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Message-ID: <20220915150417.722975-44-glider@google.com>
Date: Thu, 15 Sep 2022 17:04:17 +0200
From: Alexander Potapenko <glider@...gle.com>
To: glider@...gle.com
Cc: Alexander Viro <viro@...iv.linux.org.uk>,
Alexei Starovoitov <ast@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Andrey Konovalov <andreyknvl@...gle.com>,
Andy Lutomirski <luto@...nel.org>,
Arnd Bergmann <arnd@...db.de>, Borislav Petkov <bp@...en8.de>,
Christoph Hellwig <hch@....de>,
Christoph Lameter <cl@...ux.com>,
David Rientjes <rientjes@...gle.com>,
Dmitry Vyukov <dvyukov@...gle.com>,
Eric Biggers <ebiggers@...nel.org>,
Eric Dumazet <edumazet@...gle.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Herbert Xu <herbert@...dor.apana.org.au>,
Ilya Leoshkevich <iii@...ux.ibm.com>,
Ingo Molnar <mingo@...hat.com>, Jens Axboe <axboe@...nel.dk>,
Joonsoo Kim <iamjoonsoo.kim@....com>,
Kees Cook <keescook@...omium.org>,
Marco Elver <elver@...gle.com>,
Mark Rutland <mark.rutland@....com>,
Matthew Wilcox <willy@...radead.org>,
"Michael S. Tsirkin" <mst@...hat.com>,
Pekka Enberg <penberg@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Petr Mladek <pmladek@...e.com>,
Stephen Rothwell <sfr@...b.auug.org.au>,
Steven Rostedt <rostedt@...dmis.org>,
Thomas Gleixner <tglx@...utronix.de>,
Vasily Gorbik <gor@...ux.ibm.com>,
Vegard Nossum <vegard.nossum@...cle.com>,
Vlastimil Babka <vbabka@...e.cz>, kasan-dev@...glegroups.com,
linux-mm@...ck.org, linux-arch@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH v7 43/43] x86: kmsan: enable KMSAN builds for x86
Make KMSAN usable by adding the necessary Kconfig bits.
Also declare x86-specific functions checking address validity
in arch/x86/include/asm/kmsan.h.
Signed-off-by: Alexander Potapenko <glider@...gle.com>
---
v4:
-- per Marco Elver's request, create arch/x86/include/asm/kmsan.h
and move arch-specific inline functions there.
Link: https://linux-review.googlesource.com/id/I1d295ce8159ce15faa496d20089d953a919c125e
---
arch/x86/Kconfig | 1 +
arch/x86/include/asm/kmsan.h | 55 ++++++++++++++++++++++++++++++++++++
2 files changed, 56 insertions(+)
create mode 100644 arch/x86/include/asm/kmsan.h
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 697da8dae1418..bd9436cd0f29b 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -168,6 +168,7 @@ config X86
select HAVE_ARCH_KASAN if X86_64
select HAVE_ARCH_KASAN_VMALLOC if X86_64
select HAVE_ARCH_KFENCE
+ select HAVE_ARCH_KMSAN if X86_64
select HAVE_ARCH_KGDB
select HAVE_ARCH_MMAP_RND_BITS if MMU
select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
diff --git a/arch/x86/include/asm/kmsan.h b/arch/x86/include/asm/kmsan.h
new file mode 100644
index 0000000000000..a790b865d0a68
--- /dev/null
+++ b/arch/x86/include/asm/kmsan.h
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * x86 KMSAN support.
+ *
+ * Copyright (C) 2022, Google LLC
+ * Author: Alexander Potapenko <glider@...gle.com>
+ */
+
+#ifndef _ASM_X86_KMSAN_H
+#define _ASM_X86_KMSAN_H
+
+#ifndef MODULE
+
+#include <asm/processor.h>
+#include <linux/mmzone.h>
+
+/*
+ * Taken from arch/x86/mm/physaddr.h to avoid using an instrumented version.
+ */
+static inline bool kmsan_phys_addr_valid(unsigned long addr)
+{
+ if (IS_ENABLED(CONFIG_PHYS_ADDR_T_64BIT))
+ return !(addr >> boot_cpu_data.x86_phys_bits);
+ else
+ return true;
+}
+
+/*
+ * Taken from arch/x86/mm/physaddr.c to avoid using an instrumented version.
+ */
+static inline bool kmsan_virt_addr_valid(void *addr)
+{
+ unsigned long x = (unsigned long)addr;
+ unsigned long y = x - __START_KERNEL_map;
+
+ /* use the carry flag to determine if x was < __START_KERNEL_map */
+ if (unlikely(x > y)) {
+ x = y + phys_base;
+
+ if (y >= KERNEL_IMAGE_SIZE)
+ return false;
+ } else {
+ x = y + (__START_KERNEL_map - PAGE_OFFSET);
+
+ /* carry flag will be set if starting x was >= PAGE_OFFSET */
+ if ((x > y) || !kmsan_phys_addr_valid(x))
+ return false;
+ }
+
+ return pfn_valid(x >> PAGE_SHIFT);
+}
+
+#endif /* !MODULE */
+
+#endif /* _ASM_X86_KMSAN_H */
--
2.37.2.789.g6183377224-goog
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