public inbox for
 help / color / mirror / Atom feed
From: Lewis Zhou <>
Subject: Fwd: selected processor does not support `rev r7,r7'
Date: Thu, 21 Mar 2019 08:24:00 -0000	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>


I recently tried to compile the barebox bootloaer with the
arm-cortex_a8-linux-gnueabihf configuration which is based on the
sample configuration arm-cortex_a8-linux-gnueabi with the hardware
float enabled.

However, the compiler (gcc) seems not support -march=armv7-a flag. I
think something is wrong as the cortex_a8 is a sub-architecture of

The toolchain failed to compile both the barebox and the linux kernel
(4.19). Please help! Attached is a response from the barebox mailing

Kind regards,

---------- Forwarded message ---------
From: Sascha Hauer <>
Date: Thu, Mar 21, 2019 at 4:06 PM
Subject: Re: selected processor does not support `rev r7,r7'
To: Lewis Zhou <>
Cc: <>

On Thu, Mar 21, 2019 at 03:53:06PM +0800, Lewis Zhou wrote:
> Hi Sascha,
> Here's the log:
> make -f scripts/ obj=common
> arm-cortex_a8-linux-gnueabihf-gcc -Wp,-MD,common/.memory.o.d
> -nostdinc -isystem
> /home/lewis/x-tools/arm-cortex_a8-linux-gnueabihf/lib/gcc/arm-cortex_a8-linux-gnueabihf/8.3.0/include
> -D__KERNEL__ -D__BAREBOX__ -Iinclude
> -I/home/lewis/OpenProj/barebox/dts/include
> -I/home/lewis/OpenProj/barebox/arch/arm/include
> -I/home/lewis/OpenProj/barebox/arch/arm/include -include
> /home/lewis/OpenProj/barebox/include/linux/kconfig.h -fno-builtin
> -ffreestanding -D__ARM__ -fno-strict-aliasing -marm -mlittle-endian
> -mabi=aapcs-linux -mno-thumb-interwork -D__LINUX_ARM_ARCH__=7
> -march=armv5t -Wa,-march=armv7-a  -msoft-float -mthumb

-march=armv5t -Wa,-march=armv7-a shouldn't be here. It comes from this
line in arch/arm/Makefile:

arch-$(CONFIG_CPU_32v7)         :=-D__LINUX_ARM_ARCH__=7 $(call
cc-option,-march=armv7-a,-march=armv5t -Wa$(comma)-march=armv7-a)

This means the build process will use "-march=armv7-a" when the compiler
supports it. Apparently it does not, so it will fall back to
"-march=armv5t -Wa,-march=armv7-a". armv5t doesn't support thumb2 code,
only thumb and as it seems thumb does not support the "rev" instruction.

Your compiler should really support "-march=armv7-a". If it doesn't I
really think there is something wrong with it.


Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 |  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

       reply	other threads:[~2019-03-21  8:24 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <>
     [not found] ` <>
     [not found]   ` <>
     [not found]     ` <>
     [not found]       ` <>
     [not found]         ` <>
2019-03-21  8:24           ` Lewis Zhou [this message]
2019-03-21  8:40             ` Austin Morton
     [not found]               ` <>
2019-03-21  9:15                 ` Austin Morton
     [not found]               ` <>
     [not found]                 ` <>
2019-03-22  4:01                   ` Austin Morton

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:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \

* 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 read-only IMAP folder(s) and NNTP newsgroup(s).