lwn.git/arch/csky/kernel/probes/kprobes.c, branch header-removal

arch/csky/kernel/probes/kprobes.c: fix bugon.cocci warnings

2021-09-03T16:58:09+00:00

Use BUG_ON instead of a if condition followed by BUG. Generated by: scripts/coccinelle/misc/bugon.cocci Link: https://lkml.kernel.org/r/alpine.DEB.2.22.394.2107061049150.7197@hadrien Fixes: 7d37cb2c912d ("lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTERS") Signed-off-by: kernel test robot Signed-off-by: Julia Lawall Reported-by: kernel test robot Cc: Julian Braha Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kprobes: Do not increment probe miss count in the fault handler

2021-06-03T13:47:26+00:00

Kprobes has a counter 'nmissed', that is used to count the number of times a probe handler was not called. This generally happens when we hit a kprobe while handling another kprobe. However, if one of the probe handlers causes a fault, we are currently incrementing 'nmissed'. The comment in fault handler indicates that this can be used to account faults taken by the probe handlers. But, this has never been the intention as is evident from the comment above 'nmissed' in 'struct kprobe': /*count the number of times this probe was temporarily disarmed */ unsigned long nmissed; Signed-off-by: Naveen N. Rao Signed-off-by: Peter Zijlstra (Intel) Acked-by: Masami Hiramatsu Link: https://lkml.kernel.org/r/20210601120150.672652-1-naveen.n.rao@linux.vnet.ibm.com

kprobes: Remove kprobe::fault_handler

2021-06-01T14:00:08+00:00

The reason for kprobe::fault_handler(), as given by their comment: * We come here because instructions in the pre/post * handler caused the page_fault, this could happen * if handler tries to access user space by * copy_from_user(), get_user() etc. Let the * user-specified handler try to fix it first. Is just plain bad. Those other handlers are ran from non-preemptible context and had better use _nofault() functions. Also, there is no upstream usage of this. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Christoph Hellwig Acked-by: Masami Hiramatsu Link: https://lore.kernel.org/r/20210525073213.561116662@infradead.org

csky: kprobes: Use generic kretprobe trampoline handler

2020-09-08T09:52:33+00:00

Use the generic kretprobe trampoline handler. Don't use framepointer verification. Signed-off-by: Masami Hiramatsu Signed-off-by: Ingo Molnar Acked-by: Guo Ren Link: https://lore.kernel.org/r/159870605775.1229682.2627276871589951304.stgit@devnote2

csky: Add kprobes supported

2020-04-03T03:14:17+00:00

This patch enable kprobes, kretprobes, ftrace interface. It utilized software breakpoint and single step debug exceptions, instructions simulation on csky. We use USR_BKPT replace origin instruction, and the kprobe handler prepares an excutable memory slot for out-of-line execution with a copy of the original instruction being probed. Most of instructions could be executed by single-step, but some instructions need origin pc value to execute and we need software simulate these instructions. Signed-off-by: Guo Ren Cc: Arnd Bergmann Cc: Steven Rostedt (VMware)