diff mbox series

[054/114] kasan, vmalloc, arm64: mark vmalloc mappings as pgprot_tagged

Message ID 20220325011117.93AF3C340F1@smtp.kernel.org (mailing list archive)
State New
Headers show
Series [001/114] tools/vm/page_owner_sort.c: sort by stacktrace before culling | expand

Commit Message

Andrew Morton March 25, 2022, 1:11 a.m. UTC 
From: Andrey Konovalov <andreyknvl@google.com>
Subject: kasan, vmalloc, arm64: mark vmalloc mappings as pgprot_tagged

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.

Add 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.

Link: https://lkml.kernel.org/r/983fc33542db2f6b1e77b34ca23448d4640bbb9e.1643047180.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Co-developed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Acked-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/arm64/include/asm/vmalloc.h |    6 ++++++
 include/linux/vmalloc.h          |    7 +++++++
 mm/vmalloc.c                     |    9 +++++++++
 3 files changed, 22 insertions(+)
diff mbox series

Patch

--- a/arch/arm64/include/asm/vmalloc.h~kasan-vmalloc-arm64-mark-vmalloc-mappings-as-pgprot_tagged
+++ a/arch/arm64/include/asm/vmalloc.h
@@ -25,4 +25,10 @@  static inline bool arch_vmap_pmd_support
 
 #endif
 
+#define arch_vmap_pgprot_tagged arch_vmap_pgprot_tagged
+static inline pgprot_t arch_vmap_pgprot_tagged(pgprot_t prot)
+{
+	return pgprot_tagged(prot);
+}
+
 #endif /* _ASM_ARM64_VMALLOC_H */
--- a/include/linux/vmalloc.h~kasan-vmalloc-arm64-mark-vmalloc-mappings-as-pgprot_tagged
+++ a/include/linux/vmalloc.h
@@ -115,6 +115,13 @@  static inline int arch_vmap_pte_supporte
 }
 #endif
 
+#ifndef arch_vmap_pgprot_tagged
+static inline pgprot_t arch_vmap_pgprot_tagged(pgprot_t prot)
+{
+	return prot;
+}
+#endif
+
 /*
  *	Highlevel APIs for driver use
  */
--- a/mm/vmalloc.c~kasan-vmalloc-arm64-mark-vmalloc-mappings-as-pgprot_tagged
+++ a/mm/vmalloc.c
@@ -3128,6 +3128,15 @@  again:
 		goto fail;
 	}
 
+	/*
+	 * Modify protection bits to allow tagging.
+	 * This must be done before mapping by __vmalloc_area_node().
+	 */
+	if (kasan_hw_tags_enabled() &&
+	    pgprot_val(prot) == pgprot_val(PAGE_KERNEL))
+		prot = arch_vmap_pgprot_tagged(prot);
+
+	/* Allocate physical pages and map them into vmalloc space. */
 	addr = __vmalloc_area_node(area, gfp_mask, prot, shift, node);
 	if (!addr)
 		goto fail;