i.MX ProcessorsのトピックRe: Cannot check DEP/NX flag in imx6

Cannot check DEP/NX flag in imx6

rockie_love_nxp — Thu, 01 Feb 2024 09:51:34 GMT

Hi all,

I built my image for imx6 board with yocto project that uses meta-freescale bsp.

Currently, we want to check if DEP/NX is enable but cannot find any information from:

dmesg | grep NX

also in cat /proc/cpuinfo, there is no "nx" flag.

processor : 0
BogoMIPS : 10.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 4
processor : 1
BogoMIPS : 10.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 4
processor : 2
BogoMIPS : 10.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 4
processor : 3
BogoMIPS : 10.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 4

I only check the other board S32G with meta-alb but still the same, I cannot check if flag DEP/NX is enable.
Could you please let me know if NXP board support NX bit? Or are there any bugs in BSP?

Thank you

Re: Cannot check DEP/NX flag in imx6

Bio_TICFSL — Thu, 01 Feb 2024 15:32:09 GMT

Hello,

Neither the S32G and i.MX uses DEP / NX.

DEP is used by default in Ubuntu. This is done via the NX bit if the CPU supports it, or emulated via memory segmentation if the CPU does not support it. For more details, see the non-executable memory feature item.

regards

Re: Cannot check DEP/NX flag in imx6

rockie_love_nxp — Thu, 01 Feb 2024 15:39:31 GMT

Hi Bio_TICFSL,

Thank you for your quick reply. So that means we cannot use DEP feature on i.MX series? Otherwise, should I implement it by myself?
As i read that from armv7, it's already supported XN bit. But I cannot find any method to test if that is used in Linux or not.

Re: Cannot check DEP/NX flag in imx6

Bio_TICFSL — Fri, 02 Feb 2024 14:24:37 GMT

Hello,

in this case you should implement yourself.

Regards