From ce732a7520b093091c345cba1b84542d1abd83ed Mon Sep 17 00:00:00 2001
From: Alexander Potapenko <glider@google.com>
Date: Wed, 28 Sep 2022 14:32:19 +0200
Subject: x86: kmsan: handle CPU entry area

Among other data, CPU entry area holds exception stacks, so addresses from
this area can be passed to kmsan_get_metadata().

This previously led to kmsan_get_metadata() returning NULL, which in turn
resulted in a warning that triggered further attempts to call
kmsan_get_metadata() in the exception context, which quickly exhausted the
exception stack.

This patch allocates shadow and origin for the CPU entry area on x86 and
introduces arch_kmsan_get_meta_or_null(), which performs arch-specific
metadata mapping.

Link: https://lkml.kernel.org/r/20220928123219.1101883-1-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Fixes: 21d723a7c1409 ("kmsan: add KMSAN runtime core")
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 mm/kmsan/shadow.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

(limited to 'mm/kmsan')

diff --git a/mm/kmsan/shadow.c b/mm/kmsan/shadow.c
index 6e90a806a704..21e3e196ec3c 100644
--- a/mm/kmsan/shadow.c
+++ b/mm/kmsan/shadow.c
@@ -12,7 +12,6 @@
 #include <linux/cacheflush.h>
 #include <linux/memblock.h>
 #include <linux/mm_types.h>
-#include <linux/percpu-defs.h>
 #include <linux/slab.h>
 #include <linux/smp.h>
 #include <linux/stddef.h>
@@ -126,6 +125,7 @@ void *kmsan_get_metadata(void *address, bool is_origin)
 {
 	u64 addr = (u64)address, pad, off;
 	struct page *page;
+	void *ret;
 
 	if (is_origin && !IS_ALIGNED(addr, KMSAN_ORIGIN_SIZE)) {
 		pad = addr % KMSAN_ORIGIN_SIZE;
@@ -136,6 +136,10 @@ void *kmsan_get_metadata(void *address, bool is_origin)
 	    kmsan_internal_is_module_addr(address))
 		return (void *)vmalloc_meta(address, is_origin);
 
+	ret = arch_kmsan_get_meta_or_null(address, is_origin);
+	if (ret)
+		return ret;
+
 	page = virt_to_page_or_null(address);
 	if (!page)
 		return NULL;
-- 
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