* 4.0-rc1 breakage in FPE?
@ 2015-02-25 18:20 Paul Martin
2015-02-25 21:30 ` Måns Rullgård
2015-02-25 21:31 ` Måns Rullgård
0 siblings, 2 replies; 7+ messages in thread
From: Paul Martin @ 2015-02-25 18:20 UTC (permalink / raw)
To: linux-mips
Some change between 3.19 and 4.0-rc1 has broken the FPE such that some
code running on an Octeon II is subtly not working.
eg.
$ echo "1 2" | gawk '{ print $1 }'
1 2
which should output (and does output on 3.19)
$ echo "1 2" | gawk '{ print $1 }'
1
I'm going to try bisecting this over the next few days.
We've been here before...
cf. http://www.linux-mips.org/archives/linux-mips/2014-07/msg00431.html
--
Paul Martin http://www.codethink.co.uk/
Senior Software Developer, Codethink Ltd.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: 4.0-rc1 breakage in FPE?
2015-02-25 18:20 4.0-rc1 breakage in FPE? Paul Martin
@ 2015-02-25 21:30 ` Måns Rullgård
2015-02-25 21:31 ` Måns Rullgård
1 sibling, 0 replies; 7+ messages in thread
From: Måns Rullgård @ 2015-02-25 21:30 UTC (permalink / raw)
To: linux-mips
Paul Martin <paul.martin@codethink.co.uk> writes:
> Some change between 3.19 and 4.0-rc1 has broken the FPE such that some
> code running on an Octeon II is subtly not working.
>
> eg.
>
> $ echo "1 2" | gawk '{ print $1 }'
> 1 2
>
> which should output (and does output on 3.19)
>
> $ echo "1 2" | gawk '{ print $1 }'
> 1
>
> I'm going to try bisecting this over the next few days.
>
> We've been here before...
>
> cf. http://www.linux-mips.org/archives/linux-mips/2014-07/msg00431.html
>
> --
> Paul Martin http://www.codethink.co.uk/
> Senior Software Developer, Codethink Ltd.
>
--
Måns Rullgård
mans@mansr.com
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: 4.0-rc1 breakage in FPE?
2015-02-25 18:20 4.0-rc1 breakage in FPE? Paul Martin
2015-02-25 21:30 ` Måns Rullgård
@ 2015-02-25 21:31 ` Måns Rullgård
2015-02-25 21:40 ` David Daney
1 sibling, 1 reply; 7+ messages in thread
From: Måns Rullgård @ 2015-02-25 21:31 UTC (permalink / raw)
To: Paul Martin; +Cc: linux-mips
Paul Martin <paul.martin@codethink.co.uk> writes:
> Some change between 3.19 and 4.0-rc1 has broken the FPE such that some
> code running on an Octeon II is subtly not working.
>
> eg.
>
> $ echo "1 2" | gawk '{ print $1 }'
> 1 2
>
> which should output (and does output on 3.19)
>
> $ echo "1 2" | gawk '{ print $1 }'
> 1
>
> I'm going to try bisecting this over the next few days.
Are you running a 32-bit userland? If so, enabling
MIPS_O32_FP64_SUPPORT should fix this.
--
Måns Rullgård
mans@mansr.com
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: 4.0-rc1 breakage in FPE?
2015-02-25 21:31 ` Måns Rullgård
@ 2015-02-25 21:40 ` David Daney
2015-02-25 21:48 ` Måns Rullgård
2015-02-26 11:29 ` Måns Rullgård
0 siblings, 2 replies; 7+ messages in thread
From: David Daney @ 2015-02-25 21:40 UTC (permalink / raw)
To: Måns Rullgård; +Cc: Paul Martin, linux-mips
On 02/25/2015 01:31 PM, Måns Rullgård wrote:
> Paul Martin <paul.martin@codethink.co.uk> writes:
>
>> Some change between 3.19 and 4.0-rc1 has broken the FPE such that some
>> code running on an Octeon II is subtly not working.
>>
Can you say where your userspace comes from, so we can try to reproduce
the issue?
>> eg.
>>
>> $ echo "1 2" | gawk '{ print $1 }'
>> 1 2
>>
>> which should output (and does output on 3.19)
>>
>> $ echo "1 2" | gawk '{ print $1 }'
>> 1
>>
>> I'm going to try bisecting this over the next few days.
>
> Are you running a 32-bit userland? If so, enabling
> MIPS_O32_FP64_SUPPORT should fix this.
??
32-bit userland (Debian for instance) typically shouldn't need special
"Exprimental" config options enabled.
If we can identify the offending patch, we should revert it.
David Daney
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: 4.0-rc1 breakage in FPE?
2015-02-25 21:40 ` David Daney
@ 2015-02-25 21:48 ` Måns Rullgård
2015-02-26 11:29 ` Måns Rullgård
1 sibling, 0 replies; 7+ messages in thread
From: Måns Rullgård @ 2015-02-25 21:48 UTC (permalink / raw)
To: David Daney; +Cc: Paul Martin, linux-mips
David Daney <ddaney.cavm@gmail.com> writes:
> On 02/25/2015 01:31 PM, Måns Rullgård wrote:
>> Paul Martin <paul.martin@codethink.co.uk> writes:
>>
>>> Some change between 3.19 and 4.0-rc1 has broken the FPE such that some
>>> code running on an Octeon II is subtly not working.
>>>
>
> Can you say where your userspace comes from, so we can try to
> reproduce the issue?
>
>>> eg.
>>>
>>> $ echo "1 2" | gawk '{ print $1 }'
>>> 1 2
>>>
>>> which should output (and does output on 3.19)
>>>
>>> $ echo "1 2" | gawk '{ print $1 }'
>>> 1
>>>
>>> I'm going to try bisecting this over the next few days.
>>
>> Are you running a 32-bit userland? If so, enabling
>> MIPS_O32_FP64_SUPPORT should fix this.
>
> ??
>
> 32-bit userland (Debian for instance) typically shouldn't need special
> "Exprimental" config options enabled.
Indeed, it should not. Someone made a mistake.
> If we can identify the offending patch, we should revert it.
The offending patch is 46490b57 "MIPS: kernel: elf: Improve the overall
ABI and FPU mode checks"
There is no need for a full revert. This is enough to make things work:
diff --git a/arch/mips/kernel/elf.c b/arch/mips/kernel/elf.c
index d2c09f6..57f0353 100644
--- a/arch/mips/kernel/elf.c
+++ b/arch/mips/kernel/elf.c
@@ -148,9 +148,6 @@ int arch_check_elf(void *_ehdr, bool has_interpreter,
struct mode_req prog_req, interp_req;
int fp_abi, interp_fp_abi, abi0, abi1, max_abi;
- if (!config_enabled(CONFIG_MIPS_O32_FP64_SUPPORT))
- return 0;
-
fp_abi = get_fp_abi(state->fp_abi);
if (has_interpreter) {
@@ -245,9 +242,6 @@ void mips_set_personality_fp(struct arch_elf_state *state)
* not be worried about N32/N64 binaries.
*/
- if (!config_enabled(CONFIG_MIPS_O32_FP64_SUPPORT))
- return;
-
switch (state->overall_fp_mode) {
case FP_FRE:
set_thread_fp_mode(1, 0);
--
Måns Rullgård
mans@mansr.com
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: 4.0-rc1 breakage in FPE?
2015-02-25 21:40 ` David Daney
2015-02-25 21:48 ` Måns Rullgård
@ 2015-02-26 11:29 ` Måns Rullgård
2015-02-27 10:53 ` Paul Martin
1 sibling, 1 reply; 7+ messages in thread
From: Måns Rullgård @ 2015-02-26 11:29 UTC (permalink / raw)
To: David Daney; +Cc: Paul Martin, linux-mips
David Daney <ddaney.cavm@gmail.com> writes:
> On 02/25/2015 01:31 PM, Måns Rullgård wrote:
>> Paul Martin <paul.martin@codethink.co.uk> writes:
>>
>>> Some change between 3.19 and 4.0-rc1 has broken the FPE such that some
>>> code running on an Octeon II is subtly not working.
>>>
>
> Can you say where your userspace comes from, so we can try to
> reproduce the issue?
>
>>> eg.
>>>
>>> $ echo "1 2" | gawk '{ print $1 }'
>>> 1 2
>>>
>>> which should output (and does output on 3.19)
>>>
>>> $ echo "1 2" | gawk '{ print $1 }'
>>> 1
>>>
>>> I'm going to try bisecting this over the next few days.
>>
>> Are you running a 32-bit userland? If so, enabling
>> MIPS_O32_FP64_SUPPORT should fix this.
>
> ??
>
> 32-bit userland (Debian for instance) typically shouldn't need special
> "Exprimental" config options enabled.
>
> If we can identify the offending patch, we should revert it.
FYI, a fix (MIPS: asm: elf: Set O32 default FPU flags) has been posted
to linux-mips.
--
Måns Rullgård
mans@mansr.com
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: 4.0-rc1 breakage in FPE?
2015-02-26 11:29 ` Måns Rullgård
@ 2015-02-27 10:53 ` Paul Martin
0 siblings, 0 replies; 7+ messages in thread
From: Paul Martin @ 2015-02-27 10:53 UTC (permalink / raw)
To: linux-mips
On Thu, Feb 26, 2015 at 11:29:46AM +0000, Måns Rullgård wrote:
> FYI, a fix (MIPS: asm: elf: Set O32 default FPU flags) has been posted
> to linux-mips.
I can confirm this fix does tame gawk.
--
Paul Martin http://www.codethink.co.uk/
Senior Software Developer, Codethink Ltd.
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2015-02-27 10:54 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
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2015-02-25 18:20 4.0-rc1 breakage in FPE? Paul Martin
2015-02-25 21:30 ` Måns Rullgård
2015-02-25 21:31 ` Måns Rullgård
2015-02-25 21:40 ` David Daney
2015-02-25 21:48 ` Måns Rullgård
2015-02-26 11:29 ` Måns Rullgård
2015-02-27 10:53 ` Paul Martin
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