mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-04 18:09:57 +00:00
ab1241a1fc
The Makefile / Kconfig currently controlling compilation here is: obj-y += xenbus_dev_frontend.o [...] obj-$(CONFIG_XEN_BACKEND) += xenbus_dev_backend.o ...with: drivers/xen/Kconfig:config XEN_BACKEND drivers/xen/Kconfig: bool "Backend driver support" ...meaning that they currently are not being built as modules by anyone. Lets remove the modular code that is essentially orphaned, so that when reading the driver there is no doubt it is builtin-only. Since module_init translates to device_initcall in the non-modular case, the init ordering remains unchanged with this commit. We also delete the MODULE_LICENSE tag since all that information is already contained at the top of the file in the comments. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
133 lines
3 KiB
C
133 lines
3 KiB
C
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/slab.h>
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#include <linux/types.h>
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#include <linux/mm.h>
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#include <linux/fs.h>
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#include <linux/miscdevice.h>
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#include <linux/init.h>
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#include <linux/capability.h>
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#include <xen/xen.h>
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#include <xen/page.h>
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#include <xen/xenbus.h>
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#include <xen/xenbus_dev.h>
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#include <xen/grant_table.h>
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#include <xen/events.h>
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#include <asm/xen/hypervisor.h>
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#include "xenbus_comms.h"
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static int xenbus_backend_open(struct inode *inode, struct file *filp)
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{
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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return nonseekable_open(inode, filp);
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}
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static long xenbus_alloc(domid_t domid)
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{
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struct evtchn_alloc_unbound arg;
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int err = -EEXIST;
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xs_suspend();
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/* If xenstored_ready is nonzero, that means we have already talked to
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* xenstore and set up watches. These watches will be restored by
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* xs_resume, but that requires communication over the port established
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* below that is not visible to anyone until the ioctl returns.
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*
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* This can be resolved by splitting the ioctl into two parts
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* (postponing the resume until xenstored is active) but this is
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* unnecessarily complex for the intended use where xenstored is only
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* started once - so return -EEXIST if it's already running.
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*/
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if (xenstored_ready)
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goto out_err;
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gnttab_grant_foreign_access_ref(GNTTAB_RESERVED_XENSTORE, domid,
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virt_to_gfn(xen_store_interface), 0 /* writable */);
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arg.dom = DOMID_SELF;
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arg.remote_dom = domid;
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err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, &arg);
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if (err)
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goto out_err;
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if (xen_store_evtchn > 0)
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xb_deinit_comms();
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xen_store_evtchn = arg.port;
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xs_resume();
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return arg.port;
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out_err:
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xs_suspend_cancel();
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return err;
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}
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static long xenbus_backend_ioctl(struct file *file, unsigned int cmd,
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unsigned long data)
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{
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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switch (cmd) {
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case IOCTL_XENBUS_BACKEND_EVTCHN:
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if (xen_store_evtchn > 0)
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return xen_store_evtchn;
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return -ENODEV;
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case IOCTL_XENBUS_BACKEND_SETUP:
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return xenbus_alloc(data);
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default:
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return -ENOTTY;
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}
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}
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static int xenbus_backend_mmap(struct file *file, struct vm_area_struct *vma)
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{
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size_t size = vma->vm_end - vma->vm_start;
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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if ((size > PAGE_SIZE) || (vma->vm_pgoff != 0))
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return -EINVAL;
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if (remap_pfn_range(vma, vma->vm_start,
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virt_to_pfn(xen_store_interface),
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size, vma->vm_page_prot))
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return -EAGAIN;
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return 0;
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}
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static const struct file_operations xenbus_backend_fops = {
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.open = xenbus_backend_open,
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.mmap = xenbus_backend_mmap,
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.unlocked_ioctl = xenbus_backend_ioctl,
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};
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static struct miscdevice xenbus_backend_dev = {
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.minor = MISC_DYNAMIC_MINOR,
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.name = "xen/xenbus_backend",
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.fops = &xenbus_backend_fops,
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};
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static int __init xenbus_backend_init(void)
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{
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int err;
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if (!xen_initial_domain())
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return -ENODEV;
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err = misc_register(&xenbus_backend_dev);
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if (err)
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pr_err("Could not register xenbus backend device\n");
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return err;
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}
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device_initcall(xenbus_backend_init);
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