when and where will the LDP instruction trigger an exception ?

Where can I find the specification about this issue in ARMv8 Architecture Reference Manual ?

In the current document issue (A.k).

Section B 2.2 describes the two memory types in ARMv8 ("Normal" and "Device"); the ARMv7 "Strongly Ordered" no longer exists as a separate memory type - that has effectively been merged as sub-type of the "Device" memory type in ARMv8 (See B 2.8.2).

Section B 2.4.2 describes the limitations on unaligned access for data accesses. Specifically:

"An unaligned access to any type of Device memory causes an Alignment fault."

The behaviour when translation is disabled is defined in section D4.2.8. Specifically:

"All other accesses:

    Data access:

        The stage 1 translation assigns the Device-nGnRnE memory type."

Cheers,
Pete

Where can I find the specification about this issue in ARMv8 Architecture Reference Manual ?

In the current document issue (A.k).

Section B 2.2 describes the two memory types in ARMv8 ("Normal" and "Device"); the ARMv7 "Strongly Ordered" no longer exists as a separate memory type - that has effectively been merged as sub-type of the "Device" memory type in ARMv8 (See B 2.8.2).

Section B 2.4.2 describes the limitations on unaligned access for data accesses. Specifically:

"An unaligned access to any type of Device memory causes an Alignment fault."

The behaviour when translation is disabled is defined in section D4.2.8. Specifically:

"All other accesses:

    Data access:

        The stage 1 translation assigns the Device-nGnRnE memory type."

Cheers,
Pete

I've never felt the need to treat integers or longs as unaligned - but I can see this tripping up some things like a memory move if one just copies over the usual algorithm to early in the boot process.