> From: [email protected] [mailto:linux-omap- > [email protected]] On Behalf Of Russell King - ARM Linux > Sent: Friday, September 11, 2015 9:03 AM > To: Grazvydas Ignotas
> However, even the idea that it's ARMv7 or later is wrong. According to > the ARM ARM, the IT instruction is present in ARMv6T2 as well, which > means it's ARMv6 too (which would have __LINUX_ARM_ARCH__ = 6). I recall seeing ARMv6T2 first implemented in the ARM1156 which is a v6 CPU with T2 option added. Cortex-R class was the ARMv7 successor to the 1156 CPU which also use T2. > Looking at the ARM ARM, these bits are "reserved" in previous non-T2 > architectures, have an undefined value at reset, and are probably zero > anyway. > > Merely changing __LINUX_ARM_ARCH__ >= 7 to >= 6 should fix the > problem, > and I doubt there's any ARMv6 non-T2 systems out there that would be > affected by clearing the IT state bits. Probably you already looked, but cpsr.it usage is not restricted to this one spot. Looking back at old notes I think both debug and signal handler code keyed on bit usage. I see from LXR kernel KVM code also uses in some capacity. The 1156/Cortex-R are typically MMU-less. They may (or not) have something else to consider when fixing. Regards, Richard W.
