Okay Take 2.
This patch is a little more invasive than my original approach. It adds
a new SERHND flag for debugger output. With this version any data
written to the console of dom0 or xen will get sent to the attached GDB
process. When gdb detaches console output goes back to the serial
console.
Feedback most welcome.
---
common/gdbstub.c | 28 +++++++++++++++++++++++++++-
drivers/char/console.c | 11 +++++++++++
drivers/char/serial.c | 5 +++++
include/asm-powerpc/debugger.h | 3 +++
include/xen/gdbstub.h | 2 ++
include/xen/serial.h | 5 +++++
6 files changed, 53 insertions(+), 1 deletion(-)
---
diff -r 9c4858991254 xen/common/gdbstub.c
--- a/xen/common/gdbstub.c Tue Aug 29 07:07:57 2006 -0400
+++ b/xen/common/gdbstub.c Fri Sep 01 13:40:19 2006 +1000
@@ -470,6 +470,30 @@ __gdb_ctx = {
};
static struct gdb_context *gdb_ctx = &__gdb_ctx;
+/* FIXME: does this need to be protected by a lock?
+ * Can it clobber another packet? */
+void
+debugger_puts(const char *str)
+{
+ char *p;
+
+ gdb_start_packet(gdb_ctx);
+ gdb_write_to_packet_char('O', gdb_ctx);
+
+ for(p=(char *)str; *p != '\x0'; p++) {
+ gdb_write_to_packet_char(hex2char((*p>>4) & 0x0f), gdb_ctx );
+ gdb_write_to_packet_char(hex2char((*p) & 0x0f), gdb_ctx );
+ }
+
+ gdb_send_packet(gdb_ctx);
+}
+
+int
+in_debugger(void)
+{
+ return gdb_ctx->currently_attached;
+}
+
/* trap handler: main entry point */
int
__trap_to_gdb(struct cpu_user_regs *regs, unsigned long cookie)
@@ -560,8 +584,10 @@ initialise_gdb(void)
initialise_gdb(void)
{
gdb_ctx->serhnd = serial_parse_handle(opt_gdb);
- if ( gdb_ctx->serhnd != -1 )
+ if ( gdb_ctx->serhnd != -1 ) {
+ serial_maybe_add_flags(gdb_ctx->serhnd, SERHND_DEBUGGER);
printk("GDB stub initialised.\n");
+ }
serial_start_sync(gdb_ctx->serhnd);
}
diff -r 9c4858991254 xen/drivers/char/console.c
--- a/xen/drivers/char/console.c Tue Aug 29 07:07:57 2006 -0400
+++ b/xen/drivers/char/console.c Fri Sep 01 13:40:19 2006 +1000
@@ -115,6 +115,17 @@ long read_console_ring(XEN_GUEST_HANDLE(
#define SERIAL_RX_MASK(_i) ((_i)&(SERIAL_RX_SIZE-1))
static char serial_rx_ring[SERIAL_RX_SIZE];
static unsigned int serial_rx_cons, serial_rx_prod;
+
+/* Enable debugger output on the serial console if it's the same
+ * port as the debugger */
+void serial_maybe_add_flags(int debugger_handle, int flags)
+{
+ /* If the debugger and the serial console differ only in
+ * whether SERHND_DEBUGGER is enabled, enable it for the console */
+ if ( (debugger_handle != -1 ) &&
+ (debugger_handle & ~flags) == sercon_handle )
+ sercon_handle |= flags;
+}
/* CTRL-<switch_char> switches input direction between Xen and DOM0. */
#define SWITCH_CODE (opt_conswitch[0]-'a'+1)
diff -r 9c4858991254 xen/drivers/char/serial.c
--- a/xen/drivers/char/serial.c Tue Aug 29 07:07:57 2006 -0400
+++ b/xen/drivers/char/serial.c Fri Sep 01 13:40:19 2006 +1000
@@ -14,6 +14,7 @@
#include <xen/sched.h>
#include <xen/mm.h>
#include <xen/serial.h>
+#include <asm/debugger.h> /* in_debugger() and debugger_puts() */
static struct serial_port com[2] = {
{ .rx_lock = SPIN_LOCK_UNLOCKED, .tx_lock = SPIN_LOCK_UNLOCKED },
@@ -153,6 +154,10 @@ void serial_puts(int handle, const char
if ( (handle == -1) || !port->driver || !port->driver->putc )
return;
+ if ( (handle & SERHND_DEBUGGER) && in_debugger() ) {
+ debugger_puts(s);
+ return;
+ }
spin_lock_irqsave(&port->tx_lock, flags);
diff -r 9c4858991254 xen/include/asm-powerpc/debugger.h
--- a/xen/include/asm-powerpc/debugger.h Tue Aug 29 07:07:57 2006 -0400
+++ b/xen/include/asm-powerpc/debugger.h Fri Sep 01 13:40:19 2006 +1000
@@ -39,6 +39,9 @@ static inline int debugger_trap_fatal(
#define debugger_trap_fatal(_v, _r) (0)
#define debugger_trap_immediate() ((void)0)
+#define debugger_puts(str) ((void)0)
+#define in_debugger() (0)
+
#endif /* CRASH_DEBUG */
#endif
diff -r 9c4858991254 xen/include/xen/gdbstub.h
--- a/xen/include/xen/gdbstub.h Tue Aug 29 07:07:57 2006 -0400
+++ b/xen/include/xen/gdbstub.h Fri Sep 01 13:40:19 2006 +1000
@@ -90,6 +90,8 @@ void gdb_arch_exit(struct cpu_user_regs
#define SIGTERM 15
void initialise_gdb(void);
+void debugger_puts(const char *str);
+int in_debugger(void);
#else
diff -r 9c4858991254 xen/include/xen/serial.h
--- a/xen/include/xen/serial.h Tue Aug 29 07:07:57 2006 -0400
+++ b/xen/include/xen/serial.h Fri Sep 01 13:40:19 2006 +1000
@@ -66,6 +66,7 @@ struct uart_driver {
#define SERHND_HI (1<<1) /* Mux/demux each transferred char by MSB. */
#define SERHND_LO (1<<2) /* Ditto, except that the MSB is cleared. */
#define SERHND_COOKED (1<<3) /* Newline/carriage-return translation? */
+#define SERHND_DEBUGGER (1<<4) /* Translate console messages for the debugger
*/
/* Two-stage initialisation (before/after IRQ-subsystem initialisation). */
void serial_init_preirq(void);
@@ -132,6 +133,10 @@ void ns16550_init(int index, struct ns16
/* Baud rate was pre-configured before invoking the UART driver. */
#define BAUD_AUTO (-1)
+/* Enable debuggger output if the serial console and debugger are on the same
+ * port */
+void serial_maybe_add_flags(int debugger_handle, int flags);
+
#endif /* __XEN_SERIAL_H__ */
/*
Yours Tony
linux.conf.au http://linux.conf.au/ || http://lca2007.linux.org.au/
Jan 15-20 2007 The Australian Linux Technical Conference!
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