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Subject[PATCH v2 4/4] powerpc: Enable KFENCE on BOOK3S/64
Date
This reuses the DEBUG_PAGEALLOC logic.

Tested on qemu with ppc64_defconfig + CONFIG_KFENCE + CONFIG_KUNIT +
CONFIG_KFENCE_KUNIT_TEST.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v2: New
---
arch/powerpc/Kconfig | 2 +-
arch/powerpc/include/asm/kfence.h | 8 ++++++++
arch/powerpc/mm/book3s64/hash_utils.c | 29 +++++++++++++++++++++------
3 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index d46db0bfb998..67c47b60cc84 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -185,7 +185,7 @@ config PPC
select HAVE_ARCH_KASAN if PPC32 && PPC_PAGE_SHIFT <= 14
select HAVE_ARCH_KASAN_VMALLOC if PPC32 && PPC_PAGE_SHIFT <= 14
select HAVE_ARCH_KGDB
- select HAVE_ARCH_KFENCE if PPC32
+ select HAVE_ARCH_KFENCE if ARCH_SUPPORTS_DEBUG_PAGEALLOC
select HAVE_ARCH_MMAP_RND_BITS
select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
select HAVE_ARCH_NVRAM_OPS
diff --git a/arch/powerpc/include/asm/kfence.h b/arch/powerpc/include/asm/kfence.h
index a9846b68c6b9..532cc1a92fa5 100644
--- a/arch/powerpc/include/asm/kfence.h
+++ b/arch/powerpc/include/asm/kfence.h
@@ -11,11 +11,18 @@
#include <linux/mm.h>
#include <asm/pgtable.h>

+#if defined(CONFIG_PPC64) && !defined(PPC64_ELF_ABI_v2)
+#define ARCH_FUNC_PREFIX "."
+#endif
+
static inline bool arch_kfence_init_pool(void)
{
return true;
}

+#ifdef CONFIG_PPC64
+bool kfence_protect_page(unsigned long addr, bool protect);
+#else
static inline bool kfence_protect_page(unsigned long addr, bool protect)
{
pte_t *kpte = virt_to_kpte(addr);
@@ -29,5 +36,6 @@ static inline bool kfence_protect_page(unsigned long addr, bool protect)

return true;
}
+#endif

#endif /* __ASM_POWERPC_KFENCE_H */
diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
index cb09a49be798..b967a6403e59 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c
@@ -323,8 +323,8 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
break;

cond_resched();
- if (debug_pagealloc_enabled() &&
- (paddr >> PAGE_SHIFT) < linear_map_hash_count)
+ if (debug_pagealloc_enabled_or_kfence() &&
+ (paddr >> PAGE_SHIFT) < linear_map_hash_count)
linear_map_hash_slots[paddr >> PAGE_SHIFT] = ret | 0x80;
}
return ret < 0 ? ret : 0;
@@ -661,7 +661,7 @@ static void __init htab_init_page_sizes(void)
bool aligned = true;
init_hpte_page_sizes();

- if (!debug_pagealloc_enabled()) {
+ if (!debug_pagealloc_enabled_or_kfence()) {
/*
* Pick a size for the linear mapping. Currently, we only
* support 16M, 1M and 4K which is the default
@@ -949,7 +949,7 @@ static void __init htab_initialize(void)

prot = pgprot_val(PAGE_KERNEL);

- if (debug_pagealloc_enabled()) {
+ if (debug_pagealloc_enabled_or_kfence()) {
linear_map_hash_count = memblock_end_of_DRAM() >> PAGE_SHIFT;
linear_map_hash_slots = memblock_alloc_try_nid(
linear_map_hash_count, 1, MEMBLOCK_LOW_LIMIT,
@@ -1927,7 +1927,7 @@ long hpte_insert_repeating(unsigned long hash, unsigned long vpn,
return slot;
}

-#ifdef CONFIG_DEBUG_PAGEALLOC
+#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)
static DEFINE_SPINLOCK(linear_map_hash_lock);

static void kernel_map_linear_page(unsigned long vaddr, unsigned long lmi)
@@ -1982,6 +1982,21 @@ static void kernel_unmap_linear_page(unsigned long vaddr, unsigned long lmi)
mmu_kernel_ssize, 0);
}

+#ifdef CONFIG_KFENCE
+bool kfence_protect_page(unsigned long addr, bool protect)
+{
+ unsigned long lmi = __pa(addr) >> PAGE_SHIFT;
+
+ if (protect)
+ kernel_unmap_linear_page(addr, lmi);
+ else
+ kernel_map_linear_page(addr, lmi);
+
+ return true;
+}
+#endif
+
+#ifdef CONFIG_DEBUG_PAGEALLOC
void __kernel_map_pages(struct page *page, int numpages, int enable)
{
unsigned long flags, vaddr, lmi;
@@ -2000,7 +2015,9 @@ void __kernel_map_pages(struct page *page, int numpages, int enable)
}
local_irq_restore(flags);
}
-#endif /* CONFIG_DEBUG_PAGEALLOC */
+#endif
+
+#endif /* CONFIG_DEBUG_PAGEALLOC || CONFIG_KFENCE */

void hash__setup_initial_memory_limit(phys_addr_t first_memblock_base,
phys_addr_t first_memblock_size)
--
2.25.0
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