Atsushi Nemoto wrote: > I'm trying to compile kernel with gcc 3.3.1 and binutils 2.14. I > found this report on this ML: > > >>>>> On Tue, 13 May 2003 13:33:16 +0200, Guido Guenther <agx@sigxcpu.org> said: > Guido> Just for completeness: I had to use: > Guido> GCCFLAGS += -mabi=32 -march=r4600 -mtune=r4600 -Wa,--trap > Guido> to make gcc-3.3 happy (note the 32 instead of o32). gcc-3.2 > Guido> doesn't seem to handle these options correctly at all. > > It can compile the kernel, but handle_adel_int (and handle_ades_int) > contain wrong codes. > > 8002630c <handle_adel_int> 40284000 dmfc0 t0,$8 > 80026310 <handle_adel_int+0x4> 00000000 nop > 80026314 <handle_adel_int+0x8> ffa800a4 sd t0,164(sp) > > The source code for this instructions are: > > #define __BUILD_clear_ade(exception) \ > .set reorder; \ > MFC0 t0,CP0_BADVADDR; \ > .set noreorder; \ > REG_S t0,PT_BVADDR(sp); \ > KMODE > > The macro MFC0 and REG_S are defined asm.h and depend on _MIPS_ISA. > > #if (_MIPS_ISA == _MIPS_ISA_MIPS1) || (_MIPS_ISA == _MIPS_ISA_MIPS2) || \ > (_MIPS_ISA == _MIPS_ISA_MIPS32) > #define MFC0 mfc0 > #define MTC0 mtc0 > #endif > #if (_MIPS_ISA == _MIPS_ISA_MIPS3) || (_MIPS_ISA == _MIPS_ISA_MIPS4) || \ > (_MIPS_ISA == _MIPS_ISA_MIPS5) || (_MIPS_ISA == _MIPS_ISA_MIPS64) > #define MFC0 dmfc0 > #define MTC0 dmtc0 > #endif > > The option -march=r4600 seems to make gcc 3.3.x choose MIPS_ISA_MIPS3. Which is ok, because the available ISA has little to do with the actually used register width. If the intention is to use mfc0 for 32bit kernels and dmfc0 for 64bit, the check should probably be #ifdef __mips64 # define MFC0 dmfc0 # define MTC0 dmtc0 #else # define MFC0 mfc0 # define MTC0 mtc0 #endif > So, the right options is: > > GCCFLAGS += -mabi=32 -march=mips2 -mtune=r4600 -Wa,--trap > (or GCCFLAGS += $(call check_gcc, -mcpu=r4600 -mips2, -mabi=32 -march=mips2 -mtune=r4600) -Wa,--trap) > > Isn't it? -march=mips2 is an alias for -march=r6000, I don't think that's a good choice. Thiemo
