#include <drm/drmP.h>
#include <drm/drm_core.h>
+#include <drm/drm_auth.h>
#include "drm_legacy.h"
#include "drm_internal.h"
#include "drm_crtc_internal.h"
#include <linux/pci.h>
#include <linux/export.h>
+/**
+ * DOC: getunique and setversion story
+ *
+ * BEWARE THE DRAGONS! MIND THE TRAPDOORS!
+ *
+ * In an attempt to warn anyone else who's trying to figure out what's going
+ * on here, I'll try to summarize the story. First things first, let's clear up
+ * the names, because the kernel internals, libdrm and the ioctls are all named
+ * differently:
+ *
+ * - GET_UNIQUE ioctl, implemented by drm_getunique is wrapped up in libdrm
+ * through the drmGetBusid function.
+ * - The libdrm drmSetBusid function is backed by the SET_UNIQUE ioctl. All
+ * that code is nerved in the kernel with drm_invalid_op().
+ * - The internal set_busid kernel functions and driver callbacks are
+ * exclusively use by the SET_VERSION ioctl, because only drm 1.0 (which is
+ * nerved) allowed userspace to set the busid through the above ioctl.
+ * - Other ioctls and functions involved are named consistently.
+ *
+ * For anyone wondering what's the difference between drm 1.1 and 1.4: Correctly
+ * handling pci domains in the busid on ppc. Doing this correctly was only
+ * implemented in libdrm in 2010, hence can't be nerved yet. No one knows what's
+ * special with drm 1.2 and 1.3.
+ *
+ * Now the actual horror story of how device lookup in drm works. At large,
+ * there's 2 different ways, either by busid, or by device driver name.
+ *
+ * Opening by busid is fairly simple:
+ *
+ * 1. First call SET_VERSION to make sure pci domains are handled properly. As a
+ * side-effect this fills out the unique name in the master structure.
+ * 2. Call GET_UNIQUE to read out the unique name from the master structure,
+ * which matches the busid thanks to step 1. If it doesn't, proceed to try
+ * the next device node.
+ *
+ * Opening by name is slightly different:
+ *
+ * 1. Directly call VERSION to get the version and to match against the driver
+ * name returned by that ioctl. Note that SET_VERSION is not called, which
+ * means the the unique name for the master node just opening is _not_ filled
+ * out. This despite that with current drm device nodes are always bound to
+ * one device, and can't be runtime assigned like with drm 1.0.
+ * 2. Match driver name. If it mismatches, proceed to the next device node.
+ * 3. Call GET_UNIQUE, and check whether the unique name has length zero (by
+ * checking that the first byte in the string is 0). If that's not the case
+ * libdrm skips and proceeds to the next device node. Probably this is just
+ * copypasta from drm 1.0 times where a set unique name meant that the driver
+ * was in use already, but that's just conjecture.
+ *
+ * Long story short: To keep the open by name logic working, GET_UNIQUE must
+ * _not_ return a unique string when SET_VERSION hasn't been called yet,
+ * otherwise libdrm breaks. Even when that unique string can't ever change, and
+ * is totally irrelevant for actually opening the device because runtime
+ * assignable device instances were only support in drm 1.0, which is long dead.
+ * But the libdrm code in drmOpenByName somehow survived, hence this can't be
+ * broken.
+ */
+
static int drm_version(struct drm_device *dev, void *data,
struct drm_file *file_priv);
master->unique_len = 0;
}
-/*
- * Set the bus id.
- *
- * \param inode device inode.
- * \param file_priv DRM file private.
- * \param cmd command.
- * \param arg user argument, pointing to a drm_unique structure.
- * \return zero on success or a negative number on failure.
- *
- * Copies the bus id from userspace into drm_device::unique, and verifies that
- * it matches the device this DRM is attached to (EINVAL otherwise). Deprecated
- * in interface version 1.1 and will return EBUSY when setversion has requested
- * version 1.1 or greater. Also note that KMS is all version 1.1 and later and
- * UMS was only ever supported on pci devices.
- */
-static int drm_setunique(struct drm_device *dev, void *data,
- struct drm_file *file_priv)
-{
- struct drm_unique *u = data;
- struct drm_master *master = file_priv->master;
- int ret;
-
- if (master->unique_len || master->unique)
- return -EBUSY;
-
- if (!u->unique_len || u->unique_len > 1024)
- return -EINVAL;
-
- if (drm_core_check_feature(dev, DRIVER_MODESET))
- return 0;
-
- if (WARN_ON(!dev->pdev))
- return -EINVAL;
-
- ret = drm_pci_set_unique(dev, master, u);
- if (ret)
- goto err;
-
- return 0;
-
-err:
- drm_unset_busid(dev, master);
- return ret;
-}
-
static int drm_set_busid(struct drm_device *dev, struct drm_file *file_priv)
{
struct drm_master *master = file_priv->master;
return ret;
}
} else {
- if (WARN(dev->unique == NULL,
- "No drm_driver.set_busid() implementation provided by "
- "%ps. Use drm_dev_set_unique() to set the unique "
- "name explicitly.", dev->driver))
- return -EINVAL;
-
+ WARN_ON(!dev->unique);
master->unique = kstrdup(dev->unique, GFP_KERNEL);
if (master->unique)
master->unique_len = strlen(dev->unique);
return -EACCES;
/* MASTER is only for master or control clients */
- if (unlikely((flags & DRM_MASTER) && !file_priv->is_master &&
+ if (unlikely((flags & DRM_MASTER) &&
+ !drm_is_current_master(file_priv) &&
!drm_is_control_client(file_priv)))
return -EACCES;
DRM_IOCTL_DEF(DRM_IOCTL_VERSION, drm_version,
DRM_UNLOCKED|DRM_RENDER_ALLOW|DRM_CONTROL_ALLOW),
DRM_IOCTL_DEF(DRM_IOCTL_GET_UNIQUE, drm_getunique, 0),
- DRM_IOCTL_DEF(DRM_IOCTL_GET_MAGIC, drm_getmagic, 0),
+ DRM_IOCTL_DEF(DRM_IOCTL_GET_MAGIC, drm_getmagic, DRM_UNLOCKED),
DRM_IOCTL_DEF(DRM_IOCTL_IRQ_BUSID, drm_irq_by_busid, DRM_MASTER|DRM_ROOT_ONLY),
DRM_IOCTL_DEF(DRM_IOCTL_GET_MAP, drm_legacy_getmap_ioctl, DRM_UNLOCKED),
DRM_IOCTL_DEF(DRM_IOCTL_GET_CLIENT, drm_getclient, DRM_UNLOCKED),
DRM_IOCTL_DEF(DRM_IOCTL_SET_CLIENT_CAP, drm_setclientcap, 0),
DRM_IOCTL_DEF(DRM_IOCTL_SET_VERSION, drm_setversion, DRM_MASTER),
- DRM_IOCTL_DEF(DRM_IOCTL_SET_UNIQUE, drm_setunique, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
+ DRM_IOCTL_DEF(DRM_IOCTL_SET_UNIQUE, drm_invalid_op, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
DRM_IOCTL_DEF(DRM_IOCTL_BLOCK, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
DRM_IOCTL_DEF(DRM_IOCTL_UNBLOCK, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
- DRM_IOCTL_DEF(DRM_IOCTL_AUTH_MAGIC, drm_authmagic, DRM_AUTH|DRM_MASTER),
+ DRM_IOCTL_DEF(DRM_IOCTL_AUTH_MAGIC, drm_authmagic, DRM_AUTH|DRM_UNLOCKED|DRM_MASTER),
DRM_IOCTL_DEF(DRM_IOCTL_ADD_MAP, drm_legacy_addmap_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
DRM_IOCTL_DEF(DRM_IOCTL_RM_MAP, drm_legacy_rmmap_ioctl, DRM_AUTH),
DRM_IOCTL_DEF(DRM_IOCTL_SET_SAREA_CTX, drm_legacy_setsareactx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
DRM_IOCTL_DEF(DRM_IOCTL_GET_SAREA_CTX, drm_legacy_getsareactx, DRM_AUTH),
- DRM_IOCTL_DEF(DRM_IOCTL_SET_MASTER, drm_setmaster_ioctl, DRM_ROOT_ONLY),
- DRM_IOCTL_DEF(DRM_IOCTL_DROP_MASTER, drm_dropmaster_ioctl, DRM_ROOT_ONLY),
+ DRM_IOCTL_DEF(DRM_IOCTL_SET_MASTER, drm_setmaster_ioctl, DRM_UNLOCKED|DRM_ROOT_ONLY),
+ DRM_IOCTL_DEF(DRM_IOCTL_DROP_MASTER, drm_dropmaster_ioctl, DRM_UNLOCKED|DRM_ROOT_ONLY),
DRM_IOCTL_DEF(DRM_IOCTL_ADD_CTX, drm_legacy_addctx, DRM_AUTH|DRM_ROOT_ONLY),
DRM_IOCTL_DEF(DRM_IOCTL_RM_CTX, drm_legacy_rmctx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
int retcode = -EINVAL;
char stack_kdata[128];
char *kdata = NULL;
- unsigned int usize, asize, drv_size;
+ unsigned int in_size, out_size, drv_size, ksize;
bool is_driver_ioctl;
dev = file_priv->minor->dev;
}
drv_size = _IOC_SIZE(ioctl->cmd);
- usize = _IOC_SIZE(cmd);
- asize = max(usize, drv_size);
- cmd = ioctl->cmd;
+ out_size = in_size = _IOC_SIZE(cmd);
+ if ((cmd & ioctl->cmd & IOC_IN) == 0)
+ in_size = 0;
+ if ((cmd & ioctl->cmd & IOC_OUT) == 0)
+ out_size = 0;
+ ksize = max(max(in_size, out_size), drv_size);
DRM_DEBUG("pid=%d, dev=0x%lx, auth=%d, %s\n",
task_pid_nr(current),
if (unlikely(retcode))
goto err_i1;
- if (cmd & (IOC_IN | IOC_OUT)) {
- if (asize <= sizeof(stack_kdata)) {
- kdata = stack_kdata;
- } else {
- kdata = kmalloc(asize, GFP_KERNEL);
- if (!kdata) {
- retcode = -ENOMEM;
- goto err_i1;
- }
+ if (ksize <= sizeof(stack_kdata)) {
+ kdata = stack_kdata;
+ } else {
+ kdata = kmalloc(ksize, GFP_KERNEL);
+ if (!kdata) {
+ retcode = -ENOMEM;
+ goto err_i1;
}
- if (asize > usize)
- memset(kdata + usize, 0, asize - usize);
}
- if (cmd & IOC_IN) {
- if (copy_from_user(kdata, (void __user *)arg,
- usize) != 0) {
- retcode = -EFAULT;
- goto err_i1;
- }
- } else if (cmd & IOC_OUT) {
- memset(kdata, 0, usize);
+ if (copy_from_user(kdata, (void __user *)arg, in_size) != 0) {
+ retcode = -EFAULT;
+ goto err_i1;
}
+ if (ksize > in_size)
+ memset(kdata + in_size, 0, ksize - in_size);
+
/* Enforce sane locking for kms driver ioctls. Core ioctls are
* too messy still. */
if ((drm_core_check_feature(dev, DRIVER_MODESET) && is_driver_ioctl) ||
mutex_unlock(&drm_global_mutex);
}
- if (cmd & IOC_OUT) {
- if (copy_to_user((void __user *)arg, kdata,
- usize) != 0)
- retcode = -EFAULT;
- }
+ if (copy_to_user((void __user *)arg, kdata, out_size) != 0)
+ retcode = -EFAULT;
err_i1:
if (!ioctl)
* shouldn't be used by any drivers.
*
* Returns:
- * True if the @nr corresponds to a DRM core ioctl numer, false otherwise.
+ * True if the @nr corresponds to a DRM core ioctl number, false otherwise.
*/
bool drm_ioctl_flags(unsigned int nr, unsigned int *flags)
{
projects / cascardo / linux.git / blobdiff