On 6/10/19 8:22 AM, Yu-cheng Yu wrote:

quoted

How does glibc know the linear address space size?  We don’t want LA64 to
break old binaries because the address calculation changed.

When an application starts, its highest stack address is determined.
It uses that as the maximum the bitmap needs to cover.

Huh, I didn't think we ran code from the stack. ;)

Especially given the way that we implemented the new 5-level-paging
address space, I don't think that expecting code to be below the stack
is a good universal expectation.