From: Vijaya Kumar K Vijaya.Kumar@caviumnetworks.com
Based on the step-handler and break-handler hooks patch from Sandeepa, KGDB debugging support is added for EL1 debug in AArch64 mode.
In first patch, PSTATE.D is set correctly
In second patch,register layout is updated to be inline with GDB tool. Basic GDB connection, break point set/clear and info commands are supported except step/next debugging
With second patch, step/next debugging support is added, where in pc is updated to point to the instruction to be stepped and stopped.
With third patch, the compile time breakpoint instruction reordering is fixed by making kgbd_breakpoint() as noinline
Tested with ARM64 simulator
v7: - Changes made to set PSTATE.D properly - Performed KGDB boot tests - Fixed compilation warnings in driver/misc/kgbdts.c
Results:
kgdb boot test:
[32927.237895] Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled [32927.266066] kgdb: Registered I/O driver kgdbts. [32927.266419] kgdb: Waiting for connection from remote gdb... [32927.268598] kgdbts:RUN plant and detach test [32927.270683] kgdbts:RUN sw breakpoint test [32927.287659] kgdbts:RUN bad memory access test [32927.290322] kgdbts:RUN singlestep test 1000 iterations [32927.330342] kgdbts:RUN singlestep [0/1000] [32931.286356] kgdbts:RUN singlestep [100/1000] [32935.242536] kgdbts:RUN singlestep [200/1000] [32939.205392] kgdbts:RUN singlestep [300/1000] [32943.169522] kgdbts:RUN singlestep [400/1000] [32947.231868] kgdbts:RUN singlestep [500/1000] [32951.188008] kgdbts:RUN singlestep [600/1000] [32955.332243] kgdbts:RUN singlestep [700/1000] [32959.467109] kgdbts:RUN singlestep [800/1000] [32963.430888] kgdbts:RUN singlestep [900/1000] [32967.346992] kgdbts:RUN do_fork for 100 breakpoints
kgdb test from sysfs:
~ # echo V1F1000 > /sys/module/kgdbts/parameters/kgdbts [33231.554237] kgdb: Registered I/O driver kgdbts. [33231.554677] kgdbts:RUN plant and detach test [33231.557072] kgdbts:RUN sw breakpoint test [33231.576980] kgdbts:RUN bad memory access test [33231.580022] kgdbts:RUN singlestep test 1000 iterations [33231.627056] kgdbts:RUN singlestep [0/1000] [33235.954027] kgdbts:RUN singlestep [100/1000] [33240.429086] kgdbts:RUN singlestep [200/1000] [33244.687118] kgdbts:RUN singlestep [300/1000] [33248.945191] kgdbts:RUN singlestep [400/1000] [33253.203751] kgdbts:RUN singlestep [500/1000] [33257.462019] kgdbts:RUN singlestep [600/1000] [33261.817809] kgdbts:RUN singlestep [700/1000] [33266.081268] kgdbts:RUN singlestep [800/1000] [33270.339813] kgdbts:RUN singlestep [900/1000] [33274.712404] kgdbts:RUN do_fork for 1000 breakpoints ~ #
v6: - Change pstate register to 8 bytes to make endian nuetral. Use GDB below GDB patch to display pstate in Big endian mode. https://sourceware.org/ml/gdb-patches/2013-12/msg00720.html Thanks to Andrew.
v5: - Updated BRK #imm16 value to 0x400 & 0x401 as per recommendation as per Marcus recommendataion http://patchwork.ozlabs.org/patch/290801/ - Rebased to 3.13 AArch64 kernel
v4: - Updated kgdb_single_step and kgdb_cpu_doing_single_step variables properly based on gdb state
v3: - Rebased to v4 version of Sandeepa Prabhu's patch (patch 1) - Made dynamic break point instruction encoding generic - Made ESR value encoding generic for dynamic and compile break point - Used memcpy and memset to copy register contents to gdb buffer - Fixed reordering of break point instruction by compiler with patch 3 - Rebased against AAach64 upstream kernel
v2: - Moved break instruction encoding to debug-monitors.h file - Fixed endianess of compile break instruction encoding - Updated I/O buffer sizes - Updated register buffer size - Remove changes to debug_exception handler in entry.S for - ELR update and step debugging with update pc instead of ELR - Rebased against AArch64 upstream kernel
v1: - Initial patch-set
Vijaya Kumar K (6): arm64: Add macros to manage processor debug state arm64: KGDB: Add Basic KGDB support arm64: KGDB: Add step debugging support KGDB: make kgdb_breakpoint() as noinline misc: debug: remove compilation warnings arm64: KGDB: Add KGDB config
arch/arm64/Kconfig | 1 + arch/arm64/include/asm/debug-monitors.h | 65 ++++-- arch/arm64/include/asm/irqflags.h | 22 ++ arch/arm64/include/asm/kgdb.h | 84 ++++++++ arch/arm64/kernel/Makefile | 1 + arch/arm64/kernel/debug-monitors.c | 3 +- arch/arm64/kernel/kgdb.c | 336 +++++++++++++++++++++++++++++++ drivers/misc/kgdbts.c | 12 +- kernel/debug/debug_core.c | 2 +- 9 files changed, 502 insertions(+), 24 deletions(-) create mode 100644 arch/arm64/include/asm/kgdb.h create mode 100644 arch/arm64/kernel/kgdb.c