David Howells | b920de1 | 2008-02-08 04:19:31 -0800 | [diff] [blame] | 1 | /* MN10300 FPU management |
| 2 | * |
| 3 | * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. |
| 4 | * Written by David Howells (dhowells@redhat.com) |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public Licence |
| 8 | * as published by the Free Software Foundation; either version |
| 9 | * 2 of the Licence, or (at your option) any later version. |
| 10 | */ |
| 11 | #include <asm/uaccess.h> |
| 12 | #include <asm/fpu.h> |
| 13 | #include <asm/elf.h> |
| 14 | #include <asm/exceptions.h> |
| 15 | |
| 16 | struct task_struct *fpu_state_owner; |
| 17 | |
| 18 | /* |
| 19 | * handle an exception due to the FPU being disabled |
| 20 | */ |
| 21 | asmlinkage void fpu_disabled(struct pt_regs *regs, enum exception_code code) |
| 22 | { |
| 23 | struct task_struct *tsk = current; |
| 24 | |
| 25 | if (!user_mode(regs)) |
| 26 | die_if_no_fixup("An FPU Disabled exception happened in" |
| 27 | " kernel space\n", |
| 28 | regs, code); |
| 29 | |
| 30 | #ifdef CONFIG_FPU |
| 31 | preempt_disable(); |
| 32 | |
| 33 | /* transfer the last process's FPU state to memory */ |
| 34 | if (fpu_state_owner) { |
| 35 | fpu_save(&fpu_state_owner->thread.fpu_state); |
| 36 | fpu_state_owner->thread.uregs->epsw &= ~EPSW_FE; |
| 37 | } |
| 38 | |
| 39 | /* the current process now owns the FPU state */ |
| 40 | fpu_state_owner = tsk; |
| 41 | regs->epsw |= EPSW_FE; |
| 42 | |
| 43 | /* load the FPU with the current process's FPU state or invent a new |
| 44 | * clean one if the process doesn't have one */ |
| 45 | if (is_using_fpu(tsk)) { |
| 46 | fpu_restore(&tsk->thread.fpu_state); |
| 47 | } else { |
| 48 | fpu_init_state(); |
| 49 | set_using_fpu(tsk); |
| 50 | } |
| 51 | |
| 52 | preempt_enable(); |
| 53 | #else |
| 54 | { |
| 55 | siginfo_t info; |
| 56 | |
| 57 | info.si_signo = SIGFPE; |
| 58 | info.si_errno = 0; |
| 59 | info.si_addr = (void *) tsk->thread.uregs->pc; |
| 60 | info.si_code = FPE_FLTINV; |
| 61 | |
| 62 | force_sig_info(SIGFPE, &info, tsk); |
| 63 | } |
| 64 | #endif /* CONFIG_FPU */ |
| 65 | } |
| 66 | |
| 67 | /* |
| 68 | * handle an FPU operational exception |
| 69 | * - there's a possibility that if the FPU is asynchronous, the signal might |
| 70 | * be meant for a process other than the current one |
| 71 | */ |
| 72 | asmlinkage void fpu_exception(struct pt_regs *regs, enum exception_code code) |
| 73 | { |
| 74 | struct task_struct *tsk = fpu_state_owner; |
| 75 | siginfo_t info; |
| 76 | |
| 77 | if (!user_mode(regs)) |
| 78 | die_if_no_fixup("An FPU Operation exception happened in" |
| 79 | " kernel space\n", |
| 80 | regs, code); |
| 81 | |
| 82 | if (!tsk) |
| 83 | die_if_no_fixup("An FPU Operation exception happened," |
| 84 | " but the FPU is not in use", |
| 85 | regs, code); |
| 86 | |
| 87 | info.si_signo = SIGFPE; |
| 88 | info.si_errno = 0; |
| 89 | info.si_addr = (void *) tsk->thread.uregs->pc; |
| 90 | info.si_code = FPE_FLTINV; |
| 91 | |
| 92 | #ifdef CONFIG_FPU |
| 93 | { |
| 94 | u32 fpcr; |
| 95 | |
| 96 | /* get FPCR (we need to enable the FPU whilst we do this) */ |
| 97 | asm volatile(" or %1,epsw \n" |
| 98 | #ifdef CONFIG_MN10300_PROC_MN103E010 |
| 99 | " nop \n" |
| 100 | " nop \n" |
| 101 | " nop \n" |
| 102 | #endif |
| 103 | " fmov fpcr,%0 \n" |
| 104 | #ifdef CONFIG_MN10300_PROC_MN103E010 |
| 105 | " nop \n" |
| 106 | " nop \n" |
| 107 | " nop \n" |
| 108 | #endif |
| 109 | " and %2,epsw \n" |
| 110 | : "=&d"(fpcr) |
| 111 | : "i"(EPSW_FE), "i"(~EPSW_FE) |
| 112 | ); |
| 113 | |
| 114 | if (fpcr & FPCR_EC_Z) |
| 115 | info.si_code = FPE_FLTDIV; |
| 116 | else if (fpcr & FPCR_EC_O) |
| 117 | info.si_code = FPE_FLTOVF; |
| 118 | else if (fpcr & FPCR_EC_U) |
| 119 | info.si_code = FPE_FLTUND; |
| 120 | else if (fpcr & FPCR_EC_I) |
| 121 | info.si_code = FPE_FLTRES; |
| 122 | } |
| 123 | #endif |
| 124 | |
| 125 | force_sig_info(SIGFPE, &info, tsk); |
| 126 | } |
| 127 | |
| 128 | /* |
| 129 | * save the FPU state to a signal context |
| 130 | */ |
| 131 | int fpu_setup_sigcontext(struct fpucontext *fpucontext) |
| 132 | { |
| 133 | #ifdef CONFIG_FPU |
| 134 | struct task_struct *tsk = current; |
| 135 | |
| 136 | if (!is_using_fpu(tsk)) |
| 137 | return 0; |
| 138 | |
| 139 | /* transfer the current FPU state to memory and cause fpu_init() to be |
| 140 | * triggered by the next attempted FPU operation by the current |
| 141 | * process. |
| 142 | */ |
| 143 | preempt_disable(); |
| 144 | |
| 145 | if (fpu_state_owner == tsk) { |
| 146 | fpu_save(&tsk->thread.fpu_state); |
| 147 | fpu_state_owner->thread.uregs->epsw &= ~EPSW_FE; |
| 148 | fpu_state_owner = NULL; |
| 149 | } |
| 150 | |
| 151 | preempt_enable(); |
| 152 | |
| 153 | /* we no longer have a valid current FPU state */ |
| 154 | clear_using_fpu(tsk); |
| 155 | |
| 156 | /* transfer the saved FPU state onto the userspace stack */ |
| 157 | if (copy_to_user(fpucontext, |
| 158 | &tsk->thread.fpu_state, |
| 159 | min(sizeof(struct fpu_state_struct), |
| 160 | sizeof(struct fpucontext)))) |
| 161 | return -1; |
| 162 | |
| 163 | return 1; |
| 164 | #else |
| 165 | return 0; |
| 166 | #endif |
| 167 | } |
| 168 | |
| 169 | /* |
| 170 | * kill a process's FPU state during restoration after signal handling |
| 171 | */ |
| 172 | void fpu_kill_state(struct task_struct *tsk) |
| 173 | { |
| 174 | #ifdef CONFIG_FPU |
| 175 | /* disown anything left in the FPU */ |
| 176 | preempt_disable(); |
| 177 | |
| 178 | if (fpu_state_owner == tsk) { |
| 179 | fpu_state_owner->thread.uregs->epsw &= ~EPSW_FE; |
| 180 | fpu_state_owner = NULL; |
| 181 | } |
| 182 | |
| 183 | preempt_enable(); |
| 184 | #endif |
| 185 | /* we no longer have a valid current FPU state */ |
| 186 | clear_using_fpu(tsk); |
| 187 | } |
| 188 | |
| 189 | /* |
| 190 | * restore the FPU state from a signal context |
| 191 | */ |
| 192 | int fpu_restore_sigcontext(struct fpucontext *fpucontext) |
| 193 | { |
| 194 | struct task_struct *tsk = current; |
| 195 | int ret; |
| 196 | |
| 197 | /* load up the old FPU state */ |
| 198 | ret = copy_from_user(&tsk->thread.fpu_state, |
| 199 | fpucontext, |
| 200 | min(sizeof(struct fpu_state_struct), |
| 201 | sizeof(struct fpucontext))); |
| 202 | if (!ret) |
| 203 | set_using_fpu(tsk); |
| 204 | |
| 205 | return ret; |
| 206 | } |
| 207 | |
| 208 | /* |
| 209 | * fill in the FPU structure for a core dump |
| 210 | */ |
| 211 | int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpreg) |
| 212 | { |
| 213 | struct task_struct *tsk = current; |
| 214 | int fpvalid; |
| 215 | |
| 216 | fpvalid = is_using_fpu(tsk); |
| 217 | if (fpvalid) { |
| 218 | unlazy_fpu(tsk); |
| 219 | memcpy(fpreg, &tsk->thread.fpu_state, sizeof(*fpreg)); |
| 220 | } |
| 221 | |
| 222 | return fpvalid; |
| 223 | } |