| 1 | |
| 2 | |
| 3 | * S390 version
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| 4 | * Copyright IBM Corp. 1999, 2007
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| 5 | * Author(s): Martin Schwidefsky ([email protected]),
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| 6 | * Christian Borntraeger ([email protected]),
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| 7 |
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| 8 |
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| 9 | #define pr_fmt(fmt) "cpcmd: " fmt
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| 10 |
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| 11 | #include <linux/kernel.h>
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| 12 | #include <linux/export.h>
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| 13 | #include <linux/slab.h>
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| 14 | #include <linux/spinlock.h>
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| 15 | #include <linux/stddef.h>
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| 16 | #include <linux/string.h>
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| 17 | #include <linux/mm.h>
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| 18 | #include <linux/io.h>
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| 19 | #include <asm/diag.h>
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| 20 | #include <asm/ebcdic.h>
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| 21 | #include <asm/cpcmd.h>
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| 22 | #include <asm/asm.h>
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| 23 |
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| 24 | static DEFINE_SPINLOCK(cpcmd_lock);
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| 25 | static char cpcmd_buf[241];
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| 26 |
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| 27 | static int diag8_noresponse(int cmdlen)
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| 28 | {
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| 29 | asm volatile(
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| 30 | " diag %[rx],%[ry],0x8\n"
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| 31 | : [ry] "+&d" (cmdlen)
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| 32 | : [rx] "d" (__pa(cpcmd_buf))
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| 33 | : "cc");
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| 34 | return cmdlen;
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| 35 | }
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| 36 |
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| 37 | static int diag8_response(int cmdlen, char *response, int *rlen)
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| 38 | {
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| 39 | union register_pair rx, ry;
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| 40 | int cc;
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| 41 |
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| 42 | rx.even = __pa(cpcmd_buf);
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| 43 | rx.odd = __pa(response);
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| 44 | ry.even = cmdlen | 0x40000000L;
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| 45 | ry.odd = *rlen;
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| 46 | asm volatile(
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| 47 | " diag %[rx],%[ry],0x8\n"
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| 48 | CC_IPM(cc)
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| 49 | : CC_OUT(cc, cc), [ry] "+d" (ry.pair)
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| 50 | : [rx] "d" (rx.pair)
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| 51 | : CC_CLOBBER);
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| 52 | if (CC_TRANSFORM(cc))
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| 53 | *rlen += ry.odd;
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| 54 | else
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| 55 | *rlen = ry.odd;
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| 56 | return ry.even;
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| 57 | }
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| 58 |
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| 59 | |
| 60 | * __cpcmd has some restrictions over cpcmd
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| 61 | * - __cpcmd is unlocked and therefore not SMP-safe
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| 62 |
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| 63 | int __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
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| 64 | {
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| 65 | int cmdlen;
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| 66 | int rc;
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| 67 | int response_len;
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| 68 |
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| 69 | cmdlen = strlen(cmd);
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| 70 | BUG_ON(cmdlen > 240);
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| 71 | memcpy(cpcmd_buf, cmd, cmdlen);
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| 72 | ASCEBC(cpcmd_buf, cmdlen);
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| 73 |
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| 74 | diag_stat_inc(DIAG_STAT_X008);
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| 75 | if (response) {
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| 76 | memset(response, 0, rlen);
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| 77 | response_len = rlen;
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| 78 | rc = diag8_response(cmdlen, response, &rlen);
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| 79 | EBCASC(response, response_len);
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| 80 | } else {
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| 81 | rc = diag8_noresponse(cmdlen);
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| 82 | }
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| 83 | if (response_code)
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| 84 | *response_code = rc;
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| 85 | return rlen;
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| 86 | }
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| 87 | EXPORT_SYMBOL(__cpcmd);
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| 88 |
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| 89 | int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
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| 90 | {
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| 91 | unsigned long flags;
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| 92 | char *lowbuf;
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| 93 | int len;
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| 94 |
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| 95 | if (is_vmalloc_or_module_addr(response)) {
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| 96 | lowbuf = kmalloc(rlen, GFP_KERNEL);
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| 97 | if (!lowbuf) {
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| 98 | pr_warn("The cpcmd kernel function failed to allocate a response buffer\n");
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| 99 | return -ENOMEM;
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| 100 | }
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| 101 | spin_lock_irqsave(&cpcmd_lock, flags);
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| 102 | len = __cpcmd(cmd, lowbuf, rlen, response_code);
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| 103 | spin_unlock_irqrestore(&cpcmd_lock, flags);
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| 104 | memcpy(response, lowbuf, rlen);
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| 105 | kfree(lowbuf);
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| 106 | } else {
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| 107 | spin_lock_irqsave(&cpcmd_lock, flags);
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| 108 | len = __cpcmd(cmd, response, rlen, response_code);
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| 109 | spin_unlock_irqrestore(&cpcmd_lock, flags);
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| 110 | }
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| 111 | return len;
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| 112 | }
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| 113 | EXPORT_SYMBOL(cpcmd);
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