On Thu, Jan 26, 2023 at 12:09:53AM +1100, Michael Ellerman wrote: > Andrew Donnellan <ajd@xxxxxxxxxxxxx> writes: > > A number of structures and buffers passed to PKS hcalls have alignment > > requirements, which could on occasion cause problems: > > > > - Authorisation structures must be 16-byte aligned and must not cross a > > page boundary > > > > - Label structures must not cross page boundaries > > > > - Password output buffers must not cross page boundaries > > > > Round up the allocations of these structures/buffers to the next power of > > 2 to make sure this happens. > > It's not the *next* power of 2, it's the *nearest* power of 2, including > the initial value if it's already a power of 2. It's not the nearest either, the nearest power of two to 65 is 64. You could say "but, round up" to which I would say "round?" :-P "Adjust the allocation size to be the smallest power of two greater than or equal to the given size." "Pad to a power of two" in shorthand. "Padded to a power of two if necessary" if you want to emphasise it can be a no-op. Segher
