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-rw-r--r--arch/mn10300/kernel/fpu.c223
1 files changed, 223 insertions, 0 deletions
diff --git a/arch/mn10300/kernel/fpu.c b/arch/mn10300/kernel/fpu.c
new file mode 100644
index 000000000000..e705f25ad5ff
--- /dev/null
+++ b/arch/mn10300/kernel/fpu.c
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+/* MN10300 FPU management
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+#include <asm/uaccess.h>
+#include <asm/fpu.h>
+#include <asm/elf.h>
+#include <asm/exceptions.h>
+
+struct task_struct *fpu_state_owner;
+
+/*
+ * handle an exception due to the FPU being disabled
+ */
+asmlinkage void fpu_disabled(struct pt_regs *regs, enum exception_code code)
+{
+ struct task_struct *tsk = current;
+
+ if (!user_mode(regs))
+ die_if_no_fixup("An FPU Disabled exception happened in"
+ " kernel space\n",
+ regs, code);
+
+#ifdef CONFIG_FPU
+ preempt_disable();
+
+ /* transfer the last process's FPU state to memory */
+ if (fpu_state_owner) {
+ fpu_save(&fpu_state_owner->thread.fpu_state);
+ fpu_state_owner->thread.uregs->epsw &= ~EPSW_FE;
+ }
+
+ /* the current process now owns the FPU state */
+ fpu_state_owner = tsk;
+ regs->epsw |= EPSW_FE;
+
+ /* load the FPU with the current process's FPU state or invent a new
+ * clean one if the process doesn't have one */
+ if (is_using_fpu(tsk)) {
+ fpu_restore(&tsk->thread.fpu_state);
+ } else {
+ fpu_init_state();
+ set_using_fpu(tsk);
+ }
+
+ preempt_enable();
+#else
+ {
+ siginfo_t info;
+
+ info.si_signo = SIGFPE;
+ info.si_errno = 0;
+ info.si_addr = (void *) tsk->thread.uregs->pc;
+ info.si_code = FPE_FLTINV;
+
+ force_sig_info(SIGFPE, &info, tsk);
+ }
+#endif /* CONFIG_FPU */
+}
+
+/*
+ * handle an FPU operational exception
+ * - there's a possibility that if the FPU is asynchronous, the signal might
+ * be meant for a process other than the current one
+ */
+asmlinkage void fpu_exception(struct pt_regs *regs, enum exception_code code)
+{
+ struct task_struct *tsk = fpu_state_owner;
+ siginfo_t info;
+
+ if (!user_mode(regs))
+ die_if_no_fixup("An FPU Operation exception happened in"
+ " kernel space\n",
+ regs, code);
+
+ if (!tsk)
+ die_if_no_fixup("An FPU Operation exception happened,"
+ " but the FPU is not in use",
+ regs, code);
+
+ info.si_signo = SIGFPE;
+ info.si_errno = 0;
+ info.si_addr = (void *) tsk->thread.uregs->pc;
+ info.si_code = FPE_FLTINV;
+
+#ifdef CONFIG_FPU
+ {
+ u32 fpcr;
+
+ /* get FPCR (we need to enable the FPU whilst we do this) */
+ asm volatile(" or %1,epsw \n"
+#ifdef CONFIG_MN10300_PROC_MN103E010
+ " nop \n"
+ " nop \n"
+ " nop \n"
+#endif
+ " fmov fpcr,%0 \n"
+#ifdef CONFIG_MN10300_PROC_MN103E010
+ " nop \n"
+ " nop \n"
+ " nop \n"
+#endif
+ " and %2,epsw \n"
+ : "=&d"(fpcr)
+ : "i"(EPSW_FE), "i"(~EPSW_FE)
+ );
+
+ if (fpcr & FPCR_EC_Z)
+ info.si_code = FPE_FLTDIV;
+ else if (fpcr & FPCR_EC_O)
+ info.si_code = FPE_FLTOVF;
+ else if (fpcr & FPCR_EC_U)
+ info.si_code = FPE_FLTUND;
+ else if (fpcr & FPCR_EC_I)
+ info.si_code = FPE_FLTRES;
+ }
+#endif
+
+ force_sig_info(SIGFPE, &info, tsk);
+}
+
+/*
+ * save the FPU state to a signal context
+ */
+int fpu_setup_sigcontext(struct fpucontext *fpucontext)
+{
+#ifdef CONFIG_FPU
+ struct task_struct *tsk = current;
+
+ if (!is_using_fpu(tsk))
+ return 0;
+
+ /* transfer the current FPU state to memory and cause fpu_init() to be
+ * triggered by the next attempted FPU operation by the current
+ * process.
+ */
+ preempt_disable();
+
+ if (fpu_state_owner == tsk) {
+ fpu_save(&tsk->thread.fpu_state);
+ fpu_state_owner->thread.uregs->epsw &= ~EPSW_FE;
+ fpu_state_owner = NULL;
+ }
+
+ preempt_enable();
+
+ /* we no longer have a valid current FPU state */
+ clear_using_fpu(tsk);
+
+ /* transfer the saved FPU state onto the userspace stack */
+ if (copy_to_user(fpucontext,
+ &tsk->thread.fpu_state,
+ min(sizeof(struct fpu_state_struct),
+ sizeof(struct fpucontext))))
+ return -1;
+
+ return 1;
+#else
+ return 0;
+#endif
+}
+
+/*
+ * kill a process's FPU state during restoration after signal handling
+ */
+void fpu_kill_state(struct task_struct *tsk)
+{
+#ifdef CONFIG_FPU
+ /* disown anything left in the FPU */
+ preempt_disable();
+
+ if (fpu_state_owner == tsk) {
+ fpu_state_owner->thread.uregs->epsw &= ~EPSW_FE;
+ fpu_state_owner = NULL;
+ }
+
+ preempt_enable();
+#endif
+ /* we no longer have a valid current FPU state */
+ clear_using_fpu(tsk);
+}
+
+/*
+ * restore the FPU state from a signal context
+ */
+int fpu_restore_sigcontext(struct fpucontext *fpucontext)
+{
+ struct task_struct *tsk = current;
+ int ret;
+
+ /* load up the old FPU state */
+ ret = copy_from_user(&tsk->thread.fpu_state,
+ fpucontext,
+ min(sizeof(struct fpu_state_struct),
+ sizeof(struct fpucontext)));
+ if (!ret)
+ set_using_fpu(tsk);
+
+ return ret;
+}
+
+/*
+ * fill in the FPU structure for a core dump
+ */
+int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpreg)
+{
+ struct task_struct *tsk = current;
+ int fpvalid;
+
+ fpvalid = is_using_fpu(tsk);
+ if (fpvalid) {
+ unlazy_fpu(tsk);
+ memcpy(fpreg, &tsk->thread.fpu_state, sizeof(*fpreg));
+ }
+
+ return fpvalid;
+}