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/ctl_reg.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 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(&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 = strlcpy(ldfpl->fident, ftp->fname, sizeof(ldfpl->fident));
162	if (len >= HMCDRV_FTP_FIDENT_MAX) {
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(ftp->buf);
172
173	len = diag_ftp_2c4(ldfpl, 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}