// SPDX-License-Identifier: GPL-2.0-only #include #include #include #include #include #include #include #include "sfp-util.h" #include #include #include #define OPC_PAL 0x00 #define OPC_INTA 0x10 #define OPC_INTL 0x11 #define OPC_INTS 0x12 #define OPC_INTM 0x13 #define OPC_FLTC 0x14 #define OPC_FLTV 0x15 #define OPC_FLTI 0x16 #define OPC_FLTL 0x17 #define OPC_MISC 0x18 #define OPC_JSR 0x1a #define FOP_SRC_S 0 #define FOP_SRC_T 2 #define FOP_SRC_Q 3 #define FOP_FNC_ADDx 0 #define FOP_FNC_CVTQL 0 #define FOP_FNC_SUBx 1 #define FOP_FNC_MULx 2 #define FOP_FNC_DIVx 3 #define FOP_FNC_CMPxUN 4 #define FOP_FNC_CMPxEQ 5 #define FOP_FNC_CMPxLT 6 #define FOP_FNC_CMPxLE 7 #define FOP_FNC_SQRTx 11 #define FOP_FNC_CVTxS 12 #define FOP_FNC_CVTxT 14 #define FOP_FNC_CVTxQ 15 #define MISC_TRAPB 0x0000 #define MISC_EXCB 0x0400 #ifdef MODULE MODULE_DESCRIPTION("FP Software completion module"); MODULE_LICENSE("GPL v2"); extern long (*alpha_fp_emul_imprecise)(struct pt_regs *, unsigned long); extern long (*alpha_fp_emul) (unsigned long pc); static long (*save_emul_imprecise)(struct pt_regs *, unsigned long); static long (*save_emul) (unsigned long pc); long do_alpha_fp_emul_imprecise(struct pt_regs *, unsigned long); long do_alpha_fp_emul(unsigned long); static int alpha_fp_emul_init_module(void) { save_emul_imprecise = alpha_fp_emul_imprecise; save_emul = alpha_fp_emul; alpha_fp_emul_imprecise = do_alpha_fp_emul_imprecise; alpha_fp_emul = do_alpha_fp_emul; return 0; } module_init(alpha_fp_emul_init_module); static void alpha_fp_emul_cleanup_module(void) { alpha_fp_emul_imprecise = save_emul_imprecise; alpha_fp_emul = save_emul; } module_exit(alpha_fp_emul_cleanup_module); #undef alpha_fp_emul_imprecise #define alpha_fp_emul_imprecise do_alpha_fp_emul_imprecise #undef alpha_fp_emul #define alpha_fp_emul do_alpha_fp_emul #endif /* MODULE */ /* * Emulate the floating point instruction at address PC. Returns -1 if the * instruction to be emulated is illegal (such as with the opDEC trap), else * the SI_CODE for a SIGFPE signal, else 0 if everything's ok. * * Notice that the kernel does not and cannot use FP regs. This is good * because it means that instead of saving/restoring all fp regs, we simply * stick the result of the operation into the appropriate register. */ long alpha_fp_emul (unsigned long pc) { FP_DECL_EX; FP_DECL_S(SA); FP_DECL_S(SB); FP_DECL_S(SR); FP_DECL_D(DA); FP_DECL_D(DB); FP_DECL_D(DR); unsigned long fa, fb, fc, func, mode, src; unsigned long res, va, vb, vc, swcr, fpcr; __u32 insn; long si_code; get_user(insn, (__u32 __user *)pc); fc = (insn >> 0) & 0x1f; /* destination register */ fb = (insn >> 16) & 0x1f; fa = (insn >> 21) & 0x1f; func = (insn >> 5) & 0xf; src = (insn >> 9) & 0x3; mode = (insn >> 11) & 0x3; fpcr = rdfpcr(); swcr = swcr_update_status(current_thread_info()->ieee_state, fpcr); if (mode == 3) { /* Dynamic -- get rounding mode from fpcr. */ mode = (fpcr >> FPCR_DYN_SHIFT) & 3; } switch (src) { case FOP_SRC_S: va = alpha_read_fp_reg_s(fa); vb = alpha_read_fp_reg_s(fb); FP_UNPACK_SP(SA, &va); FP_UNPACK_SP(SB, &vb); switch (func) { case FOP_FNC_SUBx: FP_SUB_S(SR, SA, SB); goto pack_s; case FOP_FNC_ADDx: FP_ADD_S(SR, SA, SB); goto pack_s; case FOP_FNC_MULx: FP_MUL_S(SR, SA, SB); goto pack_s; case FOP_FNC_DIVx: FP_DIV_S(SR, SA, SB); goto pack_s; case FOP_FNC_SQRTx: FP_SQRT_S(SR, SB); goto pack_s; } goto bad_insn; case FOP_SRC_T: va = alpha_read_fp_reg(fa); vb = alpha_read_fp_reg(fb); if ((func & ~3) == FOP_FNC_CMPxUN) { FP_UNPACK_RAW_DP(DA, &va); FP_UNPACK_RAW_DP(DB, &vb); if (!DA_e && !_FP_FRAC_ZEROP_1(DA)) { FP_SET_EXCEPTION(FP_EX_DENORM); if (FP_DENORM_ZERO) _FP_FRAC_SET_1(DA, _FP_ZEROFRAC_1); } if (!DB_e && !_FP_FRAC_ZEROP_1(DB)) { FP_SET_EXCEPTION(FP_EX_DENORM); if (FP_DENORM_ZERO) _FP_FRAC_SET_1(DB, _FP_ZEROFRAC_1); } FP_CMP_D(res, DA, DB, 3); vc = 0x4000000000000000UL; /* CMPTEQ, CMPTUN don't trap on QNaN, while CMPTLT and CMPTLE do */ if (res == 3 && ((func & 3) >= 2 || FP_ISSIGNAN_D(DA) || FP_ISSIGNAN_D(DB))) { FP_SET_EXCEPTION(FP_EX_INVALID); } switch (func) { case FOP_FNC_CMPxUN: if (res != 3) vc = 0; break; case FOP_FNC_CMPxEQ: if (res) vc = 0; break; case FOP_FNC_CMPxLT: if (res != -1) vc = 0; break; case FOP_FNC_CMPxLE: if ((long)res > 0) vc = 0; break; } goto done_d; } FP_UNPACK_DP(DA, &va); FP_UNPACK_DP(DB, &vb); switch (func) { case FOP_FNC_SUBx: FP_SUB_D(DR, DA, DB); goto pack_d; case FOP_FNC_ADDx: FP_ADD_D(DR, DA, DB); goto pack_d; case FOP_FNC_MULx: FP_MUL_D(DR, DA, DB); goto pack_d; case FOP_FNC_DIVx: FP_DIV_D(DR, DA, DB); goto pack_d; case FOP_FNC_SQRTx: FP_SQRT_D(DR, DB); goto pack_d; case FOP_FNC_CVTxS: /* It is irritating that DEC encoded CVTST with SRC == T_floating. It is also interesting that the bit used to tell the two apart is /U... */ if (insn & 0x2000) { FP_CONV(S,D,1,1,SR,DB); goto pack_s; } else { vb = alpha_read_fp_reg_s(fb); FP_UNPACK_SP(SB, &vb); DR_c = DB_c; DR_s = DB_s; DR_e = DB_e + (1024 - 128); DR_f = SB_f << (52 - 23); goto pack_d; } case FOP_FNC_CVTxQ: if (DB_c == FP_CLS_NAN && (_FP_FRAC_HIGH_RAW_D(DB) & _FP_QNANBIT_D)) { /* AAHB Table B-2 says QNaN should not trigger INV */ vc = 0; } else FP_TO_INT_ROUND_D(vc, DB, 64, 2); goto done_d; } goto bad_insn; case FOP_SRC_Q: vb = alpha_read_fp_reg(fb); switch (func) { case FOP_FNC_CVTQL: /* Notice: We can get here only due to an integer overflow. Such overflows are reported as invalid ops. We return the result the hw would have computed. */ vc = ((vb & 0xc0000000) << 32 | /* sign and msb */ (vb & 0x3fffffff) << 29); /* rest of the int */ FP_SET_EXCEPTION (FP_EX_INVALID); goto done_d; case FOP_FNC_CVTxS: FP_FROM_INT_S(SR, ((long)vb), 64, long); goto pack_s; case FOP_FNC_CVTxT: FP_FROM_INT_D(DR, ((long)vb), 64, long); goto pack_d; } goto bad_insn; } goto bad_insn; pack_s: FP_PACK_SP(&vc, SR); if ((_fex & FP_EX_UNDERFLOW) && (swcr & IEEE_MAP_UMZ)) vc = 0; alpha_write_fp_reg_s(fc, vc); goto done; pack_d: FP_PACK_DP(&vc, DR); if ((_fex & FP_EX_UNDERFLOW) && (swcr & IEEE_MAP_UMZ)) vc = 0; done_d: alpha_write_fp_reg(fc, vc); goto done; /* * Take the appropriate action for each possible * floating-point result: * * - Set the appropriate bits in the FPCR * - If the specified exception is enabled in the FPCR, * return. The caller (entArith) will dispatch * the appropriate signal to the translated program. * * In addition, properly track the exception state in software * as described in the Alpha Architecture Handbook section 4.7.7.3. */ done: if (_fex) { /* Record exceptions in software control word. */ swcr |= (_fex << IEEE_STATUS_TO_EXCSUM_SHIFT); current_thread_info()->ieee_state |= (_fex << IEEE_STATUS_TO_EXCSUM_SHIFT); /* Update hardware control register. */ fpcr &= (~FPCR_MASK | FPCR_DYN_MASK); fpcr |= ieee_swcr_to_fpcr(swcr); wrfpcr(fpcr); /* Do we generate a signal? */ _fex = _fex & swcr & IEEE_TRAP_ENABLE_MASK; si_code = 0; if (_fex) { if (_fex & IEEE_TRAP_ENABLE_DNO) si_code = FPE_FLTUND; if (_fex & IEEE_TRAP_ENABLE_INE) si_code = FPE_FLTRES; if (_fex & IEEE_TRAP_ENABLE_UNF) si_code = FPE_FLTUND; if (_fex & IEEE_TRAP_ENABLE_OVF) si_code = FPE_FLTOVF; if (_fex & IEEE_TRAP_ENABLE_DZE) si_code = FPE_FLTDIV; if (_fex & IEEE_TRAP_ENABLE_INV) si_code = FPE_FLTINV; } return si_code; } /* We used to write the destination register here, but DEC FORTRAN requires that the result *always* be written... so we do the write immediately after the operations above. */ return 0; bad_insn: printk(KERN_ERR "alpha_fp_emul: Invalid FP insn %#x at %#lx\n", insn, pc); return -1; } long alpha_fp_emul_imprecise (struct pt_regs *regs, unsigned long write_mask) { unsigned long trigger_pc = regs->pc - 4; unsigned long insn, opcode, rc, si_code = 0; /* * Turn off the bits corresponding to registers that are the * target of instructions that set bits in the exception * summary register. We have some slack doing this because a * register that is the target of a trapping instruction can * be written at most once in the trap shadow. * * Branches, jumps, TRAPBs, EXCBs and calls to PALcode all * bound the trap shadow, so we need not look any further than * up to the first occurrence of such an instruction. */ while (write_mask) { get_user(insn, (__u32 __user *)(trigger_pc)); opcode = insn >> 26; rc = insn & 0x1f; switch (opcode) { case OPC_PAL: case OPC_JSR: case 0x30 ... 0x3f: /* branches */ goto egress; case OPC_MISC: switch (insn & 0xffff) { case MISC_TRAPB: case MISC_EXCB: goto egress; default: break; } break; case OPC_INTA: case OPC_INTL: case OPC_INTS: case OPC_INTM: write_mask &= ~(1UL << rc); break; case OPC_FLTC: case OPC_FLTV: case OPC_FLTI: case OPC_FLTL: write_mask &= ~(1UL << (rc + 32)); break; } if (!write_mask) { /* Re-execute insns in the trap-shadow. */ regs->pc = trigger_pc + 4; si_code = alpha_fp_emul(trigger_pc); goto egress; } trigger_pc -= 4; } egress: return si_code; }