From 9731191f75a54c4fa17e9b9b88f3144cf4b47836 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Thu, 20 May 2010 21:04:30 -0500 Subject: kgdboc: Add ekgdboc for early use of the kernel debugger The ekgdboc= differs from kgdboc= in that you can begin debuggin as soon as the exceptions are setup and the kgdb I/O driver is available, instead of waiting until the tty subsystem is available. CC: kgdb-bugreport@lists.sourceforge.net Signed-off-by: Jason Wessel --- Documentation/kernel-parameters.txt | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index bdce359..4c44d01 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -713,6 +713,12 @@ and is between 256 and 4096 characters. It is defined in the file The VGA output is eventually overwritten by the real console. + ekgdboc= [X86,KGDB] Allow early kernel console debugging + ekgdboc=kbd + + This is desgined to be used in conjunction with + the boot argument: earlyprintk=vga + eata= [HW,SCSI] edd= [EDD] -- cgit v1.1 From 4fe1da4ebc18c4c42fa56c228447f68033fce5f0 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Thu, 20 May 2010 21:04:31 -0500 Subject: echi-dbgp: Add kernel debugger support for the usb debug port This patch adds the capability to use the usb debug port with the kernel debugger. It is also still possible to use this functionality with or without the earlyprintk=dbgpX. It is possible to use the kgdbwait boot argument to debug very early in the kernel start up code. There are two ways to use this driver extension with a kernel boot argument. 1) kgdbdbgp=# -- Where # is the number of the usb debug controller You must use sysrq-g to break into the kernel debugger on another connection type other than the dbgp. 2) kgdbdbgp=#debugControlNum#,#Seconds# In this mode, the usb debug port is polled every #Seconds# for character input. It is possible to use gdb or press control-c to break into the kernel debugger. From the implementation perspective there are 3 high level changes. 1) Allow variable retries for the the hardware via dbgp_bulk_read(). The amount of retries for the dbgp_bulk_read() needed to be variable instead of fixed. We do not want to poll at all when the kernel is operating in interrupt driven mode. The polling only occurs if the kernel was booted when specifying some number of seconds via the kgdbdbgp boot argument (IE kgdbdbgp=0,1). In this case the loop count is reduced to 1 so as introduce the smallest amount of latency as possible. 2) Save the bulk IN endpoint address for use by the kgdb code. 3) The addition of the kgdb interface code. This consisted of adding in a character read function for the dbgp as well as a polling thread to allow the dbgp to interrupt the kernel execution. The rest is the typical kgdb I/O api. CC: Eric Biederman CC: Yinghai Lu CC: linux-usb@vger.kernel.org Signed-off-by: Jason Wessel Acked-by: Greg Kroah-Hartman --- Documentation/kernel-parameters.txt | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 4c44d01..f5fce48 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1127,6 +1127,17 @@ and is between 256 and 4096 characters. It is defined in the file use the HighMem zone if it exists, and the Normal zone if it does not. + kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port. + Format: [,poll interval] + The controller # is the number of the ehci usb debug + port as it is probed via PCI. The poll interval is + optional and is the number seconds in between + each poll cycle to the debug port in case you need + the functionality for interrupting the kernel with + gdb or control-c on the dbgp connection. When + not using this parameter you use sysrq-g to break into + the kernel debugger. + kgdboc= [KGDB,HW] kgdb over consoles. Requires a tty driver that supports console polling, or a supported polling keyboard driver (non-usb). -- cgit v1.1