Commit ab1e435c authored Jan 31, 2022 by Catalin Marinas Committed by Will Deacon Feb 15, 2022

arm64: mte: Define the number of bytes for storing the tags in a page



Rather than explicitly calculating the number of bytes for a compact tag
storage format corresponding to a page, just add a MTE_PAGE_TAG_STORAGE
macro. With the current MTE implementation of 4 bits per tag, we store
2 tags in a byte.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Luis Machado <luis.machado@linaro.org>
Link: https://lore.kernel.org/r/20220131165456.2160675-4-catalin.marinas@arm.com


Signed-off-by: Will Deacon <will@kernel.org>

parent 761b9b36

arch/arm64/include/asm/mte-def.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -11,6 +11,7 @@
		#define MTE_TAG_SHIFT 56
		#define MTE_TAG_SIZE 4
		#define MTE_TAG_MASK GENMASK((MTE_TAG_SHIFT + (MTE_TAG_SIZE - 1)), MTE_TAG_SHIFT)
		#define MTE_PAGE_TAG_STORAGE (MTE_GRANULES_PER_PAGE * MTE_TAG_SIZE / 8)

		#define __MTE_PREAMBLE ARM64_ASM_PREAMBLE ".arch_extension memtag\n"

arch/arm64/lib/mte.S

+2 −2

Original line number	Diff line number	Diff line
		@@ -134,7 +134,7 @@ SYM_FUNC_END(mte_copy_tags_to_user)
		/*
		* Save the tags in a page
		* x0 - page address
		* x1 - tag storage
		* x1 - tag storage, MTE_PAGE_TAG_STORAGE bytes
		*/
		SYM_FUNC_START(mte_save_page_tags)
		multitag_transfer_size x7, x5
		@@ -158,7 +158,7 @@ SYM_FUNC_END(mte_save_page_tags)
		/*
		* Restore the tags in a page
		* x0 - page address
		* x1 - tag storage
		* x1 - tag storage, MTE_PAGE_TAG_STORAGE bytes
		*/
		SYM_FUNC_START(mte_restore_page_tags)
		multitag_transfer_size x7, x5

arch/arm64/mm/mteswap.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -12,7 +12,7 @@ static DEFINE_XARRAY(mte_pages);
		void *mte_allocate_tag_storage(void)
		{
		/* tags granule is 16 bytes, 2 tags stored per byte */
		return kmalloc(PAGE_SIZE / 16 / 2, GFP_KERNEL);
		return kmalloc(MTE_PAGE_TAG_STORAGE, GFP_KERNEL);
		}

		void mte_free_tag_storage(char *storage)