4 ms·
Were you exploiting an A8 erratum, or detecting "this is an A8" somehow and then making it barf in a less processor specific way?
by pm215 2y ago
Were you exploiting an A8 erratum, or detecting "this is an A8" somehow and then making it barf in a less processor specific way?
- bobmcnamara 2y agoA8 erratum. This was ages ago, but if I recall you could place a thumb2 instruction straddling two pages, only one of which was loaded in the TLBs. If you got everything right, the A8 would hang without trapping. Edit: it was errata #657417, long since scrubbed from arm.com
- pm215 2y agoThe A8 errata doc is at https://developer.arm.com/documentation/prdc008070/latest/ https://developer.arm.com/documentation/prdc008070/latest/ these days and does have a description of 657417 with enough detail to make writing a reproducer possible. Instructions crossing page boundaries are tricky beasts :-)
- bobmcnamara 2y agoWell look at that! I had searched Google and arm.com for that number. This was definitely it.