[src/trunk]: src/sys/arch Add __HAVE_PREEMPTION support to gic_splfuncs asm f...

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

details:   https://anonhg.NetBSD.org/src/rev/4459cf6289bb
branches:  trunk
changeset: 990595:4459cf6289bb
user:      jmcneill <jmcneill%NetBSD.org@localhost>
date:      Sat Oct 30 20:23:11 2021 +0000

description:
Add __HAVE_PREEMPTION support to gic_splfuncs asm funcs.

"looks right to me" - thorpej

diffstat:

 sys/arch/aarch64/aarch64/genassym.cf     |   3 +-
 sys/arch/arm/cortex/gic_splfuncs_armv8.S |  35 ++++++++++++++++++++++++-------
 2 files changed, 29 insertions(+), 9 deletions(-)

diffs (101 lines):

diff -r 8a48a14204c1 -r 4459cf6289bb sys/arch/aarch64/aarch64/genassym.cf
--- a/sys/arch/aarch64/aarch64/genassym.cf      Sat Oct 30 20:01:46 2021 +0000
+++ b/sys/arch/aarch64/aarch64/genassym.cf      Sat Oct 30 20:23:11 2021 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: genassym.cf,v 1.36 2021/10/30 18:49:47 jmcneill Exp $
+# $NetBSD: genassym.cf,v 1.37 2021/10/30 20:23:11 jmcneill Exp $
 #-
 # Copyright (c) 2014 The NetBSD Foundation, Inc.
 # All rights reserved.
@@ -163,6 +163,7 @@
 define L_MD_DA_USER            offsetof(struct lwp, l_md.md_da_user)
 define L_MD_DB_USER            offsetof(struct lwp, l_md.md_db_user)
 define L_MD_GA_USER            offsetof(struct lwp, l_md.md_ga_user)
+define L_NOPREEMPT             offsetof(struct lwp, l_nopreempt)
 define LW_SYSTEM               LW_SYSTEM
 
 define FB_X19                  FB_X19
diff -r 8a48a14204c1 -r 4459cf6289bb sys/arch/arm/cortex/gic_splfuncs_armv8.S
--- a/sys/arch/arm/cortex/gic_splfuncs_armv8.S  Sat Oct 30 20:01:46 2021 +0000
+++ b/sys/arch/arm/cortex/gic_splfuncs_armv8.S  Sat Oct 30 20:23:11 2021 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: gic_splfuncs_armv8.S,v 1.1 2021/10/30 18:44:24 jmcneill Exp $ */
+/* $NetBSD: gic_splfuncs_armv8.S,v 1.2 2021/10/30 20:23:12 jmcneill Exp $ */
 
 /*-
  * Copyright (c) 2021 Jared McNeill <jmcneill%invisible.ca@localhost>
@@ -29,7 +29,21 @@
 #include <machine/asm.h>
 #include "assym.h"
 
-RCSID("$NetBSD: gic_splfuncs_armv8.S,v 1.1 2021/10/30 18:44:24 jmcneill Exp $")
+RCSID("$NetBSD: gic_splfuncs_armv8.S,v 1.2 2021/10/30 20:23:12 jmcneill Exp $")
+
+#ifdef __HAVE_PREEMPTION
+#define        DISABLE_PREEMPTION                      \
+       ldr     w1, [x3, #L_NOPREEMPT];         \
+       add     w1, w1, #1;                     \
+       str     w1, [x3, #L_NOPREEMPT]
+#define        ENABLE_PREEMPTION                       \
+       ldr     w1, [x3, #L_NOPREEMPT];         \
+       sub     w1, w1, #1;                     \
+       str     w1, [x3, #L_NOPREEMPT]
+#else
+#define        DISABLE_PREEMPTION
+#define        ENABLE_PREEMPTION
+#endif
 
 /*
  * int
@@ -39,9 +53,10 @@
  */
        .align 7        /* cacheline-aligned */
 ENTRY_NP(gic_splraise)
-       /* Save cpu_info pointer in x1 */
-       mrs     x1, tpidr_el1                   /* get curlwp */
-       ldr     x1, [x1, #L_CPU]                /* get curcpu */
+       /* Save curlwp in x3, curcpu in x1 */
+       mrs     x3, tpidr_el1                   /* get curlwp */
+       DISABLE_PREEMPTION
+       ldr     x1, [x3, #L_CPU]                /* get curcpu */
 
        /* If newipl > cpl, update cpl */
        ldr     w2, [x1, #CI_CPL]
@@ -50,6 +65,7 @@
        str     w0, [x1, #CI_CPL]
 
 .Lnoraise:
+       ENABLE_PREEMPTION
        mov     w0, w2                          /* return oldipl */
        ret
 END(gic_splraise)
@@ -63,9 +79,10 @@
  */
        .align 7        /* cacheline-aligned */
 ENTRY_NP(gic_splx)
-       /* Save cpu_info pointer in x1 */
-       mrs     x1, tpidr_el1                   /* get curlwp */
-       ldr     x1, [x1, #L_CPU]                /* get curcpu */
+       /* Save curlwp in x3, curcpu in x1 */
+       mrs     x3, tpidr_el1                   /* get curlwp */
+       DISABLE_PREEMPTION
+       ldr     x1, [x3, #L_CPU]                /* get curcpu */
 
        /* If newipl >= cpl, just return */
        ldr     w2, [x1, #CI_CPL]
@@ -99,6 +116,7 @@
        cbnz    w2, _C_LABEL(dosoftints)
 
 .Ldone:
+       ENABLE_PREEMPTION
        ret
 
 .Lrestart:
@@ -113,6 +131,7 @@
        str     xzr, [x1, #CI_SPLX_RESTART]
 
 .Lslow:
+       ENABLE_PREEMPTION
        /* Jump to slow path */
        b       _C_LABEL(Xgic_splx)
 END(gic_splx)