[src/trunk]: src/sys/arch/aarch64/aarch64 slightly optimized loop for trap_do...

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

details:   https://anonhg.NetBSD.org/src/rev/243458a24951
branches:  trunk
changeset: 940710:243458a24951
user:      ryo <ryo%NetBSD.org@localhost>
date:      Thu Oct 15 08:37:20 2020 +0000

description:
slightly optimized loop for trap_doast() calls

diffstat:

 sys/arch/aarch64/aarch64/vectors.S |  22 +++++++++++-----------
 1 files changed, 11 insertions(+), 11 deletions(-)

diffs (54 lines):

diff -r 8e176ba387d1 -r 243458a24951 sys/arch/aarch64/aarch64/vectors.S
--- a/sys/arch/aarch64/aarch64/vectors.S        Thu Oct 15 07:05:27 2020 +0000
+++ b/sys/arch/aarch64/aarch64/vectors.S        Thu Oct 15 08:37:20 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vectors.S,v 1.20 2020/10/06 06:26:46 skrll Exp $       */
+/*     $NetBSD: vectors.S,v 1.21 2020/10/15 08:37:20 ryo Exp $ */
 
 #include <aarch64/asm.h>
 #include <aarch64/locore.h>
@@ -10,7 +10,7 @@
 #include "opt_ddb.h"
 #include "opt_dtrace.h"
 
-RCSID("$NetBSD: vectors.S,v 1.20 2020/10/06 06:26:46 skrll Exp $")
+RCSID("$NetBSD: vectors.S,v 1.21 2020/10/15 08:37:20 ryo Exp $")
 
        ARMV8_DEFINE_OPTIONS
 
@@ -255,26 +255,26 @@
        nop                             /* dummy for DDB backtrace (for lr-4) */
 #endif
 ENTRY_NP(el0_trap_exit)
-       DISABLE_INTERRUPT               /* make sure I|F marked */
+
+       adr     lr, 1f                  /* return address from trap_doast */
 1:
        /* while (curlwp->l_md.md_astpending != 0) { */
-       mrs     x8, tpidr_el1
-       ldr     w9, [x8, #L_MD_ASTPENDING]
-       cbz     w9, 9f
+       DISABLE_INTERRUPT               /* make sure I|F marked */
+       mrs     x9, tpidr_el1
+       ldr     w8, [x9, #L_MD_ASTPENDING]
+       cbz     w8, 9f
 
        /* curlwp->l_md.md_astpending = 0; */
-       str     xzr, [x8, #L_MD_ASTPENDING]
+       str     xzr, [x9, #L_MD_ASTPENDING]
 
        /*  trap_doast(tf); */
        ENABLE_INTERRUPT
        mov     x0, sp
-       bl      _C_LABEL(trap_doast)
-       DISABLE_INTERRUPT
-       b       1b
+       b       _C_LABEL(trap_doast)    /* tail call (return to 1b) */
        /* } */
 9:
 
-       mrs     x9, tpidr_el1
+       /* x9 is tpidr_el1 */
        ldr     x23, [x9, #L_MD_CPACR]
        msr     cpacr_el1, x23          /* FP unit EL0 handover */
        isb                             /* necessary? */