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

source code of linux/drivers/s390/char/diag_ftp.c