From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763475AbdEWBHL (ORCPT ); Mon, 22 May 2017 21:07:11 -0400 Received: from mx07-00178001.pphosted.com ([62.209.51.94]:32779 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760103AbdEWBHK (ORCPT ); Mon, 22 May 2017 21:07:10 -0400 From: Vikas MANOCHA To: Patrice CHOTARD , Ard Biesheuvel CC: "linux@armlinux.org.uk" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Christophe PRIOUZEAU , Christophe KERELLO , Patrick DELAUNAY Subject: RE: [PATCH 1/1] ARM: compressed/head.S: fix __nop macro rept number for ARMv7M Thread-Topic: [PATCH 1/1] ARM: compressed/head.S: fix __nop macro rept number for ARMv7M Thread-Index: AQHSvaKPWLuUaD+E+UyEsXtLzXqRKKHwRBoAgAmviwCAAbrKAIAFl1qg Date: Tue, 23 May 2017 01:06:28 +0000 Message-ID: <489cca7ec7564ed4b6698c3da4010b2b@SFHDAG7NODE3.st.com> References: <1493110893-21857-1-git-send-email-patrice.chotard@st.com> <058263e4-458a-7939-1c1c-7bcd100cf2c5@st.com> In-Reply-To: <058263e4-458a-7939-1c1c-7bcd100cf2c5@st.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.75.127.50] Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-05-22_13:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id v4N17RIa017117 Hi Patrice, > -----Original Message----- > From: Patrice CHOTARD > Sent: Friday, May 19, 2017 6:41 AM > To: Ard Biesheuvel > Cc: linux@armlinux.org.uk; linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org; Christophe PRIOUZEAU > ; Christophe KERELLO ; Vikas MANOCHA ; > Patrick DELAUNAY > Subject: Re: [PATCH 1/1] ARM: compressed/head.S: fix __nop macro rept number for ARMv7M > > Hi Ard > > On 05/18/2017 01:16 PM, Ard Biesheuvel wrote: > > On 12 May 2017 at 08:22, Patrice CHOTARD wrote: > >> Hi all > >> > >> It's a gentle reminder to not forgot this patch. > >> > >> Thanks > >> > >> Patrice > >> > >> On 04/25/2017 11:01 AM, patrice.chotard@st.com wrote: > >>> From: Patrice Chotard > >>> > >>> In zImage, _magic_sig is located at offset 0x24. > >>> But for ARMv7M architecture which enable CPU_THUMBONLY and !EFI_STUB > >>> kernel flag, _magic_sig is located at offset 0x14 > >>> > >>> 00000000 00 46 00 46 00 46 00 46 00 46 00 46 00 46 0f f2 > >>> |.F.F.F.F.F.F.F.ò| > >>> 00000010 15 0c 60 47 18 28 6f 01 00 00 00 00 28 5c 0e 00 > >>> |..`G.(o.....(\..| > >>> 00000020 01 02 03 04 0f 46 90 46 00 00 00 00 00 00 00 00 > >>> |.....F.F........| > >>> > >>> Reproduced with stm32_defconfig with XIP_KERNEL flag disabled. > >>> > >>> To restore correct _magic_sig offset at 0x24, we add 8 additional > >>> "mov r0, r0" instruction. > >>> > >>> Signed-off-by: Patrice Chotard > >>> --- > >>> arch/arm/boot/compressed/head.S | 3 ++- > >>> 1 file changed, 2 insertions(+), 1 deletion(-) > >>> > >>> diff --git a/arch/arm/boot/compressed/head.S > >>> b/arch/arm/boot/compressed/head.S index 9150f97..5d9cda3 100644 > >>> --- a/arch/arm/boot/compressed/head.S > >>> +++ b/arch/arm/boot/compressed/head.S > >>> @@ -127,7 +127,8 @@ > >>> AR_CLASS( .arm ) > >>> start: > >>> .type start,#function > >>> - .rept 7 > >>> + ARM( .rept 7) > >>> + THUMB( .rept 15) > >>> > > > > Could you try using W(mov) instead of mov in the definition of __nop ? > > If i use W(mov) instead of mov in __nop macro, i need to add one additional "mov r0,r0" in THUMB case as following : > > > start: > .type start,#function > .rept 7 > __nop > .endr > ARM( mov r0, r0 ) > ARM( b 1f ) > + THUMB( mov r0, r0 ) No need of extra THUMB instruction, compiling previous mov r0,r0 should be good for both arm & thumb : __nop .endr mov r0, r0 /* 32 bit for arm & 16 bit for thumb */ ARM( b 1f ) THUMB( badr r12, 1f ) Cheers, Vikas > THUMB( badr r12, 1f ) > THUMB( bx r12 ) > > .word _magic_sig @ Magic numbers to help the loader > .word _magic_start @ absolute load/run zImage address > .word _magic_end @ zImage end address > .word 0x04030201 @ endianness flag > > > Which implementation do you prefer ? > > Thanks > > Patrice