diff options
| author | Guo Ren <guoren@linux.alibaba.com> | 2020-12-17 16:01:42 +0000 |
|---|---|---|
| committer | Palmer Dabbelt <palmerdabbelt@google.com> | 2021-01-14 15:09:06 -0800 |
| commit | c22b0bcb1dd024cb9caad9230e3a387d8b061df5 (patch) | |
| tree | f35a8b91116cb256acdcdd85939c6f06dc967bb9 /arch/riscv/kernel/traps.c | |
| parent | afc76b8b80112189b6f11e67e19cf58301944814 (diff) | |
riscv: Add kprobes supported
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 <guoren@linux.alibaba.com>
Co-developed-by: Patrick Stählin <me@packi.ch>
Signed-off-by: Patrick Stählin <me@packi.ch>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Zong Li <zong.li@sifive.com>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Cc: Patrick Stählin <me@packi.ch>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Björn Töpel <bjorn.topel@gmail.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Diffstat (limited to 'arch/riscv/kernel/traps.c')
| -rw-r--r-- | arch/riscv/kernel/traps.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c index ad14f4466d92..19a788a271f7 100644 --- a/arch/riscv/kernel/traps.c +++ b/arch/riscv/kernel/traps.c @@ -12,6 +12,7 @@ #include <linux/signal.h> #include <linux/kdebug.h> #include <linux/uaccess.h> +#include <linux/kprobes.h> #include <linux/mm.h> #include <linux/module.h> #include <linux/irq.h> @@ -145,6 +146,14 @@ static inline unsigned long get_break_insn_length(unsigned long pc) asmlinkage __visible void do_trap_break(struct pt_regs *regs) { +#ifdef CONFIG_KPROBES + if (kprobe_single_step_handler(regs)) + return; + + if (kprobe_breakpoint_handler(regs)) + return; +#endif + if (user_mode(regs)) force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->epc); #ifdef CONFIG_KGDB |