From 2d83fea786d7aeb5b3b76bd492d9b3bccc0f823c Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Fri, 3 Apr 2015 23:26:49 +0100 Subject: MIPS: Correct FP ISA requirements Correct ISA requirements for floating-point instructions: * the CU3 exception signifies a real COP3 instruction in MIPS I & II, * the BC1FL and BC1TL instructions are not supported in MIPS I, * the SQRT.fmt instructions are indeed supported in MIPS II, * the LDC1 and SDC1 instructions are indeed supported in MIPS32r1, * the CEIL.W.fmt, FLOOR.W.fmt, ROUND.W.fmt and TRUNC.W.fmt instructions are indeed supported in MIPS32, * the CVT.L.fmt and CVT.fmt.L instructions are indeed supported in MIPS32r2 and MIPS32r6, * the CEIL.L.fmt, FLOOR.L.fmt, ROUND.L.fmt and TRUNC.L.fmt instructions are indeed supported in MIPS32r2 and MIPS32r6, * the RSQRT.fmt and RECIP.fmt instructions are indeed supported in MIPS64r1, Also simplify conditionals for MIPS III and MIPS IV FPU instructions and the handling of the MOVCI minor opcode. Signed-off-by: Maciej W. Rozycki Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/9700/ Signed-off-by: Ralf Baechle --- arch/mips/kernel/traps.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-) (limited to 'arch/mips/kernel/traps.c') diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index dc6eaf4d93ea..88f04f0d2d21 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -1349,19 +1349,18 @@ asmlinkage void do_cpu(struct pt_regs *regs) case 3: /* - * Old (MIPS I and MIPS II) processors will set this code - * for COP1X opcode instructions that replaced the original - * COP3 space. We don't limit COP1 space instructions in - * the emulator according to the CPU ISA, so we want to - * treat COP1X instructions consistently regardless of which - * code the CPU chose. Therefore we redirect this trap to - * the FP emulator too. - * - * Then some newer FPU-less processors use this code - * erroneously too, so they are covered by this choice - * as well. + * The COP3 opcode space and consequently the CP0.Status.CU3 + * bit and the CP0.Cause.CE=3 encoding have been removed as + * of the MIPS III ISA. From the MIPS IV and MIPS32r2 ISAs + * up the space has been reused for COP1X instructions, that + * are enabled by the CP0.Status.CU1 bit and consequently + * use the CP0.Cause.CE=1 encoding for Coprocessor Unusable + * exceptions. Some FPU-less processors that implement one + * of these ISAs however use this code erroneously for COP1X + * instructions. Therefore we redirect this trap to the FP + * emulator too. */ - if (raw_cpu_has_fpu) { + if (raw_cpu_has_fpu || !cpu_has_mips_4_5_64_r2_r6) { force_sig(SIGILL, current); break; } -- cgit v1.2.2