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