1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Linux/PA-RISC Project (http://www.parisc-linux.org/) 4 * 5 * Floating-point emulation code 6 * Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org> 7 */ 8 /* 9 * linux/arch/math-emu/driver.c.c 10 * 11 * decodes and dispatches unimplemented FPU instructions 12 * 13 * Copyright (C) 1999, 2000 Philipp Rumpf <prumpf@tux.org> 14 * Copyright (C) 2001 Hewlett-Packard <bame@debian.org> 15 */ 16 17 #include <linux/sched/signal.h> 18 19 #include "float.h" 20 #include "math-emu.h" 21 22 23 #define fptpos 31 24 #define fpr1pos 10 25 #define extru(r,pos,len) (((r) >> (31-(pos))) & (( 1 << (len)) - 1)) 26 27 #define FPUDEBUG 0 28 29 /* Format of the floating-point exception registers. */ 30 struct exc_reg { 31 unsigned int exception : 6; 32 unsigned int ei : 26; 33 }; 34 35 /* Macros for grabbing bits of the instruction format from the 'ei' 36 field above. */ 37 /* Major opcode 0c and 0e */ 38 #define FP0CE_UID(i) (((i) >> 6) & 3) 39 #define FP0CE_CLASS(i) (((i) >> 9) & 3) 40 #define FP0CE_SUBOP(i) (((i) >> 13) & 7) 41 #define FP0CE_SUBOP1(i) (((i) >> 15) & 7) /* Class 1 subopcode */ 42 #define FP0C_FORMAT(i) (((i) >> 11) & 3) 43 #define FP0E_FORMAT(i) (((i) >> 11) & 1) 44 45 /* Major opcode 0c, uid 2 (performance monitoring) */ 46 #define FPPM_SUBOP(i) (((i) >> 9) & 0x1f) 47 48 /* Major opcode 2e (fused operations). */ 49 #define FP2E_SUBOP(i) (((i) >> 5) & 1) 50 #define FP2E_FORMAT(i) (((i) >> 11) & 1) 51 52 /* Major opcode 26 (FMPYSUB) */ 53 /* Major opcode 06 (FMPYADD) */ 54 #define FPx6_FORMAT(i) ((i) & 0x1f) 55 56 /* Flags and enable bits of the status word. */ 57 #define FPSW_FLAGS(w) ((w) >> 27) 58 #define FPSW_ENABLE(w) ((w) & 0x1f) 59 #define FPSW_V (1<<4) 60 #define FPSW_Z (1<<3) 61 #define FPSW_O (1<<2) 62 #define FPSW_U (1<<1) 63 #define FPSW_I (1<<0) 64 65 /* Handle a floating point exception. Return zero if the faulting 66 instruction can be completed successfully. */ 67 int 68 handle_fpe(struct pt_regs *regs) 69 { 70 extern void printbinary(unsigned long x, int nbits); 71 unsigned int orig_sw, sw; 72 int signalcode; 73 /* need an intermediate copy of float regs because FPU emulation 74 * code expects an artificial last entry which contains zero 75 * 76 * also, the passed in fr registers contain one word that defines 77 * the fpu type. the fpu type information is constructed 78 * inside the emulation code 79 */ 80 __u64 frcopy[36]; 81 82 memcpy(frcopy, regs->fr, sizeof regs->fr); 83 frcopy[32] = 0; 84 85 memcpy(&orig_sw, frcopy, sizeof(orig_sw)); 86 87 if (FPUDEBUG) { 88 printk(KERN_DEBUG "FP VZOUICxxxxCQCQCQCQCQCRMxxTDVZOUI ->\n "); 89 printbinary(orig_sw, 32); 90 printk(KERN_DEBUG "\n"); 91 } 92 93 signalcode = decode_fpu(frcopy, 0x666); 94 95 /* Status word = FR0L. */ 96 memcpy(&sw, frcopy, sizeof(sw)); 97 if (FPUDEBUG) { 98 printk(KERN_DEBUG "VZOUICxxxxCQCQCQCQCQCRMxxTDVZOUI decode_fpu returns %d|0x%x\n", 99 signalcode >> 24, signalcode & 0xffffff); 100 printbinary(sw, 32); 101 printk(KERN_DEBUG "\n"); 102 } 103 104 memcpy(regs->fr, frcopy, sizeof regs->fr); 105 if (signalcode != 0) { 106 force_sig_fault(signalcode >> 24, signalcode & 0xffffff, 107 (void __user *) regs->iaoq[0], current); 108 return -1; 109 } 110 111 return signalcode ? -1 : 0; 112 } 113