kgdb: enable arch to support XML packet.

The XML packet could be supported by required architecture if the
architecture defines CONFIG_HAVE_ARCH_KGDB_QXFER_PKT and implement its own
kgdb_arch_handle_qxfer_pkt(). Except for the kgdb_arch_handle_qxfer_pkt(),
the architecture also needs to record the feature supported by gdb stub
into the kgdb_arch_gdb_stub_feature, and these features will be reported
to host gdb when gdb stub receives the qSupported packet.

Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h
index 529116b0cabe2879ff95ca027cd8848394795f00..0e4e3a80d58c86440febed3ba842f40ece438dfb 100644 (file)
--- a/include/linux/kgdb.h
+++ b/include/linux/kgdb.h
@@ -176,6 +176,17 @@ kgdb_arch_handle_exception(int vector, int signo, int err_code,
                           char *remcom_out_buffer,
                           struct pt_regs *regs);
 
+/**
+ *     kgdb_arch_handle_qxfer_pkt - Handle architecture specific GDB XML
+ *                                  packets.
+ *     @remcom_in_buffer: The buffer of the packet we have read.
+ *     @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
+ */
+
+extern void
+kgdb_arch_handle_qxfer_pkt(char *remcom_in_buffer,
+                          char *remcom_out_buffer);
+
 /**
  *     kgdb_call_nmi_hook - Call kgdb_nmicallback() on the current CPU
  *     @ignored: This parameter is only here to match the prototype.

diff --git a/kernel/debug/gdbstub.c b/kernel/debug/gdbstub.c
index 61774aec46b4c8ee90f60daa384db9f7a9625d60..a790026e42d01006d8c9107e0a6cb303ba818023 100644 (file)
--- a/kernel/debug/gdbstub.c
+++ b/kernel/debug/gdbstub.c
@@ -792,6 +792,19 @@ static void gdb_cmd_query(struct kgdb_state *ks)
                }
                break;
 #endif
+#ifdef CONFIG_HAVE_ARCH_KGDB_QXFER_PKT
+       case 'S':
+               if (!strncmp(remcom_in_buffer, "qSupported:", 11))
+                       strcpy(remcom_out_buffer, kgdb_arch_gdb_stub_feature);
+               break;
+       case 'X':
+               if (!strncmp(remcom_in_buffer, "qXfer:", 6))
+                       kgdb_arch_handle_qxfer_pkt(remcom_in_buffer,
+                                                  remcom_out_buffer);
+               break;
+#endif
+       default:
+               break;
        }
 }
 

diff --git a/lib/Kconfig.kgdb b/lib/Kconfig.kgdb
index ffa7a76de08604f38ecdd2ee874d8f77cf3ddd7d..256f2486f9bd2f4d0dd0ef603df4955465836417 100644 (file)
--- a/lib/Kconfig.kgdb
+++ b/lib/Kconfig.kgdb
@@ -3,6 +3,11 @@
 config HAVE_ARCH_KGDB
        bool
 
+# set if architecture has the its kgdb_arch_handle_qxfer_pkt
+# function to enable gdb stub to address XML packet sent from GDB.
+config HAVE_ARCH_KGDB_QXFER_PKT
+       bool
+
 menuconfig KGDB
        bool "KGDB: kernel debugger"
        depends on HAVE_ARCH_KGDB