[PATCH 3/5] arm64: mte: Define the number of bytes for storing the tags in a page
From: Catalin Marinas <catalin.marinas@arm.com>
Date: 2021-12-08 12:21:43
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
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> --- arch/arm64/include/asm/mte-def.h | 1 + arch/arm64/lib/mte.S | 4 ++-- arch/arm64/mm/mteswap.c | 2 +- 3 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/mte-def.h b/arch/arm64/include/asm/mte-def.h
index 626d359b396e..14ee86b019c2 100644
--- a/arch/arm64/include/asm/mte-def.h
+++ b/arch/arm64/include/asm/mte-def.h@@ -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"
diff --git a/arch/arm64/lib/mte.S b/arch/arm64/lib/mte.S
index e83643b3995f..62a1025aa118 100644
--- a/arch/arm64/lib/mte.S
+++ b/arch/arm64/lib/mte.S@@ -128,7 +128,7 @@ 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
@@ -152,7 +152,7 @@ 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
diff --git a/arch/arm64/mm/mteswap.c b/arch/arm64/mm/mteswap.c
index 7c4ef56265ee..a9e50e930484 100644
--- a/arch/arm64/mm/mteswap.c
+++ b/arch/arm64/mm/mteswap.c@@ -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)
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