On Tue, Jun 11, 2019 at 05:35:31PM +0200, Andrey Konovalov wrote:
On Mon, Jun 10, 2019 at 4:28 PM Catalin Marinas catalin.marinas@arm.com wrote:
On Mon, Jun 03, 2019 at 06:55:07PM +0200, Andrey Konovalov wrote:
This patch is a part of a series that extends arm64 kernel ABI to allow to pass tagged user pointers (with the top byte set to something else other than 0x00) as syscall arguments.
This patch allows tagged pointers to be passed to the following memory syscalls: get_mempolicy, madvise, mbind, mincore, mlock, mlock2, mprotect, mremap, msync, munlock.
Signed-off-by: Andrey Konovalov andreyknvl@google.com
I would add in the commit log (and possibly in the code with a comment) that mremap() and mmap() do not currently accept tagged hint addresses. Architectures may interpret the hint tag as a background colour for the corresponding vma. With this:
I'll change the commit log. Where do you you think I should put this comment? Before mmap and mremap definitions in mm/?
On arm64 we use our own sys_mmap(). I'd say just add a comment on the generic mremap() just before the untagged_addr() along the lines that new_address is not untagged for preserving similar behaviour to mmap().