[GIT PULL] V2 kdb / early debug (2 of 2) for 2.6.34
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From: Jason Wessel on 1 Mar 2010 00:20 Linus please pull the dbg-early-merge tree which merges in the capability for early debugging for the x86 architecture. git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb.git dbg-early-merge --- Notes for Linus --- V2 of the pull request contains no changes other than to rebase on top of the kdb-merge branch. I did not receive acks or feedback from any x86 maintainers at this point for the early trap changes. These changes came from the archives from 2 years back, before the time the mainline kernel I/O drivers supported early debugger access. I did not receive acks or feedback on the changes to arch/x86/kernel/cpu/common.c which covers the initial setup of the debug registers. This change is a fix vs a feature. --- End Notes for Linus --- This patch set stacks on top of the kgdb / kdb patches and focuses on allowing the kernel debugger to activate at the same time earlyprintk becomes available. Right now early debugging is only available on x86, but the API in the debug core is generic. The only thing lacking for other architecture support is appropriate atomic safe polled I/O drivers. The first few patches address the problems in kdb and the architecture specific x86 kgdb implementation which rely on services which are not available before the kernel memory allocators are setup. The patch set includes early debug support for vga + non-USB keyboard and dbgp devices. For the vga case, it only works with kdb. For example, you could boot your kernel and optionally include kgdbwait as follows: earlyprintk=vga ekgboc=kbd kgdbwait That will stop the kernel somewhere inside setup_arch() and you can plant breakpoints, modify memory and backtrace. If you omit the kgdbwait, the kgdb shell prompt will appear on the vga console only if there is a kernel fault. The final 2 patches in the series add support for the EHCI usb debug port when using a dbgp device. You have the choice of using earlyprintk= or using only the kernel debugger on the debug port. You can also use either kgdb or kdb with this connection. Here are two example kernel boot argument lines: 1) Used in conjunction with earlyprintk on usb debug port 1 earlyprintk=dbgp1,keep kgdbdbgp=1 kgdbwait 2) Allow for the capability to break into the kernel with control-c on usb debug port 0 kgdbdbp=0,1 kgdbwait A patch to add formal documentation to the kgdb docbook for these new features will be available for the 2.6.34 cycle, because there are a number of other ways you can make use of these features not described here. Thanks, Jason. --- The following changes since commit e0e11596e21a9af6ae263613bd5b747fe2bdfde9: Jason Wessel (1): debug_core: Turn off tracing while in the debugger are available in the git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb.git dbg-early-merge Jan Kiszka (1): x86, kgdb: early trap init for early debug Jason Wessel (7): x86, kgdb, init: Add early and late debug states x86,kgdb: Implement early hardware breakpoint debugging x86,early dr regs,kgdb: Allow kernel debugger early dr register access kgdboc: Add ekgdboc for early use of the kernel debugger earlyprintk,vga,kdb: Fix \b and \r for earlyprintk=vga with kdb ehci-dbgp: split PID register updates for IN and OUT pipes echi-dbgp: Add kernel debugger support for the usb debug port Documentation/kernel-parameters.txt | 17 +++ arch/x86/include/asm/processor.h | 2 + arch/x86/kernel/cpu/common.c | 29 +++--- arch/x86/kernel/early_printk.c | 8 ++ arch/x86/kernel/kgdb.c | 47 +++++++-- arch/x86/kernel/setup.c | 1 + arch/x86/kernel/traps.c | 14 ++- drivers/serial/kgdboc.c | 19 ++++ drivers/usb/early/ehci-dbgp.c | 184 ++++++++++++++++++++++++++--------- include/linux/kgdb.h | 14 +++ init/main.c | 4 +- kernel/debug/debug_core.c | 16 +++ 12 files changed, 281 insertions(+), 74 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |