lkml.org 
[lkml]   [2020]   [Jul]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v3 3/7] riscv: Fixup kprobes handler couldn't change pc
    Date
    From: Guo Ren <guoren@linux.alibaba.com>

    The "Changing Execution Path" section in the Documentation/kprobes.txt
    said:

    Since kprobes can probe into a running kernel code, it can change the
    register set, including instruction pointer.

    Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
    Cc: Masami Hiramatsu <mhiramat@kernel.org>
    Cc: Palmer Dabbelt <palmerdabbelt@google.com>
    ---
    arch/riscv/kernel/mcount-dyn.S | 3 ++-
    1 file changed, 2 insertions(+), 1 deletion(-)

    diff --git a/arch/riscv/kernel/mcount-dyn.S b/arch/riscv/kernel/mcount-dyn.S
    index 35a6ed7..4b58b54 100644
    --- a/arch/riscv/kernel/mcount-dyn.S
    +++ b/arch/riscv/kernel/mcount-dyn.S
    @@ -123,6 +123,7 @@ ENDPROC(ftrace_caller)
    sd ra, (PT_SIZE_ON_STACK+8)(sp)
    addi s0, sp, (PT_SIZE_ON_STACK+16)

    + sd ra, PT_EPC(sp)
    sd x1, PT_RA(sp)
    sd x2, PT_SP(sp)
    sd x3, PT_GP(sp)
    @@ -157,6 +158,7 @@ ENDPROC(ftrace_caller)
    .endm

    .macro RESTORE_ALL
    + ld ra, PT_EPC(sp)
    ld x1, PT_RA(sp)
    ld x2, PT_SP(sp)
    ld x3, PT_GP(sp)
    @@ -190,7 +192,6 @@ ENDPROC(ftrace_caller)
    ld x31, PT_T6(sp)

    ld s0, (PT_SIZE_ON_STACK)(sp)
    - ld ra, (PT_SIZE_ON_STACK+8)(sp)
    addi sp, sp, (PT_SIZE_ON_STACK+16)
    .endm

    --
    2.7.4
    \
     
     \ /
      Last update: 2020-07-14 01:40    [W:3.228 / U:0.164 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site