arm64: tags: Preserve tags for addresses translated via TTBR1

Sign-extending TTBR1 addresses when converting to an untagged address
breaks the documented POSIX semantics for mlock() in some obscure error
cases where we end up returning -EINVAL instead of -ENOMEM as a direct
result of rewriting the upper address bits.

Rework the untagged_addr() macro to preserve the upper address bits for
TTBR1 addresses and only clear the tag bits for user addresses. This
matches the behaviour of the 'clear_address_tag' assembly macro, so
rename that and align the implementations at the same time so that they
use the same instruction sequences for the tag manipulation.

Link: https://lore.kernel.org/stable/[email protected]/
Reported-by: Jan Stancek <[email protected]>
Tested-by: Jan Stancek <[email protected]>
Reviewed-by: Catalin Marinas <[email protected]>
Tested-by: Catalin Marinas <[email protected]>
Reviewed-by: Vincenzo Frascino <[email protected]>
Tested-by: Vincenzo Frascino <[email protected]>
Reviewed-by: Andrey Konovalov <[email protected]>
Signed-off-by: Will Deacon <[email protected]>

0 files changed, 0 insertions, 0 deletions