[PATCH] arm64: mte: Use PAGE_KERNEL_TAGGED in arch_add_memory
From: Patrick Daly <hidden>
Date: 2021-03-03 14:32:13
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
In a system which supports MTE, the linear kernel region must allow reading/writing allocation tags. For memory present at boot this is already being done in map_mem(). Add the same in arch_add_memory(). Signed-off-by: Patrick Daly <redacted> --- arch/arm64/mm/mmu.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 9b25d60b..0fcfe90 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c@@ -1463,6 +1463,7 @@ int arch_add_memory(int nid, u64 start, u64 size, struct mhp_params *params) { int ret, flags = 0; + pgprot_t pgprot; if (!inside_linear_region(start, size)) { pr_err("[%llx %llx] is outside linear mapping region\n", start, start + size);
@@ -1477,8 +1478,17 @@ int arch_add_memory(int nid, u64 start, u64 size, IS_ENABLED(CONFIG_KFENCE)) flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; + /* + * The linear map must allow allocation tags reading/writing + * if MTE is present. Otherwise, it has the same attributes as + * PAGE_KERNEL. + */ + pgprot = params->pgprot; + if (pgprot_val(pgprot) == pgprot_val(PAGE_KERNEL)) + pgprot = PAGE_KERNEL_TAGGED; + __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), - size, params->pgprot, __pgd_pgtable_alloc, + size, pgprot, __pgd_pgtable_alloc, flags); memblock_clear_nomap(start, size);
--
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