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| 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/mm/fault.c | |
| parent | riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT (diff) | |
| download | linux-dev-c22b0bcb1dd024cb9caad9230e3a387d8b061df5.tar.xz linux-dev-c22b0bcb1dd024cb9caad9230e3a387d8b061df5.zip | |
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/mm/fault.c')
| -rw-r--r-- | arch/riscv/mm/fault.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c index 33d284188f9a..1da870f33582 100644 --- a/arch/riscv/mm/fault.c +++ b/arch/riscv/mm/fault.c @@ -13,6 +13,7 @@ #include <linux/perf_event.h> #include <linux/signal.h> #include <linux/uaccess.h> +#include <linux/kprobes.h> #include <asm/ptrace.h> #include <asm/tlbflush.h> @@ -213,6 +214,9 @@ asmlinkage void do_page_fault(struct pt_regs *regs) tsk = current; mm = tsk->mm; + if (kprobe_page_fault(regs, cause)) + return; + /* * Fault-in kernel-space virtual memory on-demand. * The 'reference' page table is init_mm.pgd. |