Commit Graph

2 Commits

Author SHA1 Message Date
Tiezhu Yang
539d7344d4 objtool/LoongArch: Mark special atomic instruction as INSN_BUG type
When compiling with LLVM and CONFIG_RUST is set, there exists the
following objtool warning:

  rust/compiler_builtins.o: warning: objtool: __rust__unordsf2(): unexpected end of section .text.unlikely.

objdump shows that the end of section .text.unlikely is an atomic
instruction:

  amswap.w        $zero, $ra, $zero

According to the LoongArch Reference Manual, if the amswap.w atomic
memory access instruction has the same register number as rd and rj,
the execution will trigger an Instruction Non-defined Exception, so
mark the above instruction as INSN_BUG type to fix the warning.

Cc: stable@vger.kernel.org
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2025-09-18 19:43:36 +08:00
Tiezhu Yang
b2d23158e6 objtool/LoongArch: Implement instruction decoder
Only copy the minimal definitions of instruction opcodes and formats
in inst.h from arch/loongarch to tools/arch/loongarch, and also copy
the definition of sign_extend64() to tools/include/linux/bitops.h to
decode the following kinds of instructions:

(1) stack pointer related instructions
addi.d, ld.d, st.d, ldptr.d and stptr.d

(2) branch and jump related instructions
beq, bne, blt, bge, bltu, bgeu, beqz, bnez, bceqz, bcnez, b, bl and jirl

(3) other instructions
break, nop and ertn

See more info about instructions in LoongArch Reference Manual:
https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html

Co-developed-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Jinyang He <hejinyang@loongson.cn>
Co-developed-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-03-11 22:23:47 +08:00