kselftest/arm64: mte: user_mem: introduce tag_offset and tag_len

These can be used to place an MTE tag at an address that is not at a
page size boundary.

The kernel prior to 295cf156231c ("arm64: Avoid premature usercopy failure"),
would infinite loop if an MTE tag was placed not at a PAGE_SIZE boundary.
This is because the kernel checked if the pages were readable by checking the
first byte of each page, but would then fault in the middle of the page due
to the MTE tag.

Signed-off-by: Joey Gouly <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Mark Brown <[email protected]>
Cc: Shuah Khan <[email protected]>
Reviewed-by: Mark Brown <[email protected]>
Tested-by: Mark Brown <[email protected]>
Reviewed-by: Shuah Khan <[email protected]>
Reviewed-by: Catalin Marinas <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Will Deacon <[email protected]>

0 files changed, 0 insertions, 0 deletions