Messages in this thread | | | Date | Thu, 26 Jan 2023 11:19:25 -0600 | From | Segher Boessenkool <> | Subject | Re: [PATCH v4 02/24] powerpc/pseries: Fix alignment of PLPKS structures and buffers |
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On Thu, Jan 26, 2023 at 12:09:53AM +1100, Michael Ellerman wrote: > Andrew Donnellan <ajd@linux.ibm.com> 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
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