| Message ID | 20221126122137.2025-3-thunder.leizhen@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ARM: Make the dumped instructions are consistent with the disassembled ones | expand |
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index a92e0763739584e..40c7c807d67f4ed 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -186,12 +186,14 @@ static void dump_instr(const char *lvl, struct pt_regs *regs) else bad = get_kernel_nofault(tmp, &((u16 *)addr)[i]); - val = tmp; + val = __mem_to_opcode_thumb16(tmp); } else { if (user_mode(regs)) bad = get_user(val, &((u32 __user *)addr)[i]); else bad = get_kernel_nofault(val, &((u32 *)addr)[i]); + + val = __mem_to_opcode_arm(val); } if (!bad)
In ARM, the mapping of instruction memory is always little-endian, except some BE-32 supported ARM architectures. Such as ARMv7-R, its instruction endianness may be BE-32. Of course, its data endianness will also be BE-32 mode. Due to two negatives make a positive, the instruction stored in the register after reading is in little-endian format. But for the case of BE-8, the instruction endianness is LE, the instruction stored in the register after reading is in big-endian format, which is inconsistent with the disassembled one. For example: The content of disassembly: c0429ee8: e3500000 cmp r0, #0 c0429eec: 159f2044 ldrne r2, [pc, #68] c0429ef0: 108f2002 addne r2, pc, r2 c0429ef4: 1882000a stmne r2, {r1, r3} c0429ef8: e7f000f0 udf #0 The output of undefined instruction exception: Internal error: Oops - undefined instruction: 0 [#1] SMP ARM ... ... Code: 000050e3 44209f15 02208f10 0a008218 (f000f0e7) This inconveniences the checking of instructions. What's worse is that, for somebody who don't know about this, might think the instructions are all broken. So, when CONFIG_CPU_ENDIAN_BE8=y, let's convert the instructions to little-endian format before they are printed. The conversion result is as follows: Code: e3500000 159f2044 108f2002 1882000a (e7f000f0) Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> --- arch/arm/kernel/traps.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)