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// SPDX-License-Identifier: GPL-2.0
/*
* CIO inject interface
*
* Copyright IBM Corp. 2021
* Author(s): Vineeth Vijayan <vneethv@linux.ibm.com>
*/
#define KMSG_COMPONENT "cio"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/debugfs.h>
#include <asm/chpid.h>
#include "cio_inject.h"
#include "cio_debug.h"
static DEFINE_SPINLOCK(crw_inject_lock);
DEFINE_STATIC_KEY_FALSE(cio_inject_enabled);
static struct crw *crw_inject_data;
/**
* crw_inject : Initiate the artificial CRW inject
* @crw: The data which needs to be injected as new CRW.
*
* The CRW handler is called, which will use the provided artificial
* data instead of the CRW from the underlying hardware.
*
* Return: 0 on success
*/
static int crw_inject(struct crw *crw)
{
int rc = 0;
struct crw *copy;
unsigned long flags;
copy = kmemdup(crw, sizeof(*crw), GFP_KERNEL);
if (!copy)
return -ENOMEM;
spin_lock_irqsave(&crw_inject_lock, flags);
if (crw_inject_data) {
kfree(copy);
rc = -EBUSY;
} else {
crw_inject_data = copy;
}
spin_unlock_irqrestore(&crw_inject_lock, flags);
if (!rc)
crw_handle_channel_report();
return rc;
}
/**
* stcrw_get_injected: Copy the artificial CRW data to CRW struct.
* @crw: The target CRW pointer.
*
* Retrieve an injected CRW data. Return 0 on success, 1 if no
* injected-CRW is available. The function reproduces the return
* code of the actual STCRW function.
*/
int stcrw_get_injected(struct crw *crw)
{
int rc = 1;
unsigned long flags;
spin_lock_irqsave(&crw_inject_lock, flags);
if (crw_inject_data) {
memcpy(crw, crw_inject_data, sizeof(*crw));
kfree(crw_inject_data);
crw_inject_data = NULL;
rc = 0;
}
spin_unlock_irqrestore(&crw_inject_lock, flags);
return rc;
}
/* The debugfs write handler for crw_inject nodes operation */
static ssize_t crw_inject_write(struct file *file, const char __user *buf,
size_t lbuf, loff_t *ppos)
{
u32 slct, oflw, chn, rsc, anc, erc, rsid;
struct crw crw;
char *buffer;
int rc;
if (!static_branch_likely(&cio_inject_enabled)) {
pr_warn("CIO inject is not enabled - ignoring CRW inject\n");
return -EINVAL;
}
buffer = vmemdup_user(buf, lbuf);
if (IS_ERR(buffer))
return -ENOMEM;
rc = sscanf(buffer, "%x %x %x %x %x %x %x", &slct, &oflw, &chn, &rsc, &anc,
&erc, &rsid);
kvfree(buffer);
if (rc != 7) {
pr_warn("crw_inject: Invalid format (need <solicited> <overflow> <chaining> <rsc> <ancillary> <erc> <rsid>)\n");
return -EINVAL;
}
memset(&crw, 0, sizeof(crw));
crw.slct = slct;
crw.oflw = oflw;
crw.chn = chn;
crw.rsc = rsc;
crw.anc = anc;
crw.erc = erc;
crw.rsid = rsid;
rc = crw_inject(&crw);
if (rc)
return rc;
return lbuf;
}
/* Debugfs write handler for inject_enable node*/
static ssize_t enable_inject_write(struct file *file, const char __user *buf,
size_t lbuf, loff_t *ppos)
{
unsigned long en = 0;
int rc;
rc = kstrtoul_from_user(buf, lbuf, 10, &en);
if (rc)
return rc;
switch (en) {
case 0:
static_branch_disable(&cio_inject_enabled);
break;
case 1:
static_branch_enable(&cio_inject_enabled);
break;
}
return lbuf;
}
static const struct file_operations crw_fops = {
.owner = THIS_MODULE,
.write = crw_inject_write,
};
static const struct file_operations cio_en_fops = {
.owner = THIS_MODULE,
.write = enable_inject_write,
};
static int __init cio_inject_init(void)
{
/* enable_inject node enables the static branching */
debugfs_create_file("enable_inject", 0200, cio_debugfs_dir,
NULL, &cio_en_fops);
debugfs_create_file("crw_inject", 0200, cio_debugfs_dir,
NULL, &crw_fops);
return 0;
}
device_initcall(cio_inject_init);
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