[PATCH 4/4] powerpc: Enable KFENCE on BOOK3S/64

[Jordan Niethe <jniethe5@gmail.com>]

From: Christophe Leroy <christophe.leroy@csgroup.eu>

This reuses the DEBUG_PAGEALLOC logic.

Tested with CONFIG_KFENCE + CONFIG_KUNIT + CONFIG_KFENCE_KUNIT_TEST on
radix and hash.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[jpn: Handle radix]
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
---
 arch/powerpc/Kconfig                         |  2 +-
 arch/powerpc/include/asm/book3s/64/pgtable.h |  2 +-
 arch/powerpc/include/asm/kfence.h            | 19 +++++++++++++++++++
 arch/powerpc/mm/book3s64/hash_utils.c        | 12 ++++++------
 arch/powerpc/mm/book3s64/radix_pgtable.c     |  8 +++++---
 5 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 6df64d6815df..1743364d7370 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -196,7 +196,7 @@ 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/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index b89482aed82a..35300f2ee5d0 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -822,7 +822,7 @@ static inline bool check_pte_access(unsigned long access, unsigned long ptev)
  * Generic functions with hash/radix callbacks
  */
 
-#ifdef CONFIG_DEBUG_PAGEALLOC
+#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)
 static inline void __kernel_map_pages(struct page *page, int numpages, int enable)
 {
 	if (radix_enabled())
diff --git a/arch/powerpc/include/asm/kfence.h b/arch/powerpc/include/asm/kfence.h
index a9846b68c6b9..9d388df7c1a8 100644
--- a/arch/powerpc/include/asm/kfence.h
+++ b/arch/powerpc/include/asm/kfence.h
@@ -11,11 +11,29 @@
 #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
+static inline bool kfence_protect_page(unsigned long addr, bool protect)
+{
+	struct page *page;
+
+	page = virt_to_page(addr);
+	if (protect)
+		__kernel_map_pages(page, 1, 0);
+	else
+		__kernel_map_pages(page, 1, 1);
+
+	return true;
+}
+#else
 static inline bool kfence_protect_page(unsigned long addr, bool protect)
 {
 	pte_t *kpte = virt_to_kpte(addr);
@@ -29,5 +47,6 @@ 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 fe5cf1cf4dd5..fecb379426e7 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;
@@ -672,7 +672,7 @@ 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
@@ -960,7 +960,7 @@ 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,
@@ -1936,7 +1936,7 @@ 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)
@@ -2009,7 +2009,7 @@ void hash__kernel_map_pages(struct page *page, int numpages, int enable)
 	}
 	local_irq_restore(flags);
 }
-#endif /* CONFIG_DEBUG_PAGEALLOC */
+#endif /* CONFIG_DEBUG_PAGEALLOC || CONFIG_KFENCE */
 
 void hash__setup_initial_memory_limit(phys_addr_t first_memblock_base,
 				phys_addr_t first_memblock_size)
diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index 2aa81b9e354a..b984876ff1ca 100644
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -33,6 +33,8 @@
 
 #include <trace/events/thp.h>
 
+#include <mm/mmu_decl.h>
+
 unsigned int mmu_pid_bits;
 unsigned int mmu_base_pid;
 unsigned long radix_mem_block_size __ro_after_init;
@@ -335,7 +337,7 @@ static void __init radix_init_pgtable(void)
 	phys_addr_t start, end;
 	u64 i;
 
-	if (debug_pagealloc_enabled())
+	if (debug_pagealloc_enabled_or_kfence())
 		size = PAGE_SIZE;
 
 	/* We don't support slb for radix */
@@ -879,7 +881,7 @@ int __meminit radix__create_section_mapping(unsigned long start,
 {
 	unsigned long size = radix_mem_block_size;
 
-	if (debug_pagealloc_enabled())
+	if (debug_pagealloc_enabled_or_kfence())
 		size = PAGE_SIZE;
 
 	if (end >= RADIX_VMALLOC_START) {
@@ -1176,7 +1178,7 @@ int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
 	return 1;
 }
 
-#ifdef CONFIG_DEBUG_PAGEALLOC
+#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)
 void radix__kernel_map_pages(struct page *page, int numpages, int enable)
 {
 	unsigned long addr = (unsigned long)page_address(page);
-- 
2.25.1