[src/trunk]: src/sys/arch/amd64/include amd64: Make curlwp and curcpu() flush...

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

details:   https://anonhg.NetBSD.org/src/rev/638dde63874e
branches:  trunk
changeset: 374182:638dde63874e
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sun Apr 09 08:17:56 2023 +0000

description:
amd64: Make curlwp and curcpu() flushable.

The only effect of the `volatile' qualifier on an asm block with
outputs is to force the instructions to appear in the generated code,
even if the outputs end up being unused.  Since these instructions
have no (architectural) side effects -- provided %gs is set
correctly, which must be the case here -- there's no need for the
volatile qualifier, so nix it.

diffstat:

 sys/arch/amd64/include/cpu.h |  6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diffs (27 lines):

diff -r 3d1bb2e8a8a8 -r 638dde63874e sys/arch/amd64/include/cpu.h
--- a/sys/arch/amd64/include/cpu.h      Sun Apr 09 08:17:45 2023 +0000
+++ b/sys/arch/amd64/include/cpu.h      Sun Apr 09 08:17:56 2023 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: cpu.h,v 1.70 2021/11/02 11:26:03 ryo Exp $     */
+/*     $NetBSD: cpu.h,v 1.71 2023/04/09 08:17:56 riastradh Exp $       */
 
 /*-
  * Copyright (c) 1990 The Regents of the University of California.
@@ -53,7 +53,7 @@ x86_curcpu(void)
 {
        struct cpu_info *ci;
 
-       __asm volatile("movq %%gs:%1, %0" :
+       __asm("movq %%gs:%1, %0" :
            "=r" (ci) :
            "m"
            (*(struct cpu_info * const *)offsetof(struct cpu_info, ci_self)));
@@ -65,7 +65,7 @@ x86_curlwp(void)
 {
        lwp_t *l;
 
-       __asm volatile("movq %%gs:%1, %0" :
+       __asm("movq %%gs:%1, %0" :
            "=r" (l) :
            "m"
            (*(struct cpu_info * const *)offsetof(struct cpu_info, ci_curlwp)));