[PATCH] arm64: allow vmalloc regions to be set with set_memory_*

On 28 January 2016 at 19:10, Will Deacon [off-list ref] wrote:

On Thu, Jan 28, 2016 at 05:43:41PM +0100, Ard Biesheuvel wrote:

quoted

On 28 January 2016 at 16:08, Will Deacon [off-list ref] wrote:

quoted

On Mon, Jan 18, 2016 at 03:01:05PM +0100, Ard Biesheuvel wrote:

quoted

The range of set_memory_* is currently restricted to the module address
range because of difficulties in breaking down larger block sizes.
vmalloc maps PAGE_SIZE pages so it is safe to use as well. Update the
function ranges and add a comment explaining why the range is restricted
the way it is.

Suggested-by: Laura Abbott <redacted>
Signed-off-by: Ard Biesheuvel <redacted>
---
 arch/arm64/mm/pageattr.c | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

What's the user for this? It would be better to apply along with something
that actually needs to change permission for arbitrary vmalloc mappings.

BPF already uses set_memory_ro() but doesn't bother to check the return value.

Urgh :(

Then I can take it as a fix, if you like.

I will let you decide whether it should be merged now or in v4.6. I
don't think there's any urgency here, though.

BTW I already sent a v2 based on -rc2 here
http://article.gmane.org/gmane.linux.ports.arm.kernel/472555

Thanks,
Ard.