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| author | Guo Ren <guoren@linux.alibaba.com> | 2020-12-17 17:01:43 +0100 |
|---|---|---|
| committer | Palmer Dabbelt <palmerdabbelt@google.com> | 2021-01-15 00:09:07 +0100 |
| commit | 829adda597fef2fe133d57aac681580b2e292268 (patch) | |
| tree | 0ca66d624983c00e839577749116e4d6c0a19359 /arch/riscv/Kconfig | |
| parent | riscv: Add kprobes supported (diff) | |
| download | linux-829adda597fef2fe133d57aac681580b2e292268.tar.xz linux-829adda597fef2fe133d57aac681580b2e292268.zip | |
riscv: Add KPROBES_ON_FTRACE supported
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 <guoren@linux.alibaba.com>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Diffstat (limited to 'arch/riscv/Kconfig')
| -rw-r--r-- | arch/riscv/Kconfig | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 375f6f4d3038..07a48068567e 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -72,6 +72,7 @@ config RISCV select HAVE_GENERIC_VDSO if MMU && 64BIT select HAVE_IRQ_TIME_ACCOUNTING select HAVE_KPROBES + select HAVE_KPROBES_ON_FTRACE select HAVE_KRETPROBES select HAVE_PCI select HAVE_PERF_EVENTS |