This patch adds KASAN support for nohash PPC32.

Signed-off-by: Christophe Leroy <christophe.le...@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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