arm64: mm: remove page_mapping check in __sync_icache_dcache

__sync_icache_dcache unconditionally skips the cache maintenance for
anonymous pages, under the assumption that flushing is only required in
the presence of D-side aliases [see 7249b79f6b4cc ("arm64: Do not flush
the D-cache for anonymous pages")].

Unfortunately, this breaks migration of anonymous pages holding
self-modifying code, where userspace cannot be reasonably expected to
reissue maintenance instructions in response to a migration.

This patch fixes the problem by removing the broken page_mapping(page)
check from the cache syncing code, otherwise we may end up fetching and
executing stale instructions from the PoU.

Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: <[email protected]>
Reviewed-by: Catalin Marinas <[email protected]>
Signed-off-by: Shaokun Zhang <[email protected]>
Signed-off-by: Will Deacon <[email protected]>

0 files changed, 0 insertions, 0 deletions