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linux/arch/riscv/kernel/probes
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Nam Cao 13134cc949
riscv: kprobes: Fix incorrect address calculation 
p->ainsn.api.insn is a pointer to u32, therefore arithmetic operations are
multiplied by four. This is clearly undesirable for this case.

Cast it to (void *) first before any calculation.

Below is a sample before/after. The dumped memory is two kprobe slots, the
first slot has

  - c.addiw a0, 0x1c (0x7125)
  - ebreak           (0x00100073)

and the second slot has:

  - c.addiw a0, -4   (0x7135)
  - ebreak           (0x00100073)

Before this patch:

(gdb) x/16xh 0xff20000000135000
0xff20000000135000:	0x7125	0x0000	0x0000	0x0000	0x7135	0x0010	0x0000	0x0000
0xff20000000135010:	0x0073	0x0010	0x0000	0x0000	0x0000	0x0000	0x0000	0x0000

After this patch:

(gdb) x/16xh 0xff20000000125000
0xff20000000125000:	0x7125	0x0073	0x0010	0x0000	0x7135	0x0073	0x0010	0x0000
0xff20000000125010:	0x0000	0x0000	0x0000	0x0000	0x0000	0x0000	0x0000	0x0000

Fixes: b1756750a3 ("riscv: kprobes: Use patch_text_nosync() for insn slots")
Signed-off-by: Nam Cao <namcao@linutronix.de>
Cc: stable@vger.kernel.org
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20241119111056.2554419-1-namcao@linutronix.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2025-01-08 10:39:39 -08:00
..
decode-insn.c riscv: kprobes: simulate c.beqz and c.bnez 2023-08-16 07:48:40 -07:00
decode-insn.h
kprobes.c riscv: kprobes: Fix incorrect address calculation 2025-01-08 10:39:39 -08:00
Makefile trace: riscv: Remove deprecated kprobe on ftrace support 2024-07-24 06:14:05 -07:00
rethook.c riscv: add riscv rethook implementation 2022-12-02 13:04:05 -08:00
rethook.h riscv: add riscv rethook implementation 2022-12-02 13:04:05 -08:00
rethook_trampoline.S riscv: Use SYM_*() assembly macros instead of deprecated ones 2023-11-06 09:42:47 -08:00
simulate-insn.c riscv: kprobes: allow writing to x0 2023-11-05 14:12:47 -08:00
simulate-insn.h riscv: kprobes: simulate c.beqz and c.bnez 2023-08-16 07:48:40 -07:00
uprobes.c riscv: provide riscv-specific is_trap_insn() 2023-11-05 14:12:28 -08:00