[RFC PATCH v1 0/4] KASAN for nohash PPC32

[RFC PATCH v1 0/4] KASAN for nohash PPC32

[Christophe Leroy]

This serie adds support to nohash PPC32

Tested on MPC8xx

Christophe Leroy (4):
  powerpc/mm: prepare kernel for KAsan on PPC32
  powerpc: add missing header in pgtable-types.h
  powerpc/32: Move early_init() in a separate file
  powerpc/nohash32: Add KASAN support

 arch/powerpc/Kconfig                         |  1 +
 arch/powerpc/include/asm/kasan.h             | 21 ++++++++
 arch/powerpc/include/asm/nohash/32/pgtable.h |  2 +
 arch/powerpc/include/asm/pgtable-types.h     |  2 +
 arch/powerpc/include/asm/ppc_asm.h           |  5 ++
 arch/powerpc/include/asm/setup.h             |  5 ++
 arch/powerpc/include/asm/string.h            | 14 ++++++
 arch/powerpc/kernel/Makefile                 |  5 +-
 arch/powerpc/kernel/cputable.c               |  4 +-
 arch/powerpc/kernel/early_32.c               | 35 +++++++++++++
 arch/powerpc/kernel/setup-common.c           |  2 +
 arch/powerpc/kernel/setup_32.c               | 33 ++-----------
 arch/powerpc/lib/Makefile                    |  2 +
 arch/powerpc/lib/copy_32.S                   |  9 ++--
 arch/powerpc/mm/Makefile                     |  3 ++
 arch/powerpc/mm/dump_linuxpagetables.c       |  8 +++
 arch/powerpc/mm/kasan_init.c                 | 73 ++++++++++++++++++++++++++++
 arch/powerpc/mm/mem.c                        |  4 ++
 18 files changed, 193 insertions(+), 35 deletions(-)
 create mode 100644 arch/powerpc/include/asm/kasan.h
 create mode 100644 arch/powerpc/kernel/early_32.c
 create mode 100644 arch/powerpc/mm/kasan_init.c

-- 
2.13.3

[RFC PATCH v1 1/4] powerpc/mm: prepare kernel for KAsan on PPC32

[Christophe Leroy]

In kernel/cputable.c, explicitly use memcpy() in order
to allow GCC to replace it with __memcpy() when KASAN is
selected.

Since commit 400c47d81ca38 ("powerpc32: memset: only use dcbz once cache is
enabled"), memset() can be used before activation of the cache,
so no need to use memset_io() for zeroing the BSS.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 arch/powerpc/kernel/cputable.c | 4 ++--
 arch/powerpc/kernel/setup_32.c | 6 ++----
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
index c8fc9691f8c7..60ee5900bf12 100644
--- a/arch/powerpc/kernel/cputable.c
+++ b/arch/powerpc/kernel/cputable.c
@@ -2183,7 +2183,7 @@ void __init set_cur_cpu_spec(struct cpu_spec *s)
 	struct cpu_spec *t = &the_cpu_spec;
 
 	t = PTRRELOC(t);
-	*t = *s;
+	memcpy(t, s, sizeof(*t));
 
 	*PTRRELOC(&cur_cpu_spec) = &the_cpu_spec;
 }
@@ -2198,7 +2198,7 @@ static struct cpu_spec * __init setup_cpu_spec(unsigned long offset,
 	old = *t;
 
 	/* Copy everything, then do fixups */
-	*t = *s;
+	memcpy(t, s, sizeof(*t));
 
 	/*
 	 * If we are overriding a previous value derived from the real
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index 74457485574b..6a394b9e109e 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -70,10 +70,8 @@ notrace unsigned long __init early_init(unsigned long dt_ptr)
 {
 	unsigned long offset = reloc_offset();
 
-	/* First zero the BSS -- use memset_io, some platforms don't have
-	 * caches on yet */
-	memset_io((void __iomem *)PTRRELOC(&__bss_start), 0,
-			__bss_stop - __bss_start);
+	/* First zero the BSS */
+	memset(PTRRELOC(&__bss_start), 0, __bss_stop - __bss_start);
 
 	/*
 	 * Identify the CPU type and fix up code sections
-- 
2.13.3

[RFC PATCH v1 2/4] powerpc: add missing header in pgtable-types.h

[Christophe Leroy]

pte_basic_t is defined in page.h

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 arch/powerpc/include/asm/pgtable-types.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/include/asm/pgtable-types.h b/arch/powerpc/include/asm/pgtable-types.h
index eccb30b38b47..3d8f68aebea3 100644
--- a/arch/powerpc/include/asm/pgtable-types.h
+++ b/arch/powerpc/include/asm/pgtable-types.h
@@ -2,6 +2,8 @@
 #ifndef _ASM_POWERPC_PGTABLE_TYPES_H
 #define _ASM_POWERPC_PGTABLE_TYPES_H
 
+#include <asm/page.h>
+
 /* PTE level */
 typedef struct { pte_basic_t pte; } pte_t;
 #define __pte(x)	((pte_t) { (x) })
-- 
2.13.3

[RFC PATCH v1 3/4] powerpc/32: Move early_init() in a separate file

[Christophe Leroy]

In preparation of KASAN, move early_init() into a separate
file in order to allow deactivation of KASAN for that function.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 arch/powerpc/kernel/Makefile   |  2 +-
 arch/powerpc/kernel/early_32.c | 35 +++++++++++++++++++++++++++++++++++
 arch/powerpc/kernel/setup_32.c | 26 --------------------------
 3 files changed, 36 insertions(+), 27 deletions(-)
 create mode 100644 arch/powerpc/kernel/early_32.c

diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 2b4c40b255e4..70e9dbdc55f5 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -89,7 +89,7 @@ extra-y				+= vmlinux.lds
 
 obj-$(CONFIG_RELOCATABLE)	+= reloc_$(BITS).o
 
-obj-$(CONFIG_PPC32)		+= entry_32.o setup_32.o
+obj-$(CONFIG_PPC32)		+= entry_32.o setup_32.o early_32.o
 obj-$(CONFIG_PPC64)		+= dma-iommu.o iommu.o
 obj-$(CONFIG_KGDB)		+= kgdb.o
 obj-$(CONFIG_BOOTX_TEXT)	+= btext.o
diff --git a/arch/powerpc/kernel/early_32.c b/arch/powerpc/kernel/early_32.c
new file mode 100644
index 000000000000..b3e40d6d651c
--- /dev/null
+++ b/arch/powerpc/kernel/early_32.c
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Early init before relocation
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <asm/setup.h>
+#include <asm/sections.h>
+
+/*
+ * We're called here very early in the boot.
+ *
+ * Note that the kernel may be running at an address which is different
+ * from the address that it was linked at, so we must use RELOC/PTRRELOC
+ * to access static data (including strings).  -- paulus
+ */
+notrace unsigned long __init early_init(unsigned long dt_ptr)
+{
+	unsigned long offset = reloc_offset();
+
+	/* First zero the BSS */
+	memset(PTRRELOC(&__bss_start), 0, __bss_stop - __bss_start);
+
+	/*
+	 * Identify the CPU type and fix up code sections
+	 * that depend on which cpu we have.
+	 */
+	identify_cpu(offset, mfspr(SPRN_PVR));
+
+	apply_feature_fixups();
+
+	return KERNELBASE + offset;
+}
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index 6a394b9e109e..1c62f81cb257 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -60,32 +60,6 @@ EXPORT_SYMBOL(DMA_MODE_READ);
 EXPORT_SYMBOL(DMA_MODE_WRITE);
 
 /*
- * We're called here very early in the boot.
- *
- * Note that the kernel may be running at an address which is different
- * from the address that it was linked at, so we must use RELOC/PTRRELOC
- * to access static data (including strings).  -- paulus
- */
-notrace unsigned long __init early_init(unsigned long dt_ptr)
-{
-	unsigned long offset = reloc_offset();
-
-	/* First zero the BSS */
-	memset(PTRRELOC(&__bss_start), 0, __bss_stop - __bss_start);
-
-	/*
-	 * Identify the CPU type and fix up code sections
-	 * that depend on which cpu we have.
-	 */
-	identify_cpu(offset, mfspr(SPRN_PVR));
-
-	apply_feature_fixups();
-
-	return KERNELBASE + offset;
-}
-
-
-/*
  * This is run before start_kernel(), the kernel has been relocated
  * and we are running with enough of the MMU enabled to have our
  * proper kernel virtual addresses
-- 
2.13.3

[RFC PATCH v1 4/4] powerpc/nohash32: Add KASAN support

[Christophe Leroy]

This patch adds KASAN support for nohash PPC32.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 arch/powerpc/Kconfig                         |  1 +
 arch/powerpc/include/asm/kasan.h             | 21 ++++++++
 arch/powerpc/include/asm/nohash/32/pgtable.h |  2 +
 arch/powerpc/include/asm/ppc_asm.h           |  5 ++
 arch/powerpc/include/asm/setup.h             |  5 ++
 arch/powerpc/include/asm/string.h            | 14 ++++++
 arch/powerpc/kernel/Makefile                 |  3 ++
 arch/powerpc/kernel/setup-common.c           |  2 +
 arch/powerpc/kernel/setup_32.c               |  5 +-
 arch/powerpc/lib/Makefile                    |  2 +
 arch/powerpc/lib/copy_32.S                   |  9 ++--
 arch/powerpc/mm/Makefile                     |  3 ++
 arch/powerpc/mm/dump_linuxpagetables.c       |  8 +++
 arch/powerpc/mm/kasan_init.c                 | 73 ++++++++++++++++++++++++++++
 arch/powerpc/mm/mem.c                        |  4 ++
 15 files changed, 153 insertions(+), 4 deletions(-)
 create mode 100644 arch/powerpc/include/asm/kasan.h
 create mode 100644 arch/powerpc/mm/kasan_init.c

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 9f2b75fe2c2d..7519ec67fdea 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -174,6 +174,7 @@ config PPC
 	select GENERIC_TIME_VSYSCALL
 	select HAVE_ARCH_AUDITSYSCALL
 	select HAVE_ARCH_JUMP_LABEL
+	select HAVE_ARCH_KASAN			if PPC32 && PPC_MMU_NOHASH
 	select HAVE_ARCH_KGDB
 	select HAVE_ARCH_MMAP_RND_BITS
 	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if COMPAT
diff --git a/arch/powerpc/include/asm/kasan.h b/arch/powerpc/include/asm/kasan.h
new file mode 100644
index 000000000000..419366bcd5f4
--- /dev/null
+++ b/arch/powerpc/include/asm/kasan.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_KASAN_H
+#define __ASM_KASAN_H
+
+#ifndef __ASSEMBLY__
+
+#include <asm/pgtable-types.h>
+#include <asm/fixmap.h>
+
+#define KASAN_SHADOW_SCALE_SHIFT	3
+#define KASAN_SHADOW_SIZE	((~0UL - PAGE_OFFSET + 1) >> KASAN_SHADOW_SCALE_SHIFT)
+
+#define KASAN_SHADOW_START      (ALIGN_DOWN(FIXADDR_START - KASAN_SHADOW_SIZE, PGDIR_SIZE))
+#define KASAN_SHADOW_END        (KASAN_SHADOW_START + KASAN_SHADOW_SIZE)
+#define KASAN_SHADOW_OFFSET     (KASAN_SHADOW_START - (PAGE_OFFSET >> KASAN_SHADOW_SCALE_SHIFT))
+
+void kasan_early_init(void);
+void kasan_init(void);
+
+#endif
+#endif
diff --git a/arch/powerpc/include/asm/nohash/32/pgtable.h b/arch/powerpc/include/asm/nohash/32/pgtable.h
index 7c46a98cc7f4..0f1205a74212 100644
--- a/arch/powerpc/include/asm/nohash/32/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/32/pgtable.h
@@ -70,6 +70,8 @@ extern int icache_44x_need_flush;
  */
 #ifdef CONFIG_HIGHMEM
 #define KVIRT_TOP	PKMAP_BASE
+#elif defined(CONFIG_KASAN)
+#define KVIRT_TOP	KASAN_SHADOW_START
 #else
 #define KVIRT_TOP	(0xfe000000UL)	/* for now, could be FIXMAP_BASE ? */
 #endif
diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h
index 75ece56dcd62..947d945293fa 100644
--- a/arch/powerpc/include/asm/ppc_asm.h
+++ b/arch/powerpc/include/asm/ppc_asm.h
@@ -250,6 +250,11 @@ GLUE(.,name):
 
 #define _GLOBAL_TOC(name) _GLOBAL(name)
 
+#define KASAN_OVERRIDE(x, y) \
+	.weak x;	     \
+	.set x, y
+
+
 #endif
 
 /*
diff --git a/arch/powerpc/include/asm/setup.h b/arch/powerpc/include/asm/setup.h
index 8721fd004291..2da38c990278 100644
--- a/arch/powerpc/include/asm/setup.h
+++ b/arch/powerpc/include/asm/setup.h
@@ -62,6 +62,11 @@ void do_barrier_nospec_fixups_range(bool enable, void *start, void *end);
 static inline void do_barrier_nospec_fixups_range(bool enable, void *start, void *end) { };
 #endif
 
+#ifndef CONFIG_KASAN
+static inline void kasan_early_init(void) { }
+static inline void kasan_init(void) { }
+#endif
+
 #endif /* !__ASSEMBLY__ */
 
 #endif	/* _ASM_POWERPC_SETUP_H */
diff --git a/arch/powerpc/include/asm/string.h b/arch/powerpc/include/asm/string.h
index 9b8cedf618f4..93be88bfe439 100644
--- a/arch/powerpc/include/asm/string.h
+++ b/arch/powerpc/include/asm/string.h
@@ -27,6 +27,20 @@ extern int memcmp(const void *,const void *,__kernel_size_t);
 extern void * memchr(const void *,int,__kernel_size_t);
 extern void * memcpy_flushcache(void *,const void *,__kernel_size_t);
 
+void * __memset(void *, int, __kernel_size_t);
+void * __memcpy(void *, const void *, __kernel_size_t);
+void * __memmove(void *, const void *, __kernel_size_t);
+
+#if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__)
+/*
+ * For files that are not instrumented (e.g. mm/slub.c) we
+ * should use not instrumented version of mem* functions.
+ */
+#define memcpy(dst, src, len) __memcpy(dst, src, len)
+#define memmove(dst, src, len) __memmove(dst, src, len)
+#define memset(s, c, n) __memset(s, c, n)
+#endif
+
 #ifdef CONFIG_PPC64
 #define __HAVE_ARCH_MEMSET32
 #define __HAVE_ARCH_MEMSET64
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 70e9dbdc55f5..b08072f19349 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -28,6 +28,9 @@ CFLAGS_REMOVE_btext.o = -mno-sched-epilog $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_prom.o = -mno-sched-epilog $(CC_FLAGS_FTRACE)
 endif
 
+KASAN_SANITIZE_early_32.o := n
+KASAN_SANITIZE_cputable.o := n
+
 obj-y				:= cputable.o ptrace.o syscalls.o \
 				   irq.o align.o signal_32.o pmc.o vdso.o \
 				   process.o systbl.o idle.o \
diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 40b44bb53a4e..a030a373fbb3 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -974,6 +974,8 @@ void __init setup_arch(char **cmdline_p)
 
 	paging_init();
 
+	kasan_init();
+
 	/* Initialize the MMU context management stuff. */
 	mmu_context_init();
 
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index 1c62f81cb257..c581f1c6adcd 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -17,6 +17,7 @@
 #include <linux/console.h>
 #include <linux/memblock.h>
 #include <linux/export.h>
+#include <linux/kasan.h>
 
 #include <asm/io.h>
 #include <asm/prom.h>
@@ -74,13 +75,15 @@ notrace void __init machine_init(u64 dt_ptr)
 	unsigned int *addr = &memset_nocache_branch;
 	unsigned long insn;
 
+	kasan_early_init();
+
 	/* Configure static keys first, now that we're relocated. */
 	setup_feature_keys();
 
 	/* Enable early debugging if any specified (see udbg.h) */
 	udbg_early_init();
 
-	patch_instruction((unsigned int *)&memcpy, PPC_INST_NOP);
+	patch_instruction((unsigned int *)&__memcpy, PPC_INST_NOP);
 
 	insn = create_cond_branch(addr, branch_target(addr), 0x820000);
 	patch_instruction(addr, insn);	/* replace b by bne cr0 */
diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile
index d0ca13ad8231..4a378d10fd83 100644
--- a/arch/powerpc/lib/Makefile
+++ b/arch/powerpc/lib/Makefile
@@ -10,6 +10,8 @@ ccflags-$(CONFIG_PPC64)	:= $(NO_MINIMAL_TOC)
 CFLAGS_REMOVE_code-patching.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_feature-fixups.o = $(CC_FLAGS_FTRACE)
 
+KASAN_SANITIZE_feature-fixups.o := n
+
 obj-y += string.o alloc.o code-patching.o feature-fixups.o
 
 obj-$(CONFIG_PPC32)	+= div64.o copy_32.o crtsavres.o
diff --git a/arch/powerpc/lib/copy_32.S b/arch/powerpc/lib/copy_32.S
index da425bb6b369..76b4d86c0c8f 100644
--- a/arch/powerpc/lib/copy_32.S
+++ b/arch/powerpc/lib/copy_32.S
@@ -90,7 +90,8 @@ EXPORT_SYMBOL(memset16)
  * We therefore skip the optimised bloc that uses dcbz. This jump is
  * replaced by a nop once cache is active. This is done in machine_init()
  */
-_GLOBAL(memset)
+_GLOBAL(__memset)
+KASAN_OVERRIDE(memset, __memset)
 	cmplwi	0,r5,4
 	blt	7f
 
@@ -162,12 +163,14 @@ EXPORT_SYMBOL(memset)
  * We therefore jump to generic_memcpy which doesn't use dcbz. This jump is
  * replaced by a nop once cache is active. This is done in machine_init()
  */
-_GLOBAL(memmove)
+_GLOBAL(__memmove)
+KASAN_OVERRIDE(memmove, __memmove)
 	cmplw	0,r3,r4
 	bgt	backwards_memcpy
 	/* fall through */
 
-_GLOBAL(memcpy)
+_GLOBAL(__memcpy)
+KASAN_OVERRIDE(memcpy, __memcpy)
 	b	generic_memcpy
 	add	r7,r3,r5		/* test if the src & dst overlap */
 	add	r8,r4,r5
diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
index f06f3577d8d1..8b755143204b 100644
--- a/arch/powerpc/mm/Makefile
+++ b/arch/powerpc/mm/Makefile
@@ -7,6 +7,8 @@ subdir-ccflags-$(CONFIG_PPC_WERROR) := -Werror
 
 ccflags-$(CONFIG_PPC64)	:= $(NO_MINIMAL_TOC)
 
+KASAN_SANITIZE_kasan_init.o := n
+
 obj-y				:= fault.o mem.o pgtable.o mmap.o \
 				   init_$(BITS).o pgtable_$(BITS).o \
 				   init-common.o mmu_context.o drmem.o
@@ -45,3 +47,4 @@ obj-$(CONFIG_SPAPR_TCE_IOMMU)	+= mmu_context_iommu.o
 obj-$(CONFIG_PPC_PTDUMP)	+= dump_linuxpagetables.o
 obj-$(CONFIG_PPC_HTDUMP)	+= dump_hashpagetable.o
 obj-$(CONFIG_PPC_MEM_KEYS)	+= pkeys.o
+obj-$(CONFIG_KASAN)		+= kasan_init.o
diff --git a/arch/powerpc/mm/dump_linuxpagetables.c b/arch/powerpc/mm/dump_linuxpagetables.c
index 876e2a3c79f2..8e0c8a0f06ba 100644
--- a/arch/powerpc/mm/dump_linuxpagetables.c
+++ b/arch/powerpc/mm/dump_linuxpagetables.c
@@ -91,6 +91,10 @@ static struct addr_marker address_markers[] = {
 	{ 0,	"Consistent mem start" },
 	{ 0,	"Consistent mem end" },
 #endif
+#ifdef CONFIG_KASAN
+	{ 0,	"kasan shadow mem start" },
+	{ 0,	"kasan shadow mem end" },
+#endif
 #ifdef CONFIG_HIGHMEM
 	{ 0,	"Highmem PTEs start" },
 	{ 0,	"Highmem PTEs end" },
@@ -459,6 +463,10 @@ static void populate_markers(void)
 	address_markers[i++].start_address = IOREMAP_TOP +
 					     CONFIG_CONSISTENT_SIZE;
 #endif
+#ifdef CONFIG_KASAN
+	address_markers[i++].start_address = KASAN_SHADOW_START;
+	address_markers[i++].start_address = KASAN_SHADOW_END;
+#endif
 #ifdef CONFIG_HIGHMEM
 	address_markers[i++].start_address = PKMAP_BASE;
 	address_markers[i++].start_address = PKMAP_ADDR(LAST_PKMAP);
diff --git a/arch/powerpc/mm/kasan_init.c b/arch/powerpc/mm/kasan_init.c
new file mode 100644
index 000000000000..3331239edcbb
--- /dev/null
+++ b/arch/powerpc/mm/kasan_init.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/kasan.h>
+#include <linux/printk.h>
+#include <linux/memblock.h>
+#include <linux/bootmem.h>
+#include <asm/pgalloc.h>
+
+void __init kasan_early_init(void)
+{
+	unsigned long addr = KASAN_SHADOW_START & PGDIR_MASK;
+	unsigned long end = KASAN_SHADOW_END;
+	unsigned long next;
+	pmd_t *pmd = pmd_offset(pud_offset(pgd_offset_k(addr), addr), addr);
+	int i;
+	phys_addr_t pa = __pa(kasan_zero_page);
+
+	for (i = 0; i < PTRS_PER_PTE; i++)
+		kasan_zero_pte[i] = pfn_pte(pa >> PAGE_SHIFT, PAGE_KERNEL_RO);
+
+	do {
+		next = pgd_addr_end(addr, end);
+		pmd_populate_kernel(&init_mm, pmd, kasan_zero_pte);
+	} while (pmd++, addr = next, addr != end);
+
+	pr_info("KASAN early init done\n");
+}
+
+static void __init kasan_init_region(struct memblock_region *reg)
+{
+	void *start = __va(reg->base);
+	void *end = __va(reg->base + reg->size);
+	unsigned long k_start, k_end, k_cur, k_next;
+	pmd_t *pmd;
+
+	if (start >= end)
+		return;
+
+	k_start = (unsigned long)kasan_mem_to_shadow(start);
+	k_end = (unsigned long)kasan_mem_to_shadow(end);
+	pmd = pmd_offset(pud_offset(pgd_offset_k(k_start), k_start), k_start);
+
+	for (k_cur = k_start; k_cur != k_end; k_cur = k_next, pmd++) {
+		k_next = pgd_addr_end(k_cur, k_end);
+		if ((void*)pmd_page_vaddr(*pmd) == kasan_zero_pte) {
+			pte_t *new = pte_alloc_one_kernel(&init_mm, k_cur);
+
+			if (!new)
+				panic("kasan: pte_alloc_one_kernel() failed");
+			memcpy(new, kasan_zero_pte, PTE_TABLE_SIZE);
+			pmd_populate_kernel(&init_mm, pmd, new);
+		}
+	};
+
+	for (k_cur = k_start; k_cur < k_end; k_cur += PAGE_SIZE) {
+		phys_addr_t pa = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
+		pte_t pte = pfn_pte(pa >> PAGE_SHIFT, PAGE_KERNEL);
+
+		pmd = pmd_offset(pud_offset(pgd_offset_k(k_cur), k_cur), k_cur);
+		pte_update(pte_offset_kernel(pmd, k_cur), ~0, pte_val(pte));
+	}
+	flush_tlb_kernel_range(k_start, k_end);
+}
+
+void __init kasan_init(void)
+{
+	struct memblock_region *reg;
+
+	for_each_memblock(memory, reg)
+		kasan_init_region(reg);
+
+	pr_info("KASAN init done\n");
+}
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 5c8530d0c611..b5f6c2c2ac45 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -381,6 +381,10 @@ void __init mem_init(void)
 	pr_info("  * 0x%08lx..0x%08lx  : highmem PTEs\n",
 		PKMAP_BASE, PKMAP_ADDR(LAST_PKMAP));
 #endif /* CONFIG_HIGHMEM */
+#ifdef CONFIG_KASAN
+	pr_info("  * 0x%08lx..0x%08lx  : kasan shadow mem\n",
+		KASAN_SHADOW_START, KASAN_SHADOW_END);
+#endif
 #ifdef CONFIG_NOT_COHERENT_CACHE
 	pr_info("  * 0x%08lx..0x%08lx  : consistent mem\n",
 		IOREMAP_TOP, IOREMAP_TOP + CONFIG_CONSISTENT_SIZE);
-- 
2.13.3