[src/trunk]: src/sys/arch/usermode/dev Only set requested parts of the mconte...

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

details:   https://anonhg.NetBSD.org/src/rev/a8692be5e1df
branches:  trunk
changeset: 319423:a8692be5e1df
user:      reinoud <reinoud%NetBSD.org@localhost>
date:      Tue May 29 07:09:21 2018 +0000

description:
Only set requested parts of the mcontext in cpu_setmcontext()
Make the atomic switcher `atomic' by using splhigh()

diffstat:

 sys/arch/usermode/dev/cpu.c |  39 ++++++++++++++++++++++++++++++---------
 1 files changed, 30 insertions(+), 9 deletions(-)

diffs (103 lines):

diff -r 3186e3f379ac -r a8692be5e1df sys/arch/usermode/dev/cpu.c
--- a/sys/arch/usermode/dev/cpu.c       Tue May 29 06:14:33 2018 +0000
+++ b/sys/arch/usermode/dev/cpu.c       Tue May 29 07:09:21 2018 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: cpu.c,v 1.76 2018/05/24 19:39:04 reinoud Exp $ */
+/* $NetBSD: cpu.c,v 1.77 2018/05/29 07:09:21 reinoud Exp $ */
 
 /*-
  * Copyright (c) 2007 Jared D. McNeill <jmcneill%invisible.ca@localhost>
@@ -30,7 +30,7 @@
 #include "opt_hz.h"
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.76 2018/05/24 19:39:04 reinoud Exp $");
+__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.77 2018/05/29 07:09:21 reinoud Exp $");
 
 #include <sys/param.h>
 #include <sys/conf.h>
@@ -194,7 +194,6 @@
 }
 
 
-/* XXX make sure this is atomic? */
 static
 void
 cpu_switchto_atomic(lwp_t *oldlwp, lwp_t *newlwp)
@@ -202,19 +201,22 @@
        struct pcb *oldpcb;
        struct pcb *newpcb;
        struct cpu_info *ci;
+       int s;
 
        oldpcb = oldlwp ? lwp_getpcb(oldlwp) : NULL;
        newpcb = lwp_getpcb(newlwp);
        ci = curcpu();
 
+       s = splhigh();
+
        ci->ci_stash = oldlwp;
-
        if (oldpcb)
                oldpcb->pcb_errno = thunk_geterrno();
 
        thunk_seterrno(newpcb->pcb_errno);
 
        /* set both ucontexts up for TLS just in case */
+
        newpcb->pcb_ucp.uc_mcontext._mc_tlsbase =
                (uintptr_t) newlwp->l_private;
        newpcb->pcb_ucp.uc_flags |= _UC_TLSBASE;
@@ -224,8 +226,11 @@
        newpcb->pcb_userret_ucp.uc_flags |= _UC_TLSBASE;
 
        curlwp = newlwp;
+       splx(s);
+
        if (thunk_setcontext(&newpcb->pcb_ucp))
                panic("setcontext failed");
+
        /* not reached */
 }
 
@@ -341,11 +346,28 @@
 #ifdef CPU_DEBUG
        thunk_printf_debug("cpu_setmcontext\n");
 #endif
-       ucp->uc_flags = flags;
-       memcpy(&ucp->uc_mcontext, mcp, sizeof(mcontext_t));
+       if ((flags & _UC_CPU) != 0)
+               memcpy(&ucp->uc_mcontext.__gregs, mcp->__gregs, sizeof(__gregset_t));
+       if ((flags & _UC_FPU) != 0)
+               memcpy(&ucp->uc_mcontext.__fpregs, mcp->__fpregs, sizeof(__fpregset_t));
+       if ((flags & _UC_TLSBASE) != 0)
+               lwp_setprivate(l, (void *) (uintptr_t) mcp->_mc_tlsbase);
 
-       /* update our private, it might be altered in userland */
-       l->l_private = (void *) ucp->uc_mcontext._mc_tlsbase;
+#if 0
+       /*
+        * XXX we ignore the set and clear stack since signals are done
+        * slightly differently.
+        */
+thunk_printf("%s: flags %x\n", __func__, flags);
+       mutex_enter(l->l_proc->p_lock);
+       if (flags & _UC_SETSTACK)
+               l->l_sigstk.ss_flags |= SS_ONSTACK;
+       if (flags & _UC_CLRSTACK)
+               l->l_sigstk.ss_flags &= ~SS_ONSTACK;
+       mutex_exit(l->l_proc->p_lock);
+#endif
+
+       ucp->uc_flags |= (flags & (_UC_CPU | _UC_FPU | _UC_TLSBASE));
 
        return 0;
 }
@@ -410,7 +432,6 @@
            l2 ? l2->l_name : "none", l2,
            stack, (int)stacksize);
 #endif
-
        if (stack)
                panic("%s: stack passed, can't handle\n", __func__);