[src/trunk]: src/sys/arch/aarch64/aarch64 Add kthread_fpu_enter/exit support ...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/fefd06d3b944
branches:  trunk
changeset: 936626:fefd06d3b944
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sat Aug 01 02:06:59 2020 +0000

description:
Add kthread_fpu_enter/exit support to aarch64.

diffstat:

 sys/arch/aarch64/aarch64/fpu.c  |  50 +++++++++++++++++++++++++++++++++++++---
 sys/arch/aarch64/aarch64/trap.c |  10 ++++++-
 2 files changed, 54 insertions(+), 6 deletions(-)

diffs (124 lines):

diff -r 6cd900d5e0c5 -r fefd06d3b944 sys/arch/aarch64/aarch64/fpu.c
--- a/sys/arch/aarch64/aarch64/fpu.c    Sat Aug 01 02:05:45 2020 +0000
+++ b/sys/arch/aarch64/aarch64/fpu.c    Sat Aug 01 02:06:59 2020 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: fpu.c,v 1.7 2020/07/13 16:54:03 riastradh Exp $ */
+/* $NetBSD: fpu.c,v 1.8 2020/08/01 02:06:59 riastradh Exp $ */
 
 /*-
  * Copyright (c) 2014 The NetBSD Foundation, Inc.
@@ -31,10 +31,12 @@
 
 #include <sys/cdefs.h>
 
-__KERNEL_RCSID(1, "$NetBSD: fpu.c,v 1.7 2020/07/13 16:54:03 riastradh Exp $");
+__KERNEL_RCSID(1, "$NetBSD: fpu.c,v 1.8 2020/08/01 02:06:59 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/types.h>
+#include <sys/cpu.h>
+#include <sys/kthread.h>
 #include <sys/lwp.h>
 #include <sys/evcnt.h>
 
@@ -176,12 +178,30 @@
        __asm __volatile ("isb");
 }
 
+static const struct fpreg zero_fpreg;
+
+/*
+ * True if this is a system thread with its own private FPU state.
+ */
+static inline bool
+lwp_system_fpu_p(struct lwp *l)
+{
+
+       return (l->l_flag & (LW_SYSTEM|LW_SYSTEM_FPU)) ==
+           (LW_SYSTEM|LW_SYSTEM_FPU);
+}
+
 void
 fpu_kern_enter(void)
 {
        struct cpu_info *ci;
        int s;
 
+       if (lwp_system_fpu_p(curlwp) && !cpu_intr_p()) {
+               KASSERT(!cpu_softintr_p());
+               return;
+       }
+
        /*
         * Block interrupts up to IPL_VM.  We must block preemption
         * since -- if this is a user thread -- there is nowhere to
@@ -209,10 +229,16 @@
 void
 fpu_kern_leave(void)
 {
-       static const struct fpreg zero_fpreg;
-       struct cpu_info *ci = curcpu();
+       struct cpu_info *ci;
        int s;
 
+       if (lwp_system_fpu_p(curlwp) && !cpu_intr_p()) {
+               KASSERT(!cpu_softintr_p());
+               return;
+       }
+
+       ci = curcpu();
+
        KASSERT(ci->ci_cpl == IPL_VM);
        KASSERT(ci->ci_kfpu_spl != -1);
 
@@ -234,3 +260,19 @@
        ci->ci_kfpu_spl = -1;
        splx(s);
 }
+
+void
+kthread_fpu_enter_md(void)
+{
+
+       fpu_load(curlwp);
+}
+
+void
+kthread_fpu_exit_md(void)
+{
+
+       /* XXX Should fpu_state_release zero the registers itself?  */
+       load_fpregs(&zero_fpreg);
+       fpu_discard(curlwp, 0);
+}
diff -r 6cd900d5e0c5 -r fefd06d3b944 sys/arch/aarch64/aarch64/trap.c
--- a/sys/arch/aarch64/aarch64/trap.c   Sat Aug 01 02:05:45 2020 +0000
+++ b/sys/arch/aarch64/aarch64/trap.c   Sat Aug 01 02:06:59 2020 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: trap.c,v 1.34 2020/07/27 07:32:48 ryo Exp $ */
+/* $NetBSD: trap.c,v 1.35 2020/08/01 02:06:59 riastradh Exp $ */
 
 /*-
  * Copyright (c) 2014 The NetBSD Foundation, Inc.
@@ -31,7 +31,7 @@
 
 #include <sys/cdefs.h>
 
-__KERNEL_RCSID(1, "$NetBSD: trap.c,v 1.34 2020/07/27 07:32:48 ryo Exp $");
+__KERNEL_RCSID(1, "$NetBSD: trap.c,v 1.35 2020/08/01 02:06:59 riastradh Exp $");
 
 #include "opt_arm_intr_impl.h"
 #include "opt_compat_netbsd32.h"
@@ -242,6 +242,12 @@
                break;
 
        case ESR_EC_FP_ACCESS:
+               if ((curlwp->l_flag & (LW_SYSTEM|LW_SYSTEM_FPU)) ==
+                   (LW_SYSTEM|LW_SYSTEM_FPU)) {
+                       fpu_load(curlwp);
+                       break;
+               }
+               /*FALLTHROUGH*/
        case ESR_EC_FP_TRAP_A64:
        case ESR_EC_PC_ALIGNMENT:
        case ESR_EC_SP_ALIGNMENT: