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.
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?
--- Atsushi Nemoto
I don't claim to be an expert on all things mips yet, but If I recall correctly, the R4K processor line is a MIPS III capable processor. So -mips3 -mabi=32 should be safe for it. I've been building kernels off linux-mips.org CVS using "-mips3 -mabi=32 -Wa,--trap" in the arch/mips/Makefile, and it works great.
Several people I know using Indy's with R5000 processors use "-mips4 -mabi=32 -Wa,--trap" (cause R5K is MIPS IV). I know with gcc-3.3.x, -mipsX is just a synonym for the appropriate -march specifier, so it doesn't seem to make a different whether one uses -march or -mipsX.
I'm slowly working on building a Gentoo install using "-mips3 -mabi=32" code on my Indigo2 (Right now, it's a mix of -mips2 and -mips3 with a random -mips1 binary scattered around). Quite a fun, albeit slow, experiment.
--Kumba
--
"Such is oft the course of deeds that move the wheels of the world: small hands do them because they must, while the eyes of the great are elsewhere." --Elrond
