From: Michael Ellerman <mpe@ellerman•id.au>
To: Anshuman Khandual <khandual@linux•vnet.ibm.com>
Cc: linuxppc-dev@ozlabs•org, linuxram@us•ibm.com,
Jeremy Kerr <jk@ozlabs•org>
Subject: Re: [PATCH v3 2/2] selftests/powerpc: Add a test of the switch_endian() syscall
Date: Tue, 17 Mar 2015 10:04:00 +1100 [thread overview]
Message-ID: <1426547040.31646.2.camel@ellerman.id.au> (raw)
In-Reply-To: <5506B7DC.80702@linux.vnet.ibm.com>
On Mon, 2015-03-16 at 16:30 +0530, Anshuman Khandual wrote:
> On 03/16/2015 12:27 PM, Michael Ellerman wrote:
> > This adds a test of the switch_endian() syscall we added in the previous
> > commit.
> >
> > We test it by calling the endian switch syscall, and then executing some
> > code in the other endian to check everything went as expected. That code
> > checks registers we expect to be maintained are, and then writes to
> > stdout. If the endian switch failed to happen that code sequence will be
> > illegal and cause the test to abort.
> >
> > We then switch back to the original endian, do the same checks and
> > finally write a success message and exit(0).
> >
> > Signed-off-by: Michael Ellerman <mpe@ellerman•id.au>
>
> Hey Michael,
>
> Did a quick test, passes on LE but seems like failing on BE.
>
> On LE:
>
> Hello wrong-endian world
> Hello right-endian world
> success: switch_endian_test
>
> on BE:
>
> Hello wrong-endian world (returns 176)
>
> The previous version of the test was passing both on LE
> and BE (after applying the compiler trick in the assembly)
Hmm, odd. Works for me:
$ uname -a
Linux bebuntu 4.0.0-rc3-00002-g9dd2601a490a #1 SMP Fri Mar 13 15:52:11 AEDT 2015 ppc64 ppc64 ppc64 GNU/Linux
$ make
cc -O2 -Wall -g -nostdlib -m64 -c -o check.o check.S
objcopy -j .text --reverse-bytes=4 -O binary check.o check-reversed.o
hexdump -v -e '/1 ".byte 0x%02X\n"' check-reversed.o > check-reversed.S
cc -O2 -Wall -g -nostdlib -m64 switch_endian_test.S check-reversed.S -o switch_endian_test
$ ./switch_endian_test
Hello wrong-endian world
Hello right-endian world
success: switch_endian_test
What are you seeing exactly?
cheers
next prev parent reply other threads:[~2015-03-16 23:04 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-16 6:57 [PATCH v3 1/2] powerpc: Add a proper syscall for switching endianness Michael Ellerman
2015-03-16 6:57 ` [PATCH v3 2/2] selftests/powerpc: Add a test of the switch_endian() syscall Michael Ellerman
2015-03-16 11:00 ` Anshuman Khandual
2015-03-16 23:04 ` Michael Ellerman [this message]
2015-03-17 6:05 ` Anshuman Khandual
2015-03-18 5:04 ` Michael Ellerman
2015-03-25 5:28 ` Michael Ellerman
2015-03-25 11:32 ` Anshuman Khandual
2015-03-26 0:36 ` Michael Ellerman
2015-03-26 6:24 ` Anshuman Khandual
2015-03-28 2:34 ` Michael Ellerman
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