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| author | Vincenzo Frascino <vincenzo.frascino@arm.com> | 2019-08-06 13:37:53 +0300 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2020-09-04 14:46:06 +0300 |
| commit | 2563776b41c3190849c6b011c72b47bff314963d (patch) | |
| tree | e2ae176783c6a2d18fccf3e6927ec01289534ed8 /arch/arm64/lib/mte.S | |
| parent | 34bfeea4a9e9cdae713637541f240c3adfdfede3 (diff) | |
| download | linux-2563776b41c3190849c6b011c72b47bff314963d.tar.xz | |
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 <vincenzo.frascino@arm.com>
Co-developed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/lib/mte.S')
| -rw-r--r-- | arch/arm64/lib/mte.S | 19 |
1 files changed, 19 insertions, 0 deletions
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 <linux/linkage.h> #include <asm/assembler.h> +#include <asm/page.h> #include <asm/sysreg.h> .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) |