From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1GEvD4-0008LG-L6 for qemu-devel@nongnu.org; Sun, 20 Aug 2006 17:51:58 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1GEvD1-0008HX-PU for qemu-devel@nongnu.org; Sun, 20 Aug 2006 17:51:58 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1GEvD1-0008HL-L1 for qemu-devel@nongnu.org; Sun, 20 Aug 2006 17:51:55 -0400 Received: from [66.249.92.174] (helo=ug-out-1314.google.com) by monty-python.gnu.org with esmtp (Exim 4.52) id 1GEvKG-00008B-E4 for qemu-devel@nongnu.org; Sun, 20 Aug 2006 17:59:24 -0400 Received: by ug-out-1314.google.com with SMTP id s2so1503134uge for ; Sun, 20 Aug 2006 14:51:53 -0700 (PDT) Message-ID: Date: Mon, 21 Aug 2006 01:51:53 +0400 From: "Igor Kovalenko" Subject: Re: [Qemu-devel] [PATCH] handle multibyte NOPs In-Reply-To: <200608190128.12476.paul@codesourcery.com> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_25047_22488380.1156110713093" References: <200608190128.12476.paul@codesourcery.com> Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org ------=_Part_25047_22488380.1156110713093 Content-Type: multipart/alternative; boundary="----=_Part_25048_5091292.1156110713093" ------=_Part_25048_5091292.1156110713093 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline On 8/19/06, Paul Brook wrote: > > On Saturday 19 August 2006 00:40, Igor Kovalenko wrote: > > Hi! > > > > This patch adds handling of multi-byte NOPs, recent gcc/gas uses them > for > > x86 code padding. > > Patch checked with current opensuse-factory x86 guest installation which > is > > built with new gcc/gas tools. > > According to my amd64 documentation all of the opcodes 0f 19 through 0f 1f > should be implemented as a NOP. Also, I suspect the "invalid" prefetch ops > (0f 18) should also be implemented as nops. > The same implementation should be useable to all these opcodes. > > Updated patch, extracted noop modrm processing into separate function and used it for 0f 18 case as well. I also removed reg sense from noop processing. -- Kind Regards, Igor V. Kovalenko ------=_Part_25048_5091292.1156110713093 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline On 8/19/06, Paul Brook <paul@codesourcery.com> wrote:
On Saturday 19 August 2006 00:40, Igor Kovalenko wrote:
> Hi!
>
> This patch adds handling of multi-byte NOPs, recent gcc/gas uses them for
> x86 code padding.
> Patch checked with current opensuse-factory x86 guest installation which is
> built with new gcc/gas tools.

According to my amd64 documentation all of the opcodes 0f 19 through 0f 1f
should be implemented as a NOP. Also, I suspect the "invalid" prefetch ops
(0f 18) should also be implemented as nops.
The same implementation should be useable to all these opcodes.


Updated patch, extracted noop modrm processing into separate function and used it for 0f 18 case as well. I also removed reg sense from noop processing.

--
Kind Regards,
Igor V. Kovalenko ------=_Part_25048_5091292.1156110713093-- ------=_Part_25047_22488380.1156110713093 Content-Type: text/plain; name=x86-multibyte-noop-4.diff; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: base64 X-Attachment-Id: f_er3wkyki Content-Disposition: attachment; filename="x86-multibyte-noop-4.diff" SW5kZXg6IHRhcmdldC1pMzg2L3RyYW5zbGF0ZS5jCj09PT09PT09PT09PT09PT09PT09PT09PT09 PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT0KUkNTIGZpbGU6IC9jdnNy b290L3FlbXUvcWVtdS90YXJnZXQtaTM4Ni90cmFuc2xhdGUuYyx2CnJldHJpZXZpbmcgcmV2aXNp b24gMS41OQpkaWZmIC11IC1yMS41OSB0cmFuc2xhdGUuYwotLS0gdGFyZ2V0LWkzODYvdHJhbnNs YXRlLmMJMTAgSnVsIDIwMDYgMTk6NTM6MDQgLTAwMDAJMS41OQorKysgdGFyZ2V0LWkzODYvdHJh bnNsYXRlLmMJMjAgQXVnIDIwMDYgMjA6NTQ6MzcgLTAwMDAKQEAgLTE2MTUsNiArMTYxNSw0MyBA QAogICAgICpvZmZzZXRfcHRyID0gZGlzcDsKIH0KIAorc3RhdGljIHZvaWQgZ2VuX25vcF9tb2Ry bShEaXNhc0NvbnRleHQgKnMsIGludCBtb2RybSkKK3sKKyAgICBpbnQgcm0sIG1vZDsKKyAgICBy bSAgPSBtb2RybSAmIDc7CisgICAgbW9kID0gKG1vZHJtID4+IDYpICYgMzsKKworICAgIGlmIChy bSA9PSAweDA0KQorICAgIHsKKyAgICAgICAgLyogU0lCIGJ5dGUgZm9sbG93cyAqLworICAgICAg ICBzLT5wYyArPSAxOworICAgIH0KKworICAgIHN3aXRjaCAobW9kKQorICAgIHsKKyAgICAgICAg Y2FzZSAweDAwOgorICAgICAgICAgICAgaWYgKHJtID09IDB4MDUpCisgICAgICAgICAgICB7Cisg ICAgICAgICAgICAgICAgLyogMzJiaXQgZGF0YSBmb2xsb3dzICovCisgICAgICAgICAgICAgICAg cy0+cGMgKz0gNDsKKyAgICAgICAgICAgIH0KKyAgICAgICAgICAgIC8qIGVsc2UgcmVnaXN0ZXIg aXMgc3BlY2lmaWVkICovCisgICAgICAgICAgICBicmVhazsKKyAgICAgICAgY2FzZSAweDAxOgor ICAgICAgICAgICAgLyogOGJpdCBkYXRhIGZvbGxvd3MgKi8KKyAgICAgICAgICAgIHMtPnBjICs9 IDE7CisgICAgICAgICAgICBicmVhazsKKyAgICAgICAgY2FzZSAweDEwOgorICAgICAgICAgICAg LyogMzJiaXQgZGF0YSBmb2xsb3dzICovCisgICAgICAgICAgICBzLT5wYyArPSA0OworICAgICAg ICAgICAgYnJlYWs7CisgICAgICAgIGNhc2UgMHgxMToKKyAgICAgICAgZGVmYXVsdDoKKyAgICAg ICAgICAgIC8qIHJlZ2lzdGVyIGlzIHNwZWNpZmllZCAqLworICAgICAgICAgICAgYnJlYWs7Cisg ICAgfQorfQorCiAvKiB1c2VkIGZvciBMRUEgYW5kIE1PViBBWCwgbWVtICovCiBzdGF0aWMgdm9p ZCBnZW5fYWRkX0EwX2RzX3NlZyhEaXNhc0NvbnRleHQgKnMpCiB7CkBAIC01NzkyLDkgKzU4Mjks MTUgQEAKICAgICAgICAgICAgIC8qIG5vdGhpbmcgbW9yZSB0byBkbyAqLwogICAgICAgICAgICAg YnJlYWs7CiAgICAgICAgIGRlZmF1bHQ6Ci0gICAgICAgICAgICBnb3RvIGlsbGVnYWxfb3A7Cisg ICAgICAgICAgICBnZW5fbm9wX21vZHJtKHMsIG1vZHJtKTsKKyAgICAgICAgICAgIGJyZWFrOwog ICAgICAgICB9CiAgICAgICAgIGJyZWFrOworICAgIGNhc2UgMHgxMTkgLi4uIDB4MTFmOgorICAg ICAgICAvKiBtdWx0aS1ieXRlIG5vb3AgKi8KKyAgICAgICAgbW9kcm0gPSBsZHViX2NvZGUocy0+ cGMrKyk7CisgICAgICAgIGdlbl9ub3BfbW9kcm0ocywgbW9kcm0pOworICAgICAgICBicmVhazsK ICAgICBjYXNlIDB4MTIwOiAvKiBtb3YgcmVnLCBjck4gKi8KICAgICBjYXNlIDB4MTIyOiAvKiBt b3YgY3JOLCByZWcgKi8KICAgICAgICAgaWYgKHMtPmNwbCAhPSAwKSB7Cg== ------=_Part_25047_22488380.1156110713093--