[PATCH v2 0/9] Convert powerpc to default topdown mmap layout

[PATCH v2 0/9] Convert powerpc to default topdown mmap layout

[Christophe Leroy]

This series converts powerpc to default topdown mmap layout.

powerpc provides its own arch_get_unmapped_area() only when
slices are needed, which is only for book3s/64. First part of
the series moves slices into book3s/64 specific directories
and cleans up other subarchitectures.

Then a small modification is done to core mm to allow
powerpc to still provide its own arch_randomize_brk()

Last part converts to default topdown mmap layout.

Changes in v2:
- Moved patch 4 before patch 2
- Make generic arch_randomize_brk() __weak
- Added patch 9

Christophe Leroy (9):
  powerpc/mm: Make slice specific to book3s/64
  powerpc/mm: Move vma_mmu_pagesize() and hugetlb_get_unmapped_area() to
    slice.c
  powerpc/mm: Remove CONFIG_PPC_MM_SLICES
  powerpc/mm: Remove asm/slice.h
  powerpc/mm: Call radix__arch_get_unmapped_area() from
    arch_get_unmapped_area()
  mm: Allow arch specific arch_randomize_brk() with
    CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
  powerpc/mm: Convert to default topdown mmap layout
  powerpc/mm: Properly randomise mmap with slices
  powerpc: Simplify and move arch_randomize_brk()

 arch/powerpc/Kconfig                          |   2 +-
 arch/powerpc/include/asm/book3s/64/hash.h     |   5 +-
 arch/powerpc/include/asm/book3s/64/hugetlb.h  |   4 -
 arch/powerpc/include/asm/book3s/64/mmu-hash.h |   1 +
 arch/powerpc/include/asm/book3s/64/slice.h    |  18 ++
 arch/powerpc/include/asm/hugetlb.h            |   2 +-
 arch/powerpc/include/asm/paca.h               |   5 -
 arch/powerpc/include/asm/page.h               |   1 -
 arch/powerpc/include/asm/processor.h          |   2 -
 arch/powerpc/include/asm/slice.h              |  46 ----
 arch/powerpc/kernel/paca.c                    |   5 -
 arch/powerpc/kernel/process.c                 |  40 ---
 arch/powerpc/mm/Makefile                      |   3 +-
 arch/powerpc/mm/book3s64/Makefile             |   2 +-
 arch/powerpc/mm/book3s64/hash_utils.c         |  32 +--
 arch/powerpc/mm/book3s64/radix_hugetlbpage.c  |  55 -----
 arch/powerpc/mm/{ => book3s64}/slice.c        | 200 ++++++++++++++-
 arch/powerpc/mm/hugetlbpage.c                 |  28 ---
 arch/powerpc/mm/mmap.c                        | 228 ------------------
 arch/powerpc/mm/nohash/mmu_context.c          |   9 -
 arch/powerpc/mm/nohash/tlb.c                  |   4 -
 arch/powerpc/platforms/Kconfig.cputype        |   4 -
 include/linux/sizes.h                         |   2 +
 mm/util.c                                     |   2 +-
 24 files changed, 234 insertions(+), 466 deletions(-)
 delete mode 100644 arch/powerpc/include/asm/slice.h
 rename arch/powerpc/mm/{ => book3s64}/slice.c (80%)
 delete mode 100644 arch/powerpc/mm/mmap.c

-- 
2.33.1

[PATCH v2 1/9] powerpc/mm: Make slice specific to book3s/64

[Christophe Leroy]

Since commit 555904d07eef ("powerpc/8xx: MM_SLICE is not needed
anymore") only book3s/64 selects CONFIG_PPC_MM_SLICES.

Move slice.c into mm/book3s64/

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v2: Remove now unnecessary #ifdef CONFIG_PPC_BOOK3S_64 in slice.c
---
 arch/powerpc/mm/Makefile               | 1 -
 arch/powerpc/mm/book3s64/Makefile      | 1 +
 arch/powerpc/mm/{ => book3s64}/slice.c | 2 --
 arch/powerpc/mm/nohash/mmu_context.c   | 9 ---------
 arch/powerpc/mm/nohash/tlb.c           | 4 ----
 5 files changed, 1 insertion(+), 16 deletions(-)
 rename arch/powerpc/mm/{ => book3s64}/slice.c (99%)

diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
index df8172da2301..d4c20484dad9 100644
--- a/arch/powerpc/mm/Makefile
+++ b/arch/powerpc/mm/Makefile
@@ -14,7 +14,6 @@ obj-$(CONFIG_PPC_MMU_NOHASH)	+= nohash/
 obj-$(CONFIG_PPC_BOOK3S_32)	+= book3s32/
 obj-$(CONFIG_PPC_BOOK3S_64)	+= book3s64/
 obj-$(CONFIG_NUMA) += numa.o
-obj-$(CONFIG_PPC_MM_SLICES)	+= slice.o
 obj-$(CONFIG_HUGETLB_PAGE)	+= hugetlbpage.o
 obj-$(CONFIG_NOT_COHERENT_CACHE) += dma-noncoherent.o
 obj-$(CONFIG_PPC_COPRO_BASE)	+= copro_fault.o
diff --git a/arch/powerpc/mm/book3s64/Makefile b/arch/powerpc/mm/book3s64/Makefile
index 1b56d3af47d4..30951668c684 100644
--- a/arch/powerpc/mm/book3s64/Makefile
+++ b/arch/powerpc/mm/book3s64/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += hash_hugepage.o
 obj-$(CONFIG_PPC_SUBPAGE_PROT)	+= subpage_prot.o
 obj-$(CONFIG_SPAPR_TCE_IOMMU)	+= iommu_api.o
 obj-$(CONFIG_PPC_PKEY)	+= pkeys.o
+obj-$(CONFIG_PPC_MM_SLICES)	+= slice.o
 
 # Instrumenting the SLB fault path can lead to duplicate SLB entries
 KCOV_INSTRUMENT_slb.o := n
diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/book3s64/slice.c
similarity index 99%
rename from arch/powerpc/mm/slice.c
rename to arch/powerpc/mm/book3s64/slice.c
index 82b45b1cb973..c83be371c6e7 100644
--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/book3s64/slice.c
@@ -712,7 +712,6 @@ void slice_init_new_context_exec(struct mm_struct *mm)
 		bitmap_fill(mask->high_slices, SLICE_NUM_HIGH);
 }
 
-#ifdef CONFIG_PPC_BOOK3S_64
 void slice_setup_new_exec(void)
 {
 	struct mm_struct *mm = current->mm;
@@ -724,7 +723,6 @@ void slice_setup_new_exec(void)
 
 	mm_ctx_set_slb_addr_limit(&mm->context, DEFAULT_MAP_WINDOW);
 }
-#endif
 
 void slice_set_range_psize(struct mm_struct *mm, unsigned long start,
 			   unsigned long len, unsigned int psize)
diff --git a/arch/powerpc/mm/nohash/mmu_context.c b/arch/powerpc/mm/nohash/mmu_context.c
index 44b2b5e7cabe..dc3528e815b9 100644
--- a/arch/powerpc/mm/nohash/mmu_context.c
+++ b/arch/powerpc/mm/nohash/mmu_context.c
@@ -313,15 +313,6 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next,
  */
 int init_new_context(struct task_struct *t, struct mm_struct *mm)
 {
-	/*
-	 * We have MMU_NO_CONTEXT set to be ~0. Hence check
-	 * explicitly against context.id == 0. This ensures that we properly
-	 * initialize context slice details for newly allocated mm's (which will
-	 * have id == 0) and don't alter context slice inherited via fork (which
-	 * will have id != 0).
-	 */
-	if (mm->context.id == 0)
-		slice_init_new_context_exec(mm);
 	mm->context.id = MMU_NO_CONTEXT;
 	mm->context.active = 0;
 	pte_frag_set(&mm->context, NULL);
diff --git a/arch/powerpc/mm/nohash/tlb.c b/arch/powerpc/mm/nohash/tlb.c
index 647bf454a0fa..cb771d9f50cb 100644
--- a/arch/powerpc/mm/nohash/tlb.c
+++ b/arch/powerpc/mm/nohash/tlb.c
@@ -782,9 +782,5 @@ void __init early_init_mmu(void)
 #ifdef CONFIG_PPC_47x
 	early_init_mmu_47x();
 #endif
-
-#ifdef CONFIG_PPC_MM_SLICES
-	mm_ctx_set_slb_addr_limit(&init_mm.context, SLB_ADDR_LIMIT_DEFAULT);
-#endif
 }
 #endif /* CONFIG_PPC64 */
-- 
2.33.1

[PATCH v2 2/9] powerpc/mm: Move vma_mmu_pagesize() and hugetlb_get_unmapped_area() to slice.c

[Christophe Leroy]

vma_mmu_pagesize() is only required for slices,
otherwise there is a generic weak version.

hugetlb_get_unmapped_area() is dedicated to slices.
radix__hugetlb_get_unmapped_area() as well.

Move them to slice.c

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/include/asm/book3s/64/hugetlb.h |  4 --
 arch/powerpc/mm/book3s64/radix_hugetlbpage.c | 55 --------------
 arch/powerpc/mm/book3s64/slice.c             | 76 ++++++++++++++++++++
 arch/powerpc/mm/hugetlbpage.c                | 28 --------
 4 files changed, 76 insertions(+), 87 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/hugetlb.h b/arch/powerpc/include/asm/book3s/64/hugetlb.h
index 12e150e615b7..b37a28f62cf6 100644
--- a/arch/powerpc/include/asm/book3s/64/hugetlb.h
+++ b/arch/powerpc/include/asm/book3s/64/hugetlb.h
@@ -8,10 +8,6 @@
  */
 void radix__flush_hugetlb_page(struct vm_area_struct *vma, unsigned long vmaddr);
 void radix__local_flush_hugetlb_page(struct vm_area_struct *vma, unsigned long vmaddr);
-extern unsigned long
-radix__hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
-				unsigned long len, unsigned long pgoff,
-				unsigned long flags);
 
 extern void radix__huge_ptep_modify_prot_commit(struct vm_area_struct *vma,
 						unsigned long addr, pte_t *ptep,
diff --git a/arch/powerpc/mm/book3s64/radix_hugetlbpage.c b/arch/powerpc/mm/book3s64/radix_hugetlbpage.c
index 23d3e08911d3..d2fb776febb4 100644
--- a/arch/powerpc/mm/book3s64/radix_hugetlbpage.c
+++ b/arch/powerpc/mm/book3s64/radix_hugetlbpage.c
@@ -41,61 +41,6 @@ void radix__flush_hugetlb_tlb_range(struct vm_area_struct *vma, unsigned long st
 		radix__flush_tlb_range_psize(vma->vm_mm, start, end, psize);
 }
 
-/*
- * A vairant of hugetlb_get_unmapped_area doing topdown search
- * FIXME!! should we do as x86 does or non hugetlb area does ?
- * ie, use topdown or not based on mmap_is_legacy check ?
- */
-unsigned long
-radix__hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
-				unsigned long len, unsigned long pgoff,
-				unsigned long flags)
-{
-	struct mm_struct *mm = current->mm;
-	struct vm_area_struct *vma;
-	struct hstate *h = hstate_file(file);
-	int fixed = (flags & MAP_FIXED);
-	unsigned long high_limit;
-	struct vm_unmapped_area_info info;
-
-	high_limit = DEFAULT_MAP_WINDOW;
-	if (addr >= high_limit || (fixed && (addr + len > high_limit)))
-		high_limit = TASK_SIZE;
-
-	if (len & ~huge_page_mask(h))
-		return -EINVAL;
-	if (len > high_limit)
-		return -ENOMEM;
-
-	if (fixed) {
-		if (addr > high_limit - len)
-			return -ENOMEM;
-		if (prepare_hugepage_range(file, addr, len))
-			return -EINVAL;
-		return addr;
-	}
-
-	if (addr) {
-		addr = ALIGN(addr, huge_page_size(h));
-		vma = find_vma(mm, addr);
-		if (high_limit - len >= addr && addr >= mmap_min_addr &&
-		    (!vma || addr + len <= vm_start_gap(vma)))
-			return addr;
-	}
-	/*
-	 * We are always doing an topdown search here. Slice code
-	 * does that too.
-	 */
-	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
-	info.length = len;
-	info.low_limit = max(PAGE_SIZE, mmap_min_addr);
-	info.high_limit = mm->mmap_base + (high_limit - DEFAULT_MAP_WINDOW);
-	info.align_mask = PAGE_MASK & ~huge_page_mask(h);
-	info.align_offset = 0;
-
-	return vm_unmapped_area(&info);
-}
-
 void radix__huge_ptep_modify_prot_commit(struct vm_area_struct *vma,
 					 unsigned long addr, pte_t *ptep,
 					 pte_t old_pte, pte_t pte)
diff --git a/arch/powerpc/mm/book3s64/slice.c b/arch/powerpc/mm/book3s64/slice.c
index c83be371c6e7..4c3e9601fdf6 100644
--- a/arch/powerpc/mm/book3s64/slice.c
+++ b/arch/powerpc/mm/book3s64/slice.c
@@ -777,4 +777,80 @@ int slice_is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,
 
 	return !slice_check_range_fits(mm, maskp, addr, len);
 }
+
+unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
+{
+	/* With radix we don't use slice, so derive it from vma*/
+	if (radix_enabled())
+		return vma_kernel_pagesize(vma);
+
+	return 1UL << mmu_psize_to_shift(get_slice_psize(vma->vm_mm, vma->vm_start));
+}
+
+/*
+ * A variant of hugetlb_get_unmapped_area() doing topdown search
+ * FIXME!! should we do as x86 does or non hugetlb area does ?
+ * ie, use topdown or not based on mmap_is_legacy check ?
+ */
+static unsigned long
+radix__hugetlb_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
+				 unsigned long pgoff, unsigned long flags)
+{
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+	struct hstate *h = hstate_file(file);
+	int fixed = (flags & MAP_FIXED);
+	unsigned long high_limit;
+	struct vm_unmapped_area_info info;
+
+	high_limit = DEFAULT_MAP_WINDOW;
+	if (addr >= high_limit || (fixed && (addr + len > high_limit)))
+		high_limit = TASK_SIZE;
+
+	if (len & ~huge_page_mask(h))
+		return -EINVAL;
+	if (len > high_limit)
+		return -ENOMEM;
+
+	if (fixed) {
+		if (addr > high_limit - len)
+			return -ENOMEM;
+		if (prepare_hugepage_range(file, addr, len))
+			return -EINVAL;
+		return addr;
+	}
+
+	if (addr) {
+		addr = ALIGN(addr, huge_page_size(h));
+		vma = find_vma(mm, addr);
+		if (high_limit - len >= addr && addr >= mmap_min_addr &&
+		    (!vma || addr + len <= vm_start_gap(vma)))
+			return addr;
+	}
+	/*
+	 * We are always doing an topdown search here. Slice code
+	 * does that too.
+	 */
+	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
+	info.length = len;
+	info.low_limit = max(PAGE_SIZE, mmap_min_addr);
+	info.high_limit = mm->mmap_base + (high_limit - DEFAULT_MAP_WINDOW);
+	info.align_mask = PAGE_MASK & ~huge_page_mask(h);
+	info.align_offset = 0;
+
+	return vm_unmapped_area(&info);
+}
+
+unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
+					unsigned long len, unsigned long pgoff,
+					unsigned long flags)
+{
+	struct hstate *hstate = hstate_file(file);
+	int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate));
+
+	if (radix_enabled())
+		return radix__hugetlb_get_unmapped_area(file, addr, len, pgoff, flags);
+
+	return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1);
+}
 #endif
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 82d8b368ca6d..eb9de09e49a3 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -542,34 +542,6 @@ struct page *follow_huge_pd(struct vm_area_struct *vma,
 	return page;
 }
 
-#ifdef CONFIG_PPC_MM_SLICES
-unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
-					unsigned long len, unsigned long pgoff,
-					unsigned long flags)
-{
-	struct hstate *hstate = hstate_file(file);
-	int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate));
-
-#ifdef CONFIG_PPC_RADIX_MMU
-	if (radix_enabled())
-		return radix__hugetlb_get_unmapped_area(file, addr, len,
-						       pgoff, flags);
-#endif
-	return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1);
-}
-#endif
-
-unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
-{
-	/* With radix we don't use slice, so derive it from vma*/
-	if (IS_ENABLED(CONFIG_PPC_MM_SLICES) && !radix_enabled()) {
-		unsigned int psize = get_slice_psize(vma->vm_mm, vma->vm_start);
-
-		return 1UL << mmu_psize_to_shift(psize);
-	}
-	return vma_kernel_pagesize(vma);
-}
-
 bool __init arch_hugetlb_valid_size(unsigned long size)
 {
 	int shift = __ffs(size);
-- 
2.33.1

[PATCH v2 3/9] powerpc/mm: Remove CONFIG_PPC_MM_SLICES

[Christophe Leroy]

CONFIG_PPC_MM_SLICES is always selected by book3s/64.
CONFIG_PPC_MM_SLICES is never selected by other platforms.

Remove it.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/include/asm/book3s/64/hash.h |  2 --
 arch/powerpc/include/asm/hugetlb.h        |  2 +-
 arch/powerpc/include/asm/paca.h           |  5 -----
 arch/powerpc/include/asm/slice.h          | 13 ++-----------
 arch/powerpc/kernel/paca.c                |  5 -----
 arch/powerpc/mm/book3s64/Makefile         |  3 +--
 arch/powerpc/mm/book3s64/hash_utils.c     | 14 --------------
 arch/powerpc/platforms/Kconfig.cputype    |  4 ----
 8 files changed, 4 insertions(+), 44 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h
index 674fe0e890dc..25f8e90985eb 100644
--- a/arch/powerpc/include/asm/book3s/64/hash.h
+++ b/arch/powerpc/include/asm/book3s/64/hash.h
@@ -99,10 +99,8 @@
  * Defines the address of the vmemap area, in its own region on
  * hash table CPUs.
  */
-#ifdef CONFIG_PPC_MM_SLICES
 #define HAVE_ARCH_UNMAPPED_AREA
 #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
-#endif /* CONFIG_PPC_MM_SLICES */
 
 /* PTEIDX nibble */
 #define _PTEIDX_SECONDARY	0x8
diff --git a/arch/powerpc/include/asm/hugetlb.h b/arch/powerpc/include/asm/hugetlb.h
index f18c543bc01d..83f067d4d2f3 100644
--- a/arch/powerpc/include/asm/hugetlb.h
+++ b/arch/powerpc/include/asm/hugetlb.h
@@ -24,7 +24,7 @@ static inline int is_hugepage_only_range(struct mm_struct *mm,
 					 unsigned long addr,
 					 unsigned long len)
 {
-	if (IS_ENABLED(CONFIG_PPC_MM_SLICES) && !radix_enabled())
+	if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && !radix_enabled())
 		return slice_is_hugepage_only_range(mm, addr, len);
 	return 0;
 }
diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h
index dc05a862e72a..20bef2e8533b 100644
--- a/arch/powerpc/include/asm/paca.h
+++ b/arch/powerpc/include/asm/paca.h
@@ -149,13 +149,8 @@ struct paca_struct {
 #endif /* CONFIG_PPC_BOOK3E */
 
 #ifdef CONFIG_PPC_BOOK3S
-#ifdef CONFIG_PPC_MM_SLICES
 	unsigned char mm_ctx_low_slices_psize[BITS_PER_LONG / BITS_PER_BYTE];
 	unsigned char mm_ctx_high_slices_psize[SLICE_ARRAY_SIZE];
-#else
-	u16 mm_ctx_user_psize;
-	u16 mm_ctx_sllp;
-#endif
 #endif
 
 	/*
diff --git a/arch/powerpc/include/asm/slice.h b/arch/powerpc/include/asm/slice.h
index 0bdd9c62eca0..be4acc52e8ec 100644
--- a/arch/powerpc/include/asm/slice.h
+++ b/arch/powerpc/include/asm/slice.h
@@ -10,7 +10,7 @@
 
 struct mm_struct;
 
-#ifdef CONFIG_PPC_MM_SLICES
+#ifdef CONFIG_PPC_BOOK3S_64
 
 #ifdef CONFIG_HUGETLB_PAGE
 #define HAVE_ARCH_HUGETLB_UNMAPPED_AREA
@@ -30,16 +30,7 @@ void slice_set_range_psize(struct mm_struct *mm, unsigned long start,
 void slice_init_new_context_exec(struct mm_struct *mm);
 void slice_setup_new_exec(void);
 
-#else /* CONFIG_PPC_MM_SLICES */
-
-static inline void slice_init_new_context_exec(struct mm_struct *mm) {}
-
-static inline unsigned int get_slice_psize(struct mm_struct *mm, unsigned long addr)
-{
-	return 0;
-}
-
-#endif /* CONFIG_PPC_MM_SLICES */
+#endif /* CONFIG_PPC_BOOK3S_64 */
 
 #endif /* __ASSEMBLY__ */
 
diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
index 4208b4044d12..a61f6fdcfb00 100644
--- a/arch/powerpc/kernel/paca.c
+++ b/arch/powerpc/kernel/paca.c
@@ -346,16 +346,11 @@ void copy_mm_to_paca(struct mm_struct *mm)
 #ifdef CONFIG_PPC_BOOK3S
 	mm_context_t *context = &mm->context;
 
-#ifdef CONFIG_PPC_MM_SLICES
 	VM_BUG_ON(!mm_ctx_slb_addr_limit(context));
 	memcpy(&get_paca()->mm_ctx_low_slices_psize, mm_ctx_low_slices(context),
 	       LOW_SLICE_ARRAY_SZ);
 	memcpy(&get_paca()->mm_ctx_high_slices_psize, mm_ctx_high_slices(context),
 	       TASK_SLICE_ARRAY_SZ(context));
-#else /* CONFIG_PPC_MM_SLICES */
-	get_paca()->mm_ctx_user_psize = context->user_psize;
-	get_paca()->mm_ctx_sllp = context->sllp;
-#endif
 #else /* !CONFIG_PPC_BOOK3S */
 	return;
 #endif
diff --git a/arch/powerpc/mm/book3s64/Makefile b/arch/powerpc/mm/book3s64/Makefile
index 30951668c684..f8562c79c59f 100644
--- a/arch/powerpc/mm/book3s64/Makefile
+++ b/arch/powerpc/mm/book3s64/Makefile
@@ -4,7 +4,7 @@ ccflags-y	:= $(NO_MINIMAL_TOC)
 
 CFLAGS_REMOVE_slb.o = $(CC_FLAGS_FTRACE)
 
-obj-y				+= hash_pgtable.o hash_utils.o slb.o \
+obj-y				+= hash_pgtable.o hash_utils.o slb.o slice.o \
 				   mmu_context.o pgtable.o hash_tlb.o
 obj-$(CONFIG_PPC_NATIVE)	+= hash_native.o
 obj-$(CONFIG_PPC_RADIX_MMU)	+= radix_pgtable.o radix_tlb.o
@@ -18,7 +18,6 @@ obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += hash_hugepage.o
 obj-$(CONFIG_PPC_SUBPAGE_PROT)	+= subpage_prot.o
 obj-$(CONFIG_SPAPR_TCE_IOMMU)	+= iommu_api.o
 obj-$(CONFIG_PPC_PKEY)	+= pkeys.o
-obj-$(CONFIG_PPC_MM_SLICES)	+= slice.o
 
 # Instrumenting the SLB fault path can lead to duplicate SLB entries
 KCOV_INSTRUMENT_slb.o := n
diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
index cfd45245d009..1d09d4aeddbf 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c
@@ -1165,7 +1165,6 @@ unsigned int hash_page_do_lazy_icache(unsigned int pp, pte_t pte, int trap)
 	return pp;
 }
 
-#ifdef CONFIG_PPC_MM_SLICES
 static unsigned int get_paca_psize(unsigned long addr)
 {
 	unsigned char *psizes;
@@ -1182,12 +1181,6 @@ static unsigned int get_paca_psize(unsigned long addr)
 	return (psizes[index >> 1] >> (mask_index * 4)) & 0xF;
 }
 
-#else
-unsigned int get_paca_psize(unsigned long addr)
-{
-	return get_paca()->mm_ctx_user_psize;
-}
-#endif
 
 /*
  * Demote a segment to using 4k pages.
@@ -1611,7 +1604,6 @@ DEFINE_INTERRUPT_HANDLER_RAW(do_hash_fault)
 	return 0;
 }
 
-#ifdef CONFIG_PPC_MM_SLICES
 static bool should_hash_preload(struct mm_struct *mm, unsigned long ea)
 {
 	int psize = get_slice_psize(mm, ea);
@@ -1628,12 +1620,6 @@ static bool should_hash_preload(struct mm_struct *mm, unsigned long ea)
 
 	return true;
 }
-#else
-static bool should_hash_preload(struct mm_struct *mm, unsigned long ea)
-{
-	return true;
-}
-#endif
 
 static void hash_preload(struct mm_struct *mm, pte_t *ptep, unsigned long ea,
 			 bool is_exec, unsigned long trap)
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index a208997ade88..580339c0c5bc 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -105,7 +105,6 @@ config PPC_BOOK3S_64
 	select HAVE_MOVE_PMD
 	select HAVE_MOVE_PUD
 	select IRQ_WORK
-	select PPC_MM_SLICES
 	select PPC_HAVE_KUEP
 	select PPC_HAVE_KUAP
 
@@ -432,9 +431,6 @@ config PPC_BOOK3E_MMU
 	def_bool y
 	depends on FSL_BOOKE || PPC_BOOK3E
 
-config PPC_MM_SLICES
-	bool
-
 config PPC_HAVE_PMU_SUPPORT
 	bool
 
-- 
2.33.1

[PATCH v2 4/9] powerpc/mm: Remove asm/slice.h

[Christophe Leroy]

Move necessary stuff in asm/book3s/64/slice.h and
remove asm/slice.h

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/include/asm/book3s/64/hash.h     |  3 ++
 arch/powerpc/include/asm/book3s/64/mmu-hash.h |  1 +
 arch/powerpc/include/asm/book3s/64/slice.h    | 18 +++++++++
 arch/powerpc/include/asm/page.h               |  1 -
 arch/powerpc/include/asm/slice.h              | 37 -------------------
 5 files changed, 22 insertions(+), 38 deletions(-)
 delete mode 100644 arch/powerpc/include/asm/slice.h

diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h
index 25f8e90985eb..27be22e6f848 100644
--- a/arch/powerpc/include/asm/book3s/64/hash.h
+++ b/arch/powerpc/include/asm/book3s/64/hash.h
@@ -99,6 +99,9 @@
  * Defines the address of the vmemap area, in its own region on
  * hash table CPUs.
  */
+#ifdef CONFIG_HUGETLB_PAGE
+#define HAVE_ARCH_HUGETLB_UNMAPPED_AREA
+#endif
 #define HAVE_ARCH_UNMAPPED_AREA
 #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
 
diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
index 3004f3323144..b4b2ca111f75 100644
--- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h
+++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
@@ -18,6 +18,7 @@
  * complete pgtable.h but only a portion of it.
  */
 #include <asm/book3s/64/pgtable.h>
+#include <asm/book3s/64/slice.h>
 #include <asm/task_size_64.h>
 #include <asm/cpu_has_feature.h>
 
diff --git a/arch/powerpc/include/asm/book3s/64/slice.h b/arch/powerpc/include/asm/book3s/64/slice.h
index f0d3194ba41b..5b0f7105bc8b 100644
--- a/arch/powerpc/include/asm/book3s/64/slice.h
+++ b/arch/powerpc/include/asm/book3s/64/slice.h
@@ -2,6 +2,8 @@
 #ifndef _ASM_POWERPC_BOOK3S_64_SLICE_H
 #define _ASM_POWERPC_BOOK3S_64_SLICE_H
 
+#ifndef __ASSEMBLY__
+
 #define SLICE_LOW_SHIFT		28
 #define SLICE_LOW_TOP		(0x100000000ul)
 #define SLICE_NUM_LOW		(SLICE_LOW_TOP >> SLICE_LOW_SHIFT)
@@ -13,4 +15,20 @@
 
 #define SLB_ADDR_LIMIT_DEFAULT	DEFAULT_MAP_WINDOW_USER64
 
+struct mm_struct;
+
+unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
+				      unsigned long flags, unsigned int psize,
+				      int topdown);
+
+unsigned int get_slice_psize(struct mm_struct *mm, unsigned long addr);
+
+void slice_set_range_psize(struct mm_struct *mm, unsigned long start,
+			   unsigned long len, unsigned int psize);
+
+void slice_init_new_context_exec(struct mm_struct *mm);
+void slice_setup_new_exec(void);
+
+#endif /* __ASSEMBLY__ */
+
 #endif /* _ASM_POWERPC_BOOK3S_64_SLICE_H */
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index 254687258f42..62e0c6f12869 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -329,6 +329,5 @@ static inline unsigned long kaslr_offset(void)
 
 #include <asm-generic/memory_model.h>
 #endif /* __ASSEMBLY__ */
-#include <asm/slice.h>
 
 #endif /* _ASM_POWERPC_PAGE_H */
diff --git a/arch/powerpc/include/asm/slice.h b/arch/powerpc/include/asm/slice.h
deleted file mode 100644
index be4acc52e8ec..000000000000
--- a/arch/powerpc/include/asm/slice.h
+++ /dev/null
@@ -1,37 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_POWERPC_SLICE_H
-#define _ASM_POWERPC_SLICE_H
-
-#ifdef CONFIG_PPC_BOOK3S_64
-#include <asm/book3s/64/slice.h>
-#endif
-
-#ifndef __ASSEMBLY__
-
-struct mm_struct;
-
-#ifdef CONFIG_PPC_BOOK3S_64
-
-#ifdef CONFIG_HUGETLB_PAGE
-#define HAVE_ARCH_HUGETLB_UNMAPPED_AREA
-#endif
-#define HAVE_ARCH_UNMAPPED_AREA
-#define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
-
-unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
-				      unsigned long flags, unsigned int psize,
-				      int topdown);
-
-unsigned int get_slice_psize(struct mm_struct *mm, unsigned long addr);
-
-void slice_set_range_psize(struct mm_struct *mm, unsigned long start,
-			   unsigned long len, unsigned int psize);
-
-void slice_init_new_context_exec(struct mm_struct *mm);
-void slice_setup_new_exec(void);
-
-#endif /* CONFIG_PPC_BOOK3S_64 */
-
-#endif /* __ASSEMBLY__ */
-
-#endif /* _ASM_POWERPC_SLICE_H */
-- 
2.33.1

[PATCH v2 5/9] powerpc/mm: Call radix__arch_get_unmapped_area() from arch_get_unmapped_area()

[Christophe Leroy]

Instead of setting mm->get_unmapped_area() to either
arch_get_unmapped_area() or radix__arch_get_unmapped_area(),
always set it to arch_get_unmapped_area() and call
radix__arch_get_unmapped_area() from there when radix is enabled.

To keep radix__arch_get_unmapped_area() static, move it to slice.c

Do the same with radix__arch_get_unmapped_area_topdown()

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/mm/book3s64/slice.c | 104 ++++++++++++++++++++++++++
 arch/powerpc/mm/mmap.c           | 123 -------------------------------
 2 files changed, 104 insertions(+), 123 deletions(-)

diff --git a/arch/powerpc/mm/book3s64/slice.c b/arch/powerpc/mm/book3s64/slice.c
index 4c3e9601fdf6..99742dde811c 100644
--- a/arch/powerpc/mm/book3s64/slice.c
+++ b/arch/powerpc/mm/book3s64/slice.c
@@ -639,12 +639,113 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
 }
 EXPORT_SYMBOL_GPL(slice_get_unmapped_area);
 
+/*
+ * Same function as generic code used only for radix, because we don't need to overload
+ * the generic one. But we will have to duplicate, because hash select
+ * HAVE_ARCH_UNMAPPED_AREA
+ */
+static unsigned long
+radix__arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len,
+			      unsigned long pgoff, unsigned long flags)
+{
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+	int fixed = (flags & MAP_FIXED);
+	unsigned long high_limit;
+	struct vm_unmapped_area_info info;
+
+	high_limit = DEFAULT_MAP_WINDOW;
+	if (addr >= high_limit || (fixed && (addr + len > high_limit)))
+		high_limit = TASK_SIZE;
+
+	if (len > high_limit)
+		return -ENOMEM;
+
+	if (fixed) {
+		if (addr > high_limit - len)
+			return -ENOMEM;
+		return addr;
+	}
+
+	if (addr) {
+		addr = PAGE_ALIGN(addr);
+		vma = find_vma(mm, addr);
+		if (high_limit - len >= addr && addr >= mmap_min_addr &&
+		    (!vma || addr + len <= vm_start_gap(vma)))
+			return addr;
+	}
+
+	info.flags = 0;
+	info.length = len;
+	info.low_limit = mm->mmap_base;
+	info.high_limit = high_limit;
+	info.align_mask = 0;
+
+	return vm_unmapped_area(&info);
+}
+
+static unsigned long
+radix__arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
+				      const unsigned long len, const unsigned long pgoff,
+				      const unsigned long flags)
+{
+	struct vm_area_struct *vma;
+	struct mm_struct *mm = current->mm;
+	unsigned long addr = addr0;
+	int fixed = (flags & MAP_FIXED);
+	unsigned long high_limit;
+	struct vm_unmapped_area_info info;
+
+	high_limit = DEFAULT_MAP_WINDOW;
+	if (addr >= high_limit || (fixed && (addr + len > high_limit)))
+		high_limit = TASK_SIZE;
+
+	if (len > high_limit)
+		return -ENOMEM;
+
+	if (fixed) {
+		if (addr > high_limit - len)
+			return -ENOMEM;
+		return addr;
+	}
+
+	if (addr) {
+		addr = PAGE_ALIGN(addr);
+		vma = find_vma(mm, addr);
+		if (high_limit - len >= addr && addr >= mmap_min_addr &&
+		    (!vma || addr + len <= vm_start_gap(vma)))
+			return addr;
+	}
+
+	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
+	info.length = len;
+	info.low_limit = max(PAGE_SIZE, mmap_min_addr);
+	info.high_limit = mm->mmap_base + (high_limit - DEFAULT_MAP_WINDOW);
+	info.align_mask = 0;
+
+	addr = vm_unmapped_area(&info);
+	if (!(addr & ~PAGE_MASK))
+		return addr;
+	VM_BUG_ON(addr != -ENOMEM);
+
+	/*
+	 * A failed mmap() very likely causes application failure,
+	 * so fall back to the bottom-up function here. This scenario
+	 * can happen with large stack limits and large mmap()
+	 * allocations.
+	 */
+	return radix__arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
+}
+
 unsigned long arch_get_unmapped_area(struct file *filp,
 				     unsigned long addr,
 				     unsigned long len,
 				     unsigned long pgoff,
 				     unsigned long flags)
 {
+	if (radix_enabled())
+		return radix__arch_get_unmapped_area(filp, addr, len, pgoff, flags);
+
 	return slice_get_unmapped_area(addr, len, flags,
 				       mm_ctx_user_psize(&current->mm->context), 0);
 }
@@ -655,6 +756,9 @@ unsigned long arch_get_unmapped_area_topdown(struct file *filp,
 					     const unsigned long pgoff,
 					     const unsigned long flags)
 {
+	if (radix_enabled())
+		return radix__arch_get_unmapped_area_topdown(filp, addr0, len, pgoff, flags);
+
 	return slice_get_unmapped_area(addr0, len, flags,
 				       mm_ctx_user_psize(&current->mm->context), 1);
 }
diff --git a/arch/powerpc/mm/mmap.c b/arch/powerpc/mm/mmap.c
index ae683fdc716c..5972d619d274 100644
--- a/arch/powerpc/mm/mmap.c
+++ b/arch/powerpc/mm/mmap.c
@@ -80,126 +80,6 @@ static inline unsigned long mmap_base(unsigned long rnd,
 	return PAGE_ALIGN(DEFAULT_MAP_WINDOW - gap - rnd);
 }
 
-#ifdef CONFIG_PPC_RADIX_MMU
-/*
- * Same function as generic code used only for radix, because we don't need to overload
- * the generic one. But we will have to duplicate, because hash select
- * HAVE_ARCH_UNMAPPED_AREA
- */
-static unsigned long
-radix__arch_get_unmapped_area(struct file *filp, unsigned long addr,
-			     unsigned long len, unsigned long pgoff,
-			     unsigned long flags)
-{
-	struct mm_struct *mm = current->mm;
-	struct vm_area_struct *vma;
-	int fixed = (flags & MAP_FIXED);
-	unsigned long high_limit;
-	struct vm_unmapped_area_info info;
-
-	high_limit = DEFAULT_MAP_WINDOW;
-	if (addr >= high_limit || (fixed && (addr + len > high_limit)))
-		high_limit = TASK_SIZE;
-
-	if (len > high_limit)
-		return -ENOMEM;
-
-	if (fixed) {
-		if (addr > high_limit - len)
-			return -ENOMEM;
-		return addr;
-	}
-
-	if (addr) {
-		addr = PAGE_ALIGN(addr);
-		vma = find_vma(mm, addr);
-		if (high_limit - len >= addr && addr >= mmap_min_addr &&
-		    (!vma || addr + len <= vm_start_gap(vma)))
-			return addr;
-	}
-
-	info.flags = 0;
-	info.length = len;
-	info.low_limit = mm->mmap_base;
-	info.high_limit = high_limit;
-	info.align_mask = 0;
-
-	return vm_unmapped_area(&info);
-}
-
-static unsigned long
-radix__arch_get_unmapped_area_topdown(struct file *filp,
-				     const unsigned long addr0,
-				     const unsigned long len,
-				     const unsigned long pgoff,
-				     const unsigned long flags)
-{
-	struct vm_area_struct *vma;
-	struct mm_struct *mm = current->mm;
-	unsigned long addr = addr0;
-	int fixed = (flags & MAP_FIXED);
-	unsigned long high_limit;
-	struct vm_unmapped_area_info info;
-
-	high_limit = DEFAULT_MAP_WINDOW;
-	if (addr >= high_limit || (fixed && (addr + len > high_limit)))
-		high_limit = TASK_SIZE;
-
-	if (len > high_limit)
-		return -ENOMEM;
-
-	if (fixed) {
-		if (addr > high_limit - len)
-			return -ENOMEM;
-		return addr;
-	}
-
-	if (addr) {
-		addr = PAGE_ALIGN(addr);
-		vma = find_vma(mm, addr);
-		if (high_limit - len >= addr && addr >= mmap_min_addr &&
-		    (!vma || addr + len <= vm_start_gap(vma)))
-			return addr;
-	}
-
-	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
-	info.length = len;
-	info.low_limit = max(PAGE_SIZE, mmap_min_addr);
-	info.high_limit = mm->mmap_base + (high_limit - DEFAULT_MAP_WINDOW);
-	info.align_mask = 0;
-
-	addr = vm_unmapped_area(&info);
-	if (!(addr & ~PAGE_MASK))
-		return addr;
-	VM_BUG_ON(addr != -ENOMEM);
-
-	/*
-	 * A failed mmap() very likely causes application failure,
-	 * so fall back to the bottom-up function here. This scenario
-	 * can happen with large stack limits and large mmap()
-	 * allocations.
-	 */
-	return radix__arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
-}
-
-static void radix__arch_pick_mmap_layout(struct mm_struct *mm,
-					unsigned long random_factor,
-					struct rlimit *rlim_stack)
-{
-	if (mmap_is_legacy(rlim_stack)) {
-		mm->mmap_base = TASK_UNMAPPED_BASE;
-		mm->get_unmapped_area = radix__arch_get_unmapped_area;
-	} else {
-		mm->mmap_base = mmap_base(random_factor, rlim_stack);
-		mm->get_unmapped_area = radix__arch_get_unmapped_area_topdown;
-	}
-}
-#else
-/* dummy */
-extern void radix__arch_pick_mmap_layout(struct mm_struct *mm,
-					unsigned long random_factor,
-					struct rlimit *rlim_stack);
-#endif
 /*
  * This function, called very early during the creation of a new
  * process VM image, sets up which VM layout function to use:
@@ -211,9 +91,6 @@ void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
 	if (current->flags & PF_RANDOMIZE)
 		random_factor = arch_mmap_rnd();
 
-	if (radix_enabled())
-		return radix__arch_pick_mmap_layout(mm, random_factor,
-						    rlim_stack);
 	/*
 	 * Fall back to the standard layout if the personality
 	 * bit is set, or if the expected stack growth is unlimited:
-- 
2.33.1

[PATCH v2 6/9] mm: Allow arch specific arch_randomize_brk() with CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT

[Christophe Leroy]

Commit e7142bf5d231 ("arm64, mm: make randomization selected by
generic topdown mmap layout") introduced a default version of
arch_randomize_brk() provided when
CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT is selected.

powerpc could select CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
but needs to provide its own arch_randomize_brk().

In order to allow that, define generic version of arch_randomize_brk()
as a __weak symbol.

Cc: Alexandre Ghiti <alex@ghiti.fr>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v2: Make the generic version of it a __weak symbol instead of a messy play with CONFIG_ items.
---
 mm/util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/util.c b/mm/util.c
index e58151a61255..7eb69f697b38 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -344,7 +344,7 @@ unsigned long randomize_stack_top(unsigned long stack_top)
 }
 
 #ifdef CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
-unsigned long arch_randomize_brk(struct mm_struct *mm)
+unsigned long __weak arch_randomize_brk(struct mm_struct *mm)
 {
 	/* Is the current task 32bit ? */
 	if (!IS_ENABLED(CONFIG_64BIT) || is_compat_task())
-- 
2.33.1

[PATCH v2 7/9] powerpc/mm: Convert to default topdown mmap layout

[Christophe Leroy]

Select CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT and
remove arch/powerpc/mm/mmap.c

This change provides standard randomisation of mmaps.

See commit 8b8addf891de ("x86/mm/32: Enable full randomization on i386
and X86_32") for all the benefits of mmap randomisation.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v2: Also remove selection of ARCH_HAS_ELF_RANDOMIZE as it is already selected by CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
---
 arch/powerpc/Kconfig                 |   2 +-
 arch/powerpc/include/asm/processor.h |   2 -
 arch/powerpc/mm/Makefile             |   2 +-
 arch/powerpc/mm/mmap.c               | 105 ---------------------------
 4 files changed, 2 insertions(+), 109 deletions(-)
 delete mode 100644 arch/powerpc/mm/mmap.c

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index dea74d7717c0..f2d02d462558 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -122,7 +122,6 @@ config PPC
 	select ARCH_HAS_DEBUG_WX		if STRICT_KERNEL_RWX
 	select ARCH_HAS_DEVMEM_IS_ALLOWED
 	select ARCH_HAS_DMA_MAP_DIRECT 		if PPC_PSERIES
-	select ARCH_HAS_ELF_RANDOMIZE
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_HUGEPD			if HUGETLB_PAGE
@@ -158,6 +157,7 @@ config PPC
 	select ARCH_USE_MEMTEST
 	select ARCH_USE_QUEUED_RWLOCKS		if PPC_QUEUED_SPINLOCKS
 	select ARCH_USE_QUEUED_SPINLOCKS	if PPC_QUEUED_SPINLOCKS
+	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
 	select ARCH_WANT_LD_ORPHAN_WARN
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index e39bd0ff69f3..d906b14dd599 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -378,8 +378,6 @@ static inline void prefetchw(const void *x)
 
 #define spin_lock_prefetch(x)	prefetchw(x)
 
-#define HAVE_ARCH_PICK_MMAP_LAYOUT
-
 /* asm stubs */
 extern unsigned long isa300_idle_stop_noloss(unsigned long psscr_val);
 extern unsigned long isa300_idle_stop_mayloss(unsigned long psscr_val);
diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
index d4c20484dad9..503a6e249940 100644
--- a/arch/powerpc/mm/Makefile
+++ b/arch/powerpc/mm/Makefile
@@ -5,7 +5,7 @@
 
 ccflags-$(CONFIG_PPC64)	:= $(NO_MINIMAL_TOC)
 
-obj-y				:= fault.o mem.o pgtable.o mmap.o maccess.o pageattr.o \
+obj-y				:= fault.o mem.o pgtable.o maccess.o pageattr.o \
 				   init_$(BITS).o pgtable_$(BITS).o \
 				   pgtable-frag.o ioremap.o ioremap_$(BITS).o \
 				   init-common.o mmu_context.o drmem.o \
diff --git a/arch/powerpc/mm/mmap.c b/arch/powerpc/mm/mmap.c
deleted file mode 100644
index 5972d619d274..000000000000
--- a/arch/powerpc/mm/mmap.c
+++ /dev/null
@@ -1,105 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- *  flexible mmap layout support
- *
- * Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
- * All Rights Reserved.
- *
- * Started by Ingo Molnar <mingo@elte.hu>
- */
-
-#include <linux/personality.h>
-#include <linux/mm.h>
-#include <linux/random.h>
-#include <linux/sched/signal.h>
-#include <linux/sched/mm.h>
-#include <linux/elf-randomize.h>
-#include <linux/security.h>
-#include <linux/mman.h>
-
-/*
- * Top of mmap area (just below the process stack).
- *
- * Leave at least a ~128 MB hole.
- */
-#define MIN_GAP (128*1024*1024)
-#define MAX_GAP (TASK_SIZE/6*5)
-
-static inline int mmap_is_legacy(struct rlimit *rlim_stack)
-{
-	if (current->personality & ADDR_COMPAT_LAYOUT)
-		return 1;
-
-	if (rlim_stack->rlim_cur == RLIM_INFINITY)
-		return 1;
-
-	return sysctl_legacy_va_layout;
-}
-
-unsigned long arch_mmap_rnd(void)
-{
-	unsigned long shift, rnd;
-
-	shift = mmap_rnd_bits;
-#ifdef CONFIG_COMPAT
-	if (is_32bit_task())
-		shift = mmap_rnd_compat_bits;
-#endif
-	rnd = get_random_long() % (1ul << shift);
-
-	return rnd << PAGE_SHIFT;
-}
-
-static inline unsigned long stack_maxrandom_size(void)
-{
-	if (!(current->flags & PF_RANDOMIZE))
-		return 0;
-
-	/* 8MB for 32bit, 1GB for 64bit */
-	if (is_32bit_task())
-		return (1<<23);
-	else
-		return (1<<30);
-}
-
-static inline unsigned long mmap_base(unsigned long rnd,
-				      struct rlimit *rlim_stack)
-{
-	unsigned long gap = rlim_stack->rlim_cur;
-	unsigned long pad = stack_maxrandom_size() + stack_guard_gap;
-
-	/* Values close to RLIM_INFINITY can overflow. */
-	if (gap + pad > gap)
-		gap += pad;
-
-	if (gap < MIN_GAP)
-		gap = MIN_GAP;
-	else if (gap > MAX_GAP)
-		gap = MAX_GAP;
-
-	return PAGE_ALIGN(DEFAULT_MAP_WINDOW - gap - rnd);
-}
-
-/*
- * This function, called very early during the creation of a new
- * process VM image, sets up which VM layout function to use:
- */
-void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
-{
-	unsigned long random_factor = 0UL;
-
-	if (current->flags & PF_RANDOMIZE)
-		random_factor = arch_mmap_rnd();
-
-	/*
-	 * Fall back to the standard layout if the personality
-	 * bit is set, or if the expected stack growth is unlimited:
-	 */
-	if (mmap_is_legacy(rlim_stack)) {
-		mm->mmap_base = TASK_UNMAPPED_BASE;
-		mm->get_unmapped_area = arch_get_unmapped_area;
-	} else {
-		mm->mmap_base = mmap_base(random_factor, rlim_stack);
-		mm->get_unmapped_area = arch_get_unmapped_area_topdown;
-	}
-}
-- 
2.33.1

[PATCH v2 8/9] powerpc/mm: Properly randomise mmap with slices

[Christophe Leroy]

Now that powerpc switched to default topdown mmap layout,
mm->mmap_base is properly randomised.  However
slice_find_area_bottomup() doesn't use mm->mmap_base but
uses the fixed TASK_UNMAPPED_BASE instead.

slice_find_area_bottomup() being used as a fallback to
slice_find_area_topdown(), it can't use mm->mmap_base
directly.

Instead of always using TASK_UNMAPPED_BASE as base address, leave
it to the caller. When called from slice_find_area_topdown()
TASK_UNMAPPED_BASE is used. Otherwise mm->mmap_base is used.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/mm/book3s64/slice.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/mm/book3s64/slice.c b/arch/powerpc/mm/book3s64/slice.c
index 99742dde811c..997f40184e97 100644
--- a/arch/powerpc/mm/book3s64/slice.c
+++ b/arch/powerpc/mm/book3s64/slice.c
@@ -276,20 +276,18 @@ static bool slice_scan_available(unsigned long addr,
 }
 
 static unsigned long slice_find_area_bottomup(struct mm_struct *mm,
-					      unsigned long len,
+					      unsigned long addr, unsigned long len,
 					      const struct slice_mask *available,
 					      int psize, unsigned long high_limit)
 {
 	int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
-	unsigned long addr, found, next_end;
+	unsigned long found, next_end;
 	struct vm_unmapped_area_info info;
 
 	info.flags = 0;
 	info.length = len;
 	info.align_mask = PAGE_MASK & ((1ul << pshift) - 1);
 	info.align_offset = 0;
-
-	addr = TASK_UNMAPPED_BASE;
 	/*
 	 * Check till the allow max value for this mmap request
 	 */
@@ -322,12 +320,12 @@ static unsigned long slice_find_area_bottomup(struct mm_struct *mm,
 }
 
 static unsigned long slice_find_area_topdown(struct mm_struct *mm,
-					     unsigned long len,
+					     unsigned long addr, unsigned long len,
 					     const struct slice_mask *available,
 					     int psize, unsigned long high_limit)
 {
 	int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
-	unsigned long addr, found, prev;
+	unsigned long found, prev;
 	struct vm_unmapped_area_info info;
 	unsigned long min_addr = max(PAGE_SIZE, mmap_min_addr);
 
@@ -335,8 +333,6 @@ static unsigned long slice_find_area_topdown(struct mm_struct *mm,
 	info.length = len;
 	info.align_mask = PAGE_MASK & ((1ul << pshift) - 1);
 	info.align_offset = 0;
-
-	addr = mm->mmap_base;
 	/*
 	 * If we are trying to allocate above DEFAULT_MAP_WINDOW
 	 * Add the different to the mmap_base.
@@ -377,7 +373,7 @@ static unsigned long slice_find_area_topdown(struct mm_struct *mm,
 	 * can happen with large stack limits and large mmap()
 	 * allocations.
 	 */
-	return slice_find_area_bottomup(mm, len, available, psize, high_limit);
+	return slice_find_area_bottomup(mm, TASK_UNMAPPED_BASE, len, available, psize, high_limit);
 }
 
 
@@ -386,9 +382,9 @@ static unsigned long slice_find_area(struct mm_struct *mm, unsigned long len,
 				     int topdown, unsigned long high_limit)
 {
 	if (topdown)
-		return slice_find_area_topdown(mm, len, mask, psize, high_limit);
+		return slice_find_area_topdown(mm, mm->mmap_base, len, mask, psize, high_limit);
 	else
-		return slice_find_area_bottomup(mm, len, mask, psize, high_limit);
+		return slice_find_area_bottomup(mm, mm->mmap_base, len, mask, psize, high_limit);
 }
 
 static inline void slice_copy_mask(struct slice_mask *dst,
-- 
2.33.1

[PATCH v2 9/9] powerpc: Simplify and move arch_randomize_brk()

[Christophe Leroy]

arch_randomize_brk() is only needed for hash on book3s/64, for other
platforms the one provided by the default mmap layout is good enough.

Move it to hash_utils.c and use randomize_page() like the generic one.

And properly opt out the radix case instead of making an assumption
on mmu_highuser_ssize.

Also change to a 32M range like most other architectures instead of 8M.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v2: New
---
 arch/powerpc/kernel/process.c         | 40 ---------------------------
 arch/powerpc/mm/book3s64/hash_utils.c | 18 ++++++++++++
 include/linux/sizes.h                 |  2 ++
 3 files changed, 20 insertions(+), 40 deletions(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 406d7ee9e322..f1f2f17543d6 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -2274,43 +2274,3 @@ unsigned long arch_align_stack(unsigned long sp)
 		sp -= get_random_int() & ~PAGE_MASK;
 	return sp & ~0xf;
 }
-
-static inline unsigned long brk_rnd(void)
-{
-        unsigned long rnd = 0;
-
-	/* 8MB for 32bit, 1GB for 64bit */
-	if (is_32bit_task())
-		rnd = (get_random_long() % (1UL<<(23-PAGE_SHIFT)));
-	else
-		rnd = (get_random_long() % (1UL<<(30-PAGE_SHIFT)));
-
-	return rnd << PAGE_SHIFT;
-}
-
-unsigned long arch_randomize_brk(struct mm_struct *mm)
-{
-	unsigned long base = mm->brk;
-	unsigned long ret;
-
-#ifdef CONFIG_PPC_BOOK3S_64
-	/*
-	 * If we are using 1TB segments and we are allowed to randomise
-	 * the heap, we can put it above 1TB so it is backed by a 1TB
-	 * segment. Otherwise the heap will be in the bottom 1TB
-	 * which always uses 256MB segments and this may result in a
-	 * performance penalty. We don't need to worry about radix. For
-	 * radix, mmu_highuser_ssize remains unchanged from 256MB.
-	 */
-	if (!is_32bit_task() && (mmu_highuser_ssize == MMU_SEGSIZE_1T))
-		base = max_t(unsigned long, mm->brk, 1UL << SID_SHIFT_1T);
-#endif
-
-	ret = PAGE_ALIGN(base + brk_rnd());
-
-	if (ret < mm->brk)
-		return mm->brk;
-
-	return ret;
-}
-
diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
index 1d09d4aeddbf..3521fad6a479 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c
@@ -37,6 +37,7 @@
 #include <linux/cpu.h>
 #include <linux/pgtable.h>
 #include <linux/debugfs.h>
+#include <linux/random.h>
 
 #include <asm/interrupt.h>
 #include <asm/processor.h>
@@ -2072,3 +2073,20 @@ void __init print_system_hash_info(void)
 	if (htab_hash_mask)
 		pr_info("htab_hash_mask    = 0x%lx\n", htab_hash_mask);
 }
+
+unsigned long arch_randomize_brk(struct mm_struct *mm)
+{
+	/*
+	 * If we are using 1TB segments and we are allowed to randomise
+	 * the heap, we can put it above 1TB so it is backed by a 1TB
+	 * segment. Otherwise the heap will be in the bottom 1TB
+	 * which always uses 256MB segments and this may result in a
+	 * performance penalty.
+	 */
+	if (is_32bit_task())
+		return randomize_page(mm->brk, SZ_32M);
+	else if (!radix_enabled() && mmu_highuser_ssize == MMU_SEGSIZE_1T)
+		return randomize_page(max_t(unsigned long, mm->brk, SZ_1T), SZ_1G);
+	else
+		return randomize_page(mm->brk, SZ_1G);
+}
diff --git a/include/linux/sizes.h b/include/linux/sizes.h
index 1ac79bcee2bb..84aa448d8bb3 100644
--- a/include/linux/sizes.h
+++ b/include/linux/sizes.h
@@ -47,6 +47,8 @@
 #define SZ_8G				_AC(0x200000000, ULL)
 #define SZ_16G				_AC(0x400000000, ULL)
 #define SZ_32G				_AC(0x800000000, ULL)
+
+#define SZ_1T				_AC(0x10000000000, ULL)
 #define SZ_64T				_AC(0x400000000000, ULL)
 
 #endif /* __LINUX_SIZES_H__ */
-- 
2.33.1

Re: [PATCH v2 9/9] powerpc: Simplify and move arch_randomize_brk()

[Christophe Leroy]

Le 25/11/2021 à 09:23, Christophe Leroy a écrit :
> arch_randomize_brk() is only needed for hash on book3s/64, for other
> platforms the one provided by the default mmap layout is good enough.
> 
> Move it to hash_utils.c and use randomize_page() like the generic one.
> 
> And properly opt out the radix case instead of making an assumption
> on mmu_highuser_ssize.
> 
> Also change to a 32M range like most other architectures instead of 8M.
> 
> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> ---
> v2: New
> ---
>   arch/powerpc/kernel/process.c         | 40 ---------------------------
>   arch/powerpc/mm/book3s64/hash_utils.c | 18 ++++++++++++
>   include/linux/sizes.h                 |  2 ++
>   3 files changed, 20 insertions(+), 40 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
> index 406d7ee9e322..f1f2f17543d6 100644
> --- a/arch/powerpc/kernel/process.c
> +++ b/arch/powerpc/kernel/process.c
> @@ -2274,43 +2274,3 @@ unsigned long arch_align_stack(unsigned long sp)
>   		sp -= get_random_int() & ~PAGE_MASK;
>   	return sp & ~0xf;
>   }
> -
> -static inline unsigned long brk_rnd(void)
> -{
> -        unsigned long rnd = 0;
> -
> -	/* 8MB for 32bit, 1GB for 64bit */
> -	if (is_32bit_task())
> -		rnd = (get_random_long() % (1UL<<(23-PAGE_SHIFT)));
> -	else
> -		rnd = (get_random_long() % (1UL<<(30-PAGE_SHIFT)));
> -
> -	return rnd << PAGE_SHIFT;
> -}
> -
> -unsigned long arch_randomize_brk(struct mm_struct *mm)
> -{
> -	unsigned long base = mm->brk;
> -	unsigned long ret;
> -
> -#ifdef CONFIG_PPC_BOOK3S_64
> -	/*
> -	 * If we are using 1TB segments and we are allowed to randomise
> -	 * the heap, we can put it above 1TB so it is backed by a 1TB
> -	 * segment. Otherwise the heap will be in the bottom 1TB
> -	 * which always uses 256MB segments and this may result in a
> -	 * performance penalty. We don't need to worry about radix. For
> -	 * radix, mmu_highuser_ssize remains unchanged from 256MB.
> -	 */
> -	if (!is_32bit_task() && (mmu_highuser_ssize == MMU_SEGSIZE_1T))
> -		base = max_t(unsigned long, mm->brk, 1UL << SID_SHIFT_1T);
> -#endif
> -
> -	ret = PAGE_ALIGN(base + brk_rnd());
> -
> -	if (ret < mm->brk)
> -		return mm->brk;
> -
> -	return ret;
> -}
> -
> diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
> index 1d09d4aeddbf..3521fad6a479 100644
> --- a/arch/powerpc/mm/book3s64/hash_utils.c
> +++ b/arch/powerpc/mm/book3s64/hash_utils.c
> @@ -37,6 +37,7 @@
>   #include <linux/cpu.h>
>   #include <linux/pgtable.h>
>   #include <linux/debugfs.h>
> +#include <linux/random.h>

Also need <linux/elf-randomize.h> to get the declaration of 
arch_randomize_brk() and make sparse happy :)

Michael can you add it if you apply this version ?

Thanks

>   
>   #include <asm/interrupt.h>
>   #include <asm/processor.h>
> @@ -2072,3 +2073,20 @@ void __init print_system_hash_info(void)
>   	if (htab_hash_mask)
>   		pr_info("htab_hash_mask    = 0x%lx\n", htab_hash_mask);
>   }
> +
> +unsigned long arch_randomize_brk(struct mm_struct *mm)
> +{
> +	/*
> +	 * If we are using 1TB segments and we are allowed to randomise
> +	 * the heap, we can put it above 1TB so it is backed by a 1TB
> +	 * segment. Otherwise the heap will be in the bottom 1TB
> +	 * which always uses 256MB segments and this may result in a
> +	 * performance penalty.
> +	 */
> +	if (is_32bit_task())
> +		return randomize_page(mm->brk, SZ_32M);
> +	else if (!radix_enabled() && mmu_highuser_ssize == MMU_SEGSIZE_1T)
> +		return randomize_page(max_t(unsigned long, mm->brk, SZ_1T), SZ_1G);
> +	else
> +		return randomize_page(mm->brk, SZ_1G);
> +}
> diff --git a/include/linux/sizes.h b/include/linux/sizes.h
> index 1ac79bcee2bb..84aa448d8bb3 100644
> --- a/include/linux/sizes.h
> +++ b/include/linux/sizes.h
> @@ -47,6 +47,8 @@
>   #define SZ_8G				_AC(0x200000000, ULL)
>   #define SZ_16G				_AC(0x400000000, ULL)
>   #define SZ_32G				_AC(0x800000000, ULL)
> +
> +#define SZ_1T				_AC(0x10000000000, ULL)
>   #define SZ_64T				_AC(0x400000000000, ULL)
>   
>   #endif /* __LINUX_SIZES_H__ */
> 

Re: [PATCH v2 9/9] powerpc: Simplify and move arch_randomize_brk()

[kernel test robot]

Hi Christophe,

I love your patch! Perhaps something to improve:

[auto build test WARNING on powerpc/next]
[also build test WARNING on hnaz-mm/master linus/master v5.16-rc2 next-20211125]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Christophe-Leroy/Convert-powerpc-to-default-topdown-mmap-layout/20211125-162916
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: riscv-allyesconfig (https://download.01.org/0day-ci/archive/20211126/202111260844.kcgKX5Uk-lkp@intel.com/config)
compiler: riscv64-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/554c475dfb73dc352708dff3589b55845b3dd751
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Christophe-Leroy/Convert-powerpc-to-default-topdown-mmap-layout/20211125-162916
        git checkout 554c475dfb73dc352708dff3589b55845b3dd751
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=riscv SHELL=/bin/bash drivers/net/wireless/mediatek/mt76/mt7915/ drivers/pci/controller/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> drivers/pci/controller/pci-xgene.c:52: warning: "SZ_1T" redefined
      52 | #define SZ_1T                           (SZ_1G*1024ULL)
         | 
   In file included from arch/riscv/include/asm/pgtable.h:10,
                    from include/linux/pgtable.h:6,
                    from arch/riscv/include/asm/io.h:15,
                    from include/linux/io.h:13,
                    from drivers/pci/controller/pci-xgene.c:11:
   include/linux/sizes.h:51: note: this is the location of the previous definition
      51 | #define SZ_1T                           _AC(0x10000000000, ULL)
         | 


vim +/SZ_1T +52 drivers/pci/controller/pci-xgene.c

5f6b6ccdbe1cdfa drivers/pci/host/pci-xgene.c Tanmay Inamdar 2014-10-01  45  
5f6b6ccdbe1cdfa drivers/pci/host/pci-xgene.c Tanmay Inamdar 2014-10-01  46  #define LINK_UP_MASK			0x00000100
5f6b6ccdbe1cdfa drivers/pci/host/pci-xgene.c Tanmay Inamdar 2014-10-01  47  #define AXI_EP_CFG_ACCESS		0x10000
5f6b6ccdbe1cdfa drivers/pci/host/pci-xgene.c Tanmay Inamdar 2014-10-01  48  #define EN_COHERENCY			0xF0000000
5f6b6ccdbe1cdfa drivers/pci/host/pci-xgene.c Tanmay Inamdar 2014-10-01  49  #define EN_REG				0x00000001
5f6b6ccdbe1cdfa drivers/pci/host/pci-xgene.c Tanmay Inamdar 2014-10-01  50  #define OB_LO_IO			0x00000002
5f6b6ccdbe1cdfa drivers/pci/host/pci-xgene.c Tanmay Inamdar 2014-10-01  51  #define XGENE_PCIE_DEVICEID		0xE004
5f6b6ccdbe1cdfa drivers/pci/host/pci-xgene.c Tanmay Inamdar 2014-10-01 @52  #define SZ_1T				(SZ_1G*1024ULL)
5f6b6ccdbe1cdfa drivers/pci/host/pci-xgene.c Tanmay Inamdar 2014-10-01  53  #define PIPE_PHY_RATE_RD(src)		((0xc000 & (u32)(src)) >> 0xe)
5f6b6ccdbe1cdfa drivers/pci/host/pci-xgene.c Tanmay Inamdar 2014-10-01  54  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

Re: [PATCH v2 9/9] powerpc: Simplify and move arch_randomize_brk()

[kernel test robot]

Hi Christophe,

I love your patch! Perhaps something to improve:

[auto build test WARNING on powerpc/next]
[also build test WARNING on hnaz-mm/master linus/master v5.16-rc2 next-20211126]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Christophe-Leroy/Convert-powerpc-to-default-topdown-mmap-layout/20211125-162916
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc64-buildonly-randconfig-r006-20211125 (https://download.01.org/0day-ci/archive/20211127/202111270342.b1Y85fuz-lkp@intel.com/config)
compiler: powerpc64-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/554c475dfb73dc352708dff3589b55845b3dd751
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Christophe-Leroy/Convert-powerpc-to-default-topdown-mmap-layout/20211125-162916
        git checkout 554c475dfb73dc352708dff3589b55845b3dd751
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=powerpc SHELL=/bin/bash arch/powerpc/mm/book3s64/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> arch/powerpc/mm/book3s64/hash_utils.c:2077:15: warning: no previous prototype for 'arch_randomize_brk' [-Wmissing-prototypes]
    2077 | unsigned long arch_randomize_brk(struct mm_struct *mm)
         |               ^~~~~~~~~~~~~~~~~~


vim +/arch_randomize_brk +2077 arch/powerpc/mm/book3s64/hash_utils.c

  2076	
> 2077	unsigned long arch_randomize_brk(struct mm_struct *mm)

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org