diff options
Diffstat (limited to 'drivers/s390/cio/cio_inject.c')
| -rw-r--r-- | drivers/s390/cio/cio_inject.c | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/drivers/s390/cio/cio_inject.c b/drivers/s390/cio/cio_inject.c new file mode 100644 index 000000000000..8613fa937237 --- /dev/null +++ b/drivers/s390/cio/cio_inject.c @@ -0,0 +1,171 @@ +// 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); |