Unable to handle kernel paging request at virtual address ffff00001a9cd000 in i.mx8mm evk

[sreedhar_appala]

Hi,

I am working with i.mx8mm evk and one dsp is interfaced to it. Yocto distribution 4.19.35 imx-warrior.

SAI1 interface connected to serial port of DSP for I2S playback and

SAI5 interface connected to another serial port of DSP for I2S capture.

when i tried to do pass-through test (aplay, followed by arecord alsa utils)

hw_params for playback and capture: channels : 8, format : S32_LE and sampling rate : 48000

The capture starts and i get the paging request error, please find the log below:

root@imx8mmevk:~# ./play32.sh
root@imx8mmevk:~# Playing WAVE 'ref8_32bit.wav' : Signed 32 bit Little Endian, Rate 48000 Hz, Channels 8

root@imx8mmevk:~# ./cap.sh
[ 26.962635] MIC BE: adsp_pcm_be_startup [be_mic_rec]
[ 26.977791] MIC_FE: adsp_pcm_fe_startup [fe_mic_rec]
Recording WAVE 'mic.wav' : [ 26.995513] MIC BE: adsp_pcm_be_hw_params [be_mic_rec] rate 48000 ch 8 bits 32 period 160-4
Signed 32 bit Little Endian, Rate[ 27.007136] MIC BE: adsp_pcm_be_hw_params [be_mic_rec] mclk 24576000 lrck_width 32
48000 Hz, Channels 8
[ 27.020052] MIC BE: adsp_pcm_be_hw_params [be_mic_rec] lrck_inv 0 bck_inv 0
[ 27.038681] MIC_FE: adsp_pcm_fe_hw_params [fe_mic_rec] rate 48000 ch 8 bits 32 period 160-4
[ 27.154868] MIC_FE: buf : 0xf3b7cf0 , hwbuf : 0x1a9c5000 , copy_bytes : 163840
[ 27.169518] Unable to handle kernel paging request at virtual address ffff00001a9cd000
[ 27.177450] Mem abort info:
[ 27.180242] ESR = 0x96000007
[ 27.183318] Exception class = DABT (current EL), IL = 32 bits
[ 27.189254] SET = 0, FnV = 0
[ 27.192307] EA = 0, S1PTW = 0
[ 27.195466] Data abort info:
[ 27.198362] ISV = 0, ISS = 0x00000007
[ 27.202215] CM = 0, WnR = 0
[ 27.205201] swapper pgtable: 4k pages, 48-bit VAs, pgdp = 00000000a64ad819
[ 27.212099] [ffff00001a9cd000] pgd=00000000bdffe803, pud=00000000bdffd803, pmd=00000000b02e7003, pte=0000000000000000
[ 27.222739] Internal error: Oops: 96000007 [#1] PREEMPT SMP
[ 27.228311] Modules linked in: 8021q garp stp mrp qca9377(O) crc32_ce crct10dif_ce galcore(O)
[ 27.236847] Process arecord (pid: 4276, stack limit = 0x00000000444534a6)
[ 27.243635] CPU: 2 PID: 4276 Comm: arecord Tainted: G O 4.19.35-1.1.0+g0f9917c #1
[ 27.252416] Hardware name: FSL i.MX8MM EVK board (DT)
[ 27.257465] pstate: 20000005 (nzCv daif -PAN -UAO)
[ 27.262260] pc : __memcpy_fromio+0x48/0x88
[ 27.266357] lr : copy_to_user_fromio+0xf4/0x108
[ 27.270884] sp : ffff00001a98ba80
[ 27.274196] x29: ffff00001a98ba80 x28: 0000000000000000
[ 27.279507] x27: 0000000000000000 x26: ffff8000752c8880
[ 27.284817] x25: 0000000000000000 x24: ffff80007542d000
[ 27.290128] x23: ffff0000096086c8 x22: ffff00001a9cd000
[ 27.295439] x21: 000000000f3bfcf0 x20: 0000000000000010
[ 27.300749] x19: 0000000000000010 x18: 0000000000000010
[ 27.306059] x17: 0000000000000000 x16: 0000000000000000
[ 27.311370] x15: ffffffffffffffff x14: ffff0000096086c8
[ 27.316680] x13: ffff0000897d0437 x12: ffff0000097d043f
[ 27.316684] x11: ffff000009620000 x10: ffff00001a98b7f0
[ 27.316688] x9 : 00000000ffffffd0 x8 : ffff000008663c28
[ 27.316692] x7 : 5f707364615f3037 x6 : 0000000000000010
[ 27.316696] x5 : 000000000f3bfcf0 x4 : ffff00001a9cd000
[ 27.316700] x3 : ffff00001a98bad8 x2 : 0000000000000010
[ 27.357669] x1 : ffff00001a9cd000 x0 : ffff00001a98bac8
[ 27.362981] Call trace:
[ 27.365428] __memcpy_fromio+0x48/0x88

imx8mmevk kernel: [ 27.222739] Internal error: Oops: 96000007 [#1] PREEMPT SMP

Message from syslogd@imx8mmevk at Tue May 18 07:40:03 2021 ...
imx8mmevk kernel: [ 27.236847] Process arecord (pid: 4276, stack limit = 0x00000000444534a6)
[ 27.369178] adsp_pcm_pcm_copy+0x104/0x200
[ 27.369183] soc_rtdcom_copy_user+0x3c/0x60
[ 27.369189] interleaved_copy+0x54/0x60
[ 27.369197] __snd_pcm_lib_xfer+0x414/0x6c8
[ 27.422797] snd_pcm_common_ioctl+0x570/0xec8
[ 27.427152] snd_pcm_ioctl+0x28/0x40
[ 27.430726] do_vfs_ioctl+0xb8/0x890
[ 27.434299] ksys_ioctl+0x78/0xa8
[ 27.437612] __arm64_sys_ioctl+0x1c/0x28
[ 27.441535] el0_svc_common+0x84/0xf0
[ 27.445195] el0_svc_handler+0x2c/0x80
[ 27.448942] el0_svc+0x8/0xc
[ 27.451823] Code: 927df0c6 910020c6 8b060003 d503201f (f9400085)
[ 27.457916] ---[ end trace 843b67e7e18b29be ]---

Message from syslogd@imx8mmevk at Tue May 18 07:40:03 2021 ...
imx8mmevk kernel: [ 27.451823] Code: 927df0c6 910020c6 8b060003 d503201f (f9400085)
./cap.sh: line 1: 4276 Segmentation fault arecord -D hw:3,0 -f S32_LE -c 8 -r 48000 mic.wav
root@imx8mmevk:~#

The page request is failing exactly after 32768 (0x8000) bytes copy. The hwbuf base addr : 0x1a9c5000

paging request failure at ffff00001a9cd000, 0x1a9cd000 - 0x1a9c5000 = 0x8000.

Since the HW is EVK, I am ruling out the DDR issue.

Could you please tell me where i could look at hwbuf allocation for the programmed hardware parameters.

Any pointers and suggestions will definitely help in me in resolving this issue.

Thank you, Sreedhar

[NXP_USER_05]

Hi @sreedhar_appala 

We are working with a custom i.MX8M Plus DDR4 board that includes 32 MB QSPI NOR flash.
Our objective is to boot U-Boot, Linux kernel, device tree, and initramfs (rootfs.img) entirely from QSPI flash, without using SD/eMMC.

We are able to successfully boot up to U-Boot (flash.bin) from QSPI flash.

-----Flash Layout and Image Sizes----------------

QSPI flash size: 32 MB

flash.bin (U-Boot + SPL) ~2.4 MB
Image.gz (Kernel) ~15 MB
imx8mp-evk.dtb ~85 KB
rootfs.img ~12.6 MB

----QSPI Offset Layout----------
flash.bin @ 0x00000000
Image.gz @ 0x0024D000
imx8mp-evk.dtb @ 0x010A6B00
rootfs.img @ 0x010BB800

U-Boot Environment Setup

After booting into U-Boot from QSPI, we configure the following environment variables to load the kernel, device tree, and initramfs from flash:

sf probe 0
setenv loadaddr 0x40480000 // kernel
setenv fdt_addr 0x43000000 //dtb
setenv initrd_addr 0x43800000 //rootfs (minimal initramfs)
setenv kernel_comp_addr_r 0x50000000
setenv kernel_comp_size 0x04000000

Reading Images from QSPI Flash

sf read ${loadaddr} 0x0024D000 0x00E59A6F
sf read ${fdt_addr} 0x010A6B00 0x00014BBA
sf read ${initrd_addr} 0x010BB800 0x00C04DB0

Boot Command

setenv bootargs console=${console},${baudrate} earlycon=${earlycon},${baudrate} rdinit=/dev

booti ${loadaddr} ${initrd_addr} ${fdt_addr}

Issue Observed

• The kernel starts executing but hangs at “Starting kernel …”.

• Please refer to the attached kernel boot log (kernel_bootlog1).

When using the following boot arguments:

setenv bootargs setenv bootargs "console=ttymxc1,115200 earlycon root=/dev/ram0 rw rdinit=/sbin/init loglevel=8"

• The kernel progresses further but hangs midway during boot.

• Please refer to the attached kernel boot log (kernel_bootlog2).

Attached the kernel DTS and kernel defconfig for reference.
Kindly let us know if any modifications are required.

Also getting same error like you Unable to handle kernel paging request at virtual address. can you please give any suggistions to resolve it and successful kernel boot. 

Questions:

1. Are there any recommended changes required in the kernel DTS for booting initramfs entirely from QSPI on a custom i.MX8M Plus DDR4 board?

2. Are there any additional boot arguments recommended by NXP for initramfs-based boot on i.MX8MP from QSPI flash?

3. What could be the possible reason for the kernel not booting correctly?
We followed the same procedure that works successfully on the i.MX8MP LPDDR4  EVK, where the kernel and root filesystem boot properly from QSPI flash.
The only differences in our setup are the flash.bin and device tree, which were modified according to the DDR configuration of our custom board.

thank you.

[Zhiming_Liu]

It seem when you use that capture command ,the pointer is beyond the max hardware address. can you attach your test command?

[sreedhar_appala]

Hi Zhiming Liu,

Please find the test cmd:

play32.sh : aplay -D hw:2,0 ref8_32bit.wav

cap.sh : arecord -D hw:3,0 -f S32_LE -c 8 -r 48000 mic.wav

Thank you, Sreedhar

[sreedhar_appala · Accepted solution]

Hi Zhiming Liu,

The number of bytes to copy/read is more than the dma buffer (hwbuff) size.

So I am facing the above issue. Now I have controlled the number of bytes to read based on the allocated hwbuf size, and the above issue is resolved.

Thank you, Sreedhar