[U-Boot] Unaligned memory accesses exception

Hello all,
I'm bringing up U-Boot for an iMX6UL board, and I've encountered unaligned memory accesses exceptions while I was trying to test the ETH commands (e.g., 'ping').
After investigation, I found out that the iMX6UL processor traps unaligned memory accesses by default. As a workaround, I disabled theses checks, hoping for negligible performance loss.
I'm wondering if it is a bad idea to disable unaligned memory accesses during the U-Boot execution, regarding performance issues or other drawbacks at the kernel level.
Thanks for your suggestions. Best regards, Fernando A. E.

Hi Fernando,
On Wed, Aug 22, 2018 at 3:44 PM, Fernando AE fernando.ae2017@gmail.com wrote:
Hello all,
I'm bringing up U-Boot for an iMX6UL board, and I've encountered unaligned memory accesses exceptions while I was trying to test the ETH commands (e.g., 'ping').
Have you located the place where this unaligned memory access happens in U-Boot source codes?
After investigation, I found out that the iMX6UL processor traps unaligned memory accesses by default. As a workaround, I disabled theses checks, hoping for negligible performance loss.
How does other ARMv7 targets behave? Do they all turn ff the unaligned memory access trap?
I'm wondering if it is a bad idea to disable unaligned memory accesses during the U-Boot execution, regarding performance issues or other drawbacks at the kernel level.
Regards, Bin

On Wed, Aug 22, 2018 at 09:44:16AM +0200, Fernando AE wrote:
Hello all,
I'm bringing up U-Boot for an iMX6UL board, and I've encountered unaligned memory accesses exceptions while I was trying to test the ETH commands (e.g., 'ping').
After investigation, I found out that the iMX6UL processor traps unaligned memory accesses by default. As a workaround, I disabled theses checks, hoping for negligible performance loss.
I'm wondering if it is a bad idea to disable unaligned memory accesses during the U-Boot execution, regarding performance issues or other drawbacks at the kernel level.
What exactly do you mean by encountered? Can you post logs? Thanks.
participants (3)
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Bin Meng
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Fernando AE
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Tom Rini