Bluetooth: Introduce debug feature when dynamic debug is disabled

In case dynamic debug is disabled, this feature allows a vendor platform
to provide debug statement printing.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>

diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
index 3fa7b1e..1819005 100644 (file)
--- a/include/net/bluetooth/bluetooth.h
+++ b/include/net/bluetooth/bluetooth.h
@@ -153,6 +153,12 @@ __printf(1, 2)
 void bt_warn(const char *fmt, ...);
 __printf(1, 2)
 void bt_err(const char *fmt, ...);
+#if IS_ENABLED(CONFIG_BT_FEATURE_DEBUG)
+void bt_dbg_set(bool enable);
+bool bt_dbg_get(void);
+__printf(1, 2)
+void bt_dbg(const char *fmt, ...);
+#endif
 __printf(1, 2)
 void bt_warn_ratelimited(const char *fmt, ...);
 __printf(1, 2)
@@ -161,7 +167,12 @@ void bt_err_ratelimited(const char *fmt, ...);
 #define BT_INFO(fmt, ...)      bt_info(fmt "\n", ##__VA_ARGS__)
 #define BT_WARN(fmt, ...)      bt_warn(fmt "\n", ##__VA_ARGS__)
 #define BT_ERR(fmt, ...)       bt_err(fmt "\n", ##__VA_ARGS__)
+
+#if IS_ENABLED(CONFIG_BT_FEATURE_DEBUG)
+#define BT_DBG(fmt, ...)       bt_dbg(fmt "\n", ##__VA_ARGS__)
+#else
 #define BT_DBG(fmt, ...)       pr_debug(fmt "\n", ##__VA_ARGS__)
+#endif
 
 #define bt_dev_info(hdev, fmt, ...)                            \
        BT_INFO("%s: " fmt, (hdev)->name, ##__VA_ARGS__)

diff --git a/net/bluetooth/Kconfig b/net/bluetooth/Kconfig
index 9e25c65..1d6d243 100644 (file)
--- a/net/bluetooth/Kconfig
+++ b/net/bluetooth/Kconfig
@@ -135,4 +135,11 @@ config BT_SELFTEST_SMP
          Run test cases for SMP cryptographic functionality, including both
          legacy SMP as well as the Secure Connections features.
 
+config BT_FEATURE_DEBUG
+       bool "Enable runtime option for debugging statements"
+       depends on BT && !DYNAMIC_DEBUG
+       help
+         This provides an option to enable/disable debugging statements
+         at runtime via the experimental features interface.
+
 source "drivers/bluetooth/Kconfig"

diff --git a/net/bluetooth/lib.c b/net/bluetooth/lib.c
index c09e0a3..5326f41 100644 (file)
--- a/net/bluetooth/lib.c
+++ b/net/bluetooth/lib.c
@@ -183,6 +183,39 @@ void bt_err(const char *format, ...)
 }
 EXPORT_SYMBOL(bt_err);
 
+#ifdef CONFIG_BT_FEATURE_DEBUG
+static bool debug_enable;
+
+void bt_dbg_set(bool enable)
+{
+       debug_enable = enable;
+}
+
+bool bt_dbg_get(void)
+{
+       return debug_enable;
+}
+
+void bt_dbg(const char *format, ...)
+{
+       struct va_format vaf;
+       va_list args;
+
+       if (likely(!debug_enable))
+               return;
+
+       va_start(args, format);
+
+       vaf.fmt = format;
+       vaf.va = &args;
+
+       printk(KERN_DEBUG pr_fmt("%pV"), &vaf);
+
+       va_end(args);
+}
+EXPORT_SYMBOL(bt_dbg);
+#endif
+
 void bt_warn_ratelimited(const char *format, ...)
 {
        struct va_format vaf;

diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 3c6be70..9e8a3cc 100644 (file)
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -3715,6 +3715,14 @@ static int read_security_info(struct sock *sk, struct hci_dev *hdev,
                                 rp, sizeof(*rp) + sec_len);
 }
 
+#ifdef CONFIG_BT_FEATURE_DEBUG
+/* d4992530-b9ec-469f-ab01-6c481c47da1c */
+static const u8 debug_uuid[16] = {
+       0x1c, 0xda, 0x47, 0x1c, 0x48, 0x6c, 0x01, 0xab,
+       0x9f, 0x46, 0xec, 0xb9, 0x30, 0x25, 0x99, 0xd4,
+};
+#endif
+
 static int read_exp_features_info(struct sock *sk, struct hci_dev *hdev,
                                  void *data, u16 data_len)
 {
@@ -3726,6 +3734,16 @@ static int read_exp_features_info(struct sock *sk, struct hci_dev *hdev,
 
        memset(&buf, 0, sizeof(buf));
 
+#ifdef CONFIG_BT_FEATURE_DEBUG
+       if (!hdev) {
+               u32 flags = bt_dbg_get() ? BIT(0) : 0;
+
+               memcpy(rp->features[idx].uuid, debug_uuid, 16);
+               rp->features[idx].flags = cpu_to_le32(flags);
+               idx++;
+       }
+#endif
+
        rp->feature_count = cpu_to_le16(idx);
 
        /* After reading the experimental features information, enable
@@ -3738,6 +3756,21 @@ static int read_exp_features_info(struct sock *sk, struct hci_dev *hdev,
                                 0, rp, sizeof(*rp) + (20 * idx));
 }
 
+#ifdef CONFIG_BT_FEATURE_DEBUG
+static int exp_debug_feature_changed(bool enabled, struct sock *skip)
+{
+       struct mgmt_ev_exp_feature_changed ev;
+
+       memset(&ev, 0, sizeof(ev));
+       memcpy(ev.uuid, debug_uuid, 16);
+       ev.flags = cpu_to_le32(enabled ? BIT(0) : 0);
+
+       return mgmt_limited_event(MGMT_EV_EXP_FEATURE_CHANGED, NULL,
+                                 &ev, sizeof(ev),
+                                 HCI_MGMT_EXP_FEATURE_EVENTS, skip);
+}
+#endif
+
 static int set_exp_feature(struct sock *sk, struct hci_dev *hdev,
                           void *data, u16 data_len)
 {
@@ -3750,6 +3783,17 @@ static int set_exp_feature(struct sock *sk, struct hci_dev *hdev,
                memset(rp.uuid, 0, 16);
                rp.flags = cpu_to_le32(0);
 
+#ifdef CONFIG_BT_FEATURE_DEBUG
+               if (!hdev) {
+                       bool changed = bt_dbg_get();
+
+                       bt_dbg_set(false);
+
+                       if (changed)
+                               exp_debug_feature_changed(false, sk);
+               }
+#endif
+
                hci_sock_set_flag(sk, HCI_MGMT_EXP_FEATURE_EVENTS);
 
                return mgmt_cmd_complete(sk, hdev ? hdev->id : MGMT_INDEX_NONE,
@@ -3757,6 +3801,49 @@ static int set_exp_feature(struct sock *sk, struct hci_dev *hdev,
                                         &rp, sizeof(rp));
        }
 
+#ifdef CONFIG_BT_FEATURE_DEBUG
+       if (!memcmp(cp->uuid, debug_uuid, 16)) {
+               bool val, changed;
+               int err;
+
+               /* Command requires to use the non-controller index */
+               if (hdev)
+                       return mgmt_cmd_status(sk, hdev->id,
+                                              MGMT_OP_SET_EXP_FEATURE,
+                                              MGMT_STATUS_INVALID_INDEX);
+
+               /* Parameters are limited to a single octet */
+               if (data_len != MGMT_SET_EXP_FEATURE_SIZE + 1)
+                       return mgmt_cmd_status(sk, MGMT_INDEX_NONE,
+                                              MGMT_OP_SET_EXP_FEATURE,
+                                              MGMT_STATUS_INVALID_PARAMS);
+
+               /* Only boolean on/off is supported */
+               if (cp->param[0] != 0x00 && cp->param[0] != 0x01)
+                       return mgmt_cmd_status(sk, MGMT_INDEX_NONE,
+                                              MGMT_OP_SET_EXP_FEATURE,
+                                              MGMT_STATUS_INVALID_PARAMS);
+
+               val = !!cp->param[0];
+               changed = val ? !bt_dbg_get() : bt_dbg_get();
+               bt_dbg_set(val);
+
+               memcpy(rp.uuid, debug_uuid, 16);
+               rp.flags = cpu_to_le32(val ? BIT(0) : 0);
+
+               hci_sock_set_flag(sk, HCI_MGMT_EXP_FEATURE_EVENTS);
+
+               err = mgmt_cmd_complete(sk, MGMT_INDEX_NONE,
+                                       MGMT_OP_SET_EXP_FEATURE, 0,
+                                       &rp, sizeof(rp));
+
+               if (changed)
+                       exp_debug_feature_changed(val, sk);
+
+               return err;
+       }
+#endif
+
        return mgmt_cmd_status(sk, hdev ? hdev->id : MGMT_INDEX_NONE,
                               MGMT_OP_SET_EXP_FEATURE,
                               MGMT_STATUS_NOT_SUPPORTED);