Date: Fri, 2 Sep 2022 15:02:31 +0200 From: =?UTF-8?B?VMSzbA==?= Coosemans <tijl@FreeBSD.org> To: Konstantin Belousov <kib@FreeBSD.org> Cc: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: Re: git: e8b2980e4a12 - main - i386 doreti: stop saving/restoring %ecx around calls into C Message-ID: <20220902150231.3ad4f16d@FreeBSD.org> In-Reply-To: <202208241925.27OJPCm0069172@gitrepo.freebsd.org> References: <202208241925.27OJPCm0069172@gitrepo.freebsd.org>
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On Wed, 24 Aug 2022 19:25:12 GMT Konstantin Belousov <kib@FreeBSD.org> wrote: > The branch main has been updated by kib: > > URL: https://cgit.FreeBSD.org/src/commit/?id=e8b2980e4a126407e15d33ee8d987385c8321261 > > commit e8b2980e4a126407e15d33ee8d987385c8321261 > Author: Konstantin Belousov <kib@FreeBSD.org> > AuthorDate: 2022-08-18 04:07:29 +0000 > Commit: Konstantin Belousov <kib@FreeBSD.org> > CommitDate: 2022-08-24 19:12:05 +0000 > > i386 doreti: stop saving/restoring %ecx around calls into C > > There is no reason to do this. Instead just calculate it later. > > Reviewed by: jhb > Tested by: pho > Sponsored by: The FreeBSD Foundation > MFC after: 1 week > Differential revision: https://reviews.freebsd.org/D36302 > --- > sys/i386/i386/exception.s | 17 ++++++++--------- > 1 file changed, 8 insertions(+), 9 deletions(-) > > diff --git a/sys/i386/i386/exception.s b/sys/i386/i386/exception.s > index 5eef9c1d512c..8279a4602ebf 100644 > --- a/sys/i386/i386/exception.s > +++ b/sys/i386/i386/exception.s > @@ -518,22 +518,21 @@ doreti_exit: > je doreti_iret_nmi > cmpl $T_TRCTRAP, TF_TRAPNO(%esp) > je doreti_iret_nmi > - movl $TF_SZ, %ecx > testl $PSL_VM,TF_EFLAGS(%esp) > - jz 1f /* PCB_VM86CALL is not set */ > - addl $VM86_STACK_SPACE, %ecx > - jmp 2f > -1: testl $SEL_RPL_MASK, TF_CS(%esp) > + jnz 1f /* PCB_VM86CALL is not set */ > + testl $SEL_RPL_MASK, TF_CS(%esp) > jz doreti_popl_fs > -2: movl $handle_ibrs_exit,%eax > - pushl %ecx /* preserve enough call-used regs */ > +1: movl $handle_ibrs_exit,%eax > call *%eax > movl mds_handler,%eax > call *%eax > - popl %ecx > movl %esp, %esi > movl PCPU(TRAMPSTK), %edx > - subl %ecx, %edx > + movl $TF_SZ, %ecx > + testl $PSL_VM,TF_EFLAGS(%esp) > + jz 2f /* PCB_VM86CALL is not set */ > + addl $VM86_STACK_SPACE, %ecx > +2: subl $TF_SZ, %edx Shouldn't this be "subl %ecx, %edx"?
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