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Subject[RFC PATCH v2 3/3] powerpc/nohash32: Add KASAN support
Date
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 | 22 +++++++++
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 | 3 ++
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(+), 3 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 8ea7c2c02cbf..44be55c087be 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..3c2f98c40307
--- /dev/null
+++ b/arch/powerpc/include/asm/kasan.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_KASAN_H
+#define __ASM_KASAN_H
+
+#ifndef __ASSEMBLY__
+
+#include <asm/page.h>
+#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 bed433358260..b3b52f02be1a 100644
--- a/arch/powerpc/include/asm/nohash/32/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/32/pgtable.h
@@ -71,6 +71,8 @@ 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 b5d023680801..80d520e34552 100644
--- a/arch/powerpc/include/asm/ppc_asm.h
+++ b/arch/powerpc/include/asm/ppc_asm.h
@@ -251,6 +251,11 @@ 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 1fffbba8d6a5..16572484149c 100644
--- a/arch/powerpc/include/asm/setup.h
+++ b/arch/powerpc/include/asm/setup.h
@@ -67,6 +67,11 @@ 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 1647de15a31e..28795a72aba1 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 e9a9419b98b6..edcb65188d3e 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -31,6 +31,9 @@ CFLAGS_REMOVE_btext.o = $(CC_FLAGS_FTRACE)
CFLAGS_REMOVE_prom.o = $(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 4fe7740917a7..31958e014c10 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -977,6 +977,8 @@ 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 62efe32d890d..6676b2c786af 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>
@@ -77,6 +78,8 @@ notrace void __init machine_init(u64 dt_ptr)
patch__memset_nocache);
unsigned long insn;

+ kasan_early_init();
+
/* Configure static keys first, now that we're relocated. */
setup_feature_keys();

diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile
index 3bf9fc6fd36c..0e7c6ae1ab7c 100644
--- a/arch/powerpc/lib/Makefile
+++ b/arch/powerpc/lib/Makefile
@@ -8,6 +8,8 @@ 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 strlen_32.o
diff --git a/arch/powerpc/lib/copy_32.S b/arch/powerpc/lib/copy_32.S
index ba66846fe973..4d8a1c73b4cf 100644
--- a/arch/powerpc/lib/copy_32.S
+++ b/arch/powerpc/lib/copy_32.S
@@ -91,7 +91,8 @@ 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

@@ -163,12 +164,14 @@ 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)
1: b generic_memcpy
patch_site 1b, patch__memcpy_nocache

diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
index f965fc33a8b7..d6b76f25f6de 100644
--- a/arch/powerpc/mm/Makefile
+++ b/arch/powerpc/mm/Makefile
@@ -7,6 +7,8 @@ ccflags-$(CONFIG_PPC64) := $(NO_MINIMAL_TOC)

CFLAGS_REMOVE_slb.o = $(CC_FLAGS_FTRACE)

+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
@@ -55,3 +57,4 @@ obj-$(CONFIG_PPC_BOOK3S_64) += dump_linuxpagetables-book3s64.o
endif
obj-$(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 6aa41669ac1a..c862b48118f1 100644
--- a/arch/powerpc/mm/dump_linuxpagetables.c
+++ b/arch/powerpc/mm/dump_linuxpagetables.c
@@ -94,6 +94,10 @@ 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" },
@@ -310,6 +314,10 @@ 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..5547c82673f9
--- /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 <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++)
+ __set_pte_at(&init_mm, (unsigned long)kasan_zero_page, kasan_zero_pte + i,
+ pfn_pte(PHYS_PFN(pa), PAGE_KERNEL_RO), 0);
+
+ 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_phys_alloc(PAGE_SIZE, PAGE_SIZE);
+ pte_t pte = pfn_pte(PHYS_PFN(pa), 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 065c37d54b49..4fc3183654de 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
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