From 2563776b41c3190849c6b011c72b47bff314963d Mon Sep 17 00:00:00 2001 From: Vincenzo Frascino Date: Tue, 6 Aug 2019 11:37:53 +0100 Subject: arm64: mte: Tags-aware copy_{user_,}highpage() implementations When the Memory Tagging Extension is enabled, the tags need to be preserved across page copy (e.g. for copy-on-write, page migration). Introduce MTE-aware copy_{user_,}highpage() functions to copy tags to the destination if the source page has the PG_mte_tagged flag set. copy_user_page() does not need to handle tag copying since, with this patch, it is only called by the DAX code where there is no source page structure (and no source tags). Signed-off-by: Vincenzo Frascino Co-developed-by: Catalin Marinas Signed-off-by: Catalin Marinas Cc: Will Deacon --- arch/arm64/lib/mte.S | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'arch/arm64/lib') diff --git a/arch/arm64/lib/mte.S b/arch/arm64/lib/mte.S index a36705640086..3c3d0edbbca3 100644 --- a/arch/arm64/lib/mte.S +++ b/arch/arm64/lib/mte.S @@ -5,6 +5,7 @@ #include #include +#include #include .arch armv8.5-a+memtag @@ -32,3 +33,21 @@ SYM_FUNC_START(mte_clear_page_tags) b.ne 1b ret SYM_FUNC_END(mte_clear_page_tags) + +/* + * Copy the tags from the source page to the destination one + * x0 - address of the destination page + * x1 - address of the source page + */ +SYM_FUNC_START(mte_copy_page_tags) + mov x2, x0 + mov x3, x1 + multitag_transfer_size x5, x6 +1: ldgm x4, [x3] + stgm x4, [x2] + add x2, x2, x5 + add x3, x3, x5 + tst x2, #(PAGE_SIZE - 1) + b.ne 1b + ret +SYM_FUNC_END(mte_copy_page_tags) -- cgit v1.2.3