This adds support for swapping and hibernation with MTE tagged memory. It's based on Catalin's v3 series[1]. To support swap, a new page flag is added which tracks whether a page has been mapped into user space with MTE enabled (and therefore may have valid data in the tags). Arch hooks are added to enable the saving/restoring of these tags (in memory) when the pages are swapped out. Hibernation builds on the swap support by simply copying the tags out of hardware tag storage into normal memory before the hibernation image is created. On restore the tags are returned to the hardware tag storage. Feedback on the approach is welcomed. [1] https://lore.kernel.org/linux-arm-kernel/20200421142603.3894-1-catalin.marinas@xxxxxxx/ Steven Price (4): mm: Add PG_ARCH_2 page flag mm: Add arch hooks for saving/restoring tags arm64: mte: Enable swap of tagged pages arm64: mte: Save tags when hibernating arch/arm64/Kconfig | 2 +- arch/arm64/include/asm/mte.h | 6 ++ arch/arm64/include/asm/pgtable.h | 44 ++++++++++++ arch/arm64/kernel/hibernate.c | 116 ++++++++++++++++++++++++++++++ arch/arm64/lib/mte.S | 50 +++++++++++++ arch/arm64/mm/Makefile | 2 +- arch/arm64/mm/mteswap.c | 98 +++++++++++++++++++++++++ fs/proc/page.c | 3 + include/asm-generic/pgtable.h | 23 ++++++ include/linux/kernel-page-flags.h | 1 + include/linux/page-flags.h | 3 + include/trace/events/mmflags.h | 9 ++- mm/Kconfig | 3 + mm/page_io.c | 6 ++ mm/shmem.c | 6 ++ mm/swapfile.c | 2 + tools/vm/page-types.c | 2 + 17 files changed, 373 insertions(+), 3 deletions(-) create mode 100644 arch/arm64/mm/mteswap.c -- 2.20.1
