[src/trunk]: src/sys/arch/amd64/amd64 Don't push/pop %rdx, we don't care abou...

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

details:   https://anonhg.NetBSD.org/src/rev/9fdb03e73828
branches:  trunk
changeset: 991342:9fdb03e73828
user:      maxv <maxv%NetBSD.org@localhost>
date:      Mon Jul 09 18:52:04 2018 +0000

description:
Don't push/pop %rdx, we don't care about preserving its value.

diffstat:

 sys/arch/amd64/amd64/locore.S |  8 +-------
 1 files changed, 1 insertions(+), 7 deletions(-)

diffs (47 lines):

diff -r 2061ee4c63c6 -r 9fdb03e73828 sys/arch/amd64/amd64/locore.S
--- a/sys/arch/amd64/amd64/locore.S     Mon Jul 09 18:43:05 2018 +0000
+++ b/sys/arch/amd64/amd64/locore.S     Mon Jul 09 18:52:04 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: locore.S,v 1.168 2018/07/09 18:43:05 maxv Exp $        */
+/*     $NetBSD: locore.S,v 1.169 2018/07/09 18:52:04 maxv Exp $        */
 
 /*
  * Copyright-o-rama!
@@ -1105,21 +1105,17 @@
        jnz     .Lswitch_return
 
 #ifdef SVS
-       pushq   %rdx
        movb    _C_LABEL(svs_enabled),%dl
        testb   %dl,%dl
        jz      .Lskip_svs
        callq   _C_LABEL(svs_lwp_switch)
 .Lskip_svs:
-       popq    %rdx
 #endif
 
 #ifndef XEN
-       pushq   %rdx
        movq    %r13,%rdi
        movq    %r12,%rsi
        callq   _C_LABEL(speculation_barrier)
-       popq    %rdx
 #endif
 
        /* Switch ring0 stack */
@@ -1147,7 +1143,6 @@
 .Lring0_switched:
 
 #ifndef XEN
-       pushq   %rdx
        movb    _C_LABEL(x86_fpu_eager),%dl
        testb   %dl,%dl
        jz      .Lno_eagerfpu
@@ -1155,7 +1150,6 @@
        movq    %r12,%rsi
        callq   _C_LABEL(fpu_eagerswitch)
 .Lno_eagerfpu:
-       popq    %rdx
 #endif
 
        /* Don't bother with the rest if switching to a system process. */