NXP Semiconductors i.MX 6Dual Reference Manual

Contents

ERR003723Chip Errata for the i.MX 6Dual/6Quad and i.MX 6DualPlus/6QuadPlus, Rev. 6.1, 06/2016NXP Semiconductors 25Description:Under rare conditions, a watchpoint on the second part of an unaligned access that crosses a 4 KBpage boundary and that is missed in the micro-TLB for the second part of its request might beundetected.The erratum requires a previous conditional instruction that accesses the second 4 KB memoryregion (= where the watchpoint is set), is missed in the micro-TLB, and is condition failed. Theerratum also requires that no other micro-TLB miss occurs between this conditional failedinstruction and the unaligned access. This implies that the unaligned access must hit in themicro-TLB for the first part of its request.Projected Impact:A valid watchpoint trigger is missed.Workarounds:In case, a watchpoint is set on any of the first 3 bytes of a 4 KB memory region, and unalignedaccesses are not being faulted, then the erratum might happen.The workaround then requires setting a guard watchpoint on the last byte of the previous page, anddealing with any “false positive” matches as and when they occur.Proposed Solution:No fix scheduledLinux BSP Status:The Linux BSP does not use this debug feature—the ARM workaround should be followed.Software workaround is not needed because this erratum will not be encountered in normal deviceoperation.ERR003723 ARM: 751476—May miss a watchpoint on the second part of anunaligned access that crosses a page boundary