Bug 366079

Summary:	FPXX Support for MIPS32 Valgrind
Product:	[Developer tools] valgrind	Reporter:	Aleksandar Rikalo <aleksandar.rikalo>
Component:	general	Assignee:	Julian Seward <jseward>
Status:	RESOLVED FIXED
Severity:	major	CC:	aleksandar.rikalo, mips32r2
Priority:	NOR
Version First Reported In:	unspecified
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:
Attachments:	Support for mips32 FPXX MIPS32 test for syscalls prctl(GET/SET_FP_MODE) FP32 support on MIPS64 MIPS64 version of test

Description Aleksandar Rikalo 2016-07-25 10:09:54 UTC

Currently, support for MIPS32 FPXX ABI is incomplete. Programs compiled with options -mfp64 or -mfpxx are not interpreted correctly on Valgrind which is compiled with -mfpxx.


Reproducible: Always

Steps to Reproduce:
1. Build Valgrind with this configure: ./configure --host=mipsel-linux-gnu CFLAGS="-march=mips32r2 -mabi=32 -mfpxx -EL"
2. Build FP test sample (eg. none/tests/mips32/round.c), with -mfp64
3. Run through the Valgrind on Linux 4.1+.

Actual Results:  
Illegal instruction / incorrect calculations.

Expected Results:  
Correctly executed test.

Comment 1 Aleksandar Rikalo 2016-07-25 10:50:58 UTC

Created attachment 100286 [details]
Support for mips32 FPXX

With this patch, MIPS32 Valgrind compiled with -mfpxx can handle all types (regarding FP_ABI flag) of MIPS32 ELFs.

- Functions arch_elf_pt_proc() and arch_check_elf() are added to elf reader according to linux/fs/binfmt_elf.c from Linux 4.1;
- Processing .MIPS.abiflags section and initializing appropriate FPU mode for MIPS32 are added;
- Emulation of prctl(GET/SET_FP_MODE) sys-calls are implemented for MIPS32.

Applying the patch:
patch -p1 < mips_fpxx_full_support.diff

The patch is tested on MIPS32 platforms with Linux 3.13 and 4.1.
Also, there are no regressions on MIPS64.

Regtests need to be performed on other architectures.

Comment 2 Aleksandar Rikalo 2016-07-25 10:53:52 UTC

Created attachment 100287 [details]
MIPS32 test for syscalls prctl(GET/SET_FP_MODE)

Comment 3 Petar Jovanovic 2016-08-10 15:18:53 UTC

(In reply to Aleksandar Rikalo from comment #1)
> Created attachment 100286 [details]
> Support for mips32 FPXX
> 
> With this patch, MIPS32 Valgrind compiled with -mfpxx can handle all types
> (regarding FP_ABI flag) of MIPS32 ELFs.
> 
> - Functions arch_elf_pt_proc() and arch_check_elf() are added to elf reader
> according to linux/fs/binfmt_elf.c from Linux 4.1;
> - Processing .MIPS.abiflags section and initializing appropriate FPU mode
> for MIPS32 are added;
> - Emulation of prctl(GET/SET_FP_MODE) sys-calls are implemented for MIPS32.
> 
> Applying the patch:
> patch -p1 < mips_fpxx_full_support.diff
> 
> The patch is tested on MIPS32 platforms with Linux 3.13 and 4.1.
> Also, there are no regressions on MIPS64.
> 
> Regtests need to be performed on other architectures.

The patch with minor modifications committed as:

VEX r3243.
Valgrind r15934.

Thank you.

Comment 4 Petar Jovanovic 2016-08-10 15:20:58 UTC

(In reply to Aleksandar Rikalo from comment #2)
> Created attachment 100287 [details]
> MIPS32 test for syscalls prctl(GET/SET_FP_MODE)

Can you make similar changes for MIPS64 for prctl(GET/SET_FP_MODE), so this
test can be correctly executed for MIPS64 as well?

Comment 5 Aleksandar Rikalo 2016-08-19 16:17:56 UTC

Created attachment 100683 [details]
FP32 support on MIPS64

Support for FP32 emulation on MIPS64 platforms (including prctl(GET/SET_FP_MODE)  syscalls).

Comment 6 Aleksandar Rikalo 2016-08-19 16:18:15 UTC

Created attachment 100684 [details]
MIPS64 version of test

Comment 7 Julian Seward 2016-09-14 15:20:18 UTC

Petar, is it possible you could test/land the follow-on patches in
comment 5 and comment 6?

Comment 8 Petar Jovanovic 2016-10-04 13:11:06 UTC

(In reply to Aleksandar Rikalo from comment #2)
> Created attachment 100287 [details]
> MIPS32 test for syscalls prctl(GET/SET_FP_MODE)

The test commited as r16001.

Comment 9 Petar Jovanovic 2016-10-04 15:19:47 UTC

(In reply to Aleksandar Rikalo from comment #5)
> Created attachment 100683 [details]
> FP32 support on MIPS64
> 
> Support for FP32 emulation on MIPS64 platforms (including
> prctl(GET/SET_FP_MODE)  syscalls).

Committed as:

VEX r3253
Valgrind r16003.

Comment 10 Petar Jovanovic 2016-10-04 15:26:16 UTC

(In reply to Aleksandar Rikalo from comment #6)
> Created attachment 100684 [details]
> MIPS64 version of test

The test commited as r16004.
Thank you for these changes.

Comment 11 Petar Jovanovic 2016-10-05 12:45:55 UTC

This issue can be closed now.