From 688abddcfa17d23cb15bc7e082cf22b136029205 Mon Sep 17 00:00:00 2001
From: Andrey Konovalov <andreyknvl@google.com>
Date: Thu, 27 Jan 2022 16:25:52 +1100
Subject: [PATCH] BACKPORT: FROMGIT: kasan, vmalloc, arm64: mark vmalloc
 mappings as pgprot_tagged

(Backport: conflicts due to adjacent lines changed;
 add pgtable.h include to arch/arm64/include/asm/vmalloc.h.)

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>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
(cherry picked from commit df70c9aebdba46948cf5af35a82c23a8e8376797
 git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git akpm)
Bug: 217222520
Change-Id: I1ea6aa7cfa907a75fa1b8cab3d33538f89fe0fca
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 arch/arm64/include/asm/vmalloc.h | 7 +++++++
 include/linux/vmalloc.h          | 7 +++++++
 mm/vmalloc.c                     | 9 +++++++++
 3 files changed, 23 insertions(+)

diff --git a/arch/arm64/include/asm/vmalloc.h b/arch/arm64/include/asm/vmalloc.h
index 7a22aeea9bb5..1ed0aace67b4 100644
--- a/arch/arm64/include/asm/vmalloc.h
+++ b/arch/arm64/include/asm/vmalloc.h
@@ -2,6 +2,7 @@
 #define _ASM_ARM64_VMALLOC_H
 
 #include <asm/page.h>
+#include <asm/pgtable.h>
 
 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
 
@@ -25,4 +26,10 @@ static inline bool arch_vmap_pmd_supported(pgprot_t prot)
 
 #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 */
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index eb065e772002..ecbcafc00133 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -115,6 +115,13 @@ static inline int arch_vmap_pte_supported_shift(unsigned long size)
 }
 #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
  */
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 4de9486873c1..ea9d8dd44a56 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -3034,6 +3034,15 @@ 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;