From 2d83fea786d7aeb5b3b76bd492d9b3bccc0f823c Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Fri, 3 Apr 2015 23:26:49 +0100 Subject: [PATCH] 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/include/asm/cpu-features.h | 7 +++- arch/mips/kernel/traps.c | 23 ++++++------ arch/mips/math-emu/cp1emu.c | 55 ++++++++++++++-------------- 3 files changed, 43 insertions(+), 42 deletions(-) diff --git a/arch/mips/include/asm/cpu-features.h b/arch/mips/include/asm/cpu-features.h index 62a4730de86a..fc2ad332541c 100644 --- a/arch/mips/include/asm/cpu-features.h +++ b/arch/mips/include/asm/cpu-features.h @@ -221,8 +221,11 @@ #define cpu_has_mips_4_5_r (cpu_has_mips_4 | cpu_has_mips_5_r) #define cpu_has_mips_5_r (cpu_has_mips_5 | cpu_has_mips_r) -#define cpu_has_mips_4_5_r2_r6 (cpu_has_mips_4_5 | cpu_has_mips_r2 | \ - cpu_has_mips_r6) +#define cpu_has_mips_3_4_5_64_r2_r6 \ + (cpu_has_mips_3 | cpu_has_mips_4_5_64_r2_r6) +#define cpu_has_mips_4_5_64_r2_r6 \ + (cpu_has_mips_4_5 | cpu_has_mips64r1 | \ + cpu_has_mips_r2 | cpu_has_mips_r6) #define cpu_has_mips32 (cpu_has_mips32r1 | cpu_has_mips32r2 | cpu_has_mips32r6) #define cpu_has_mips64 (cpu_has_mips64r1 | cpu_has_mips64r2 | cpu_has_mips64r6) 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; } diff --git a/arch/mips/math-emu/cp1emu.c b/arch/mips/math-emu/cp1emu.c index be983850eb39..732c3a37d7b9 100644 --- a/arch/mips/math-emu/cp1emu.c +++ b/arch/mips/math-emu/cp1emu.c @@ -1115,17 +1115,18 @@ emul: likely = 0; switch (MIPSInst_RT(ir) & 3) { case bcfl_op: - likely = 1; + if (cpu_has_mips_2_3_4_5_r) + likely = 1; + /* Fall through */ case bcf_op: cond = !cond; break; case bctl_op: - likely = 1; + if (cpu_has_mips_2_3_4_5_r) + likely = 1; + /* Fall through */ case bct_op: break; - default: - /* thats an illegal instruction */ - return SIGILL; } set_delay_slot(xcp); @@ -1165,36 +1166,34 @@ emul: switch (MIPSInst_OPCODE(ir)) { case lwc1_op: - goto emul; - case swc1_op: goto emul; case ldc1_op: case sdc1_op: - if (cpu_has_mips_2_3_4_5 || - cpu_has_mips64) + if (cpu_has_mips_2_3_4_5_r) goto emul; return SIGILL; - goto emul; case cop1_op: goto emul; case cop1x_op: - if (cpu_has_mips_4_5 || cpu_has_mips64 || cpu_has_mips32r2) + if (cpu_has_mips_4_5_64_r2_r6) /* its one of ours */ goto emul; return SIGILL; case spec_op: - if (!cpu_has_mips_4_5_r) - return SIGILL; + switch (MIPSInst_FUNC(ir)) { + case movc_op: + if (cpu_has_mips_4_5_r) + goto emul; - if (MIPSInst_FUNC(ir) == movc_op) - goto emul; + return SIGILL; + } break; } @@ -1228,7 +1227,7 @@ emul: break; case cop1x_op: - if (!cpu_has_mips_4_5 && !cpu_has_mips64 && !cpu_has_mips32r2) + if (!cpu_has_mips_4_5_64_r2_r6) return SIGILL; sig = fpux_emu(xcp, ctx, ir, fault_addr); @@ -1561,7 +1560,7 @@ static int fpu_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx, /* unary ops */ case fsqrt_op: - if (!cpu_has_mips_4_5_r) + if (!cpu_has_mips_2_3_4_5_r) return SIGILL; handler.u = ieee754sp_sqrt; @@ -1573,14 +1572,14 @@ static int fpu_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx, * achieve full IEEE-754 accuracy - however this emulator does. */ case frsqrt_op: - if (!cpu_has_mips_4_5_r2_r6) + if (!cpu_has_mips_4_5_64_r2_r6) return SIGILL; handler.u = fpemu_sp_rsqrt; goto scopuop; case frecip_op: - if (!cpu_has_mips_4_5_r2_r6) + if (!cpu_has_mips_4_5_64_r2_r6) return SIGILL; handler.u = fpemu_sp_recip; @@ -1682,7 +1681,7 @@ copcsr: case ftrunc_op: case fceil_op: case ffloor_op: - if (!cpu_has_mips_2_3_4_5 && !cpu_has_mips64) + if (!cpu_has_mips_2_3_4_5_r) return SIGILL; oldrm = ieee754_csr.rm; @@ -1694,7 +1693,7 @@ copcsr: goto copcsr; case fcvtl_op: - if (!cpu_has_mips_3_4_5 && !cpu_has_mips64) + if (!cpu_has_mips_3_4_5_64_r2_r6) return SIGILL; SPFROMREG(fs, MIPSInst_FS(ir)); @@ -1706,7 +1705,7 @@ copcsr: case ftruncl_op: case fceill_op: case ffloorl_op: - if (!cpu_has_mips_3_4_5 && !cpu_has_mips64) + if (!cpu_has_mips_3_4_5_64_r2_r6) return SIGILL; oldrm = ieee754_csr.rm; @@ -1775,13 +1774,13 @@ copcsr: * achieve full IEEE-754 accuracy - however this emulator does. */ case frsqrt_op: - if (!cpu_has_mips_4_5_r2_r6) + if (!cpu_has_mips_4_5_64_r2_r6) return SIGILL; handler.u = fpemu_dp_rsqrt; goto dcopuop; case frecip_op: - if (!cpu_has_mips_4_5_r2_r6) + if (!cpu_has_mips_4_5_64_r2_r6) return SIGILL; handler.u = fpemu_dp_recip; @@ -1871,7 +1870,7 @@ dcopuop: goto copcsr; case fcvtl_op: - if (!cpu_has_mips_3_4_5 && !cpu_has_mips64) + if (!cpu_has_mips_3_4_5_64_r2_r6) return SIGILL; DPFROMREG(fs, MIPSInst_FS(ir)); @@ -1883,7 +1882,7 @@ dcopuop: case ftruncl_op: case fceill_op: case ffloorl_op: - if (!cpu_has_mips_3_4_5 && !cpu_has_mips64) + if (!cpu_has_mips_3_4_5_64_r2_r6) return SIGILL; oldrm = ieee754_csr.rm; @@ -1942,7 +1941,7 @@ dcopuop: case l_fmt: - if (!cpu_has_mips_3_4_5 && !cpu_has_mips64) + if (!cpu_has_mips_3_4_5_64_r2_r6) return SIGILL; DIFROMREG(bits, MIPSInst_FS(ir)); @@ -2006,7 +2005,7 @@ dcopuop: SITOREG(rv.w, MIPSInst_FD(ir)); break; case l_fmt: - if (!cpu_has_mips_3_4_5 && !cpu_has_mips64) + if (!cpu_has_mips_3_4_5_64_r2_r6) return SIGILL; DITOREG(rv.l, MIPSInst_FD(ir));