From 283e6f5a8166f075eba78da6b867d76cc5d47e77 Mon Sep 17 00:00:00 2001 From: Sergey Ryazanov Date: Tue, 7 Dec 2021 12:21:40 +0300 Subject: [PATCH] net: wwan: make debugfs optional Debugfs interface is optional for the regular modem use. Some distros and users will want to disable this feature for security or kernel size reasons. So add a configuration option that allows to completely disable the debugfs interface of the WWAN devices. A primary considered use case for this option was embedded firmwares. For example, in OpenWrt, you can not completely disable debugfs, as a lot of wireless stuff can only be configured and monitored with the debugfs knobs. At the same time, reducing the size of a kernel and modules is an essential task in the world of embedded software. Disabling the WWAN and IOSM debugfs interfaces allows us to save 50K (x86-64 build) of space for module storage. Not much, but already considerable when you only have 16MB of storage. So it is hard to just disable whole debugfs. Users need some fine grained set of options to control which debugfs interface is important and should be available and which is not. The new configuration symbol is enabled by default and is hidden under the EXPERT option. So a regular user would not be bothered by another one configuration question. While an embedded distro maintainer will be able to a little more reduce the final image size. Signed-off-by: Sergey Ryazanov Reviewed-by: Leon Romanovsky Reviewed-by: Loic Poulain Acked-by: M Chetan Kumar Signed-off-by: Jakub Kicinski --- drivers/net/wwan/Kconfig | 13 ++++++++++++- drivers/net/wwan/iosm/Makefile | 4 +++- drivers/net/wwan/iosm/iosm_ipc_debugfs.h | 5 +++++ drivers/net/wwan/iosm/iosm_ipc_imem.c | 2 +- drivers/net/wwan/iosm/iosm_ipc_imem.h | 4 ++++ drivers/net/wwan/iosm/iosm_ipc_trace.c | 6 ++++-- drivers/net/wwan/iosm/iosm_ipc_trace.h | 20 +++++++++++++++++++- drivers/net/wwan/wwan_core.c | 17 +++++++++++++---- include/linux/wwan.h | 7 +++++++ 9 files changed, 68 insertions(+), 10 deletions(-) diff --git a/drivers/net/wwan/Kconfig b/drivers/net/wwan/Kconfig index 9f5111a77da9..609fd4a2c865 100644 --- a/drivers/net/wwan/Kconfig +++ b/drivers/net/wwan/Kconfig @@ -16,6 +16,17 @@ config WWAN if WWAN +config WWAN_DEBUGFS + bool "WWAN devices debugfs interface" if EXPERT + depends on DEBUG_FS + default y + help + Enables debugfs infrastructure for the WWAN core and device drivers. + + If this option is selected, then you can find the debug interface + elements for each WWAN device in a directory that is corresponding to + the device name: debugfs/wwan/wwanX. + config WWAN_HWSIM tristate "Simulated WWAN device" help @@ -85,7 +96,7 @@ config IOSM tristate "IOSM Driver for Intel M.2 WWAN Device" depends on INTEL_IOMMU select NET_DEVLINK - select RELAY + select RELAY if WWAN_DEBUGFS help This driver enables Intel M.2 WWAN Device communication. diff --git a/drivers/net/wwan/iosm/Makefile b/drivers/net/wwan/iosm/Makefile index 5091f664af0d..fa8d6afd18e1 100644 --- a/drivers/net/wwan/iosm/Makefile +++ b/drivers/net/wwan/iosm/Makefile @@ -21,7 +21,9 @@ iosm-y = \ iosm_ipc_mux_codec.o \ iosm_ipc_devlink.o \ iosm_ipc_flash.o \ - iosm_ipc_coredump.o \ + iosm_ipc_coredump.o + +iosm-$(CONFIG_WWAN_DEBUGFS) += \ iosm_ipc_debugfs.o \ iosm_ipc_trace.o diff --git a/drivers/net/wwan/iosm/iosm_ipc_debugfs.h b/drivers/net/wwan/iosm/iosm_ipc_debugfs.h index 35788039f13f..8a84bfa2c14a 100644 --- a/drivers/net/wwan/iosm/iosm_ipc_debugfs.h +++ b/drivers/net/wwan/iosm/iosm_ipc_debugfs.h @@ -6,7 +6,12 @@ #ifndef IOSM_IPC_DEBUGFS_H #define IOSM_IPC_DEBUGFS_H +#ifdef CONFIG_WWAN_DEBUGFS void ipc_debugfs_init(struct iosm_imem *ipc_imem); void ipc_debugfs_deinit(struct iosm_imem *ipc_imem); +#else +static inline void ipc_debugfs_init(struct iosm_imem *ipc_imem) {} +static inline void ipc_debugfs_deinit(struct iosm_imem *ipc_imem) {} +#endif #endif diff --git a/drivers/net/wwan/iosm/iosm_ipc_imem.c b/drivers/net/wwan/iosm/iosm_ipc_imem.c index 25b889922912..2a6ddd7c6c88 100644 --- a/drivers/net/wwan/iosm/iosm_ipc_imem.c +++ b/drivers/net/wwan/iosm/iosm_ipc_imem.c @@ -274,7 +274,7 @@ static void ipc_imem_dl_skb_process(struct iosm_imem *ipc_imem, ipc_imem_sys_devlink_notify_rx(ipc_imem->ipc_devlink, skb); else if (ipc_is_trace_channel(ipc_imem, port_id)) - ipc_trace_port_rx(ipc_imem->trace, skb); + ipc_trace_port_rx(ipc_imem, skb); else wwan_port_rx(ipc_imem->ipc_port[port_id]->iosm_port, skb); diff --git a/drivers/net/wwan/iosm/iosm_ipc_imem.h b/drivers/net/wwan/iosm/iosm_ipc_imem.h index 1b8c7b8959c6..86a1ffe61729 100644 --- a/drivers/net/wwan/iosm/iosm_ipc_imem.h +++ b/drivers/net/wwan/iosm/iosm_ipc_imem.h @@ -351,7 +351,9 @@ struct iosm_imem { struct iosm_mux *mux; struct iosm_cdev *ipc_port[IPC_MEM_MAX_CHANNELS]; struct iosm_pcie *pcie; +#ifdef CONFIG_WWAN_DEBUGFS struct iosm_trace *trace; +#endif struct device *dev; enum ipc_mem_device_ipc_state ipc_requested_state; struct ipc_mem_channel channels[IPC_MEM_MAX_CHANNELS]; @@ -381,7 +383,9 @@ struct iosm_imem { ev_mux_net_transmit_pending:1, reset_det_n:1, pcie_wake_n:1; +#ifdef CONFIG_WWAN_DEBUGFS struct dentry *debugfs_dir; +#endif }; /** diff --git a/drivers/net/wwan/iosm/iosm_ipc_trace.c b/drivers/net/wwan/iosm/iosm_ipc_trace.c index 5243ead90b5f..eeecfa3d10c5 100644 --- a/drivers/net/wwan/iosm/iosm_ipc_trace.c +++ b/drivers/net/wwan/iosm/iosm_ipc_trace.c @@ -17,11 +17,13 @@ /** * ipc_trace_port_rx - Receive trace packet from cp and write to relay buffer - * @ipc_trace: Pointer to the ipc trace data-struct + * @ipc_imem: Pointer to iosm_imem structure * @skb: Pointer to struct sk_buff */ -void ipc_trace_port_rx(struct iosm_trace *ipc_trace, struct sk_buff *skb) +void ipc_trace_port_rx(struct iosm_imem *ipc_imem, struct sk_buff *skb) { + struct iosm_trace *ipc_trace = ipc_imem->trace; + if (ipc_trace->ipc_rchan) relay_write(ipc_trace->ipc_rchan, skb->data, skb->len); diff --git a/drivers/net/wwan/iosm/iosm_ipc_trace.h b/drivers/net/wwan/iosm/iosm_ipc_trace.h index 419540c91219..5ebe7790585c 100644 --- a/drivers/net/wwan/iosm/iosm_ipc_trace.h +++ b/drivers/net/wwan/iosm/iosm_ipc_trace.h @@ -45,6 +45,8 @@ struct iosm_trace { enum trace_ctrl_mode mode; }; +#ifdef CONFIG_WWAN_DEBUGFS + static inline bool ipc_is_trace_channel(struct iosm_imem *ipc_mem, u16 chl_id) { return ipc_mem->trace && ipc_mem->trace->chl_id == chl_id; @@ -52,5 +54,21 @@ static inline bool ipc_is_trace_channel(struct iosm_imem *ipc_mem, u16 chl_id) struct iosm_trace *ipc_trace_init(struct iosm_imem *ipc_imem); void ipc_trace_deinit(struct iosm_trace *ipc_trace); -void ipc_trace_port_rx(struct iosm_trace *ipc_trace, struct sk_buff *skb); +void ipc_trace_port_rx(struct iosm_imem *ipc_imem, struct sk_buff *skb); + +#else + +static inline bool ipc_is_trace_channel(struct iosm_imem *ipc_mem, u16 chl_id) +{ + return false; +} + +static inline void ipc_trace_port_rx(struct iosm_imem *ipc_imem, + struct sk_buff *skb) +{ + dev_kfree_skb(skb); +} + +#endif + #endif diff --git a/drivers/net/wwan/wwan_core.c b/drivers/net/wwan/wwan_core.c index 5bf62dc35ac7..1508dc2a497b 100644 --- a/drivers/net/wwan/wwan_core.c +++ b/drivers/net/wwan/wwan_core.c @@ -50,7 +50,9 @@ struct wwan_device { atomic_t port_id; const struct wwan_ops *ops; void *ops_ctxt; +#ifdef CONFIG_WWAN_DEBUGFS struct dentry *debugfs_dir; +#endif }; /** @@ -146,6 +148,7 @@ static struct wwan_device *wwan_dev_get_by_name(const char *name) return to_wwan_dev(dev); } +#ifdef CONFIG_WWAN_DEBUGFS struct dentry *wwan_get_debugfs_dir(struct device *parent) { struct wwan_device *wwandev; @@ -157,6 +160,7 @@ struct dentry *wwan_get_debugfs_dir(struct device *parent) return wwandev->debugfs_dir; } EXPORT_SYMBOL_GPL(wwan_get_debugfs_dir); +#endif /* This function allocates and registers a new WWAN device OR if a WWAN device * already exist for the given parent, it gets a reference and return it. @@ -166,7 +170,6 @@ EXPORT_SYMBOL_GPL(wwan_get_debugfs_dir); static struct wwan_device *wwan_create_dev(struct device *parent) { struct wwan_device *wwandev; - const char *wwandev_name; int err, id; /* The 'find-alloc-register' operation must be protected against @@ -206,9 +209,11 @@ static struct wwan_device *wwan_create_dev(struct device *parent) goto done_unlock; } - wwandev_name = kobject_name(&wwandev->dev.kobj); - wwandev->debugfs_dir = debugfs_create_dir(wwandev_name, - wwan_debugfs_dir); +#ifdef CONFIG_WWAN_DEBUGFS + wwandev->debugfs_dir = + debugfs_create_dir(kobject_name(&wwandev->dev.kobj), + wwan_debugfs_dir); +#endif done_unlock: mutex_unlock(&wwan_register_lock); @@ -240,7 +245,9 @@ static void wwan_remove_dev(struct wwan_device *wwandev) ret = device_for_each_child(&wwandev->dev, NULL, is_wwan_child); if (!ret) { +#ifdef CONFIG_WWAN_DEBUGFS debugfs_remove_recursive(wwandev->debugfs_dir); +#endif device_unregister(&wwandev->dev); } else { put_device(&wwandev->dev); @@ -1140,7 +1147,9 @@ static int __init wwan_init(void) goto destroy; } +#ifdef CONFIG_WWAN_DEBUGFS wwan_debugfs_dir = debugfs_create_dir("wwan", NULL); +#endif return 0; diff --git a/include/linux/wwan.h b/include/linux/wwan.h index 1646aa3e6779..e143c88bf4b0 100644 --- a/include/linux/wwan.h +++ b/include/linux/wwan.h @@ -171,6 +171,13 @@ int wwan_register_ops(struct device *parent, const struct wwan_ops *ops, void wwan_unregister_ops(struct device *parent); +#ifdef CONFIG_WWAN_DEBUGFS struct dentry *wwan_get_debugfs_dir(struct device *parent); +#else +static inline struct dentry *wwan_get_debugfs_dir(struct device *parent) +{ + return ERR_PTR(-ENODEV); +} +#endif #endif /* __WWAN_H */