1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * DIAGNOSE X'2C4' instruction based HMC FTP services, useable on z/VM
4 *
5 * Copyright IBM Corp. 2013
6 * Author(s): Ralf Hoppe (rhoppe@de.ibm.com)
7 *
8 */
9
10 #define KMSG_COMPONENT "hmcdrv"
11 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
12
13 #include <linux/kernel.h>
14 #include <linux/mm.h>
15 #include <linux/irq.h>
16 #include <linux/wait.h>
17 #include <linux/string.h>
18 #include <asm/asm-extable.h>
19 #include <asm/ctl_reg.h>
20 #include <asm/diag.h>
21
22 #include "hmcdrv_ftp.h"
23 #include "diag_ftp.h"
24
25 /* DIAGNOSE X'2C4' return codes in Ry */
26 #define DIAG_FTP_RET_OK 0 /* HMC FTP started successfully */
27 #define DIAG_FTP_RET_EBUSY 4 /* HMC FTP service currently busy */
28 #define DIAG_FTP_RET_EIO 8 /* HMC FTP service I/O error */
29 /* and an artificial extension */
30 #define DIAG_FTP_RET_EPERM 2 /* HMC FTP service privilege error */
31
32 /* FTP service status codes (after INTR at guest real location 133) */
33 #define DIAG_FTP_STAT_OK 0U /* request completed successfully */
34 #define DIAG_FTP_STAT_PGCC 4U /* program check condition */
35 #define DIAG_FTP_STAT_PGIOE 8U /* paging I/O error */
36 #define DIAG_FTP_STAT_TIMEOUT 12U /* timeout */
37 #define DIAG_FTP_STAT_EBASE 16U /* base of error codes from SCLP */
38 #define DIAG_FTP_STAT_LDFAIL (DIAG_FTP_STAT_EBASE + 1U) /* failed */
39 #define DIAG_FTP_STAT_LDNPERM (DIAG_FTP_STAT_EBASE + 2U) /* not allowed */
40 #define DIAG_FTP_STAT_LDRUNS (DIAG_FTP_STAT_EBASE + 3U) /* runs */
41 #define DIAG_FTP_STAT_LDNRUNS (DIAG_FTP_STAT_EBASE + 4U) /* not runs */
42
43 /**
44 * struct diag_ftp_ldfpl - load file FTP parameter list (LDFPL)
45 * @bufaddr: real buffer address (at 4k boundary)
46 * @buflen: length of buffer
47 * @offset: dir/file offset
48 * @intparm: interruption parameter (unused)
49 * @transferred: bytes transferred
50 * @fsize: file size, filled on GET
51 * @failaddr: failing address
52 * @spare: padding
53 * @fident: file name - ASCII
54 */
55 struct diag_ftp_ldfpl {
56 u64 bufaddr;
57 u64 buflen;
58 u64 offset;
59 u64 intparm;
60 u64 transferred;
61 u64 fsize;
62 u64 failaddr;
63 u64 spare;
64 u8 fident[HMCDRV_FTP_FIDENT_MAX];
65 } __packed;
66
67 static DECLARE_COMPLETION(diag_ftp_rx_complete);
68 static int diag_ftp_subcode;
69
70 /**
71 * diag_ftp_handler() - FTP services IRQ handler
72 * @extirq: external interrupt (sub-) code
73 * @param32: 32-bit interruption parameter from &struct diag_ftp_ldfpl
74 * @param64: unused (for 64-bit interrupt parameters)
75 */
diag_ftp_handler(struct ext_code extirq,unsigned int param32,unsigned long param64)76 static void diag_ftp_handler(struct ext_code extirq,
77 unsigned int param32,
78 unsigned long param64)
79 {
80 if ((extirq.subcode >> 8) != 8)
81 return; /* not a FTP services sub-code */
82
83 inc_irq_stat(IRQEXT_FTP);
84 diag_ftp_subcode = extirq.subcode & 0xffU;
85 complete(&diag_ftp_rx_complete);
86 }
87
88 /**
89 * diag_ftp_2c4() - DIAGNOSE X'2C4' service call
90 * @fpl: pointer to prepared LDFPL
91 * @cmd: FTP command to be executed
92 *
93 * Performs a DIAGNOSE X'2C4' call with (input/output) FTP parameter list
94 * @fpl and FTP function code @cmd. In case of an error the function does
95 * nothing and returns an (negative) error code.
96 *
97 * Notes:
98 * 1. This function only initiates a transfer, so the caller must wait
99 * for completion (asynchronous execution).
100 * 2. The FTP parameter list @fpl must be aligned to a double-word boundary.
101 * 3. fpl->bufaddr must be a real address, 4k aligned
102 */
diag_ftp_2c4(struct diag_ftp_ldfpl * fpl,enum hmcdrv_ftp_cmdid cmd)103 static int diag_ftp_2c4(struct diag_ftp_ldfpl *fpl,
104 enum hmcdrv_ftp_cmdid cmd)
105 {
106 int rc;
107
108 diag_stat_inc(DIAG_STAT_X2C4);
109 asm volatile(
110 " diag %[addr],%[cmd],0x2c4\n"
111 "0: j 2f\n"
112 "1: la %[rc],%[err]\n"
113 "2:\n"
114 EX_TABLE(0b, 1b)
115 : [rc] "=d" (rc), "+m" (*fpl)
116 : [cmd] "0" (cmd), [addr] "d" (virt_to_phys(fpl)),
117 [err] "i" (DIAG_FTP_RET_EPERM)
118 : "cc");
119
120 switch (rc) {
121 case DIAG_FTP_RET_OK:
122 return 0;
123 case DIAG_FTP_RET_EBUSY:
124 return -EBUSY;
125 case DIAG_FTP_RET_EPERM:
126 return -EPERM;
127 case DIAG_FTP_RET_EIO:
128 default:
129 return -EIO;
130 }
131 }
132
133 /**
134 * diag_ftp_cmd() - executes a DIAG X'2C4' FTP command, targeting a HMC
135 * @ftp: pointer to FTP command specification
136 * @fsize: return of file size (or NULL if undesirable)
137 *
138 * Attention: Notice that this function is not reentrant - so the caller
139 * must ensure locking.
140 *
141 * Return: number of bytes read/written or a (negative) error code
142 */
diag_ftp_cmd(const struct hmcdrv_ftp_cmdspec * ftp,size_t * fsize)143 ssize_t diag_ftp_cmd(const struct hmcdrv_ftp_cmdspec *ftp, size_t *fsize)
144 {
145 struct diag_ftp_ldfpl *ldfpl;
146 ssize_t len;
147 #ifdef DEBUG
148 unsigned long start_jiffies;
149
150 pr_debug("starting DIAG X'2C4' on '%s', requesting %zd bytes\n",
151 ftp->fname, ftp->len);
152 start_jiffies = jiffies;
153 #endif
154 init_completion(&diag_ftp_rx_complete);
155
156 ldfpl = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
157 if (!ldfpl) {
158 len = -ENOMEM;
159 goto out;
160 }
161
162 len = strscpy(ldfpl->fident, ftp->fname, sizeof(ldfpl->fident));
163 if (len < 0) {
164 len = -EINVAL;
165 goto out_free;
166 }
167
168 ldfpl->transferred = 0;
169 ldfpl->fsize = 0;
170 ldfpl->offset = ftp->ofs;
171 ldfpl->buflen = ftp->len;
172 ldfpl->bufaddr = virt_to_phys(ftp->buf);
173
174 len = diag_ftp_2c4(ldfpl, ftp->id);
175 if (len)
176 goto out_free;
177
178 /*
179 * There is no way to cancel the running diag X'2C4', the code
180 * needs to wait unconditionally until the transfer is complete.
181 */
182 wait_for_completion(&diag_ftp_rx_complete);
183
184 #ifdef DEBUG
185 pr_debug("completed DIAG X'2C4' after %lu ms\n",
186 (jiffies - start_jiffies) * 1000 / HZ);
187 pr_debug("status of DIAG X'2C4' is %u, with %lld/%lld bytes\n",
188 diag_ftp_subcode, ldfpl->transferred, ldfpl->fsize);
189 #endif
190
191 switch (diag_ftp_subcode) {
192 case DIAG_FTP_STAT_OK: /* success */
193 len = ldfpl->transferred;
194 if (fsize)
195 *fsize = ldfpl->fsize;
196 break;
197 case DIAG_FTP_STAT_LDNPERM:
198 len = -EPERM;
199 break;
200 case DIAG_FTP_STAT_LDRUNS:
201 len = -EBUSY;
202 break;
203 case DIAG_FTP_STAT_LDFAIL:
204 len = -ENOENT; /* no such file or media */
205 break;
206 default:
207 len = -EIO;
208 break;
209 }
210
211 out_free:
212 free_page((unsigned long) ldfpl);
213 out:
214 return len;
215 }
216
217 /**
218 * diag_ftp_startup() - startup of FTP services, when running on z/VM
219 *
220 * Return: 0 on success, else an (negative) error code
221 */
diag_ftp_startup(void)222 int diag_ftp_startup(void)
223 {
224 int rc;
225
226 rc = register_external_irq(EXT_IRQ_CP_SERVICE, diag_ftp_handler);
227 if (rc)
228 return rc;
229
230 irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
231 return 0;
232 }
233
234 /**
235 * diag_ftp_shutdown() - shutdown of FTP services, when running on z/VM
236 */
diag_ftp_shutdown(void)237 void diag_ftp_shutdown(void)
238 {
239 irq_subclass_unregister(IRQ_SUBCLASS_SERVICE_SIGNAL);
240 unregister_external_irq(EXT_IRQ_CP_SERVICE, diag_ftp_handler);
241 }
242
