c22b0bcb1d
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>
86 lines
1.9 KiB
C
86 lines
1.9 KiB
C
// SPDX-License-Identifier: GPL-2.0+
|
|
|
|
#include <linux/bitops.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/kprobes.h>
|
|
|
|
#include "decode-insn.h"
|
|
#include "simulate-insn.h"
|
|
|
|
static inline bool rv_insn_reg_get_val(struct pt_regs *regs, u32 index,
|
|
unsigned long *ptr)
|
|
{
|
|
if (index == 0)
|
|
*ptr = 0;
|
|
else if (index <= 31)
|
|
*ptr = *((unsigned long *)regs + index);
|
|
else
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
static inline bool rv_insn_reg_set_val(struct pt_regs *regs, u32 index,
|
|
unsigned long val)
|
|
{
|
|
if (index == 0)
|
|
return false;
|
|
else if (index <= 31)
|
|
*((unsigned long *)regs + index) = val;
|
|
else
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
bool __kprobes simulate_jal(u32 opcode, unsigned long addr, struct pt_regs *regs)
|
|
{
|
|
/*
|
|
* 31 30 21 20 19 12 11 7 6 0
|
|
* imm [20] | imm[10:1] | imm[11] | imm[19:12] | rd | opcode
|
|
* 1 10 1 8 5 JAL/J
|
|
*/
|
|
bool ret;
|
|
u32 imm;
|
|
u32 index = (opcode >> 7) & 0x1f;
|
|
|
|
ret = rv_insn_reg_set_val(regs, index, addr + 4);
|
|
if (!ret)
|
|
return ret;
|
|
|
|
imm = ((opcode >> 21) & 0x3ff) << 1;
|
|
imm |= ((opcode >> 20) & 0x1) << 11;
|
|
imm |= ((opcode >> 12) & 0xff) << 12;
|
|
imm |= ((opcode >> 31) & 0x1) << 20;
|
|
|
|
instruction_pointer_set(regs, addr + sign_extend32((imm), 20));
|
|
|
|
return ret;
|
|
}
|
|
|
|
bool __kprobes simulate_jalr(u32 opcode, unsigned long addr, struct pt_regs *regs)
|
|
{
|
|
/*
|
|
* 31 20 19 15 14 12 11 7 6 0
|
|
* offset[11:0] | rs1 | 010 | rd | opcode
|
|
* 12 5 3 5 JALR/JR
|
|
*/
|
|
bool ret;
|
|
unsigned long base_addr;
|
|
u32 imm = (opcode >> 20) & 0xfff;
|
|
u32 rd_index = (opcode >> 7) & 0x1f;
|
|
u32 rs1_index = (opcode >> 15) & 0x1f;
|
|
|
|
ret = rv_insn_reg_set_val(regs, rd_index, addr + 4);
|
|
if (!ret)
|
|
return ret;
|
|
|
|
ret = rv_insn_reg_get_val(regs, rs1_index, &base_addr);
|
|
if (!ret)
|
|
return ret;
|
|
|
|
instruction_pointer_set(regs, (base_addr + sign_extend32((imm), 11))&~1);
|
|
|
|
return ret;
|
|
}
|