On 06/12/17 15:18, Konrad Rzeszutek Wilk wrote: > On Wed, Dec 06, 2017 at 02:57:29PM +0000, Marc Zyngier wrote: >> On 06/12/17 14:48, Konrad Rzeszutek Wilk wrote: >>> On Wed, Dec 06, 2017 at 02:38:25PM +0000, Marc Zyngier wrote: >>>> We're playing a dangerous game with struct alt_instr, as we produce >>>> it using assembly tricks, but parse them using the C structure. >>>> We just assume that the respective alignments of the two will >>>> be the same. >>>> >>>> But as we add more fields to this structure, the alignment requirements >>>> of the structure may change, and lead to all kind of funky bugs. >>>> >>>> TO solve this, let's move the definition of struct alt_instr to its >>>> own file, and use this to generate the alignment constraint from >>>> asm-offsets.c. The various macros are then patched to take the >>>> alignment into account. >>> >>> Would it be better to use .p2align as on 32-bit ARM you must >>> have it 4-byte aligned. Or at least have and BUILD_BUG_ON >>> to make sure the size can be divided by four?? >>> >>> Oh wait. You are not even touching ARM-32, how come? The alternative >>> code can run on ARM-32 ... >> >> How? Given that I haven't written yet, I'd be grateful if you could >> share your time machine... > > Oh! I assumed it would be there as the Xen variant runs on ARM-32 and > it borrowed a bunch of code from Linux. KVM definitely runs on 32bit, but doesn't have any alternative facility, at least not in the way arm64 does. > Please disregard my comment. I will go back to tweaking the time machine. Let me know once you've debugged it, I have a couple of issues to address in the past... Thanks, M. -- Jazz is not dead. It just smells funny...
