// SPDX-License-Identifier: GPL-2.0
/*
* DIAGNOSE X'2C4' instruction based HMC FTP services, useable on z/VM
*
* Copyright IBM Corp. 2013
* Author(s): Ralf Hoppe (rhoppe@de.ibm.com)
*
*/
#define KMSG_COMPONENT "hmcdrv"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/irq.h>
#include <linux/wait.h>
#include <linux/string.h>
#include <asm/asm-extable.h>
#include <asm/ctl_reg.h>
#include <asm/diag.h>
#include "hmcdrv_ftp.h"
#include "diag_ftp.h"
/* DIAGNOSE X'2C4' return codes in Ry */
#define DIAG_FTP_RET_OK 0 /* HMC FTP started successfully */
#define DIAG_FTP_RET_EBUSY 4 /* HMC FTP service currently busy */
#define DIAG_FTP_RET_EIO 8 /* HMC FTP service I/O error */
/* and an artificial extension */
#define DIAG_FTP_RET_EPERM 2 /* HMC FTP service privilege error */
/* FTP service status codes (after INTR at guest real location 133) */
#define DIAG_FTP_STAT_OK 0U /* request completed successfully */
#define DIAG_FTP_STAT_PGCC 4U /* program check condition */
#define DIAG_FTP_STAT_PGIOE 8U /* paging I/O error */
#define DIAG_FTP_STAT_TIMEOUT 12U /* timeout */
#define DIAG_FTP_STAT_EBASE 16U /* base of error codes from SCLP */
#define DIAG_FTP_STAT_LDFAIL (DIAG_FTP_STAT_EBASE + 1U) /* failed */
#define DIAG_FTP_STAT_LDNPERM (DIAG_FTP_STAT_EBASE + 2U) /* not allowed */
#define DIAG_FTP_STAT_LDRUNS (DIAG_FTP_STAT_EBASE + 3U) /* runs */
#define DIAG_FTP_STAT_LDNRUNS (DIAG_FTP_STAT_EBASE + 4U) /* not runs */
/**
* struct diag_ftp_ldfpl - load file FTP parameter list (LDFPL)
* @bufaddr: real buffer address (at 4k boundary)
* @buflen: length of buffer
* @offset: dir/file offset
* @intparm: interruption parameter (unused)
* @transferred: bytes transferred
* @fsize: file size, filled on GET
* @failaddr: failing address
* @spare: padding
* @fident: file name - ASCII
*/
struct diag_ftp_ldfpl {
u64 bufaddr;
u64 buflen;
u64 offset;
u64 intparm;
u64 transferred;
u64 fsize;
u64 failaddr;
u64 spare;
u8 fident[HMCDRV_FTP_FIDENT_MAX];
} __packed;
static DECLARE_COMPLETION(diag_ftp_rx_complete);
static int diag_ftp_subcode;
/**
* diag_ftp_handler() - FTP services IRQ handler
* @extirq: external interrupt (sub-) code
* @param32: 32-bit interruption parameter from &struct diag_ftp_ldfpl
* @param64: unused (for 64-bit interrupt parameters)
*/
static void diag_ftp_handler(struct ext_code extirq,
unsigned int param32,
unsigned long param64)
{
if ((extirq.subcode >> 8) != 8)
return; /* not a FTP services sub-code */
inc_irq_stat(IRQEXT_FTP);
diag_ftp_subcode = extirq.subcode & 0xffU;
complete(&diag_ftp_rx_complete);
}
/**
* diag_ftp_2c4() - DIAGNOSE X'2C4' service call
* @fpl: pointer to prepared LDFPL
* @cmd: FTP command to be executed
*
* Performs a DIAGNOSE X'2C4' call with (input/output) FTP parameter list
* @fpl and FTP function code @cmd. In case of an error the function does
* nothing and returns an (negative) error code.
*
* Notes:
* 1. This function only initiates a transfer, so the caller must wait
* for completion (asynchronous execution).
* 2. The FTP parameter list @fpl must be aligned to a double-word boundary.
* 3. fpl->bufaddr must be a real address, 4k aligned
*/
static int diag_ftp_2c4(struct diag_ftp_ldfpl *fpl,
enum hmcdrv_ftp_cmdid cmd)
{
int rc;
diag_stat_inc(DIAG_STAT_X2C4);
asm volatile(
" diag %[addr],%[cmd],0x2c4\n"
"0: j 2f\n"
"1: la %[rc],%[err]\n"
"2:\n"
EX_TABLE(0b, 1b)
: [rc] "=d" (rc), "+m" (*fpl)
: [cmd] "0" (cmd), [addr] "d" (virt_to_phys(fpl)),
[err] "i" (DIAG_FTP_RET_EPERM)
: "cc");
switch (rc) {
case DIAG_FTP_RET_OK:
return 0;
case DIAG_FTP_RET_EBUSY:
return -EBUSY;
case DIAG_FTP_RET_EPERM:
return -EPERM;
case DIAG_FTP_RET_EIO:
default:
return -EIO;
}
}
/**
* diag_ftp_cmd() - executes a DIAG X'2C4' FTP command, targeting a HMC
* @ftp: pointer to FTP command specification
* @fsize: return of file size (or NULL if undesirable)
*
* Attention: Notice that this function is not reentrant - so the caller
* must ensure locking.
*
* Return: number of bytes read/written or a (negative) error code
*/
ssize_t diag_ftp_cmd(const struct hmcdrv_ftp_cmdspec *ftp, size_t *fsize)
{
struct diag_ftp_ldfpl *ldfpl;
ssize_t len;
#ifdef DEBUG
unsigned long start_jiffies;
pr_debug("starting DIAG X'2C4' on '%s', requesting %zd bytes\n",
ftp->fname, ftp->len);
start_jiffies = jiffies;
#endif
init_completion(&diag_ftp_rx_complete);
ldfpl = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
if (!ldfpl) {
len = -ENOMEM;
goto out;
}
len = strscpy(ldfpl->fident, ftp->fname, sizeof(ldfpl->fident));
if (len < 0) {
len = -EINVAL;
goto out_free;
}
ldfpl->transferred = 0;
ldfpl->fsize = 0;
ldfpl->offset = ftp->ofs;
ldfpl->buflen = ftp->len;
ldfpl->bufaddr = virt_to_phys(ftp->buf);
len = diag_ftp_2c4(ldfpl, ftp->id);
if (len)
goto out_free;
/*
* There is no way to cancel the running diag X'2C4', the code
* needs to wait unconditionally until the transfer is complete.
*/
wait_for_completion(&diag_ftp_rx_complete);
#ifdef DEBUG
pr_debug("completed DIAG X'2C4' after %lu ms\n",
(jiffies - start_jiffies) * 1000 / HZ);
pr_debug("status of DIAG X'2C4' is %u, with %lld/%lld bytes\n",
diag_ftp_subcode, ldfpl->transferred, ldfpl->fsize);
#endif
switch (diag_ftp_subcode) {
case DIAG_FTP_STAT_OK: /* success */
len = ldfpl->transferred;
if (fsize)
*fsize = ldfpl->fsize;
break;
case DIAG_FTP_STAT_LDNPERM:
len = -EPERM;
break;
case DIAG_FTP_STAT_LDRUNS:
len = -EBUSY;
break;
case DIAG_FTP_STAT_LDFAIL:
len = -ENOENT; /* no such file or media */
break;
default:
len = -EIO;
break;
}
out_free:
free_page((unsigned long) ldfpl);
out:
return len;
}
/**
* diag_ftp_startup() - startup of FTP services, when running on z/VM
*
* Return: 0 on success, else an (negative) error code
*/
int diag_ftp_startup(void)
{
int rc;
rc = register_external_irq(EXT_IRQ_CP_SERVICE, diag_ftp_handler);
if (rc)
return rc;
irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
return 0;
}
/**
* diag_ftp_shutdown() - shutdown of FTP services, when running on z/VM
*/
void diag_ftp_shutdown(void)
{
irq_subclass_unregister(IRQ_SUBCLASS_SERVICE_SIGNAL);
unregister_external_irq(EXT_IRQ_CP_SERVICE, diag_ftp_handler);
}