From: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> When the Memory Tagging Extension is enabled, the tags need to be preserved across page copy (e.g. for copy-on-write). Introduce MTE-aware copy_page() which preserves the tags across page copy. Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> Co-developed-by: Catalin Marinas <catalin.marinas@xxxxxxx> Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Will Deacon <will@xxxxxxxxxx> --- arch/arm64/lib/copy_page.S | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/arch/arm64/lib/copy_page.S b/arch/arm64/lib/copy_page.S index e7a793961408..c3234175efe0 100644 --- a/arch/arm64/lib/copy_page.S +++ b/arch/arm64/lib/copy_page.S @@ -25,6 +25,29 @@ alternative_if ARM64_HAS_NO_HW_PREFETCH prfm pldl1strm, [x1, #384] alternative_else_nop_endif +#ifdef CONFIG_ARM64_MTE +alternative_if_not ARM64_MTE + b 2f +alternative_else_nop_endif + /* + * Copy tags if MTE has been enabled. + */ + mov x2, x0 + mov x3, x1 + + multitag_transfer_size x7, x5 +1: + ldgm x4, [x3] + stgm x4, [x2] + + add x2, x2, x7 + add x3, x3, x7 + + tst x2, #(PAGE_SIZE - 1) + b.ne 1b +2: +#endif + ldp x2, x3, [x1] ldp x4, x5, [x1, #16] ldp x6, x7, [x1, #32]
