#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/slab.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/init.h>
#include <linux/capability.h>

#include <xen/xen.h>
#include <xen/page.h>
#include <xen/xenbus.h>
#include <xen/xenbus_dev.h>
#include <xen/grant_table.h>
#include <xen/events.h>
#include <asm/xen/hypervisor.h>

#include "xenbus_comms.h"

static int xenbus_backend_open(struct inode *inode, struct file *filp)
{
	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	return nonseekable_open(inode, filp);
}

static long xenbus_alloc(domid_t domid)
{
	struct evtchn_alloc_unbound arg;
	int err = -EEXIST;

	xs_suspend();

	/* If xenstored_ready is nonzero, that means we have already talked to
	 * xenstore and set up watches. These watches will be restored by
	 * xs_resume, but that requires communication over the port established
	 * below that is not visible to anyone until the ioctl returns.
	 *
	 * This can be resolved by splitting the ioctl into two parts
	 * (postponing the resume until xenstored is active) but this is
	 * unnecessarily complex for the intended use where xenstored is only
	 * started once - so return -EEXIST if it's already running.
	 */
	if (xenstored_ready)
		goto out_err;

	gnttab_grant_foreign_access_ref(GNTTAB_RESERVED_XENSTORE, domid,
			virt_to_gfn(xen_store_interface), 0 /* writable */);

	arg.dom = DOMID_SELF;
	arg.remote_dom = domid;

	err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, &arg);
	if (err)
		goto out_err;

	if (xen_store_evtchn > 0)
		xb_deinit_comms();

	xen_store_evtchn = arg.port;

	xs_resume();

	return arg.port;

 out_err:
	xs_suspend_cancel();
	return err;
}

static long xenbus_backend_ioctl(struct file *file, unsigned int cmd,
				 unsigned long data)
{
	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	switch (cmd) {
	case IOCTL_XENBUS_BACKEND_EVTCHN:
		if (xen_store_evtchn > 0)
			return xen_store_evtchn;
		return -ENODEV;
	case IOCTL_XENBUS_BACKEND_SETUP:
		return xenbus_alloc(data);
	default:
		return -ENOTTY;
	}
}

static int xenbus_backend_mmap(struct file *file, struct vm_area_struct *vma)
{
	size_t size = vma->vm_end - vma->vm_start;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	if ((size > PAGE_SIZE) || (vma->vm_pgoff != 0))
		return -EINVAL;

	if (remap_pfn_range(vma, vma->vm_start,
			    virt_to_pfn(xen_store_interface),
			    size, vma->vm_page_prot))
		return -EAGAIN;

	return 0;
}

static const struct file_operations xenbus_backend_fops = {
	.open = xenbus_backend_open,
	.mmap = xenbus_backend_mmap,
	.unlocked_ioctl = xenbus_backend_ioctl,
};

static struct miscdevice xenbus_backend_dev = {
	.minor = MISC_DYNAMIC_MINOR,
	.name = "xen/xenbus_backend",
	.fops = &xenbus_backend_fops,
};

static int __init xenbus_backend_init(void)
{
	int err;

	if (!xen_initial_domain())
		return -ENODEV;

	err = misc_register(&xenbus_backend_dev);
	if (err)
		pr_err("Could not register xenbus backend device\n");
	return err;
}
device_initcall(xenbus_backend_init);
nds-private-remove&amp;id=075ad765ef7541b2860de8408c165a92b78aefa3&amp;showmsg=1'>net</a>/<a href='/cgit.cgi/linux/net-next.git/log/net/phonet?h=nds-private-remove&amp;id=075ad765ef7541b2860de8408c165a92b78aefa3&amp;showmsg=1'>phonet</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/cgit.cgi/linux/net-next.git/log/net/phonet?h=nds-private-remove&amp;id=075ad765ef7541b2860de8408c165a92b78aefa3'>Collapse</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>
31'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2016-12-25 14:05:56 -0800</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2016-12-25 14:05:56 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/ipv4/Makefile?h=nds-private-remove&amp;id=b272f732f888d4cf43c943a40c9aaa836f9b7431'>b272f732f888d4cf43c943a40c9aaa836f9b7431</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/ipv4/Makefile?id=b272f732f888d4cf43c943a40c9aaa836f9b7431'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?h=nds-private-remove&amp;id=b272f732f888d4cf43c943a40c9aaa836f9b7431'>da9cac6b9d12b83592c16d3503c0e3f2f00f146f</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/ipv4/Makefile?h=nds-private-remove&amp;id=b272f732f888d4cf43c943a40c9aaa836f9b7431'>net/ipv4/Makefile</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/ipv4/Makefile?h=nds-private-remove&amp;id=10bbe7599e2755d3f3e100103967788b8b5a4bce'>10bbe7599e2755d3f3e100103967788b8b5a4bce</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/ipv4/Makefile?h=nds-private-remove&amp;id=b272f732f888d4cf43c943a40c9aaa836f9b7431&amp;id2=10bbe7599e2755d3f3e100103967788b8b5a4bce'>diff</a>)</td></tr><tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/ipv4/Makefile?h=nds-private-remove&amp;id=008b69e4d52f2cbee3ed0d0502edd78155000b1a'>008b69e4d52f2cbee3ed0d0502edd78155000b1a</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/ipv4/Makefile?h=nds-private-remove&amp;id=b272f732f888d4cf43c943a40c9aaa836f9b7431&amp;id2=008b69e4d52f2cbee3ed0d0502edd78155000b1a'>diff</a>)</td></tr></table>
<div class='commit-subject'>Merge branch 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</div><div class='commit-msg'>Pull SMP hotplug notifier removal from Thomas Gleixner:
 "This is the final cleanup of the hotplug notifier infrastructure. The
  series has been reintgrated in the last two days because there came a
  new driver using the old infrastructure via the SCSI tree.

  Summary:

   - convert the last leftover drivers utilizing notifiers

   - fixup for a completely broken hotplug user

   - prevent setup of already used states

   - removal of the notifiers

   - treewide cleanup of hotplug state names

   - consolidation of state space

  There is a sphinx based documentation pending, but that needs review
  from the documentation folks"

* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/armada-xp: Consolidate hotplug state space
  irqchip/gic: Consolidate hotplug state space
  coresight/etm3/4x: Consolidate hotplug state space
  cpu/hotplug: Cleanup state names
  cpu/hotplug: Remove obsolete cpu hotplug register/unregister functions
  staging/lustre/libcfs: Convert to hotplug state machine
  scsi/bnx2i: Convert to hotplug state machine
  scsi/bnx2fc: Convert to hotplug state machine
  cpu/hotplug: Prevent overwriting of callbacks
  x86/msr: Remove bogus cleanup from the error path
  bus: arm-ccn: Prevent hotplug callback leak
  perf/x86/intel/cstate: Prevent hotplug callback leak
  ARM/imx/mmcd: Fix broken cpu hotplug handling
  scsi: qedi: Convert to hotplug state machine
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?h=nds-private-remove&amp;id=b272f732f888d4cf43c943a40c9aaa836f9b7431'>Diffstat</a> (limited to 'net/ipv4/Makefile')</div><table summary='diffstat' class='diffstat'>