imx6s - Can the toolchain use soft-float ?

[quentinchang]

Hi Sirs,

I am using FSL Yocto toolchain (fsl-yocto-L3.14.52_1.1.0-ga) to build a chip driver which will be used on i.MX6 solo platform.

The build process is stopped due the following error.

------------------------------------------------------------------------------------------------------------------------

/opt/fsl-imx-x11/3.14.52-1.1.0/sysroots/cortexa9hf-vfp-neon-poky-linux-gnueabi/usr/include/gnu/stubs.h:7:29: fatal error: gnu/stubs-soft.h: No such file or directory

# include <gnu/stubs-soft.h>

                 ^

compilation terminated.

------------------------------------------------------------------------------------------------------------------------

I know it due to that I didn't add "-mfloat-abi=hard -mfpu=neon" to the makefile.

My question is may I build my driver with "-mfpu=vfp -mfloat-abi=soft" ?

Is FSL provides the the option or toolchain for this requirement ?

Thank you very much.

[gusarambula]

Hello Quentin Chang,

There are a couple of threads referring to a similar symptom. In most cases this error appears when compiling using CC and not $CC as the $CC variable should contain the complete cross compiler command.

Would you please review these threads to see if what you are seeing is similar and let us know if they helped?

https://community.nxp.com/message/499896

https://community.nxp.com/message/633989

Regards,

[quentinchang]

Hi Gusarambula,

Many thanks for your reply.

In fact, I have modified the Makefile (adding "-mfloat-abi=hard -mfpu=neon") of the driver and built it successfully.

I also modified the kernel defconfig as below

-----------------------------------------------------------------------------------------------

CONFIG_VFP=y

CONFIG_VFPv3=y

CONFIG_NEON=y

CONFIG_KERNEL_MODE_NEON=y

-----------------------------------------------------------------------------------------------

However, I got "Segmentation fault" when I tried to insert this module.

-----------------------------------------------------------------------------------------------

root@imx6qsabresd:/tmp# insmod linux-kernel-bde.ko

linux_kernel_bde: module license 'Proprietary' taints kernel.

Disabling lock debugging due to kernel taint

BUG: FP instruction issued in kernel mode with FP unit disabled

Internal error: Oops - undefined instruction: 0 [#1] PREEMPT SMP ARM

Modules linked in: linux_kernel_bde(PO+)

CPU: 1 PID: 519 Comm: insmod Tainted: P           O 3.14.52-1.1.0_ga+g5f6f0a5 #2

task: a86f8900 ti: a88e4000 task.ti: a88e4000

PC is at _pgalloc+0x328/0x3d8 [linux_kernel_bde]

LR is at _raw_spin_unlock+0x24/0x50

pc : [<7f001a60>]    lr : [<80746270>]    psr: 80070013

sp : a88e5ca0  ip : 80291890  fp : 80a95ec4

r10: a4000000  r9 : 00000084  r8 : 80b4c540

r7 : 800a80e8  r6 : 02000000  r5 : 00000021  r4 : a8c52080

r3 : a4080000  r2 : 00080000  r1 : 00000002  r0 : 00000000

Flags: Nzcv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user

Control: 10c53c7d  Table: 389b404a  DAC: 00000015

Process insmod (pid: 519, stack limit = 0xa88e4238)

Stack: (0xa88e5ca0 to 0xa88e6000)

5ca0: a8a8f000 8092f6d0 7f0056f8 80746270 00000012 8073b9a8 0003eb50 00034484

5cc0: 00000000 000000fa 802bdeac 802bec2c 00000000 00000000 00000000 00001000

5ce0: 7f007df0 00000000 00000000 00000000 7f007df0 7f007df0 02000000 8001b22c

5d00: 00000000 7f007c98 7f0056f8 7f0024b4 02000000 7f007df0 7f007df0 00000000

5d20: 00000000 7f007df0 802bec2c 7f00328c 60070013 80a8a0b0 a8001e80 a88e4000

5d40: a87fdd00 80400040 a864fb80 80910e70 80910e72 00000002 a88e5df4 00000000

5d60: a8001f00 000000d0 a88e4000 2aca5000 000050c9 00000000 800df02c 800d735c

5d80: 800df460 a864fc80 00000100 0000007f a800d400 00000001 a8a85f5c 8036e334

5da0: 00000000 0000001c a864fc80 800df460 00003571 a864fc80 a864fc80 7f007bc0

5dc0: 00000100 00000000 a8040100 a864fc80 00000000 800df4d0 800df02c 800df460

5de0: a864fc80 a88e5df0 800df5c4 a87fdd00 a864fc80 00000000 7f008a2c 7f008a2c

5e00: a88b9780 00000001 a88b9788 7f007c98 00000000 7f00d088 7f007bc0 00000001

5e20: a88e4030 7f00d000 7f007ca4 8000889c a8a85f40 8040003e abc6fa40 a88e4030

5e40: 80a86cdc abc6fa40 00000000 8040003e 00000000 8040003f 00000001 80a92804

5e60: a88e4030 00000001 7f007ce0 8040003e 0000000f a8a85f40 2aca5000 800d68ec

5e80: 80a8a0ac a88e5f58 00000001 7f007ca4 a88b9780 00000001 a88b9788 7f007c98

5ea0: 7f007ce0 8008a830 7f007ca4 00007fff 80087b38 00000000 a8a85f00 00000000

5ec0: a88e5f58 7f007ca4 a88e4028 c0de2606 00000000 a88e5f60 0000023f a88e5f8c

5ee0: a8a85f40 000000d2 000002d2 8000e6e4 a88e4000 7f00466c 00000013 00000000

5f00: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

5f20: 00000000 00000000 00000000 00000000 01174058 0000e61c 01174058 01174008

5f40: 00000080 8000e6e4 a88e4000 00000000 00000000 8008ae48 c0dd5000 0000e61c

5f60: c0dde550 c0dde42f c0de0e40 00008b38 0000a6a8 00000000 00000000 00000000

5f80: 0000001e 0000001f 00000017 00000014 0000000f 00000000 0000e61c 7eb95f0c

5fa0: 00000043 8000e560 0000e61c 7eb95f0c 01174058 0000e61c 01174008 7eb95e14

5fc0: 0000e61c 7eb95f0c 00000043 00000080 0009579c 7eb95f0c 000957cc 00000000

5fe0: 7eb95c58 7eb95c48 00018550 76e65420 60070010 01174058 3ae7bf6b ea4fbffd

unwind: Index not found 7f001a60

Code: e7933009 e0833002 e15a0003 2affffe9 (eddb0b00)

---[ end trace a36eb6057765a90d ]---

note: insmod[519] exited with preempt_count 1

Segmentation fault

root@imx6qsabresd:/tmp#

-----------------------------------------------------------------------------------------------

So far, I have no idea why kernel shows "FP unit disabled"

BUG: FP instruction issued in kernel mode with FP unit disabled  <-----

That's why I want to try another floating pointoptions (soft) to compile my driver.

This is my first time using i.MX series CPU.

Do you have any suggestion about this problem ?

Thank you very much.

Best regards,

Quentin

[yuqianli]

Hi Quentin,

Have you fixed this issue yet? I have same issue, just different CPU that I am using the LS1021.

Yuqian