Re: [PATCH RESEND] remoteproc: core: Remove casting to rproc_handle_resource_t

[Mathieu Poirier]

On Wed, Feb 24, 2021 at 01:58:25PM +0800, Jindong Yue wrote:
> There are four different callback functions that are used for the
> rproc_handle_resource_t callback that all have different second
> parameter types.
> 
> rproc_handle_vdev -> struct fw_rsc_vdev
> rproc_handle_trace -> struct fw_rsc_trace
> rproc_handle_devmem -> struct fw_rsc_devmem
> rproc_handle_carveout -> struct fw_rsc_carveout
> 
> These callbacks are cast to rproc_handle_resource_t so that there is no
> error about incompatible pointer types. Unfortunately, this is a Clang's
> Control-Flow Integrity checking violation, which verifies that the
> callback function's types match the prototypes exactly before jumping.
> 
> [    7.275750] Kernel panic - not syncing: CFI failure (target: rproc_handle_vdev+0x0/0x4)
> [    7.283763] CPU: 2 PID: 1 Comm: init Tainted: G         C O      5.4.70-03301-g527af2c96672 #17
> [    7.292463] Hardware name: NXP i.MX8MPlus EVK board (DT)
> [    7.297779] Call trace:
> [    7.300232]  dump_backtrace.cfi_jt+0x0/0x4
> [    7.304337]  show_stack+0x18/0x24
> [    7.307660]  dump_stack+0xb8/0x114
> [    7.311069]  panic+0x164/0x3d4
> [    7.314130]  __ubsan_handle_cfi_check_fail_abort+0x0/0x14
> [    7.319533]  perf_proc_update_handler+0x0/0xcc
> [    7.323983]  __cfi_check+0x63278/0x6a290
> [    7.327913]  rproc_boot+0x3f8/0x738
> [    7.331404]  rproc_add+0x68/0x110
> [    7.334738]  imx_rproc_probe+0x5e4/0x708 [imx_rproc]
> [    7.339711]  platform_drv_probe+0xac/0xf0
> [    7.343726]  really_probe+0x260/0x65c
> [    7.347393]  driver_probe_device+0x64/0x100
> [    7.351580]  device_driver_attach+0x6c/0xac
> [    7.355766]  __driver_attach+0xdc/0x184
> [    7.359609]  bus_for_each_dev+0x98/0x104
> [    7.363537]  driver_attach+0x24/0x30
> [    7.367117]  bus_add_driver+0x100/0x1e0
> [    7.370958]  driver_register+0x78/0x114
> [    7.374800]  __platform_driver_register+0x44/0x50
> [    7.379514]  init_module+0x20/0xfe8 [imx_rproc]
> [    7.384049]  do_one_initcall+0x190/0x348
> [    7.387979]  do_init_module+0x5c/0x210
> [    7.391731]  load_module+0x2fbc/0x3590
> [    7.395485]  __arm64_sys_finit_module+0xb8/0xec
> [    7.400025]  el0_svc_common+0xb4/0x19c
> [    7.403777]  el0_svc_handler+0x74/0x98
> [    7.407531]  el0_svc+0x8/0xc
> [    7.410419] SMP: stopping secondary CPUs
> [    7.414648] Kernel Offset: disabled
> [    7.418142] CPU features: 0x00010002,2000200c
> [    7.422501] Memory Limit: none
> 
> To fix this, change the second parameter of all functions to void * and
> use a local variable with the correct type so that everything works
> properly. With this, we can remove casting to rproc_handle_resource_t
> for these functions.
> 
> Signed-off-by: Jindong Yue <jindong.yue@xxxxxxx>
> Reviewed-by: Peng Fan <peng.fan@xxxxxxx>
> Reviewed-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>

Reviewed-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>

> ---
>  drivers/remoteproc/remoteproc_core.c | 29 +++++++++++++++-------------
>  1 file changed, 16 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index ab150765d124..553e42a4d2a0 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -482,7 +482,7 @@ static int copy_dma_range_map(struct device *to, struct device *from)
>  /**
>   * rproc_handle_vdev() - handle a vdev fw resource
>   * @rproc: the remote processor
> - * @rsc: the vring resource descriptor
> + * @ptr: the vring resource descriptor
>   * @offset: offset of the resource entry
>   * @avail: size of available data (for sanity checking the image)
>   *
> @@ -507,9 +507,10 @@ static int copy_dma_range_map(struct device *to, struct device *from)
>   *
>   * Returns 0 on success, or an appropriate error code otherwise
>   */
> -static int rproc_handle_vdev(struct rproc *rproc, struct fw_rsc_vdev *rsc,
> +static int rproc_handle_vdev(struct rproc *rproc, void *ptr,
>  			     int offset, int avail)
>  {
> +	struct fw_rsc_vdev *rsc = ptr;
>  	struct device *dev = &rproc->dev;
>  	struct rproc_vdev *rvdev;
>  	int i, ret;
> @@ -627,7 +628,7 @@ void rproc_vdev_release(struct kref *ref)
>  /**
>   * rproc_handle_trace() - handle a shared trace buffer resource
>   * @rproc: the remote processor
> - * @rsc: the trace resource descriptor
> + * @ptr: the trace resource descriptor
>   * @offset: offset of the resource entry
>   * @avail: size of available data (for sanity checking the image)
>   *
> @@ -641,9 +642,10 @@ void rproc_vdev_release(struct kref *ref)
>   *
>   * Returns 0 on success, or an appropriate error code otherwise
>   */
> -static int rproc_handle_trace(struct rproc *rproc, struct fw_rsc_trace *rsc,
> +static int rproc_handle_trace(struct rproc *rproc, void *ptr,
>  			      int offset, int avail)
>  {
> +	struct fw_rsc_trace *rsc = ptr;
>  	struct rproc_debug_trace *trace;
>  	struct device *dev = &rproc->dev;
>  	char name[15];
> @@ -693,7 +695,7 @@ static int rproc_handle_trace(struct rproc *rproc, struct fw_rsc_trace *rsc,
>  /**
>   * rproc_handle_devmem() - handle devmem resource entry
>   * @rproc: remote processor handle
> - * @rsc: the devmem resource entry
> + * @ptr: the devmem resource entry
>   * @offset: offset of the resource entry
>   * @avail: size of available data (for sanity checking the image)
>   *
> @@ -716,9 +718,10 @@ static int rproc_handle_trace(struct rproc *rproc, struct fw_rsc_trace *rsc,
>   * and not allow firmwares to request access to physical addresses that
>   * are outside those ranges.
>   */
> -static int rproc_handle_devmem(struct rproc *rproc, struct fw_rsc_devmem *rsc,
> +static int rproc_handle_devmem(struct rproc *rproc, void *ptr,
>  			       int offset, int avail)
>  {
> +	struct fw_rsc_devmem *rsc = ptr;
>  	struct rproc_mem_entry *mapping;
>  	struct device *dev = &rproc->dev;
>  	int ret;
> @@ -896,7 +899,7 @@ static int rproc_release_carveout(struct rproc *rproc,
>  /**
>   * rproc_handle_carveout() - handle phys contig memory allocation requests
>   * @rproc: rproc handle
> - * @rsc: the resource entry
> + * @ptr: the resource entry
>   * @offset: offset of the resource entry
>   * @avail: size of available data (for image validation)
>   *
> @@ -913,9 +916,9 @@ static int rproc_release_carveout(struct rproc *rproc,
>   * pressure is important; it may have a substantial impact on performance.
>   */
>  static int rproc_handle_carveout(struct rproc *rproc,
> -				 struct fw_rsc_carveout *rsc,
> -				 int offset, int avail)
> +				 void *ptr, int offset, int avail)
>  {
> +	struct fw_rsc_carveout *rsc = ptr;
>  	struct rproc_mem_entry *carveout;
>  	struct device *dev = &rproc->dev;
>  
> @@ -1097,10 +1100,10 @@ EXPORT_SYMBOL(rproc_of_parse_firmware);
>   * enum fw_resource_type.
>   */
>  static rproc_handle_resource_t rproc_loading_handlers[RSC_LAST] = {
> -	[RSC_CARVEOUT] = (rproc_handle_resource_t)rproc_handle_carveout,
> -	[RSC_DEVMEM] = (rproc_handle_resource_t)rproc_handle_devmem,
> -	[RSC_TRACE] = (rproc_handle_resource_t)rproc_handle_trace,
> -	[RSC_VDEV] = (rproc_handle_resource_t)rproc_handle_vdev,
> +	[RSC_CARVEOUT] = rproc_handle_carveout,
> +	[RSC_DEVMEM] = rproc_handle_devmem,
> +	[RSC_TRACE] = rproc_handle_trace,
> +	[RSC_VDEV] = rproc_handle_vdev,
>  };
>  
>  /* handle firmware resource entries before booting the remote processor */
> -- 
> 2.17.1
>