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Subject[PATCH] powerpc/32: add support of KASAN_VMALLOC
Date
Add support of KASAN_VMALLOC on PPC32.

To allow this, the early shadow covering the VMALLOC space
need to be removed once high_memory var is set and before
freeing memblock.

And the VMALLOC area need to be aligned such that boundaries
are covered by a full shadow page.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>

---
Applies on top of Daniel's series which add KASAN_VMALLOC support.
---
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/book3s/32/pgtable.h | 5 +++++
arch/powerpc/include/asm/kasan.h | 2 ++
arch/powerpc/include/asm/nohash/32/pgtable.h | 5 +++++
arch/powerpc/mm/kasan/kasan_init_32.c | 31 ++++++++++++++++++++++++++++
arch/powerpc/mm/mem.c | 3 +++
6 files changed, 47 insertions(+)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 6a7c797fa9d2..9d270d50ac9e 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -172,6 +172,7 @@ config PPC
select HAVE_ARCH_HUGE_VMAP if PPC_BOOK3S_64 && PPC_RADIX_MMU
select HAVE_ARCH_JUMP_LABEL
select HAVE_ARCH_KASAN if PPC32
+ select HAVE_ARCH_KASAN_VMALLOC if PPC32
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/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h
index 0796533d37dd..5b39c11e884a 100644
--- a/arch/powerpc/include/asm/book3s/32/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/32/pgtable.h
@@ -193,7 +193,12 @@ int map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot);
#else
#define VMALLOC_START ((((long)high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1)))
#endif
+
+#ifdef CONFIG_KASAN_VMALLOC
+#define VMALLOC_END _ALIGN_DOWN(ioremap_bot, PAGE_SIZE << KASAN_SHADOW_SCALE_SHIFT)
+#else
#define VMALLOC_END ioremap_bot
+#endif

#ifndef __ASSEMBLY__
#include <linux/sched.h>
diff --git a/arch/powerpc/include/asm/kasan.h b/arch/powerpc/include/asm/kasan.h
index 296e51c2f066..fbff9ff9032e 100644
--- a/arch/powerpc/include/asm/kasan.h
+++ b/arch/powerpc/include/asm/kasan.h
@@ -31,9 +31,11 @@
void kasan_early_init(void);
void kasan_mmu_init(void);
void kasan_init(void);
+void kasan_late_init(void);
#else
static inline void kasan_init(void) { }
static inline void kasan_mmu_init(void) { }
+static inline void kasan_late_init(void) { }
#endif

#endif /* __ASSEMBLY */
diff --git a/arch/powerpc/include/asm/nohash/32/pgtable.h b/arch/powerpc/include/asm/nohash/32/pgtable.h
index 552b96eef0c8..60c4d829152e 100644
--- a/arch/powerpc/include/asm/nohash/32/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/32/pgtable.h
@@ -114,7 +114,12 @@ int map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot);
#else
#define VMALLOC_START ((((long)high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1)))
#endif
+
+#ifdef CONFIG_KASAN_VMALLOC
+#define VMALLOC_END _ALIGN_DOWN(ioremap_bot, PAGE_SIZE << KASAN_SHADOW_SCALE_SHIFT)
+#else
#define VMALLOC_END ioremap_bot
+#endif

/*
* Bits in a linux-style PTE. These match the bits in the
diff --git a/arch/powerpc/mm/kasan/kasan_init_32.c b/arch/powerpc/mm/kasan/kasan_init_32.c
index 0e6ed4413eea..fb3cd8037f19 100644
--- a/arch/powerpc/mm/kasan/kasan_init_32.c
+++ b/arch/powerpc/mm/kasan/kasan_init_32.c
@@ -129,6 +129,31 @@ static void __init kasan_remap_early_shadow_ro(void)
flush_tlb_kernel_range(KASAN_SHADOW_START, KASAN_SHADOW_END);
}

+static void __init kasan_unmap_early_shadow_vmalloc(void)
+{
+ unsigned long k_start = (unsigned long)kasan_mem_to_shadow((void *)VMALLOC_START);
+ unsigned long k_end = (unsigned long)kasan_mem_to_shadow((void *)VMALLOC_END);
+ unsigned long k_cur;
+ phys_addr_t pa = __pa(kasan_early_shadow_page);
+
+ if (!early_mmu_has_feature(MMU_FTR_HPTE_TABLE)) {
+ int ret = kasan_init_shadow_page_tables(k_start, k_end);
+
+ if (ret)
+ panic("kasan: kasan_init_shadow_page_tables() failed");
+ }
+ for (k_cur = k_start & PAGE_MASK; k_cur < k_end; k_cur += PAGE_SIZE) {
+ pmd_t *pmd = pmd_offset(pud_offset(pgd_offset_k(k_cur), k_cur), k_cur);
+ pte_t *ptep = pte_offset_kernel(pmd, k_cur);
+
+ if ((pte_val(*ptep) & PTE_RPN_MASK) != pa)
+ continue;
+
+ __set_pte_at(&init_mm, k_cur, ptep, __pte(0), 0);
+ }
+ flush_tlb_kernel_range(k_start, k_end);
+}
+
void __init kasan_mmu_init(void)
{
int ret;
@@ -165,6 +190,12 @@ void __init kasan_init(void)
pr_info("KASAN init done\n");
}

+void __init kasan_late_init(void)
+{
+ if (IS_ENABLED(CONFIG_KASAN_VMALLOC))
+ kasan_unmap_early_shadow_vmalloc();
+}
+
#ifdef CONFIG_MODULES
void *module_alloc(unsigned long size)
{
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index be941d382c8d..34bfe2c81f15 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -265,6 +265,9 @@ void __init mem_init(void)

high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
set_max_mapnr(max_pfn);
+
+ kasan_late_init();
+
memblock_free_all();

#ifdef CONFIG_HIGHMEM
--
2.13.3
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