Message ID | 20210621125800.27696-2-arnaud.pouliquen@foss.st.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | rpmsg: ctrl: Add ability to instantiate rpmsg device locally | expand |
On Mon, Jun 21, 2021 at 02:58:00PM +0200, Arnaud Pouliquen wrote: > Allow the user space application to create and release an rpmsg device > by adding RPMSG_CREATE_DEV_IOCTL and RPMSG_RELEASE_DEV_IOCTL ioctrls to > the /dev/rpmsg_ctrl interface > > The RPMSG_CREATE_DEV_IOCTL Ioctl can be used to instantiate a local rpmsg > device. > Depending on the back-end implementation, the associated rpmsg driver is > probed and a NS announcement can be sent to the remote processor. > > The RPMSG_RELEASE_DEV_IOCTL allows the user application to release a > rpmsg device created either by the remote processor or with the > RPMSG_CREATE_DEV_IOCTL call. > Depending on the back-end implementation, the associated rpmsg driver is > removed and a NS destroy rpmsg can be sent to the remote processor. > > Suggested-by: Mathieu Poirier <mathieu.poirier@linaro.org> > Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com> > --- > drivers/rpmsg/rpmsg_ctrl.c | 37 +++++++++++++++++++++++++++++++++---- > include/uapi/linux/rpmsg.h | 10 ++++++++++ > 2 files changed, 43 insertions(+), 4 deletions(-) > > diff --git a/drivers/rpmsg/rpmsg_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c > index eeb1708548c1..cb19e32d05e1 100644 > --- a/drivers/rpmsg/rpmsg_ctrl.c > +++ b/drivers/rpmsg/rpmsg_ctrl.c > @@ -23,6 +23,7 @@ > #include <uapi/linux/rpmsg.h> > > #include "rpmsg_char.h" > +#include "rpmsg_internal.h" > > static dev_t rpmsg_major; > > @@ -37,11 +38,13 @@ static DEFINE_IDA(rpmsg_minor_ida); > * @rpdev: underlaying rpmsg device > * @cdev: cdev for the ctrl device > * @dev: device for the ctrl device > + * @ctrl_lock: serialize the ioctrls. > */ > struct rpmsg_ctrldev { > struct rpmsg_device *rpdev; > struct cdev cdev; > struct device dev; > + struct mutex ctrl_lock; > }; > > static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp) > @@ -70,9 +73,8 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd, > void __user *argp = (void __user *)arg; > struct rpmsg_endpoint_info eptinfo; > struct rpmsg_channel_info chinfo; > - > - if (cmd != RPMSG_CREATE_EPT_IOCTL) > - return -EINVAL; > + struct rpmsg_device *rpdev; > + int ret = 0; > > if (copy_from_user(&eptinfo, argp, sizeof(eptinfo))) > return -EFAULT; > @@ -82,7 +84,33 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd, > chinfo.src = eptinfo.src; > chinfo.dst = eptinfo.dst; > > - return rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo); > + mutex_lock(&ctrldev->ctrl_lock); Have you been able to verify the VFS layer doesn't take care of serializing ioctl() and file accesses in general? I did a quick search in the drivers/ directory and the vast majority of implementations don't use a lock. Thanks, Mathieu > + switch (cmd) { > + case RPMSG_CREATE_EPT_IOCTL: > + ret = rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo); > + break; > + > + case RPMSG_CREATE_DEV_IOCTL: > + rpdev = rpmsg_create_channel(ctrldev->rpdev, &chinfo); > + if (!rpdev) { > + dev_err(&ctrldev->dev, "failed to create %s channel\n", chinfo.name); > + ret = -ENXIO; > + } > + break; > + > + case RPMSG_RELEASE_DEV_IOCTL: > + ret = rpmsg_release_channel(ctrldev->rpdev, &chinfo); > + if (ret) > + dev_err(&ctrldev->dev, "failed to release %s channel (%d)\n", > + chinfo.name, ret); > + break; > + > + default: > + ret = -EINVAL; > + } > + mutex_unlock(&ctrldev->ctrl_lock); > + > + return ret; > }; > > static const struct file_operations rpmsg_ctrldev_fops = { > @@ -119,6 +147,7 @@ static int rpmsg_ctrldev_probe(struct rpmsg_device *rpdev) > device_initialize(dev); > dev->parent = &rpdev->dev; > > + mutex_init(&ctrldev->ctrl_lock); > cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops); > ctrldev->cdev.owner = THIS_MODULE; > > diff --git a/include/uapi/linux/rpmsg.h b/include/uapi/linux/rpmsg.h > index f5ca8740f3fb..1637e68177d9 100644 > --- a/include/uapi/linux/rpmsg.h > +++ b/include/uapi/linux/rpmsg.h > @@ -33,4 +33,14 @@ struct rpmsg_endpoint_info { > */ > #define RPMSG_DESTROY_EPT_IOCTL _IO(0xb5, 0x2) > > +/** > + * Instantiate a new local rpmsg service device. > + */ > +#define RPMSG_CREATE_DEV_IOCTL _IOW(0xb5, 0x3, struct rpmsg_endpoint_info) > + > +/** > + * Release a local rpmsg device. > + */ > +#define RPMSG_RELEASE_DEV_IOCTL _IOW(0xb5, 0x4, struct rpmsg_endpoint_info) > + > #endif > -- > 2.17.1 >
Hi Mathieu On 6/22/21 1:16 AM, Mathieu Poirier wrote: > On Mon, Jun 21, 2021 at 02:58:00PM +0200, Arnaud Pouliquen wrote: >> Allow the user space application to create and release an rpmsg device >> by adding RPMSG_CREATE_DEV_IOCTL and RPMSG_RELEASE_DEV_IOCTL ioctrls to >> the /dev/rpmsg_ctrl interface >> >> The RPMSG_CREATE_DEV_IOCTL Ioctl can be used to instantiate a local rpmsg >> device. >> Depending on the back-end implementation, the associated rpmsg driver is >> probed and a NS announcement can be sent to the remote processor. >> >> The RPMSG_RELEASE_DEV_IOCTL allows the user application to release a >> rpmsg device created either by the remote processor or with the >> RPMSG_CREATE_DEV_IOCTL call. >> Depending on the back-end implementation, the associated rpmsg driver is >> removed and a NS destroy rpmsg can be sent to the remote processor. >> >> Suggested-by: Mathieu Poirier <mathieu.poirier@linaro.org> >> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com> >> --- >> drivers/rpmsg/rpmsg_ctrl.c | 37 +++++++++++++++++++++++++++++++++---- >> include/uapi/linux/rpmsg.h | 10 ++++++++++ >> 2 files changed, 43 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/rpmsg/rpmsg_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c >> index eeb1708548c1..cb19e32d05e1 100644 >> --- a/drivers/rpmsg/rpmsg_ctrl.c >> +++ b/drivers/rpmsg/rpmsg_ctrl.c >> @@ -23,6 +23,7 @@ >> #include <uapi/linux/rpmsg.h> >> >> #include "rpmsg_char.h" >> +#include "rpmsg_internal.h" >> >> static dev_t rpmsg_major; >> >> @@ -37,11 +38,13 @@ static DEFINE_IDA(rpmsg_minor_ida); >> * @rpdev: underlaying rpmsg device >> * @cdev: cdev for the ctrl device >> * @dev: device for the ctrl device >> + * @ctrl_lock: serialize the ioctrls. >> */ >> struct rpmsg_ctrldev { >> struct rpmsg_device *rpdev; >> struct cdev cdev; >> struct device dev; >> + struct mutex ctrl_lock; >> }; >> >> static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp) >> @@ -70,9 +73,8 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd, >> void __user *argp = (void __user *)arg; >> struct rpmsg_endpoint_info eptinfo; >> struct rpmsg_channel_info chinfo; >> - >> - if (cmd != RPMSG_CREATE_EPT_IOCTL) >> - return -EINVAL; >> + struct rpmsg_device *rpdev; >> + int ret = 0; >> >> if (copy_from_user(&eptinfo, argp, sizeof(eptinfo))) >> return -EFAULT; >> @@ -82,7 +84,33 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd, >> chinfo.src = eptinfo.src; >> chinfo.dst = eptinfo.dst; >> >> - return rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo); >> + mutex_lock(&ctrldev->ctrl_lock); > > Have you been able to verify the VFS layer doesn't take care of serializing > ioctl() and file accesses in general? I did a quick search in the drivers/ > directory and the vast majority of implementations don't use a lock. Please find my answer here https://lkml.org/lkml/2021/6/21/235 I tested by suppressing the lock and adding msleep to check a potential atomic. in the rpmsg_ctrldev_ioctl function. Nothing seems prevent the re-entrance. Regards, Arnaud > > Thanks, > Mathieu > >> + switch (cmd) { >> + case RPMSG_CREATE_EPT_IOCTL: >> + ret = rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo); >> + break; >> + >> + case RPMSG_CREATE_DEV_IOCTL: >> + rpdev = rpmsg_create_channel(ctrldev->rpdev, &chinfo); >> + if (!rpdev) { >> + dev_err(&ctrldev->dev, "failed to create %s channel\n", chinfo.name); >> + ret = -ENXIO; >> + } >> + break; >> + >> + case RPMSG_RELEASE_DEV_IOCTL: >> + ret = rpmsg_release_channel(ctrldev->rpdev, &chinfo); >> + if (ret) >> + dev_err(&ctrldev->dev, "failed to release %s channel (%d)\n", >> + chinfo.name, ret); >> + break; >> + >> + default: >> + ret = -EINVAL; >> + } >> + mutex_unlock(&ctrldev->ctrl_lock); >> + >> + return ret; >> }; >> >> static const struct file_operations rpmsg_ctrldev_fops = { >> @@ -119,6 +147,7 @@ static int rpmsg_ctrldev_probe(struct rpmsg_device *rpdev) >> device_initialize(dev); >> dev->parent = &rpdev->dev; >> >> + mutex_init(&ctrldev->ctrl_lock); >> cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops); >> ctrldev->cdev.owner = THIS_MODULE; >> >> diff --git a/include/uapi/linux/rpmsg.h b/include/uapi/linux/rpmsg.h >> index f5ca8740f3fb..1637e68177d9 100644 >> --- a/include/uapi/linux/rpmsg.h >> +++ b/include/uapi/linux/rpmsg.h >> @@ -33,4 +33,14 @@ struct rpmsg_endpoint_info { >> */ >> #define RPMSG_DESTROY_EPT_IOCTL _IO(0xb5, 0x2) >> >> +/** >> + * Instantiate a new local rpmsg service device. >> + */ >> +#define RPMSG_CREATE_DEV_IOCTL _IOW(0xb5, 0x3, struct rpmsg_endpoint_info) >> + >> +/** >> + * Release a local rpmsg device. >> + */ >> +#define RPMSG_RELEASE_DEV_IOCTL _IOW(0xb5, 0x4, struct rpmsg_endpoint_info) >> + >> #endif >> -- >> 2.17.1 >>
On Tue, Jun 22, 2021 at 09:43:49AM +0200, Arnaud POULIQUEN wrote: > Hi Mathieu > > On 6/22/21 1:16 AM, Mathieu Poirier wrote: > > On Mon, Jun 21, 2021 at 02:58:00PM +0200, Arnaud Pouliquen wrote: > >> Allow the user space application to create and release an rpmsg device > >> by adding RPMSG_CREATE_DEV_IOCTL and RPMSG_RELEASE_DEV_IOCTL ioctrls to > >> the /dev/rpmsg_ctrl interface > >> > >> The RPMSG_CREATE_DEV_IOCTL Ioctl can be used to instantiate a local rpmsg > >> device. > >> Depending on the back-end implementation, the associated rpmsg driver is > >> probed and a NS announcement can be sent to the remote processor. > >> > >> The RPMSG_RELEASE_DEV_IOCTL allows the user application to release a > >> rpmsg device created either by the remote processor or with the > >> RPMSG_CREATE_DEV_IOCTL call. > >> Depending on the back-end implementation, the associated rpmsg driver is > >> removed and a NS destroy rpmsg can be sent to the remote processor. > >> > >> Suggested-by: Mathieu Poirier <mathieu.poirier@linaro.org> > >> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com> > >> --- > >> drivers/rpmsg/rpmsg_ctrl.c | 37 +++++++++++++++++++++++++++++++++---- > >> include/uapi/linux/rpmsg.h | 10 ++++++++++ > >> 2 files changed, 43 insertions(+), 4 deletions(-) > >> > >> diff --git a/drivers/rpmsg/rpmsg_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c > >> index eeb1708548c1..cb19e32d05e1 100644 > >> --- a/drivers/rpmsg/rpmsg_ctrl.c > >> +++ b/drivers/rpmsg/rpmsg_ctrl.c > >> @@ -23,6 +23,7 @@ > >> #include <uapi/linux/rpmsg.h> > >> > >> #include "rpmsg_char.h" > >> +#include "rpmsg_internal.h" > >> > >> static dev_t rpmsg_major; > >> > >> @@ -37,11 +38,13 @@ static DEFINE_IDA(rpmsg_minor_ida); > >> * @rpdev: underlaying rpmsg device > >> * @cdev: cdev for the ctrl device > >> * @dev: device for the ctrl device > >> + * @ctrl_lock: serialize the ioctrls. > >> */ > >> struct rpmsg_ctrldev { > >> struct rpmsg_device *rpdev; > >> struct cdev cdev; > >> struct device dev; > >> + struct mutex ctrl_lock; > >> }; > >> > >> static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp) > >> @@ -70,9 +73,8 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd, > >> void __user *argp = (void __user *)arg; > >> struct rpmsg_endpoint_info eptinfo; > >> struct rpmsg_channel_info chinfo; > >> - > >> - if (cmd != RPMSG_CREATE_EPT_IOCTL) > >> - return -EINVAL; > >> + struct rpmsg_device *rpdev; > >> + int ret = 0; > >> > >> if (copy_from_user(&eptinfo, argp, sizeof(eptinfo))) > >> return -EFAULT; > >> @@ -82,7 +84,33 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd, > >> chinfo.src = eptinfo.src; > >> chinfo.dst = eptinfo.dst; > >> > >> - return rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo); > >> + mutex_lock(&ctrldev->ctrl_lock); > > > > Have you been able to verify the VFS layer doesn't take care of serializing > > ioctl() and file accesses in general? I did a quick search in the drivers/ > > directory and the vast majority of implementations don't use a lock. > > Please find my answer here https://lkml.org/lkml/2021/6/21/235 Ah ok, I hadn't noticed that one. > I tested by suppressing the lock and adding msleep to check a potential atomic. > in the rpmsg_ctrldev_ioctl function. Nothing seems prevent the re-entrance. Thanks for testing this out. I did some research on my side and turns out unlocked_ioctl() was introduced to get rid of the Big Kernel Lock rather than indicate that serialisation is not supported by this interface. Someone also asked the exact same question here [1]. So yes, locking is required. Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> [1]. https://stackoverflow.com/questions/18874962/linux-device-driver-file-operations-it-is-possible-to-have-race-conditions > > Regards, > Arnaud > > > > > Thanks, > > Mathieu > > > >> + switch (cmd) { > >> + case RPMSG_CREATE_EPT_IOCTL: > >> + ret = rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo); > >> + break; > >> + > >> + case RPMSG_CREATE_DEV_IOCTL: > >> + rpdev = rpmsg_create_channel(ctrldev->rpdev, &chinfo); > >> + if (!rpdev) { > >> + dev_err(&ctrldev->dev, "failed to create %s channel\n", chinfo.name); > >> + ret = -ENXIO; > >> + } > >> + break; > >> + > >> + case RPMSG_RELEASE_DEV_IOCTL: > >> + ret = rpmsg_release_channel(ctrldev->rpdev, &chinfo); > >> + if (ret) > >> + dev_err(&ctrldev->dev, "failed to release %s channel (%d)\n", > >> + chinfo.name, ret); > >> + break; > >> + > >> + default: > >> + ret = -EINVAL; > >> + } > >> + mutex_unlock(&ctrldev->ctrl_lock); > >> + > >> + return ret; > >> }; > >> > >> static const struct file_operations rpmsg_ctrldev_fops = { > >> @@ -119,6 +147,7 @@ static int rpmsg_ctrldev_probe(struct rpmsg_device *rpdev) > >> device_initialize(dev); > >> dev->parent = &rpdev->dev; > >> > >> + mutex_init(&ctrldev->ctrl_lock); > >> cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops); > >> ctrldev->cdev.owner = THIS_MODULE; > >> > >> diff --git a/include/uapi/linux/rpmsg.h b/include/uapi/linux/rpmsg.h > >> index f5ca8740f3fb..1637e68177d9 100644 > >> --- a/include/uapi/linux/rpmsg.h > >> +++ b/include/uapi/linux/rpmsg.h > >> @@ -33,4 +33,14 @@ struct rpmsg_endpoint_info { > >> */ > >> #define RPMSG_DESTROY_EPT_IOCTL _IO(0xb5, 0x2) > >> > >> +/** > >> + * Instantiate a new local rpmsg service device. > >> + */ > >> +#define RPMSG_CREATE_DEV_IOCTL _IOW(0xb5, 0x3, struct rpmsg_endpoint_info) > >> + > >> +/** > >> + * Release a local rpmsg device. > >> + */ > >> +#define RPMSG_RELEASE_DEV_IOCTL _IOW(0xb5, 0x4, struct rpmsg_endpoint_info) > >> + > >> #endif > >> -- > >> 2.17.1 > >>
diff --git a/drivers/rpmsg/rpmsg_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c index eeb1708548c1..cb19e32d05e1 100644 --- a/drivers/rpmsg/rpmsg_ctrl.c +++ b/drivers/rpmsg/rpmsg_ctrl.c @@ -23,6 +23,7 @@ #include <uapi/linux/rpmsg.h> #include "rpmsg_char.h" +#include "rpmsg_internal.h" static dev_t rpmsg_major; @@ -37,11 +38,13 @@ static DEFINE_IDA(rpmsg_minor_ida); * @rpdev: underlaying rpmsg device * @cdev: cdev for the ctrl device * @dev: device for the ctrl device + * @ctrl_lock: serialize the ioctrls. */ struct rpmsg_ctrldev { struct rpmsg_device *rpdev; struct cdev cdev; struct device dev; + struct mutex ctrl_lock; }; static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp) @@ -70,9 +73,8 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd, void __user *argp = (void __user *)arg; struct rpmsg_endpoint_info eptinfo; struct rpmsg_channel_info chinfo; - - if (cmd != RPMSG_CREATE_EPT_IOCTL) - return -EINVAL; + struct rpmsg_device *rpdev; + int ret = 0; if (copy_from_user(&eptinfo, argp, sizeof(eptinfo))) return -EFAULT; @@ -82,7 +84,33 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd, chinfo.src = eptinfo.src; chinfo.dst = eptinfo.dst; - return rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo); + mutex_lock(&ctrldev->ctrl_lock); + switch (cmd) { + case RPMSG_CREATE_EPT_IOCTL: + ret = rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo); + break; + + case RPMSG_CREATE_DEV_IOCTL: + rpdev = rpmsg_create_channel(ctrldev->rpdev, &chinfo); + if (!rpdev) { + dev_err(&ctrldev->dev, "failed to create %s channel\n", chinfo.name); + ret = -ENXIO; + } + break; + + case RPMSG_RELEASE_DEV_IOCTL: + ret = rpmsg_release_channel(ctrldev->rpdev, &chinfo); + if (ret) + dev_err(&ctrldev->dev, "failed to release %s channel (%d)\n", + chinfo.name, ret); + break; + + default: + ret = -EINVAL; + } + mutex_unlock(&ctrldev->ctrl_lock); + + return ret; }; static const struct file_operations rpmsg_ctrldev_fops = { @@ -119,6 +147,7 @@ static int rpmsg_ctrldev_probe(struct rpmsg_device *rpdev) device_initialize(dev); dev->parent = &rpdev->dev; + mutex_init(&ctrldev->ctrl_lock); cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops); ctrldev->cdev.owner = THIS_MODULE; diff --git a/include/uapi/linux/rpmsg.h b/include/uapi/linux/rpmsg.h index f5ca8740f3fb..1637e68177d9 100644 --- a/include/uapi/linux/rpmsg.h +++ b/include/uapi/linux/rpmsg.h @@ -33,4 +33,14 @@ struct rpmsg_endpoint_info { */ #define RPMSG_DESTROY_EPT_IOCTL _IO(0xb5, 0x2) +/** + * Instantiate a new local rpmsg service device. + */ +#define RPMSG_CREATE_DEV_IOCTL _IOW(0xb5, 0x3, struct rpmsg_endpoint_info) + +/** + * Release a local rpmsg device. + */ +#define RPMSG_RELEASE_DEV_IOCTL _IOW(0xb5, 0x4, struct rpmsg_endpoint_info) + #endif
Allow the user space application to create and release an rpmsg device by adding RPMSG_CREATE_DEV_IOCTL and RPMSG_RELEASE_DEV_IOCTL ioctrls to the /dev/rpmsg_ctrl interface The RPMSG_CREATE_DEV_IOCTL Ioctl can be used to instantiate a local rpmsg device. Depending on the back-end implementation, the associated rpmsg driver is probed and a NS announcement can be sent to the remote processor. The RPMSG_RELEASE_DEV_IOCTL allows the user application to release a rpmsg device created either by the remote processor or with the RPMSG_CREATE_DEV_IOCTL call. Depending on the back-end implementation, the associated rpmsg driver is removed and a NS destroy rpmsg can be sent to the remote processor. Suggested-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com> --- drivers/rpmsg/rpmsg_ctrl.c | 37 +++++++++++++++++++++++++++++++++---- include/uapi/linux/rpmsg.h | 10 ++++++++++ 2 files changed, 43 insertions(+), 4 deletions(-)