From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
HW_TAGS KASAN relies on ARM Memory Tagging Extension (MTE). With MTE,
a memory region must be mapped as MT_NORMAL_TAGGED to allow setting
memory tags via MTE-specific instructions.
This change adds proper protection bits to vmalloc() allocations.
These allocations are always backed by page_alloc pages, so the tags
will actually be getting set on the corresponding physical memory.
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Co-developed-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
---
arch/arm64/include/asm/vmalloc.h | 10 ++++++++++
include/linux/vmalloc.h | 7 +++++++
mm/vmalloc.c | 2 ++
3 files changed, 19 insertions(+)
diff --git a/arch/arm64/include/asm/vmalloc.h b/arch/arm64/include/asm/vmalloc.h
index b9185503feae..3d35adf365bf 100644
--- a/arch/arm64/include/asm/vmalloc.h
+++ b/arch/arm64/include/asm/vmalloc.h
@@ -25,4 +25,14 @@ static inline bool arch_vmap_pmd_supported(pgprot_t prot)
#endif
+#define arch_vmalloc_pgprot_modify arch_vmalloc_pgprot_modify
+static inline pgprot_t arch_vmalloc_pgprot_modify(pgprot_t prot)
+{
+ if (IS_ENABLED(CONFIG_KASAN_HW_TAGS) &&
+ (pgprot_val(prot) == pgprot_val(PAGE_KERNEL)))
+ prot = pgprot_tagged(prot);
+
+ return prot;
+}
+
#endif /* _ASM_ARM64_VMALLOC_H */
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index b22369f540eb..965c4bf475f1 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -108,6 +108,13 @@ static inline int arch_vmap_pte_supported_shift(unsigned long size)
}
#endif
+#ifndef arch_vmalloc_pgprot_modify
+static inline pgprot_t arch_vmalloc_pgprot_modify(pgprot_t prot)
+{
+ return prot;
+}
+#endif
+
/*
* Highlevel APIs for driver use
*/
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 7be18b292679..f37d0ed99bf9 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -3033,6 +3033,8 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align,
return NULL;
}
+ prot = arch_vmalloc_pgprot_modify(prot);
+
if (vmap_allow_huge && !(vm_flags & VM_NO_HUGE_VMAP)) {
unsigned long size_per_node;
--
2.25.1
