Re: Max. memory size for 32 bit binaries in amd64/x86

[Tom Vier <tmv@comcast.net>]

> (There is no config parameter such as CONFIG_HIGHMEM for amd64.)

this is an interesting topic. i don't know if the 32bit compat code requires
kernel mem to be mapped into the 32bit page tables. if not, apps should be
able to alloc all 4gigs. if it does need the mapping, it should be a 2/2
split.

i would guess that the syscall entry point just translates syscall args from
x86 to x86-64. the actual syscall code should be 64bit (unless you want to
build half the kernel in 32 and 64bit modes and double the instructions).
so, in theory, userland apps should be able to alloc all 4gigs (minus a page
or two for weird x86 stuff?).

-- 
Tom Vier <tmv@comcast.net>
DSA Key ID 0xE6CB97DA