v2 -> v3 - Moved step_needed from uapi structure to kernel only structure - Re-enable interrupt if stepped instruction faults - Modified register_wide_hw_breakpoint() to accept step_needed arg v2 was here: http://marc.info/?l=linux-arm-kernel&m=149942910730496&w=2
v1 -> v2: - patch 1 of v1 has been modified to patch 1-3 of v2. - Introduced a new event attribute step_needed and implemented hw_breakpoint_needs_single_step() (patch 1) - Replaced usage of is_default_overflow_handler() with hw_breakpoint_needs_single_step(). (patch 2) - Modified sample test to set set step_needed bit field (patch 3) v1 was here: http://marc.info/?l=linux-arm-kernel&m=149910958418708&w=2 samples/hw_breakpoint/data_breakpoint.c passes with x86_64 but fails with ARM64. Even though it has been NAKed previously on upstream [1, 2], I have tried to come up with patches which can resolve it for ARM64 as well. I noticed that even perf step exception can go into an infinite loop if CPU receives an interrupt while executing breakpoint/watchpoint handler. So, event though we are not concerned about above test, we will have to find a solution for the perf issue. This patchset attempts to resolve both the issue. Please review. Since, it also takes care of SW breakpoint, so I hope kgdb should also be fine. However, I have not tested that. @Takahiro: Will it be possible to test these patches for kgdb. [1] http://marc.info/?l=linux-arm-kernel&m=149580777524910&w=2 [2] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-April/425266.html Pratyush Anand (5): hw_breakpoint: Add step_needed event attribute arm64: use hw_breakpoint_needs_single_step() to decide if step is needed register_wide_hw_breakpoint(): modify to accept step_needed arg arm64: disable irq between breakpoint and step exception arm64: fault: re-enable irq if it was disabled for single stepping arch/arm64/kernel/debug-monitors.c | 3 +++ arch/arm64/kernel/hw_breakpoint.c | 10 +++++----- arch/arm64/mm/fault.c | 28 ++++++++++++++++++++++++---- arch/x86/kernel/kgdb.c | 2 +- include/linux/hw_breakpoint.h | 10 ++++++++-- include/linux/perf_event.h | 6 ++++++ kernel/events/core.c | 2 ++ kernel/events/hw_breakpoint.c | 4 +++- samples/hw_breakpoint/data_breakpoint.c | 3 ++- 9 files changed, 54 insertions(+), 14 deletions(-) -- 2.9.4
