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From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Nicholas Piggin <npiggin@gmail.com>,
	Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Alexander Potapenko <glider@google.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	Daniel Axtens <dja@axtens.net>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	kasan-dev@googlegroups.com, linux-mm@kvack.org
Subject: [PATCH v11 08/13] powerpc/32: prepare shadow area for KASAN
Date: Fri, 26 Apr 2019 16:23:32 +0000 (UTC)	[thread overview]
Message-ID: <5aa7b8ed0620546c1f488533213a86c084e42ff2.1556295460.git.christophe.leroy@c-s.fr> (raw)
In-Reply-To: <cover.1556295459.git.christophe.leroy@c-s.fr>

This patch prepares a shadow area for KASAN.

The shadow area will be at the top of the kernel virtual
memory space above the fixmap area and will occupy one
eighth of the total kernel virtual memory space.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 arch/powerpc/Kconfig.debug        |  5 +++++
 arch/powerpc/include/asm/fixmap.h |  5 +++++
 arch/powerpc/include/asm/kasan.h  | 16 ++++++++++++++++
 arch/powerpc/mm/mem.c             |  4 ++++
 arch/powerpc/mm/ptdump/ptdump.c   |  8 ++++++++
 5 files changed, 38 insertions(+)

diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug
index 4e00cb0a5464..61febbbdd02b 100644
--- a/arch/powerpc/Kconfig.debug
+++ b/arch/powerpc/Kconfig.debug
@@ -366,3 +366,8 @@ config PPC_FAST_ENDIAN_SWITCH
         depends on DEBUG_KERNEL && PPC_BOOK3S_64
         help
 	  If you're unsure what this is, say N.
+
+config KASAN_SHADOW_OFFSET
+	hex
+	depends on KASAN
+	default 0xe0000000
diff --git a/arch/powerpc/include/asm/fixmap.h b/arch/powerpc/include/asm/fixmap.h
index b9fbed84ddca..0cfc365d814b 100644
--- a/arch/powerpc/include/asm/fixmap.h
+++ b/arch/powerpc/include/asm/fixmap.h
@@ -22,7 +22,12 @@
 #include <asm/kmap_types.h>
 #endif
 
+#ifdef CONFIG_KASAN
+#include <asm/kasan.h>
+#define FIXADDR_TOP	(KASAN_SHADOW_START - PAGE_SIZE)
+#else
 #define FIXADDR_TOP	((unsigned long)(-PAGE_SIZE))
+#endif
 
 /*
  * Here we define all the compile-time 'special' virtual
diff --git a/arch/powerpc/include/asm/kasan.h b/arch/powerpc/include/asm/kasan.h
index 2c179a39d4ba..05274dea3109 100644
--- a/arch/powerpc/include/asm/kasan.h
+++ b/arch/powerpc/include/asm/kasan.h
@@ -12,4 +12,20 @@
 #define EXPORT_SYMBOL_KASAN(fn)
 #endif
 
+#ifndef __ASSEMBLY__
+
+#include <asm/page.h>
+
+#define KASAN_SHADOW_SCALE_SHIFT	3
+
+#define KASAN_SHADOW_START	(KASAN_SHADOW_OFFSET + \
+				 (PAGE_OFFSET >> KASAN_SHADOW_SCALE_SHIFT))
+
+#define KASAN_SHADOW_OFFSET	ASM_CONST(CONFIG_KASAN_SHADOW_OFFSET)
+
+#define KASAN_SHADOW_END	0UL
+
+#define KASAN_SHADOW_SIZE	(KASAN_SHADOW_END - KASAN_SHADOW_START)
+
+#endif /* __ASSEMBLY */
 #endif
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index e12bec98366f..b91c17ba499b 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -310,6 +310,10 @@ void __init mem_init(void)
 	mem_init_print_info(NULL);
 #ifdef CONFIG_PPC32
 	pr_info("Kernel virtual memory layout:\n");
+#ifdef CONFIG_KASAN
+	pr_info("  * 0x%08lx..0x%08lx  : kasan shadow mem\n",
+		KASAN_SHADOW_START, KASAN_SHADOW_END);
+#endif
 	pr_info("  * 0x%08lx..0x%08lx  : fixmap\n", FIXADDR_START, FIXADDR_TOP);
 #ifdef CONFIG_HIGHMEM
 	pr_info("  * 0x%08lx..0x%08lx  : highmem PTEs\n",
diff --git a/arch/powerpc/mm/ptdump/ptdump.c b/arch/powerpc/mm/ptdump/ptdump.c
index 63fc56feea15..48135ba6fa74 100644
--- a/arch/powerpc/mm/ptdump/ptdump.c
+++ b/arch/powerpc/mm/ptdump/ptdump.c
@@ -101,6 +101,10 @@ static struct addr_marker address_markers[] = {
 	{ 0,	"Fixmap start" },
 	{ 0,	"Fixmap end" },
 #endif
+#ifdef CONFIG_KASAN
+	{ 0,	"kasan shadow mem start" },
+	{ 0,	"kasan shadow mem end" },
+#endif
 	{ -1,	NULL },
 };
 
@@ -323,6 +327,10 @@ static void populate_markers(void)
 #endif
 	address_markers[i++].start_address = FIXADDR_START;
 	address_markers[i++].start_address = FIXADDR_TOP;
+#ifdef CONFIG_KASAN
+	address_markers[i++].start_address = KASAN_SHADOW_START;
+	address_markers[i++].start_address = KASAN_SHADOW_END;
+#endif
 #endif /* CONFIG_PPC64 */
 }
 
-- 
2.13.3


  parent reply	other threads:[~2019-04-26 16:23 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-26 16:23 [PATCH v11 00/13] KASAN for powerpc/32 Christophe Leroy
2019-04-26 16:23 ` [PATCH v11 01/13] powerpc/32: Move early_init() in a separate file Christophe Leroy
2019-05-03  6:59   ` Michael Ellerman
2019-04-26 16:23 ` [PATCH v11 02/13] powerpc: prepare string/mem functions for KASAN Christophe Leroy
2019-04-26 16:23 ` [PATCH v11 03/13] powerpc: remove CONFIG_CMDLINE #ifdef mess Christophe Leroy
2019-04-26 16:23 ` [PATCH v11 04/13] powerpc/prom_init: don't use string functions from lib/ Christophe Leroy
2019-04-26 16:23 ` [PATCH v11 05/13] powerpc: don't use direct assignation during early boot Christophe Leroy
2019-04-26 16:23 ` [PATCH v11 06/13] powerpc/32: use memset() instead of memset_io() to zero BSS Christophe Leroy
2019-04-26 16:23 ` [PATCH v11 07/13] powerpc/32: make KVIRT_TOP dependent on FIXMAP_START Christophe Leroy
2019-04-26 16:23 ` Christophe Leroy [this message]
2019-04-26 16:23 ` [PATCH v11 09/13] powerpc: disable KASAN instrumentation on early/critical files Christophe Leroy
2019-05-03  7:38   ` Christophe Leroy
2019-04-26 16:23 ` [PATCH v11 10/13] powerpc/32: Add KASAN support Christophe Leroy
2019-05-03  6:51   ` Christophe Leroy
2019-04-26 16:23 ` [PATCH v11 11/13] powerpc/32s: move hash code patching out of MMU_init_hw() Christophe Leroy
2019-04-26 16:23 ` [PATCH v11 12/13] powerpc/32s: set up an early static hash table for KASAN Christophe Leroy
2019-04-26 16:23 ` [PATCH v11 13/13] powerpc/32s: map kasan zero shadow with PAGE_READONLY instead of PAGE_KERNEL_RO Christophe Leroy

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