On Tue, Dec 08, 2020 at 07:35:18PM +0100, Arnaud POULIQUEN wrote: > Hi Mathieu, > > > On 11/26/20 10:06 PM, Mathieu Poirier wrote: > > Introduce function rproc_detach() to enable the remoteproc > > core to release the resources associated with a remote processor > > without stopping its operation. > > > > Signed-off-by: Mathieu Poirier <[email protected]> > > Reviewed-by: Peng Fan <[email protected]> > > --- > > drivers/remoteproc/remoteproc_core.c | 65 +++++++++++++++++++++++++++- > > include/linux/remoteproc.h | 1 + > > 2 files changed, 65 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/remoteproc/remoteproc_core.c > > b/drivers/remoteproc/remoteproc_core.c > > index 928b3f975798..f5adf05762e9 100644 > > --- a/drivers/remoteproc/remoteproc_core.c > > +++ b/drivers/remoteproc/remoteproc_core.c > > @@ -1667,7 +1667,7 @@ static int rproc_stop(struct rproc *rproc, bool > > crashed) > > /* > > * __rproc_detach(): Does the opposite of rproc_attach() > > */ > > -static int __maybe_unused __rproc_detach(struct rproc *rproc) > > +static int __rproc_detach(struct rproc *rproc) > > { > > struct device *dev = &rproc->dev; > > int ret; > > @@ -1910,6 +1910,69 @@ void rproc_shutdown(struct rproc *rproc) > > } > > EXPORT_SYMBOL(rproc_shutdown); > > > > +/** > > + * rproc_detach() - Detach the remote processor from the > > + * remoteproc core > > + * > > + * @rproc: the remote processor > > + * > > + * Detach a remote processor (previously attached to with rproc_actuate()). > > + * > > + * In case @rproc is still being used by an additional user(s), then > > + * this function will just decrement the power refcount and exit, > > + * without disconnecting the device. > > + * > > + * Function rproc_detach() calls __rproc_detach() in order to let a remote > > + * processor know that services provided by the application processor are > > + * no longer available. From there it should be possible to remove the > > + * platform driver and even power cycle the application processor (if the > > HW > > + * supports it) without needing to switch off the remote processor. > > + */ > > +int rproc_detach(struct rproc *rproc) > > +{ > > + struct device *dev = &rproc->dev; > > + int ret; > > + > > + ret = mutex_lock_interruptible(&rproc->lock); > > + if (ret) { > > + dev_err(dev, "can't lock rproc %s: %d\n", rproc->name, ret); > > + return ret; > > + } > > + > > + if (rproc->state != RPROC_RUNNING && rproc->state != RPROC_ATTACHED) { > > + ret = -EPERM; > > + goto out; > > + } > > + > > + /* if the remote proc is still needed, bail out */ > > + if (!atomic_dec_and_test(&rproc->power)) { > > + ret = -EBUSY; > > + goto out; > > + } > > + > > + ret = __rproc_detach(rproc); > > + if (ret) { > > + atomic_inc(&rproc->power); > > + goto out; > > + } > > + > > + /* clean up all acquired resources */ > > + rproc_resource_cleanup(rproc); > > I started to test the series, I found 2 problems testing in STM32P1 board. > > 1) the resource_table pointer is unmapped if the firmware has been booted by > the > Linux, generating a crash in rproc_free_vring. > I attached a fix at the end of the mail. > > 2) After the detach, the rproc state is "detached" > but it is no longer possible to re-attach to it correctly. > Neither if the firmware is standalone, nor if it has been booted > by the Linux.
Thanks for the report - I thought both problems had been fixed... > > I did not investigate, but the issue is probably linked to the resource > table address which is set to NULL. > > So we either have to fix the problem in order to attach or forbid the > transition. > Perfect timing on your side as I was contemplating sending another revision. Let me look at things and I will get back to you. > > Regards, > Arnaud > > > + > > + rproc_disable_iommu(rproc); > > + > > + /* > > + * Set the remote processor's table pointer to NULL. Since mapping > > + * of the resource table to a virtual address is done in the platform > > + * driver, unmapping should also be done there. > > + */ > > + rproc->table_ptr = NULL; > > +out: > > + mutex_unlock(&rproc->lock); > > + return ret; > > +} > > +EXPORT_SYMBOL(rproc_detach); > > + > > /** > > * rproc_get_by_phandle() - find a remote processor by phandle > > * @phandle: phandle to the rproc > > diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h > > index da15b77583d3..329c1c071dcf 100644 > > --- a/include/linux/remoteproc.h > > +++ b/include/linux/remoteproc.h > > @@ -656,6 +656,7 @@ rproc_of_resm_mem_entry_init(struct device *dev, u32 > > of_resm_idx, size_t len, > > > > int rproc_boot(struct rproc *rproc); > > void rproc_shutdown(struct rproc *rproc); > > +int rproc_detach(struct rproc *rproc); > > int rproc_set_firmware(struct rproc *rproc, const char *fw_name); > > void rproc_report_crash(struct rproc *rproc, enum rproc_crash_type type); > > int rproc_coredump_add_segment(struct rproc *rproc, dma_addr_t da, size_t > > size); > > > > From: Arnaud Pouliquen <[email protected]> > Date: Tue, 8 Dec 2020 18:54:51 +0100 > Subject: [PATCH] remoteproc: core: fix detach for unmapped table_ptr > > If the firmware has been loaded and started by the kernel, the > resource table has probably been mapped by the carveout allocation > (see rproc_elf_find_loaded_rsc_table). > In this case the memory can have been unmapped before the vrings are free. > The result is a crash that occurs in rproc_free_vring while try to use the > unmapped pointer. > > Signed-off-by: Arnaud Pouliquen <[email protected]> > --- > drivers/remoteproc/remoteproc_core.c | 17 ++++++++++++++--- > 1 file changed, 14 insertions(+), 3 deletions(-) > > diff --git a/drivers/remoteproc/remoteproc_core.c > b/drivers/remoteproc/remoteproc_core.c > index 2b0a52fb3398..3508ffba4a2a 100644 > --- a/drivers/remoteproc/remoteproc_core.c > +++ b/drivers/remoteproc/remoteproc_core.c > @@ -1964,6 +1964,13 @@ int rproc_detach(struct rproc *rproc) > goto out; > } > > + /* > + * Prevent case that the installed resource table is no longer > + * accessible (e.g. memory unmapped), use the cache if available > + */ > + if (rproc->cached_table) > + rproc->table_ptr = rproc->cached_table; > + > ret = __rproc_detach(rproc); > if (ret) { > atomic_inc(&rproc->power); > @@ -1975,10 +1982,14 @@ int rproc_detach(struct rproc *rproc) > > rproc_disable_iommu(rproc); > > + /* Free the chached table memory that can has been allocated*/ > + kfree(rproc->cached_table); > + rproc->cached_table = NULL; > /* > - * Set the remote processor's table pointer to NULL. Since mapping > - * of the resource table to a virtual address is done in the platform > - * driver, unmapping should also be done there. > + * Set the remote processor's table pointer to NULL. If mapping > + * of the resource table to a virtual address has been done in the > + * platform driver(attachment to an existing firmware), > + * unmapping should also be done there. > */ > rproc->table_ptr = NULL; > out: > -- > 2.17.1 > > >
