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Re: illegal hardware instruction during MIPS-I ELF linux useremulation
From: |
Libo Zhou |
Subject: |
Re: illegal hardware instruction during MIPS-I ELF linux useremulation |
Date: |
Thu, 26 Sep 2019 22:31:35 +0800 |
> If you look at the mips_defs[] array in
> target/mips/translate_init.inc.c, the older ISA implemented is MIPS-II:
> $ git grep .insn_flags target/mips/translate_init.inc.c
> translate_init.inc.c:75: .insn_flags = CPU_MIPS32,
> translate_init.inc.c:97: .insn_flags = CPU_MIPS32 | ASE_MIPS16,
> translate_init.inc.c:117: .insn_flags = CPU_MIPS32,
> translate_init.inc.c:137: .insn_flags = CPU_MIPS32 | ASE_MIPS16,
> translate_init.inc.c:158: .insn_flags = CPU_MIPS32R2,
> translate_init.inc.c:179: .insn_flags = CPU_MIPS32R2 | ASE_MIPS16,
> translate_init.inc.c:201: .insn_flags = CPU_MIPS32R2 | ASE_MIPS16,
> translate_init.inc.c:223: .insn_flags = CPU_MIPS32R2 | ASE_MIPS16 |
> ASE_DSP,
> translate_init.inc.c:249: .insn_flags = CPU_MIPS32R2 | ASE_MIPS16,
> translate_init.inc.c:297: .insn_flags = CPU_MIPS32R2 | ASE_MIPS16 |
> ASE_DSP | ASE_MT,
> translate_init.inc.c:323: .insn_flags = CPU_MIPS32R2 | ASE_MIPS16 |
> ASE_DSP | ASE_DSP_R2,
> translate_init.inc.c:343: .insn_flags = CPU_MIPS32R2 | ASE_MICROMIPS,
> translate_init.inc.c:364: .insn_flags = CPU_MIPS32R2 | ASE_MICROMIPS,
> translate_init.inc.c:410: .insn_flags = CPU_MIPS32R5 | ASE_MSA,
> translate_init.inc.c:449: .insn_flags = CPU_MIPS32R6 | ASE_MICROMIPS,
> translate_init.inc.c:488: .insn_flags = CPU_NANOMIPS32 | ASE_DSP |
> ASE_DSP_R2 | ASE_DSP_R3 |
> translate_init.inc.c:511: .insn_flags = CPU_MIPS3,
> translate_init.inc.c:531: .insn_flags = CPU_VR54XX,
> translate_init.inc.c:552: .insn_flags = CPU_MIPS64,
> translate_init.inc.c:578: .insn_flags = CPU_MIPS64,
> translate_init.inc.c:607: .insn_flags = CPU_MIPS64 | ASE_MIPS3D,
> translate_init.inc.c:636: .insn_flags = CPU_MIPS64R2 | ASE_MIPS3D,
> translate_init.inc.c:657: .insn_flags = CPU_MIPS64R2,
> translate_init.inc.c:681: .insn_flags = CPU_MIPS64R2,
> translate_init.inc.c:721: .insn_flags = CPU_MIPS64R6 | ASE_MSA,
> translate_init.inc.c:761: .insn_flags = CPU_MIPS64R6 | ASE_MSA,
> translate_init.inc.c:781: .insn_flags = CPU_LOONGSON2E,
> translate_init.inc.c:801: .insn_flags = CPU_LOONGSON2F,
> translate_init.inc.c:830: .insn_flags = CPU_MIPS64R2 | ASE_DSP |
> ASE_DSP_R2,
> So currently there is no MIPS-I only CPU.
> Note that the code got written with MIPS32 in mind, and implementing
> MIPS-I requires a considerable amount of change in the codebase.
Hi Philippe,
I just figured out what the problem was. The custom compiler I used just
modified the opcode fields of sw and lw instructions of MIPS, so QEMU didn't
recognize them out of the box.
I just added the support in decode_opc function in translate.c, and I also
added my own CPU model in translate_init.inc.c. However, the illegal
instruction exception is still there.
I am suspecting that the way I added my own CPU model in translate_init.inc.c
is wrong. Below is what I added:
...
+{
+ .name = "MyCPU",
+ .insn_flags = CPU_MIPS1 | INSN_MYCPU,
+},
...
I just need to simulate it's instruction set in linux user emulation, I didn't
include CP0* items in the list. Is this good enough to add a new CPU model?
Thanks,
Libo Zhou