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/ctlreg.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 */
 55struct 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
 67static DECLARE_COMPLETION(diag_ftp_rx_complete);
 68static 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 */
 76static 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 */
103static 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 */
143ssize_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
211out_free:
212	free_page((unsigned long) ldfpl);
213out:
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 */
222int 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 */
237void 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}