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From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Ian Munsie <imunsie@au1.ibm.com>
Cc: Michal Marek <mmarek@suse.cz>, Sam Ravnborg <sam@ravnborg.org>,
	Albert Herranz <albert_herranz@yahoo.es>,
	linux-kernel@vger.kernel.org, paulus@samba.org,
	Andrew Morton <akpm@linux-foundation.org>,
	linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 02/18] powerpc: Add CROSSBE_COMPILE to build big endian boot wrapper
Date: Fri, 1 Oct 2010 09:13:19 +0200	[thread overview]
Message-ID: <AANLkTi=VmSXN6XeD__nkQLJAYXzxOh6WEtW6-jjJcC4Q@mail.gmail.com> (raw)
In-Reply-To: <1285916771-18033-3-git-send-email-imunsie@au1.ibm.com>

On Fri, Oct 1, 2010 at 09:05, Ian Munsie <imunsie@au1.ibm.com> wrote:
> From: Ian Munsie <imunsie@au1.ibm.com>
>
> Since the boot wrapper must be built by a big endian 32bit toolchain
> regardless of what the rest of the kernel is using introduce a new
> parameter to specify that toolchain - CROSSBE_COMPILE.
>
> We already have CROSS32_COMPILE which is already used for the boot
> wrapper, but it is also used to build the 32bit vdso which should be
> build in the same endianness as the rest of the kernel, so it is
> necessary to be able to specify the toolchain to build the boot wrapper
> separately from that used to build the vdso and again separately from
> that used to build the main kernel.
>
> CROSSBE_COMPILE should be pointed to a toolchain capable of targeting
> 32bit big endian powerpc, either specifically targetted at 32bit or
> bi-arch 64 and 32bit. If CROSSBE_COMPILE is not specified it will fall
> back to CROSS32_COMPILE to maintain compatibility with big endian
> targets.

Shouldn't the help text added by [PATCH 01/18]:

+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -329,3 +329,19 @@ config CHECK_CACHE_COHERENCY
       bool

 endmenu
+
+config ARCH_SUPPORTS_LITTLE_ENDIAN
+       bool
+
+config CPU_LITTLE_ENDIAN
+       bool "Build little endian kernel"
+       depends on ARCH_SUPPORTS_LITTLE_ENDIAN && EXPERIMENTAL
+       default n
+       help
+         This option selects whether a big endian or little endian kernel =
will
+         be built.
+
+         Note that if building a little endian kernel, CROSS_COMPILE must
+         point to a toolchain capable of targetting little endian powerpc,
+         while the toolchain specified by CROSS32_COMPILE must be capable =
of
+         targetting *BIG* endian PowerPC.

be updated here as well?

Gr{oetje,eeting}s,

=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k=
.org

In personal conversations with technical people, I call myself a hacker. Bu=
t
when I'm talking to journalists I just say "programmer" or something like t=
hat.
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0=C2=A0 =C2=A0=C2=A0 -- Linus Torvalds

  reply	other threads:[~2010-10-01  7:13 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-01  7:05 Introduce support for little endian PowerPC Ian Munsie
2010-10-01  7:05 ` [PATCH 01/18] powerpc: Add ability to build little endian kernels Ian Munsie
2010-10-01  9:18   ` Kumar Gala
2010-10-01 11:28     ` Josh Boyer
2010-10-01 12:09       ` Benjamin Herrenschmidt
2010-10-01 11:40   ` Josh Boyer
2010-10-01 12:22     ` Benjamin Herrenschmidt
2010-10-01  7:05 ` [PATCH 02/18] powerpc: Add CROSSBE_COMPILE to build big endian boot wrapper Ian Munsie
2010-10-01  7:13   ` Geert Uytterhoeven [this message]
2010-10-01  7:19     ` Ian Munsie
2010-10-01  7:05 ` [PATCH 03/18] powerpc: Support parsing a little endian kernel from zImage wrapper Ian Munsie
2010-10-01  7:05 ` [PATCH 04/18] powerpc: Allow taishan platform to boot a little endian kernel Ian Munsie
2010-10-01  7:05 ` [PATCH 05/18] powerpc: Wire up 44x little endian boot for remaining 44x targets Ian Munsie
2010-10-01 11:27   ` Josh Boyer
2010-10-06  1:28     ` Ian Munsie
2010-10-06  1:55       ` Josh Boyer
2010-10-06  2:10         ` Sean MacLennan
2010-10-01  7:05 ` [PATCH 06/18] powerpc 44x: Set E bit in TLBs and PTEs when CPU is in little endian mode Ian Munsie
2010-10-01  7:06 ` [PATCH 07/18] powerpc: Use generic bitops for little endian bitmap operations Ian Munsie
2010-10-01  7:06 ` [PATCH 08/18] powerpc: Include the appropriate endianness header Ian Munsie
2010-10-01  7:06 ` [PATCH 09/18] powerpc: Support device tree regardless of CPU endianness Ian Munsie
2010-10-03  3:15   ` Grant Likely
2010-10-03  6:22     ` Benjamin Herrenschmidt
2010-10-01  7:06 ` [PATCH 10/18] powerpc: Support endian agnostic MMIO Ian Munsie
2010-10-01  7:06 ` [PATCH 11/18] powerpc: Make assembly endian agnostic when accessing 64bit values Ian Munsie
2010-10-01  7:06 ` [PATCH 12/18] powerpc 44x: Handle TLB miss regardless of endianness Ian Munsie
2010-10-01  7:06 ` [PATCH 13/18] powerpc 44x: Make DCR endianness agnostic Ian Munsie
2010-10-01  7:06 ` [PATCH 14/18] powerpc, of_serial: Endianness issues setting up the serial ports Ian Munsie
2010-10-07 23:23   ` Grant Likely
2010-10-01  7:06 ` [PATCH 15/18] mtd: Fix endianness issues from device tree Ian Munsie
2010-10-01 19:29   ` Artem Bityutskiy
2010-10-01  7:06 ` [PATCH 16/18] powerpc: Fix endianness issues in alignment handler Ian Munsie
2010-10-01  7:06 ` [PATCH 17/18] net: Fix endianess issues in IBM newemac driver Ian Munsie
2010-10-01  7:06 ` [PATCH 18/18] powerpc: Fix jiffies variable on little endian Ian Munsie
2010-10-01  9:02 ` Introduce support for little endian PowerPC Kumar Gala
2010-10-01 11:30   ` Josh Boyer
2010-10-01 11:55     ` Gary Thomas
2010-10-01 12:15       ` Benjamin Herrenschmidt
2010-10-01 12:37         ` Gary Thomas
2010-10-01 12:14     ` Benjamin Herrenschmidt
2010-10-01 16:20       ` Michel Dänzer
2010-10-01 20:50         ` Benjamin Herrenschmidt
2010-10-04 10:30           ` Michel Dänzer
2010-10-04 22:50             ` Benjamin Herrenschmidt
2010-10-01 17:59       ` Kumar Gala
2010-10-01 20:51         ` Benjamin Herrenschmidt
2010-10-01 22:03           ` Olof Johansson
2010-10-01 22:28             ` Benjamin Herrenschmidt
2010-10-07 16:25             ` Hollis Blanchard
2010-10-01 11:36 ` Josh Boyer
2010-10-01 12:21   ` Benjamin Herrenschmidt
2010-10-06  1:04   ` Ian Munsie

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