David Daney <ddaney.cavm@xxxxxxxxx> writes:
> On 02/25/2015 01:31 PM, Måns Rullgård wrote:
>> Paul Martin <paul.martin@xxxxxxxxxxxxxxx> 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@xxxxxxxxx
