[PATCH v2 2/4] powerpc/64s: Remove unneeded #ifdef CONFIG_DEBUG_PAGEALLOC in hash_utils

[PATCH v2 2/4] powerpc/64s: Remove unneeded #ifdef CONFIG_DEBUG_PAGEALLOC in hash_utils

[Christophe Leroy]

debug_pagealloc_enabled() is always defined and constant folds to
'false' when CONFIG_DEBUG_PAGEALLOC is not enabled.

Remove the #ifdefs, the code and associated static variables will
be optimised out by the compiler when CONFIG_DEBUG_PAGEALLOC is
not defined.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v2: New
---
 arch/powerpc/mm/book3s64/hash_utils.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
index 581b20a2feaf..f1b5a5f1d3a9 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c
@@ -126,11 +126,8 @@ EXPORT_SYMBOL_GPL(mmu_slb_size);
 #ifdef CONFIG_PPC_64K_PAGES
 int mmu_ci_restrictions;
 #endif
-#ifdef CONFIG_DEBUG_PAGEALLOC
 static u8 *linear_map_hash_slots;
 static unsigned long linear_map_hash_count;
-static DEFINE_SPINLOCK(linear_map_hash_lock);
-#endif /* CONFIG_DEBUG_PAGEALLOC */
 struct mmu_hash_ops mmu_hash_ops;
 EXPORT_SYMBOL(mmu_hash_ops);
 
@@ -326,11 +323,9 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
 			break;
 
 		cond_resched();
-#ifdef CONFIG_DEBUG_PAGEALLOC
 		if (debug_pagealloc_enabled() &&
 			(paddr >> PAGE_SHIFT) < linear_map_hash_count)
 			linear_map_hash_slots[paddr >> PAGE_SHIFT] = ret | 0x80;
-#endif /* CONFIG_DEBUG_PAGEALLOC */
 	}
 	return ret < 0 ? ret : 0;
 }
@@ -954,7 +949,6 @@ static void __init htab_initialize(void)
 
 	prot = pgprot_val(PAGE_KERNEL);
 
-#ifdef CONFIG_DEBUG_PAGEALLOC
 	if (debug_pagealloc_enabled()) {
 		linear_map_hash_count = memblock_end_of_DRAM() >> PAGE_SHIFT;
 		linear_map_hash_slots = memblock_alloc_try_nid(
@@ -964,7 +958,6 @@ static void __init htab_initialize(void)
 			panic("%s: Failed to allocate %lu bytes max_addr=%pa\n",
 			      __func__, linear_map_hash_count, &ppc64_rma_size);
 	}
-#endif /* CONFIG_DEBUG_PAGEALLOC */
 
 	/* create bolted the linear mapping in the hash table */
 	for_each_mem_range(i, &base, &end) {
@@ -1935,6 +1928,8 @@ long hpte_insert_repeating(unsigned long hash, unsigned long vpn,
 }
 
 #ifdef CONFIG_DEBUG_PAGEALLOC
+static DEFINE_SPINLOCK(linear_map_hash_lock);
+
 static void kernel_map_linear_page(unsigned long vaddr, unsigned long lmi)
 {
 	unsigned long hash;
-- 
2.25.0

[PATCH v2 1/4] powerpc/64s: Add DEBUG_PAGEALLOC for radix

[Nicholas Miehlbradt]

There is support for DEBUG_PAGEALLOC on hash but not on radix.
Add support on radix.

Signed-off-by: Nicholas Miehlbradt <nicholas@linux.ibm.com>
---
v2: Revert change to radix_memory_block_size, instead set the size
in radix_init_pgtable and radix__create_section_mapping directly.
---
 arch/powerpc/mm/book3s64/radix_pgtable.c | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index db2f3d193448..623455c195d8 100644
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -30,6 +30,7 @@
 #include <asm/trace.h>
 #include <asm/uaccess.h>
 #include <asm/ultravisor.h>
+#include <asm/set_memory.h>
 
 #include <trace/events/thp.h>
 
@@ -332,6 +333,10 @@ static void __init radix_init_pgtable(void)
 	unsigned long rts_field;
 	phys_addr_t start, end;
 	u64 i;
+	unsigned long size = radix_mem_block_size;
+
+	if (debug_pagealloc_enabled())
+		size = PAGE_SIZE;
 
 	/* We don't support slb for radix */
 	slb_set_size(0);
@@ -352,7 +357,7 @@ static void __init radix_init_pgtable(void)
 		}
 
 		WARN_ON(create_physical_mapping(start, end,
-						radix_mem_block_size,
+						size,
 						-1, PAGE_KERNEL));
 	}
 
@@ -844,13 +849,18 @@ int __meminit radix__create_section_mapping(unsigned long start,
 					    unsigned long end, int nid,
 					    pgprot_t prot)
 {
+	unsigned long size = radix_mem_block_size;
+
+	if (debug_pagealloc_enabled())
+		size = PAGE_SIZE;
+
 	if (end >= RADIX_VMALLOC_START) {
 		pr_warn("Outside the supported range\n");
 		return -1;
 	}
 
 	return create_physical_mapping(__pa(start), __pa(end),
-				       radix_mem_block_size, nid, prot);
+				       size, nid, prot);
 }
 
 int __meminit radix__remove_section_mapping(unsigned long start, unsigned long end)
@@ -899,7 +909,14 @@ void __meminit radix__vmemmap_remove_mapping(unsigned long start, unsigned long
 #ifdef CONFIG_DEBUG_PAGEALLOC
 void radix__kernel_map_pages(struct page *page, int numpages, int enable)
 {
-	pr_warn_once("DEBUG_PAGEALLOC not supported in radix mode\n");
+	unsigned long addr;
+
+	addr = (unsigned long)page_address(page);
+
+	if (enable)
+		set_memory_p(addr, numpages);
+	else
+		set_memory_np(addr, numpages);
 }
 #endif
 
-- 
2.34.1

[PATCH v2 2/4] powerpc/64s: Remove unneeded #ifdef CONFIG_DEBUG_PAGEALLOC in hash_utils

[Nicholas Miehlbradt]

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

debug_pagealloc_enabled() is always defined and constant folds to
'false' when CONFIG_DEBUG_PAGEALLOC is not enabled.

Remove the #ifdefs, the code and associated static variables will
be optimised out by the compiler when CONFIG_DEBUG_PAGEALLOC is
not defined.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Nicholas Miehlbradt <nicholas@linux.ibm.com>
---
 arch/powerpc/mm/book3s64/hash_utils.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
index fc92613dc2bf..e63ff401a6ea 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c
@@ -123,11 +123,8 @@ EXPORT_SYMBOL_GPL(mmu_slb_size);
 #ifdef CONFIG_PPC_64K_PAGES
 int mmu_ci_restrictions;
 #endif
-#ifdef CONFIG_DEBUG_PAGEALLOC
 static u8 *linear_map_hash_slots;
 static unsigned long linear_map_hash_count;
-static DEFINE_SPINLOCK(linear_map_hash_lock);
-#endif /* CONFIG_DEBUG_PAGEALLOC */
 struct mmu_hash_ops mmu_hash_ops;
 EXPORT_SYMBOL(mmu_hash_ops);
 
@@ -427,11 +424,9 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
 			break;
 
 		cond_resched();
-#ifdef CONFIG_DEBUG_PAGEALLOC
 		if (debug_pagealloc_enabled() &&
 			(paddr >> PAGE_SHIFT) < linear_map_hash_count)
 			linear_map_hash_slots[paddr >> PAGE_SHIFT] = ret | 0x80;
-#endif /* CONFIG_DEBUG_PAGEALLOC */
 	}
 	return ret < 0 ? ret : 0;
 }
@@ -1066,7 +1061,6 @@ static void __init htab_initialize(void)
 
 	prot = pgprot_val(PAGE_KERNEL);
 
-#ifdef CONFIG_DEBUG_PAGEALLOC
 	if (debug_pagealloc_enabled()) {
 		linear_map_hash_count = memblock_end_of_DRAM() >> PAGE_SHIFT;
 		linear_map_hash_slots = memblock_alloc_try_nid(
@@ -1076,7 +1070,6 @@ static void __init htab_initialize(void)
 			panic("%s: Failed to allocate %lu bytes max_addr=%pa\n",
 			      __func__, linear_map_hash_count, &ppc64_rma_size);
 	}
-#endif /* CONFIG_DEBUG_PAGEALLOC */
 
 	/* create bolted the linear mapping in the hash table */
 	for_each_mem_range(i, &base, &end) {
@@ -1991,6 +1984,8 @@ long hpte_insert_repeating(unsigned long hash, unsigned long vpn,
 }
 
 #ifdef CONFIG_DEBUG_PAGEALLOC
+static DEFINE_SPINLOCK(linear_map_hash_lock);
+
 static void kernel_map_linear_page(unsigned long vaddr, unsigned long lmi)
 {
 	unsigned long hash;
-- 
2.34.1

[PATCH v2 3/4] powerpc/64s: Allow double call of kernel_[un]map_linear_page()

[Nicholas Miehlbradt]

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

If the page is already mapped resp. already unmapped, bail out.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Nicholas Miehlbradt <nicholas@linux.ibm.com>
---
 arch/powerpc/mm/book3s64/hash_utils.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
index e63ff401a6ea..b37412fe5930 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c
@@ -2000,6 +2000,9 @@ static void kernel_map_linear_page(unsigned long vaddr, unsigned long lmi)
 	if (!vsid)
 		return;
 
+	if (linear_map_hash_slots[lmi] & 0x80)
+		return;
+
 	ret = hpte_insert_repeating(hash, vpn, __pa(vaddr), mode,
 				    HPTE_V_BOLTED,
 				    mmu_linear_psize, mmu_kernel_ssize);
@@ -2019,7 +2022,10 @@ static void kernel_unmap_linear_page(unsigned long vaddr, unsigned long lmi)
 
 	hash = hpt_hash(vpn, PAGE_SHIFT, mmu_kernel_ssize);
 	spin_lock(&linear_map_hash_lock);
-	BUG_ON(!(linear_map_hash_slots[lmi] & 0x80));
+	if (!(linear_map_hash_slots[lmi] & 0x80)) {
+		spin_unlock(&linear_map_hash_lock);
+		return;
+	}
 	hidx = linear_map_hash_slots[lmi] & 0x7f;
 	linear_map_hash_slots[lmi] = 0;
 	spin_unlock(&linear_map_hash_lock);
-- 
2.34.1

[PATCH v2 4/4] powerpc/64s: Enable KFENCE on book3s64

[Nicholas Miehlbradt]

KFENCE support was added for ppc32 in commit 90cbac0e995d
("powerpc: Enable KFENCE for PPC32").
Enable KFENCE on ppc64 architecture with hash and radix MMUs.
It uses the same mechanism as debug pagealloc to
protect/unprotect pages. All KFENCE kunit tests pass on both
MMUs.

KFENCE memory is initially allocated using memblock but is
later marked as SLAB allocated. This necessitates the change
to __pud_free to ensure that the KFENCE pages are freed
appropriately.

Based on previous work by Christophe Leroy and Jordan Niethe.

Signed-off-by: Nicholas Miehlbradt <nicholas@linux.ibm.com>
---
v2: Refactor
---
 arch/powerpc/Kconfig                         |  2 +-
 arch/powerpc/include/asm/book3s/64/pgalloc.h |  6 ++++--
 arch/powerpc/include/asm/book3s/64/pgtable.h |  2 +-
 arch/powerpc/include/asm/kfence.h            | 15 +++++++++++++++
 arch/powerpc/mm/book3s64/hash_utils.c        | 10 +++++-----
 arch/powerpc/mm/book3s64/radix_pgtable.c     |  8 +++++---
 6 files changed, 31 insertions(+), 12 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index a4f8a5276e5c..f7dd0f49510d 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -194,7 +194,7 @@ config PPC
 	select HAVE_ARCH_KASAN			if PPC32 && PPC_PAGE_SHIFT <= 14
 	select HAVE_ARCH_KASAN			if PPC_RADIX_MMU
 	select HAVE_ARCH_KASAN_VMALLOC		if HAVE_ARCH_KASAN
-	select HAVE_ARCH_KFENCE			if PPC_BOOK3S_32 || PPC_8xx || 40x
+	select HAVE_ARCH_KFENCE			if ARCH_SUPPORTS_DEBUG_PAGEALLOC
 	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/64/pgalloc.h b/arch/powerpc/include/asm/book3s/64/pgalloc.h
index e1af0b394ceb..dd2cff53a111 100644
--- a/arch/powerpc/include/asm/book3s/64/pgalloc.h
+++ b/arch/powerpc/include/asm/book3s/64/pgalloc.h
@@ -113,9 +113,11 @@ static inline void __pud_free(pud_t *pud)
 
 	/*
 	 * Early pud pages allocated via memblock allocator
-	 * can't be directly freed to slab
+	 * can't be directly freed to slab. KFENCE pages have
+	 * both reserved and slab flags set so need to be freed
+	 * kmem_cache_free.
 	 */
-	if (PageReserved(page))
+	if (PageReserved(page) && !PageSlab(page))
 		free_reserved_page(page);
 	else
 		kmem_cache_free(PGT_CACHE(PUD_CACHE_INDEX), pud);
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index cb9d5fd39d7f..fd5d800f2836 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -1123,7 +1123,7 @@ static inline void vmemmap_remove_mapping(unsigned long start,
 }
 #endif
 
-#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..cff60983e88d 100644
--- a/arch/powerpc/include/asm/kfence.h
+++ b/arch/powerpc/include/asm/kfence.h
@@ -11,11 +11,25 @@
 #include <linux/mm.h>
 #include <asm/pgtable.h>
 
+#if defined(CONFIG_PPC64) && !defined(CONFIG_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 = virt_to_page(addr);
+
+	__kernel_map_pages(page, 1, !protect);
+
+	return true;
+}
+#else
 static inline bool kfence_protect_page(unsigned long addr, bool protect)
 {
 	pte_t *kpte = virt_to_kpte(addr);
@@ -29,5 +43,6 @@ 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 b37412fe5930..9cceaa5998a3 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c
@@ -424,7 +424,7 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
 			break;
 
 		cond_resched();
-		if (debug_pagealloc_enabled() &&
+		if (debug_pagealloc_enabled_or_kfence() &&
 			(paddr >> PAGE_SHIFT) < linear_map_hash_count)
 			linear_map_hash_slots[paddr >> PAGE_SHIFT] = ret | 0x80;
 	}
@@ -773,7 +773,7 @@ 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
@@ -1061,7 +1061,7 @@ 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,
@@ -1983,7 +1983,7 @@ 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)
@@ -2056,7 +2056,7 @@ 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 623455c195d8..e88f9c45f34a 100644
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -34,6 +34,8 @@
 
 #include <trace/events/thp.h>
 
+#include <mm/mmu_decl.h>
+
 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)
 	u64 i;
 	unsigned long size = radix_mem_block_size;
 
-	if (debug_pagealloc_enabled())
+	if (debug_pagealloc_enabled_or_kfence())
 		size = PAGE_SIZE;
 
 	/* We don't support slb for radix */
@@ -851,7 +853,7 @@ 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) {
@@ -906,7 +908,7 @@ void __meminit radix__vmemmap_remove_mapping(unsigned long start, unsigned long
 #endif
 #endif
 
-#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;
-- 
2.34.1

Re: [PATCH v2 1/4] powerpc/64s: Add DEBUG_PAGEALLOC for radix

[Michael Ellerman]

Nicholas Miehlbradt <nicholas@linux.ibm.com> writes:
> There is support for DEBUG_PAGEALLOC on hash but not on radix.
> Add support on radix.
>
> Signed-off-by: Nicholas Miehlbradt <nicholas@linux.ibm.com>
> ---
> v2: Revert change to radix_memory_block_size, instead set the size
> in radix_init_pgtable and radix__create_section_mapping directly.
> ---
>  arch/powerpc/mm/book3s64/radix_pgtable.c | 23 ++++++++++++++++++++---
>  1 file changed, 20 insertions(+), 3 deletions(-)
>
> diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
> index db2f3d193448..623455c195d8 100644
> --- a/arch/powerpc/mm/book3s64/radix_pgtable.c
> +++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
> @@ -30,6 +30,7 @@
>  #include <asm/trace.h>
>  #include <asm/uaccess.h>
>  #include <asm/ultravisor.h>
> +#include <asm/set_memory.h>
>  
>  #include <trace/events/thp.h>
>  
> @@ -332,6 +333,10 @@ static void __init radix_init_pgtable(void)
>  	unsigned long rts_field;
>  	phys_addr_t start, end;
>  	u64 i;
> +	unsigned long size = radix_mem_block_size;
> +
> +	if (debug_pagealloc_enabled())
> +		size = PAGE_SIZE;
>  
>  	/* We don't support slb for radix */
>  	slb_set_size(0);
> @@ -352,7 +357,7 @@ static void __init radix_init_pgtable(void)
>  		}
>  
>  		WARN_ON(create_physical_mapping(start, end,
> -						radix_mem_block_size,
> +						size,
>  						-1, PAGE_KERNEL));
>  	}

There's only two calls to create_physical_mapping().

Both pass the same value for size, and now both needed updating for
debug page alloc.

Seems like create_physical_mapping() doesn't need the size passed to it
at all, it may as well just use the right value.

> @@ -844,13 +849,18 @@ int __meminit radix__create_section_mapping(unsigned long start,
>  					    unsigned long end, int nid,
>  					    pgprot_t prot)
>  {
> +	unsigned long size = radix_mem_block_size;
> +
> +	if (debug_pagealloc_enabled())
> +		size = PAGE_SIZE;
> +
>  	if (end >= RADIX_VMALLOC_START) {
>  		pr_warn("Outside the supported range\n");
>  		return -1;
>  	}
>  
>  	return create_physical_mapping(__pa(start), __pa(end),
> -				       radix_mem_block_size, nid, prot);
> +				       size, nid, prot);
>  }

cheers

Re: [PATCH v2 4/4] powerpc/64s: Enable KFENCE on book3s64

[Christophe Leroy]

Le 21/09/2022 à 04:02, Nicholas Miehlbradt a écrit :
> KFENCE support was added for ppc32 in commit 90cbac0e995d
> ("powerpc: Enable KFENCE for PPC32").
> Enable KFENCE on ppc64 architecture with hash and radix MMUs.
> It uses the same mechanism as debug pagealloc to
> protect/unprotect pages. All KFENCE kunit tests pass on both
> MMUs.
> 
> KFENCE memory is initially allocated using memblock but is
> later marked as SLAB allocated. This necessitates the change
> to __pud_free to ensure that the KFENCE pages are freed
> appropriately.
> 
> Based on previous work by Christophe Leroy and Jordan Niethe.
> 
> Signed-off-by: Nicholas Miehlbradt <nicholas@linux.ibm.com>
> ---
> v2: Refactor
> ---
>   arch/powerpc/Kconfig                         |  2 +-
>   arch/powerpc/include/asm/book3s/64/pgalloc.h |  6 ++++--
>   arch/powerpc/include/asm/book3s/64/pgtable.h |  2 +-
>   arch/powerpc/include/asm/kfence.h            | 15 +++++++++++++++
>   arch/powerpc/mm/book3s64/hash_utils.c        | 10 +++++-----
>   arch/powerpc/mm/book3s64/radix_pgtable.c     |  8 +++++---
>   6 files changed, 31 insertions(+), 12 deletions(-)
> 

> diff --git a/arch/powerpc/include/asm/kfence.h b/arch/powerpc/include/asm/kfence.h
> index a9846b68c6b9..cff60983e88d 100644
> --- a/arch/powerpc/include/asm/kfence.h
> +++ b/arch/powerpc/include/asm/kfence.h
> @@ -11,11 +11,25 @@
>   #include <linux/mm.h>
>   #include <asm/pgtable.h>
>   
> +#if defined(CONFIG_PPC64) && !defined(CONFIG_PPC64_ELF_ABI_V2)

CONFIG_PPC64 && !CONFIG_PPC64_ELF_ABI_V2

is the same as

CONFIG_PPC64_ELF_ABI_V1

> +#define ARCH_FUNC_PREFIX "."
> +#endif
> +



Christophe