So we're designing for lala land where any and all silly systems exist are we? Just define a minimum based on real world standards which as far as I'm aware is 512 minimum which is reasonable enough for a `MIN_PAGE_SIZE 512` macro and certainly reasonable for a `MAX_INVALID_ADDRESS ((void*)512)` macro
On Thursday, 31 July 2025 07:35:31 Pacific Daylight Time zxuiji wrote:
> Then the answer to the potential null+-1 being valid is simple, mandate in
> the next standard that the 0+-PAGE_SIZE be premapped as sealed no rwx
> pages. That resolves the problem completely. They don't need to have
> anything mapped to them, just that they be mapped as invalid.
There's no PAGE_SIZE in the standard. Nor in POSIX, for that matter. POSIX
only has a runtime requirement for sysconf(_SC_PAGESIZE), with no required
minimum.
Without a minimum, there could hypothetically be a system with a page size of
1, which means the change you're proposing is useless.
--
Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
Principal Engineer - Intel Platform & System Engineering