cregit-Linux how code gets into the kernel

Release 4.7 drivers/s390/char/sclp_ctl.c

/*
 * IOCTL interface for SCLP
 *
 * Copyright IBM Corp. 2012
 *
 * Author: Michael Holzheu <holzheu@linux.vnet.ibm.com>
 */

#include <linux/compat.h>
#include <linux/uaccess.h>
#include <linux/miscdevice.h>
#include <linux/gfp.h>
#include <linux/module.h>
#include <linux/ioctl.h>
#include <linux/fs.h>
#include <asm/compat.h>
#include <asm/sclp_ctl.h>
#include <asm/sclp.h>

#include "sclp.h"

/*
 * Supported command words
 */

static unsigned int sclp_ctl_sccb_wlist[] = {
	0x00400002,
	0x00410002,
};

/*
 * Check if command word is supported
 */

static int sclp_ctl_cmdw_supported(unsigned int cmdw) { int i; for (i = 0; i < ARRAY_SIZE(sclp_ctl_sccb_wlist); i++) { if (cmdw == sclp_ctl_sccb_wlist[i]) return 1; } return 0; }

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michael holzheumichael holzheu46100.00%1100.00%
Total46100.00%1100.00%


static void __user *u64_to_uptr(u64 value) { if (is_compat_task()) return compat_ptr(value); else return (void __user *)(unsigned long)value; }

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michael holzheumichael holzheu35100.00%1100.00%
Total35100.00%1100.00%

/* * Start SCLP request */
static int sclp_ctl_ioctl_sccb(void __user *user_area) { struct sclp_ctl_sccb ctl_sccb; struct sccb_header *sccb; unsigned long copied; int rc; if (copy_from_user(&ctl_sccb, user_area, sizeof(ctl_sccb))) return -EFAULT; if (!sclp_ctl_cmdw_supported(ctl_sccb.cmdw)) return -EOPNOTSUPP; sccb = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA); if (!sccb) return -ENOMEM; copied = PAGE_SIZE - copy_from_user(sccb, u64_to_uptr(ctl_sccb.sccb), PAGE_SIZE); if (offsetof(struct sccb_header, length) + sizeof(sccb->length) > copied || sccb->length > copied) { rc = -EFAULT; goto out_free; } if (sccb->length < 8) { rc = -EINVAL; goto out_free; } rc = sclp_sync_request(ctl_sccb.cmdw, sccb); if (rc) goto out_free; if (copy_to_user(u64_to_uptr(ctl_sccb.sccb), sccb, sccb->length)) rc = -EFAULT; out_free: free_page((unsigned long) sccb); return rc; }

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michael holzheumichael holzheu17684.62%150.00%
martin schwidefskymartin schwidefsky3215.38%150.00%
Total208100.00%2100.00%

/* * SCLP SCCB ioctl function */
static long sclp_ctl_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { void __user *argp; if (is_compat_task()) argp = compat_ptr(arg); else argp = (void __user *) arg; switch (cmd) { case SCLP_CTL_SCCB: return sclp_ctl_ioctl_sccb(argp); default: /* unknown ioctl number */ return -ENOTTY; } }

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michael holzheumichael holzheu67100.00%1100.00%
Total67100.00%1100.00%

/* * File operations */ static const struct file_operations sclp_ctl_fops = { .owner = THIS_MODULE, .open = nonseekable_open, .unlocked_ioctl = sclp_ctl_ioctl, .compat_ioctl = sclp_ctl_ioctl, .llseek = no_llseek, }; /* * Misc device definition */ static struct miscdevice sclp_ctl_device = { .minor = MISC_DYNAMIC_MINOR, .name = "sclp", .fops = &sclp_ctl_fops, }; /* * Register sclp_ctl misc device */
static int __init sclp_ctl_init(void) { return misc_register(&sclp_ctl_device); }

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michael holzheumichael holzheu16100.00%1100.00%
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module_init(sclp_ctl_init); /* * Deregister sclp_ctl misc device */
static void __exit sclp_ctl_exit(void) { misc_deregister(&sclp_ctl_device); }

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michael holzheumichael holzheu15100.00%1100.00%
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module_exit(sclp_ctl_exit);

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michael holzheumichael holzheu47593.69%150.00%
martin schwidefskymartin schwidefsky326.31%150.00%
Total507100.00%2100.00%
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