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1// SPDX-License-Identifier: GPL-2.02/*3 * CIO inject interface4 *5 * Copyright IBM Corp. 20216 * Author(s): Vineeth Vijayan <vneethv@linux.ibm.com>7 */8 9#define KMSG_COMPONENT "cio"10#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt11 12#include <linux/slab.h>13#include <linux/spinlock.h>14#include <linux/mm.h>15#include <linux/debugfs.h>16#include <asm/chpid.h>17 18#include "cio_inject.h"19#include "cio_debug.h"20 21static DEFINE_SPINLOCK(crw_inject_lock);22DEFINE_STATIC_KEY_FALSE(cio_inject_enabled);23static struct crw *crw_inject_data;24 25/**26 * crw_inject : Initiate the artificial CRW inject27 * @crw: The data which needs to be injected as new CRW.28 *29 * The CRW handler is called, which will use the provided artificial30 * data instead of the CRW from the underlying hardware.31 *32 * Return: 0 on success33 */34static int crw_inject(struct crw *crw)35{36 int rc = 0;37 struct crw *copy;38 unsigned long flags;39 40 copy = kmemdup(crw, sizeof(*crw), GFP_KERNEL);41 if (!copy)42 return -ENOMEM;43 44 spin_lock_irqsave(&crw_inject_lock, flags);45 if (crw_inject_data) {46 kfree(copy);47 rc = -EBUSY;48 } else {49 crw_inject_data = copy;50 }51 spin_unlock_irqrestore(&crw_inject_lock, flags);52 53 if (!rc)54 crw_handle_channel_report();55 56 return rc;57}58 59/**60 * stcrw_get_injected: Copy the artificial CRW data to CRW struct.61 * @crw: The target CRW pointer.62 *63 * Retrieve an injected CRW data. Return 0 on success, 1 if no64 * injected-CRW is available. The function reproduces the return65 * code of the actual STCRW function.66 */67int stcrw_get_injected(struct crw *crw)68{69 int rc = 1;70 unsigned long flags;71 72 spin_lock_irqsave(&crw_inject_lock, flags);73 if (crw_inject_data) {74 memcpy(crw, crw_inject_data, sizeof(*crw));75 kfree(crw_inject_data);76 crw_inject_data = NULL;77 rc = 0;78 }79 spin_unlock_irqrestore(&crw_inject_lock, flags);80 81 return rc;82}83 84/* The debugfs write handler for crw_inject nodes operation */85static ssize_t crw_inject_write(struct file *file, const char __user *buf,86 size_t lbuf, loff_t *ppos)87{88 u32 slct, oflw, chn, rsc, anc, erc, rsid;89 struct crw crw;90 char *buffer;91 int rc;92 93 if (!static_branch_likely(&cio_inject_enabled)) {94 pr_warn("CIO inject is not enabled - ignoring CRW inject\n");95 return -EINVAL;96 }97 98 buffer = memdup_user_nul(buf, lbuf);99 if (IS_ERR(buffer))100 return -ENOMEM;101 102 rc = sscanf(buffer, "%x %x %x %x %x %x %x", &slct, &oflw, &chn, &rsc, &anc,103 &erc, &rsid);104 105 kvfree(buffer);106 if (rc != 7) {107 pr_warn("crw_inject: Invalid format (need <solicited> <overflow> <chaining> <rsc> <ancillary> <erc> <rsid>)\n");108 return -EINVAL;109 }110 111 memset(&crw, 0, sizeof(crw));112 crw.slct = slct;113 crw.oflw = oflw;114 crw.chn = chn;115 crw.rsc = rsc;116 crw.anc = anc;117 crw.erc = erc;118 crw.rsid = rsid;119 120 rc = crw_inject(&crw);121 if (rc)122 return rc;123 124 return lbuf;125}126 127/* Debugfs write handler for inject_enable node*/128static ssize_t enable_inject_write(struct file *file, const char __user *buf,129 size_t lbuf, loff_t *ppos)130{131 unsigned long en = 0;132 int rc;133 134 rc = kstrtoul_from_user(buf, lbuf, 10, &en);135 if (rc)136 return rc;137 138 switch (en) {139 case 0:140 static_branch_disable(&cio_inject_enabled);141 break;142 case 1:143 static_branch_enable(&cio_inject_enabled);144 break;145 }146 147 return lbuf;148}149 150static const struct file_operations crw_fops = {151 .owner = THIS_MODULE,152 .write = crw_inject_write,153};154 155static const struct file_operations cio_en_fops = {156 .owner = THIS_MODULE,157 .write = enable_inject_write,158};159 160static int __init cio_inject_init(void)161{162 /* enable_inject node enables the static branching */163 debugfs_create_file("enable_inject", 0200, cio_debugfs_dir,164 NULL, &cio_en_fops);165 166 debugfs_create_file("crw_inject", 0200, cio_debugfs_dir,167 NULL, &crw_fops);168 return 0;169}170 171device_initcall(cio_inject_init);172