linux-dev/arch/riscv/kernel/probes/Makefile, branch master

riscv: Add uprobes supported

2021-01-14T23:09:08Z

This patch adds support for uprobes on riscv architecture. Just like kprobe, it support single-step and simulate instructions. Signed-off-by: Guo Ren Reviewed-by: Pekka Enberg Cc: Oleg Nesterov Cc: Masami Hiramatsu Cc: Palmer Dabbelt Signed-off-by: Palmer Dabbelt

riscv: Add KPROBES_ON_FTRACE supported

2021-01-14T23:09:07Z

This patch adds support for kprobes on ftrace call sites to avoids much of the overhead with regular kprobes. Try it with simple steps: echo 'p:myprobe sys_clone a0=%a0 a1=%a1 stack_val=+4($stack)' > /sys/kernel/de bug/tracing/kprobe_events echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable cat /sys/kernel/debug/tracing/trace tracer: nop entries-in-buffer/entries-written: 1/1 #P:1 _-----=> irqs-off / _----=> need-resched | / _---=> hardirq/softirq || / _--=> preempt-depth ||| / delay TASK-PID CPU# |||| TIMESTAMP FUNCTION | | | |||| | | sh-92 [000] .... 369.899962: myprobe: (sys_clone+0x0/0x28) a0=0x1200011 a1=0x0 stack_val=0x201c20ffffffe0 cat /sys/kernel/debug/kprobes/list ffffffe00020b584 k sys_clone+0x0 [FTRACE] ^^^^^^ Signed-off-by: Guo Ren Reviewed-by: Masami Hiramatsu Signed-off-by: Palmer Dabbelt

riscv: Add kprobes supported

2021-01-14T23:09:06Z

This patch enables "kprobe & kretprobe" to work with ftrace interface. It utilized software breakpoint as single-step mechanism. Some instructions which can't be single-step executed must be simulated in kernel execution slot, such as: branch, jal, auipc, la ... Some instructions should be rejected for probing and we use a blacklist to filter, such as: ecall, ebreak, ... We use ebreak & c.ebreak to replace origin instruction and the kprobe handler prepares an executable memory slot for out-of-line execution with a copy of the original instruction being probed. In execution slot we add ebreak behind original instruction to simulate a single-setp mechanism. The patch is based on packi's work [1] and csky's work [2]. - The kprobes_trampoline.S is all from packi's patch - The single-step mechanism is new designed for riscv without hw single-step trap - The simulation codes are from csky - Frankly, all codes refer to other archs' implementation [1] https://lore.kernel.org/linux-riscv/20181113195804.22825-1-me@packi.ch/ [2] https://lore.kernel.org/linux-csky/20200403044150.20562-9-guoren@kernel.org/ Signed-off-by: Guo Ren Co-developed-by: Patrick Stählin Signed-off-by: Patrick Stählin Acked-by: Masami Hiramatsu Tested-by: Zong Li Reviewed-by: Pekka Enberg Cc: Patrick Stählin Cc: Palmer Dabbelt Cc: Björn Töpel Signed-off-by: Palmer Dabbelt