From: Daniel Axtens <dja@axtens.net>
To: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linuxppc-dev@lists.ozlabs.org, kasan-dev@googlegroups.com,
christophe.leroy@c-s.fr, aneesh.kumar@linux.ibm.com,
bsingharora@gmail.com
Cc: Daniel Axtens <dja@axtens.net>
Subject: [PATCH v7 2/4] kasan: Document support on 32-bit powerpc
Date: Thu, 13 Feb 2020 11:47:50 +1100 [thread overview]
Message-ID: <20200213004752.11019-3-dja@axtens.net> (raw)
In-Reply-To: <20200213004752.11019-1-dja@axtens.net>
KASAN is supported on 32-bit powerpc and the docs should reflect this.
Document s390 support while we're at it.
Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Daniel Axtens <dja@axtens.net>
---
Changes since v5:
- rebase - riscv has now got support.
- document s390 support while we're at it
- clarify when kasan_vmalloc support is required
---
Documentation/dev-tools/kasan.rst | 7 +++++--
Documentation/powerpc/kasan.txt | 12 ++++++++++++
2 files changed, 17 insertions(+), 2 deletions(-)
create mode 100644 Documentation/powerpc/kasan.txt
diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst
index c652d740735d..012ef3d91d1f 100644
--- a/Documentation/dev-tools/kasan.rst
+++ b/Documentation/dev-tools/kasan.rst
@@ -22,7 +22,8 @@ global variables yet.
Tag-based KASAN is only supported in Clang and requires version 7.0.0 or later.
Currently generic KASAN is supported for the x86_64, arm64, xtensa, s390 and
-riscv architectures, and tag-based KASAN is supported only for arm64.
+riscv architectures. It is also supported on 32-bit powerpc kernels. Tag-based
+KASAN is supported only on arm64.
Usage
-----
@@ -255,7 +256,9 @@ CONFIG_KASAN_VMALLOC
~~~~~~~~~~~~~~~~~~~~
With ``CONFIG_KASAN_VMALLOC``, KASAN can cover vmalloc space at the
-cost of greater memory usage. Currently this is only supported on x86.
+cost of greater memory usage. Currently this supported on x86, s390
+and 32-bit powerpc. It is optional, except on 32-bit powerpc kernels
+with module support, where it is required.
This works by hooking into vmalloc and vmap, and dynamically
allocating real shadow memory to back the mappings.
diff --git a/Documentation/powerpc/kasan.txt b/Documentation/powerpc/kasan.txt
new file mode 100644
index 000000000000..26bb0e8bb18c
--- /dev/null
+++ b/Documentation/powerpc/kasan.txt
@@ -0,0 +1,12 @@
+KASAN is supported on powerpc on 32-bit only.
+
+32 bit support
+==============
+
+KASAN is supported on both hash and nohash MMUs on 32-bit.
+
+The shadow area sits at the top of the kernel virtual memory space above the
+fixmap area and occupies one eighth of the total kernel virtual memory space.
+
+Instrumentation of the vmalloc area is optional, unless built with modules,
+in which case it is required.
--
2.20.1
next prev parent reply other threads:[~2020-02-13 0:48 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-13 0:47 [PATCH v7 0/4] KASAN for powerpc64 radix Daniel Axtens
2020-02-13 0:47 ` [PATCH v7 1/4] kasan: define and use MAX_PTRS_PER_* for early shadow tables Daniel Axtens
2020-02-13 0:47 ` Daniel Axtens [this message]
2020-02-13 0:47 ` [PATCH v7 3/4] powerpc/mm/kasan: rename kasan_init_32.c to init_32.c Daniel Axtens
2020-02-13 0:47 ` [PATCH v7 4/4] powerpc: Book3S 64-bit "heavyweight" KASAN support Daniel Axtens
2020-02-13 0:47 ` Daniel Axtens
2020-02-13 6:08 ` Christophe Leroy
2020-02-13 6:08 ` Christophe Leroy
2020-02-13 11:36 ` Christophe Leroy
2020-02-13 11:36 ` Christophe Leroy
2020-03-06 13:09 ` Daniel Axtens
2020-03-06 13:09 ` Daniel Axtens
2020-02-16 23:08 ` Michael Neuling
2020-02-16 23:08 ` Michael Neuling
2020-02-17 6:45 ` Christophe Leroy
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