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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>
48 lines
1.4 KiB
C
48 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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#ifndef _RISCV_KERNEL_PROBES_SIMULATE_INSN_H
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#define _RISCV_KERNEL_PROBES_SIMULATE_INSN_H
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#define __RISCV_INSN_FUNCS(name, mask, val) \
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static __always_inline bool riscv_insn_is_##name(probe_opcode_t code) \
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{ \
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BUILD_BUG_ON(~(mask) & (val)); \
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return (code & (mask)) == (val); \
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} \
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bool simulate_##name(u32 opcode, unsigned long addr, \
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struct pt_regs *regs)
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#define RISCV_INSN_REJECTED(name, code) \
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do { \
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if (riscv_insn_is_##name(code)) { \
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return INSN_REJECTED; \
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} \
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} while (0)
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__RISCV_INSN_FUNCS(system, 0x7f, 0x73);
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__RISCV_INSN_FUNCS(fence, 0x7f, 0x0f);
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#define RISCV_INSN_SET_SIMULATE(name, code) \
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do { \
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if (riscv_insn_is_##name(code)) { \
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api->handler = simulate_##name; \
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return INSN_GOOD_NO_SLOT; \
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} \
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} while (0)
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__RISCV_INSN_FUNCS(c_j, 0xe003, 0xa001);
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__RISCV_INSN_FUNCS(c_jr, 0xf007, 0x8002);
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__RISCV_INSN_FUNCS(c_jal, 0xe003, 0x2001);
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__RISCV_INSN_FUNCS(c_jalr, 0xf007, 0x9002);
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__RISCV_INSN_FUNCS(c_beqz, 0xe003, 0xc001);
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__RISCV_INSN_FUNCS(c_bnez, 0xe003, 0xe001);
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__RISCV_INSN_FUNCS(c_ebreak, 0xffff, 0x9002);
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__RISCV_INSN_FUNCS(auipc, 0x7f, 0x17);
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__RISCV_INSN_FUNCS(branch, 0x7f, 0x63);
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__RISCV_INSN_FUNCS(jal, 0x7f, 0x6f);
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__RISCV_INSN_FUNCS(jalr, 0x707f, 0x67);
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#endif /* _RISCV_KERNEL_PROBES_SIMULATE_INSN_H */
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