From: Peter Zijlstra <peterz@infradead.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
mark.rutland@arm.com, dvyukov@google.com, seanjc@google.com,
pbonzini@redhat.com, mbenes@suse.cz
Subject: Re: [RFC][PATCH 02/22] x86,mmx_32: Remove .fixup usage
Date: Fri, 5 Nov 2021 09:05:47 +0100 [thread overview]
Message-ID: <20211105080547.GL174703@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20211104202220.xwm23nbpvwma6wds@treble>
On Thu, Nov 04, 2021 at 01:22:20PM -0700, Josh Poimboeuf wrote:
> On Thu, Nov 04, 2021 at 05:47:31PM +0100, Peter Zijlstra wrote:
> > This code puts an exception table entry on the "PREFIX" instruction to
> > overwrite it with a jmp.d8 when it triggers an exception. Except of
> > course, our code is no longer writable, also SMP.
> >
> > Replace it with ALTERNATIVE, the novel
> >
> > XXX: arguably we should just delete this code
> >
> > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> > ---
> > arch/x86/lib/mmx_32.c | 83 ++++++++++++++++----------------------------------
> > 1 file changed, 27 insertions(+), 56 deletions(-)
> >
> > --- a/arch/x86/lib/mmx_32.c
> > +++ b/arch/x86/lib/mmx_32.c
> > @@ -50,23 +50,17 @@ void *_mmx_memcpy(void *to, const void *
> > kernel_fpu_begin_mask(KFPU_387);
> >
> > __asm__ __volatile__ (
> > - "1: prefetch (%0)\n" /* This set is 28 bytes */
> > - " prefetch 64(%0)\n"
> > - " prefetch 128(%0)\n"
> > - " prefetch 192(%0)\n"
> > - " prefetch 256(%0)\n"
> > - "2: \n"
> > - ".section .fixup, \"ax\"\n"
> > - "3: movw $0x1AEB, 1b\n" /* jmp on 26 bytes */
> > - " jmp 2b\n"
> > - ".previous\n"
> > - _ASM_EXTABLE(1b, 3b)
> > - : : "r" (from));
> > + ALTERNATIVE "",
> > + "prefetch (%0)\n"
> > + "prefetch 64(%0)\n"
> > + "prefetch 128(%0)\n"
> > + "prefetch 192(%0)\n"
> > + "prefetch 256(%0)\n", X86_FEATURE_3DNOW
>
> I think this should instead be X86_FEATURE_3DNOWPREFETCH (which isn't
> 3DNow-specific and should really just be called X86_FEATURE_PREFETCH
> anyway)
Ack.
> > + : : "r" (from));
> >
> > for ( ; i > 5; i--) {
> > __asm__ __volatile__ (
> > - "1: prefetch 320(%0)\n"
> > - "2: movq (%0), %%mm0\n"
> > + " movq (%0), %%mm0\n"
>
> Not sure why this prefetch was removed? It can also be behind an
> alternative just like the first one.
Urgh, that was me just plain killing all the prefetch in there and
forgetting to put it back :/ Will fix.
next prev parent reply other threads:[~2021-11-05 8:05 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-04 16:47 [RFC][PATCH 00/22] x86: Remove anonymous out-of-line fixups Peter Zijlstra
2021-11-04 16:47 ` [RFC][PATCH 01/22] bitfield.h: Fix "type of reg too small for mask" test Peter Zijlstra
2021-11-04 16:47 ` [RFC][PATCH 02/22] x86,mmx_32: Remove .fixup usage Peter Zijlstra
2021-11-04 18:00 ` Borislav Petkov
2021-11-05 11:20 ` David Laight
2021-11-04 20:22 ` Josh Poimboeuf
2021-11-05 8:05 ` Peter Zijlstra [this message]
2021-11-04 16:47 ` [RFC][PATCH 03/22] x86,copy_user_64: " Peter Zijlstra
2021-11-04 16:47 ` [RFC][PATCH 04/22] x86,copy_mc_64: " Peter Zijlstra
2021-11-04 16:47 ` [RFC][PATCH 05/22] x86,entry_64: " Peter Zijlstra
2021-11-04 16:47 ` [RFC][PATCH 06/22] x86,entry_32: " Peter Zijlstra
2021-11-04 20:39 ` Josh Poimboeuf
2021-11-05 7:43 ` Peter Zijlstra
2021-11-04 16:47 ` [RFC][PATCH 07/22] x86,extable: Extend extable functionality Peter Zijlstra
2021-11-04 21:49 ` Josh Poimboeuf
2021-11-05 7:54 ` Peter Zijlstra
2021-11-05 10:16 ` Mark Rutland
2021-11-05 17:32 ` Sean Christopherson
2021-11-05 18:45 ` Peter Zijlstra
2021-11-05 19:17 ` Sean Christopherson
2021-11-05 19:32 ` Peter Zijlstra
2021-11-05 19:47 ` Sean Christopherson
2021-11-05 20:15 ` Peter Zijlstra
2021-11-05 20:26 ` Peter Zijlstra
2021-11-05 22:30 ` Sean Christopherson
2021-11-04 16:47 ` [RFC][PATCH 08/22] x86,msr: Remove .fixup usage Peter Zijlstra
2021-11-04 16:47 ` [RFC][PATCH 09/22] x86,futex: " Peter Zijlstra
2021-11-04 16:47 ` [RFC][PATCH 10/22] x86,uaccess: " Peter Zijlstra
2021-11-04 22:28 ` Josh Poimboeuf
2021-11-04 16:47 ` [RFC][PATCH 11/22] x86,xen: " Peter Zijlstra
2021-11-04 22:31 ` Josh Poimboeuf
2021-11-05 7:56 ` Peter Zijlstra
2021-11-04 16:47 ` [RFC][PATCH 12/22] x86,fpu: " Peter Zijlstra
2021-11-04 16:47 ` [RFC][PATCH 13/22] x86,segment: " Peter Zijlstra
2021-11-04 16:47 ` [RFC][PATCH 14/22] x86,ftrace: " Peter Zijlstra
2021-11-04 22:35 ` Josh Poimboeuf
2021-11-05 7:57 ` Peter Zijlstra
2021-11-04 16:47 ` [RFC][PATCH 15/22] x86,vmx: " Peter Zijlstra
2021-11-04 18:50 ` Paolo Bonzini
2021-11-05 18:17 ` Sean Christopherson
2021-11-05 18:52 ` Peter Zijlstra
2021-11-05 20:58 ` Peter Zijlstra
2021-11-05 22:29 ` Sean Christopherson
2021-11-06 7:05 ` Paolo Bonzini
2021-11-06 8:36 ` Peter Zijlstra
2021-11-07 19:13 ` Paolo Bonzini
2021-11-06 8:28 ` Peter Zijlstra
2021-11-04 16:47 ` [RFC][PATCH 16/22] x86,checksum_32: " Peter Zijlstra
2021-11-04 16:47 ` [RFC][PATCH 17/22] x86,sgx: " Peter Zijlstra
2021-11-04 16:47 ` [RFC][PATCH 18/22] x86,kvm: " Peter Zijlstra
2021-11-04 18:50 ` Paolo Bonzini
2021-11-05 7:58 ` Peter Zijlstra
2021-11-04 16:47 ` [RFC][PATCH 19/22] x86,usercopy_32: Simplify Peter Zijlstra
2021-11-04 16:47 ` [RFC][PATCH 20/22] x86,usercopy: Remove .fixup usage Peter Zijlstra
2021-11-04 16:47 ` [RFC][PATCH 21/22] x86,word-at-a-time: " Peter Zijlstra
2021-11-04 23:33 ` Josh Poimboeuf
2021-11-05 8:04 ` Peter Zijlstra
2021-11-04 16:47 ` [RFC][PATCH 22/22] x86: Remove .fixup section Peter Zijlstra
2021-11-04 23:00 ` Josh Poimboeuf
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20211105080547.GL174703@worktop.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=dvyukov@google.com \
--cc=jpoimboe@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=mbenes@suse.cz \
--cc=pbonzini@redhat.com \
--cc=seanjc@google.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).