| Message ID | 51E3638A.3080103@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Yes, It works now after using rev16 Regards Vijay On Mon, Jul 15, 2013 at 8:20 AM, <jgq516@gmail.com> wrote: > On 07/12/2013 08:00 PM, Ben Dooks wrote: >> >> On 12/07/13 12:56, Vijay Kilari wrote: >>> >>> On Fri, Jul 12, 2013 at 5:17 PM, Thomas Petazzoni >>> <thomas.petazzoni@free-electrons.com> wrote: >>>> >>>> Dear Vijay Kilari, >>>> >>>> On Fri, 12 Jul 2013 17:09:12 +0530, Vijay Kilari wrote: >>>> >>>>>> Ben Dooks has a separate branch on top of this base branch for >>>>>> big-endian support, that adds atags compat code to convert the ATAGs >>>>>> data from LE to BE. See the baserock/311/be/atags branch in >>>>>> git://git.baserock.org/delta/linux. Or >>>>>> >>>>>> http://git.baserock.org/cgi-bin/cgit.cgi/delta/linux.git/log/?h=baserock/311/be/atags. >>>>> >>>>> >>>>> ARM VE TC2 board, enabling CONFIG_THUMB2_KERNEL failed to boot in BE >>>>> mode >>>>> It hangs at very early stage of boot >>>> >>>> >>>> Yeah, the Thumb2 code is not supported by Ben Dooks patches, it's part >>>> of the TODO-list. I think Ben said he would probably not have much time >>>> to work on this. I might be able to spare some time on this, so just >>>> let me know if I should start working on this. If I remember correctly, >>>> it's mainly the fixup_pv_table code that needed some Thumb2/BE love. >>> >>> >>> In fact, I tried with below changes.. still it fails >>> >>> diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S >>> index 2de1114..7df64c7 100644 >>> --- a/arch/arm/kernel/head.S >>> +++ b/arch/arm/kernel/head.S >>> @@ -592,8 +592,14 @@ __fixup_a_pv_table: >>> b 2f >>> 1: add r7, r3 >>> ldrh ip, [r7, #2] >>> +#ifdef CONFIG_CPU_ENDIAN_BE8 >>> + rev ip, ip >>> +#endif >> >> >> Do you need a rev16 here? I think you may have tried >> reversing the full 32 bits here instead of just the >> 16bits of instruction that was loaded. >> > Thanks Ben, 3.4 kernel booted ok with your suggested modifications. > > gjiang@gjiang-desktop:~/work/be-a15$ git diff > diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S > index 0ad3af8..1a0196c 100644 > --- a/arch/arm/kernel/head.S > +++ b/arch/arm/kernel/head.S > @@ -600,8 +600,10 @@ __fixup_a_pv_table: > > b 2f > 1: add r7, r3 > ldrh ip, [r7, #2] > + rev16 ip, ip @be8 > > and ip, 0x8f00 > orr ip, r6 @ mask in offset bits 31-24 > + rev16 ip, ip @be8 > > strh ip, [r7, #2] > 2: cmp r4, r5 > ldrcc r7, [r4], #4 @ use branch for delay slot > > root@localhost:~# zcat /proc/config.gz |grep BE8 > CONFIG_CPU_ENDIAN_BE8=y > CONFIG_CPU_BE8_BOOT_LE=y > root@localhost:~# zcat /proc/config.gz |grep THUMB > CONFIG_ARM_THUMB=y > # CONFIG_ARM_THUMBEE is not set > CONFIG_THUMB2_KERNEL=y > CONFIG_THUMB2_AVOID_R_ARM_THM_JUMP11=y > > > Regards, > Xiao > >>> and ip, 0x8f00 >>> orr ip, r6 @ mask in offset bits 31-24 >>> +#ifdef CONFIG_CPU_ENDIAN_BE8 >>> + rev ip, ip >>> +#endif >>> strh ip, [r7, #2] >>> 2: cmp r4, r5 >>> ldrcc r7, [r4], #4 @ use branch for delay slot >>> >>>> >>>> Will, is getting Thumb2 working a requirement to get the BE support >>>> merged, or can we for now make the BE option depends on !THUMB2_KERNEL ? >>>> >>>> Thanks! >>>> >>>> Thomas >>>> -- >>>> Thomas Petazzoni, Free Electrons >>>> Kernel, drivers, real-time and embedded Linux >>>> development, consulting, training and support. >>>> http://free-electrons.com >> >> >> >
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index 0ad3af8..1a0196c 100644 --- a/arch/arm/kernel/head.S +++ b/arch/arm/kernel/head.S @@ -600,8 +600,10 @@ __fixup_a_pv_table: b 2f 1: add r7, r3 ldrh ip, [r7, #2] + rev16 ip, ip @be8 and ip, 0x8f00 orr ip, r6 @ mask in offset bits 31-24 + rev16 ip, ip @be8 strh ip, [r7, #2] 2: cmp r4, r5 ldrcc r7, [r4], #4 @ use branch for delay slot