigned long) qout_old->range[i].end;
        }
        kfree(qout_old);
    }
#endif
    if (qout->segcnt > 6) {
        rc = -EOPNOTSUPP;
        goto out_free;
    }

    if (qout->segcnt == 1) {
        seg->vm_segtype = qout->range[0].start & 0xff;
    } else {
        /* multi-part segment. only one type supported here:
            - all parts are contiguous
            - all parts are either EW or EN type
            - maximum 6 parts allowed */
        unsigned long start = qout->segstart >> PAGE_SHIFT;
        for (i=0; i<qout->segcnt; i++) {
            if (((qout->range[i].start & 0xff) != SEG_TYPE_EW) &&
                ((qout->range[i].start & 0xff) != SEG_TYPE_EN)) {
                rc = -EOPNOTSUPP;
                goto out_free;
            }
            if (start != qout->range[i].start >> PAGE_SHIFT) {
                rc = -EOPNOTSUPP;
                goto out_free;
            }
            start = (qout->range[i].end >> PAGE_SHIFT) + 1;
        }
        seg->vm_segtype = SEG_TYPE_EWEN;
    }

    /* analyze diag output and update seg */
    seg->start_addr = qout->segstart;
    seg->end = qout->segend;

    memcpy (seg->range, qout->range, 6*sizeof(struct qrange));
    seg->segcnt = qout->segcnt;

    rc = 0;

 out_free:
    kfree(qin);
    kfree(qout);
    return rc;
}

/*
 * get info about a segment
 * possible return values:
 * -ENOSYS  : we are not running on VM
 * -EIO     : could not perform query diagnose
 * -ENOENT  : no such segment
 * -EOPNOTSUPP: multi-part segment cannot be used with linux
 * -ENOMEM  : out of memory
 * 0 .. 6   : type of segment as defined in include/asm-s390/extmem.h
 */
int
segment_type (char* name)
{
    int rc;
    struct dcss_segment seg;

    if (!MACHINE_IS_VM)
        return -ENOSYS;

    dcss_mkname(name, seg.dcss_name);
    rc = query_segment_type (&seg);
    if (rc < 0)
        return rc;
    return seg.vm_segtype;
}

/*
 * check if segment collides with other segments that are currently loaded
 * returns 1 if this is the case, 0 if no collision was found
 */
static int
segment_overlaps_others (struct dcss_segment *seg)
{
    struct list_head *l;
    struct dcss_segment *tmp;

    BUG_ON(!mutex_is_locked(&dcss_lock));
    list_for_each(l, &dcss_list) {
        tmp = list_entry(l, struct dcss_segment, list);
        if ((tmp->start_addr >> 20) > (seg->end >> 20))
            continue;
        if ((tmp->end >> 20) < (seg->start_addr >> 20))
            continue;
        if (seg == tmp)
            continue;
        return 1;
    }
    return 0;
}

/*
 * real segment loading function, called from segment_load
 */
static int
__segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long *end)
{
    unsigned long start_addr, end_addr, dummy;
    struct dcss_segment *seg;
    int rc, diag_cc;

    start_addr = end_addr = 0;
    seg = kmalloc(sizeof(*seg), GFP_KERNEL | GFP_DMA);
    if (seg == NULL) {
        rc = -ENOMEM;
        goto out;
    }
    dcss_mkname (name, seg->dcss_name);
    rc = query_segment_type (seg);
    if (rc < 0)
        goto out_free;

    if (loadshr_scode == DCSS_LOADSHRX) {
        if (segment_overlaps_others(seg)) {
            rc = -EBUSY;
            goto out_free;
        }
    }

    rc = vmem_add_mapping(seg->start_addr, seg->end - seg->start_addr + 1);

    if (rc)
        goto out_free;

    seg->res = kzalloc(sizeof(struct resource), GFP_KERNEL);
    if (seg->res == NULL) {
        rc = -ENOMEM;
        goto out_shared;
    }
    seg->res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
    seg->res->start = seg->start_addr;
    seg->res->end = seg->end;
    memcpy(&seg->res_name, seg->dcss_name, 8);
    EBCASC(seg->res_name, 8);
    seg->res_name[8] = '\0';
    strncat(seg->res_name, " (DCSS)", 7);
    seg->res->name = seg->res_name;
    rc = seg->vm_segtype;
    if (rc == SEG_TYPE_SC ||
        ((rc == SEG_TYPE_SR || rc == SEG_TYPE_ER) && !do_nonshared))
        seg->res->flags |= IORESOURCE_READONLY;
    if (request_resource(&iomem_resource, seg->res)) {
        rc = -EBUSY;
        kfree(seg->res);
        goto out_shared;
    }

    if (do_nonshared)
        diag_cc = dcss_diag(&loadnsr_scode, seg->dcss_name,
                &start_addr, &end_addr);
    else
        diag_cc = dcss_diag(&loadshr_scode, seg->dcss_name,
                &start_addr, &end_addr);
    if (diag_cc < 0) {
        dcss_diag(&purgeseg_scode, seg->dcss_name,
                &dummy, &dummy);
        rc = diag_cc;
        goto out_resource;
    }
    if (diag_cc > 1) {
        pr_warning("Loading DCSS %s failed with rc=%ld\n", name,
               end_addr);
        rc = dcss_diag_translate_rc(end_addr);
        dcss_diag(&purgeseg_scode, seg->dcss_name,
                &dummy, &dummy);
        goto out_resource;
    }
    seg->start_addr = start_addr;
    seg->end = end_addr;
    seg->do_nonshared = do_nonshared;
    atomic_set(&seg->ref_count, 1);
    list_add(&seg->list, &dcss_list);
    *addr = seg->start_addr;
    *end  = seg->end;
    if (do_nonshared)
        pr_info("DCSS %s of range %p to %p and type %s loaded as "
            "exclusive-writable\n", name, (void*) seg->start_addr,
            (void*) seg->end, segtype_string[seg->vm_segtype]);
    else {
        pr_info("DCSS %s of range %p to %p and type %s loaded in "
            "shared access mode\n", name, (void*) seg->start_addr,
            (void*) seg->end, segtype_string[seg->vm_segtype]);
    }
    goto out;
 out_resource:
    release_resource(seg->res);
    kfree(seg->res);
 out_shared:
    vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
 out_free:
    kfree(seg);
 out:
    return rc;
}

/*
 * this function loads a DCSS segment
 * name         : name of the DCSS
 * do_nonshared : 0 indicates that the dcss should be shared with other linux images
 *                1 indicates that the dcss should be exclusive for this linux image
 * addr         : will be filled with start address of the segment
 * end          : will be filled with end address of the segment
 * return values:
 * -ENOSYS  : we are not running on VM
 * -EIO     : could not perform query or load diagnose
 * -ENOENT  : no such segment
 * -EOPNOTSUPP: multi-part segment cannot be used with linux
 * -ENOSPC  : segment cannot be used (overlaps with storage)
 * -EBUSY   : segment can temporarily not be used (overlaps with dcss)
 * -ERANGE  : segment cannot be used (exceeds kernel mapping range)
 * -EPERM   : segment is currently loaded with incompatible permissions
 * -ENOMEM  : out of memory
 * 0 .. 6   : type of segment as defined in include/asm-s390/extmem.h
 */
int
segment_load (char *name, int do_nonshared, unsigned long *addr,
        unsigned long *end)
{
    struct dcss_segment *seg;
    int rc;

    if (!MACHINE_IS_VM)
        return -ENOSYS;

    mutex_lock(&dcss_lock);
    seg = segment_by_name (name);
    if (seg == NULL)
        rc = __segment_load (name, do_nonshared, addr, end);
    else {
        if (do_nonshared == seg->do_nonshared) {
            atomic_inc(&seg->ref_count);
            *addr = seg->start_addr;
            *end  = seg->end;
            rc    = seg->vm_segtype;
        } else {
            *addr = *end = 0;
            rc    = -EPERM;
        }
    }
    mutex_unlock(&dcss_lock);
    return rc;
}

/*
 * this function modifies the shared state of a DCSS segment. note that
 * name         : name of the DCSS
 * do_nonshared : 0 indicates that the dcss should be shared with other linux images
 *                1 indicates that the dcss should be exclusive for this linux image
 * return values:
 * -EIO     : could not perform load diagnose (segment gone!)
 * -ENOENT  : no such segment (segment gone!)
 * -EAGAIN  : segment is in use by other exploiters, try later
 * -EINVAL  : no segment with the given name is currently loaded - name invalid
 * -EBUSY   : segment can temporarily not be used (overlaps with dcss)
 * 0        : operation succeeded
 */
int
segment_modify_shared (char *name, int do_nonshared)
{
    struct dcss_segment *seg;
    unsigned long start_addr, end_addr, dummy;
    int rc, diag_cc;

    start_addr = end_addr = 0;
    mutex_lock(&dcss_lock);
    seg = segment_by_name (name);
    if (seg == NULL) {
        rc = -EINVAL;
        goto out_unlock;
    }
    if (do_nonshared == seg->do_nonshared) {
        pr_info("DCSS %s is already in the requested access "
            "mode\n", name);
        rc = 0;
        goto out_unlock;
    }
    if (atomic_read (&seg->ref_count) != 1) {
        pr_warning("DCSS %s is in use and cannot be reloaded\n",
               name);
        rc = -EAGAIN;
        goto out_unlock;
    }
    release_resource(seg->res);
    if (do_nonshared)
        seg->res->flags &= ~IORESOURCE_READONLY;
    else
        if (seg->vm_segtype == SEG_TYPE_SR ||
            seg->vm_segtype == SEG_TYPE_ER)
            seg->res->flags |= IORESOURCE_READONLY;

    if (request_resource(&iomem_resource, seg->res)) {
        pr_warning("DCSS %s overlaps with used memory resources "
               "and cannot be reloaded\n", name);
        rc = -EBUSY;
        kfree(seg->res);
        goto out_del_mem;
    }

    dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
    if (do_nonshared)
        diag_cc = dcss_diag(&loadnsr_scode, seg->dcss_name,
                &start_addr, &end_addr);
    else
        diag_cc = dcss_diag(&loadshr_scode, seg->dcss_name,
                &start_addr, &end_addr);
    if (diag_cc < 0) {
        rc = diag_cc;
        goto out_del_res;
    }
    if (diag_cc > 1) {
        pr_warning("Reloading DCSS %s failed with rc=%ld\n", name,
               end_addr);
        rc = dcss_diag_translate_rc(end_addr);
        goto out_del_res;
    }
    seg->start_addr = start_addr;
    seg->end = end_addr;
    seg->do_nonshared = do_nonshared;
    rc = 0;
    goto out_unlock;
 out_del_res:
    release_resource(seg->res);
    kfree(seg->res);
 out_del_mem:
    vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
    list_del(&seg->list);
    dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
    kfree(seg);
 out_unlock:
    mutex_unlock(&dcss_lock);
    return rc;
}

/*
 * Decrease the use count of a DCSS segment and remove
 * it from the address space if nobody is using it
 * any longer.
 */
void
segment_unload(char *name)
{
    unsigned long dummy;
    struct dcss_segment *seg;

    if (!MACHINE_IS_VM)
        return;

    mutex_lock(&dcss_lock);
    seg = segment_by_name (name);
    if (seg == NULL) {
        pr_err("Unloading unknown DCSS %s failed\n", name);
        goto out_unlock;
    }
    if (atomic_dec_return(&seg->ref_count) != 0)
        goto out_unlock;
    release_resource(seg->res);
    kfree(seg->res);
    vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
    list_del(&seg->list);
    dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
    kfree(seg);
out_unlock:
    mutex_unlock(&dcss_lock);
}

/*
 * save segment content permanently
 */
void
segment_save(char *name)
{
    struct dcss_segment *seg;
    char cmd1[160];
    char cmd2[80];
    int i, response;

    if (!MACHINE_IS_VM)
        return;

    mutex_lock(&dcss_lock);
    seg = segment_by_name (name);

    if (seg == NULL) {
        pr_err("Saving unknown DCSS %s failed\n", name);
        goto out;
    }

    sprintf(cmd1, "DEFSEG %s", name);
    for (i=0; i<seg->segcnt; i++) {
        sprintf(cmd1+strlen(cmd1), " %lX-%lX %s",
            seg->range[i].start >> PAGE_SHIFT,
            seg->range[i].end >> PAGE_SHIFT,
            segtype_string[seg->range[i].start & 0xff]);
    }
    sprintf(cmd2, "SAVESEG %s", name);
    response = 0;
    cpcmd(cmd1, NULL, 0, &response);
    if (response) {
        pr_err("Saving a DCSS failed with DEFSEG response code "
               "%i\n", response);
        goto out;
    }
    cpcmd(cmd2, NULL, 0, &response);
    if (response) {
        pr_err("Saving a DCSS failed with SAVESEG response code "
               "%i\n", response);
        goto out;
    }
out:
    mutex_unlock(&dcss_lock);
}

/*
 * print appropriate error message for segment_load()/segment_type()
 * return code
 */
void segment_warning(int rc, char *seg_name)
{
    switch (rc) {
    case -ENOENT:
        pr_err("DCSS %s cannot be loaded or queried\n", seg_name);
        break;
    case -ENOSYS:
        pr_err("DCSS %s cannot be loaded or queried without "
               "z/VM\n", seg_name);
        break;
    case -EIO:
        pr_err("Loading or querying DCSS %s resulted in a "
               "hardware error\n", seg_name);
        break;
    case -EOPNOTSUPP:
        pr_err("DCSS %s has multiple page ranges and cannot be "
               "loaded or queried\n", seg_name);
        break;
    case -ENOSPC:
        pr_err("DCSS %s overlaps with used storage and cannot "
               "be loaded\n", seg_name);
        break;
    case -EBUSY:
        pr_err("%s needs used memory resources and cannot be "
               "loaded or queried\n", seg_name);
        break;
    case -EPERM:
        pr_err("DCSS %s is already loaded in a different access "
               "mode\n", seg_name);
        break;
    case -ENOMEM:
        pr_err("There is not enough memory to load or query "
               "DCSS %s\n", seg_name);
        break;
    case -ERANGE:
        pr_err("DCSS %s exceeds the kernel mapping range (%lu) "
               "and cannot be loaded\n", seg_name, VMEM_MAX_PHYS);
        break;
    default:
        break;
    }
}

EXPORT_SYMBOL(segment_load);
EXPORT_SYMBOL(segment_unload);
EXPORT_SYMBOL(segment_save);
EXPORT_SYMBOL(segment_type);
EXPORT_SYMBOL(segment_modify_shared);
EXPORT_SYMBOL(segment_warning);