[PATCH v4 1/6] mm, x86: Add ARCH_HAS_ZONE_DEVICE to Kconfig

[PATCH v4 1/6] mm, x86: Add ARCH_HAS_ZONE_DEVICE to Kconfig

[Oliver O'Halloran]

Currently ZONE_DEVICE depends on X86_64 and this will get unwieldly as
new architectures (and platforms) get ZONE_DEVICE support. Move to an
arch selected Kconfig option to save us the trouble.

Cc: linux-mm@kvack.org
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
---
Andew, the rest of the series should be going in via the ppc tree, but
since there's nothing ppc specific about this patch do you want to
take it via mm?
--
v2: Added missing hunk.
---
 arch/x86/Kconfig | 1 +
 mm/Kconfig       | 6 +++++-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 37a14d7a4e3f..569e39a8293d 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -61,6 +61,7 @@ config X86
 	select ARCH_HAS_STRICT_KERNEL_RWX
 	select ARCH_HAS_STRICT_MODULE_RWX
 	select ARCH_HAS_UBSAN_SANITIZE_ALL
+	select ARCH_HAS_ZONE_DEVICE		if X86_64
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
 	select ARCH_MIGHT_HAVE_PC_PARPORT
diff --git a/mm/Kconfig b/mm/Kconfig
index 5027cbc251f9..48b1af447fa7 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -668,12 +668,16 @@ config IDLE_PAGE_TRACKING
 
 	  See Documentation/vm/idle_page_tracking.txt for more details.
 
+# arch_add_memory() comprehends device memory
+config ARCH_HAS_ZONE_DEVICE
+	bool
+
 config ZONE_DEVICE
 	bool "Device memory (pmem, etc...) hotplug support"
 	depends on MEMORY_HOTPLUG
 	depends on MEMORY_HOTREMOVE
 	depends on SPARSEMEM_VMEMMAP
-	depends on X86_64 #arch_add_memory() comprehends device memory
+	depends on ARCH_HAS_ZONE_DEVICE
 
 	help
 	  Device memory hotplug support allows for establishing pmem,
-- 
2.9.4

[PATCH v4 2/6] powerpc/vmemmap: Reshuffle vmemmap_free()

[Oliver O'Halloran]

Removes an indentation level and shuffles some code around to make the
following patch cleaner. No functional changes.

Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
---
v1 -> v2: Remove broken initialiser
---
 arch/powerpc/mm/init_64.c | 48 ++++++++++++++++++++++++-----------------------
 1 file changed, 25 insertions(+), 23 deletions(-)

diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index ec84b31c6c86..8851e4f5dbab 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -234,13 +234,15 @@ static unsigned long vmemmap_list_free(unsigned long start)
 void __ref vmemmap_free(unsigned long start, unsigned long end)
 {
 	unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
+	unsigned long page_order = get_order(page_size);
 
 	start = _ALIGN_DOWN(start, page_size);
 
 	pr_debug("vmemmap_free %lx...%lx\n", start, end);
 
 	for (; start < end; start += page_size) {
-		unsigned long addr;
+		unsigned long nr_pages, addr;
+		struct page *page;
 
 		/*
 		 * the section has already be marked as invalid, so
@@ -251,29 +253,29 @@ void __ref vmemmap_free(unsigned long start, unsigned long end)
 			continue;
 
 		addr = vmemmap_list_free(start);
-		if (addr) {
-			struct page *page = pfn_to_page(addr >> PAGE_SHIFT);
-
-			if (PageReserved(page)) {
-				/* allocated from bootmem */
-				if (page_size < PAGE_SIZE) {
-					/*
-					 * this shouldn't happen, but if it is
-					 * the case, leave the memory there
-					 */
-					WARN_ON_ONCE(1);
-				} else {
-					unsigned int nr_pages =
-						1 << get_order(page_size);
-					while (nr_pages--)
-						free_reserved_page(page++);
-				}
-			} else
-				free_pages((unsigned long)(__va(addr)),
-							get_order(page_size));
-
-			vmemmap_remove_mapping(start, page_size);
+		if (!addr)
+			continue;
+
+		page = pfn_to_page(addr >> PAGE_SHIFT);
+		nr_pages = 1 << page_order;
+
+		if (PageReserved(page)) {
+			/* allocated from bootmem */
+			if (page_size < PAGE_SIZE) {
+				/*
+				 * this shouldn't happen, but if it is
+				 * the case, leave the memory there
+				 */
+				WARN_ON_ONCE(1);
+			} else {
+				while (nr_pages--)
+					free_reserved_page(page++);
+			}
+		} else {
+			free_pages((unsigned long)(__va(addr)), page_order);
 		}
+
+		vmemmap_remove_mapping(start, page_size);
 	}
 }
 #endif
-- 
2.9.4

[PATCH v4 3/6] powerpc/vmemmap: Add altmap support

[Oliver O'Halloran]

Adds support to powerpc for the altmap feature of ZONE_DEVICE memory. An
altmap is a driver provided region that is used to provide the backing
storage for the struct pages of ZONE_DEVICE memory. In situations where
large amount of ZONE_DEVICE memory is being added to the system the
altmap reduces pressure on main system memory by allowing the mm/
metadata to be stored on the device itself rather in main memory.

Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
---
 arch/powerpc/mm/init_64.c | 15 +++++++++++++--
 arch/powerpc/mm/mem.c     | 16 +++++++++++++---
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 8851e4f5dbab..225fbb8034e6 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -44,6 +44,7 @@
 #include <linux/slab.h>
 #include <linux/of_fdt.h>
 #include <linux/libfdt.h>
+#include <linux/memremap.h>
 
 #include <asm/pgalloc.h>
 #include <asm/page.h>
@@ -171,13 +172,17 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
 	pr_debug("vmemmap_populate %lx..%lx, node %d\n", start, end, node);
 
 	for (; start < end; start += page_size) {
+		struct vmem_altmap *altmap;
 		void *p;
 		int rc;
 
 		if (vmemmap_populated(start, page_size))
 			continue;
 
-		p = vmemmap_alloc_block(page_size, node);
+		/* altmap lookups only work at section boundaries */
+		altmap = to_vmem_altmap(SECTION_ALIGN_DOWN(start));
+
+		p =  __vmemmap_alloc_block_buf(page_size, node, altmap);
 		if (!p)
 			return -ENOMEM;
 
@@ -242,6 +247,8 @@ void __ref vmemmap_free(unsigned long start, unsigned long end)
 
 	for (; start < end; start += page_size) {
 		unsigned long nr_pages, addr;
+		struct vmem_altmap *altmap;
+		struct page *section_base;
 		struct page *page;
 
 		/*
@@ -257,9 +264,13 @@ void __ref vmemmap_free(unsigned long start, unsigned long end)
 			continue;
 
 		page = pfn_to_page(addr >> PAGE_SHIFT);
+		section_base = pfn_to_page(vmemmap_section_start(start));
 		nr_pages = 1 << page_order;
 
-		if (PageReserved(page)) {
+		altmap = to_vmem_altmap((unsigned long) section_base);
+		if (altmap) {
+			vmem_altmap_free(altmap, nr_pages);
+		} else if (PageReserved(page)) {
 			/* allocated from bootmem */
 			if (page_size < PAGE_SIZE) {
 				/*
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 8e9bef964dbf..8541f18694a4 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -36,6 +36,7 @@
 #include <linux/hugetlb.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
+#include <linux/memremap.h>
 
 #include <asm/pgalloc.h>
 #include <asm/prom.h>
@@ -151,11 +152,20 @@ int arch_remove_memory(u64 start, u64 size)
 {
 	unsigned long start_pfn = start >> PAGE_SHIFT;
 	unsigned long nr_pages = size >> PAGE_SHIFT;
-	struct zone *zone;
+	struct vmem_altmap *altmap;
+	struct page *page;
 	int ret;
 
-	zone = page_zone(pfn_to_page(start_pfn));
-	ret = __remove_pages(zone, start_pfn, nr_pages);
+	/*
+	 * If we have an altmap then we need to skip over any reserved PFNs
+	 * when querying the zone.
+	 */
+	page = pfn_to_page(start_pfn);
+	altmap = to_vmem_altmap((unsigned long) page);
+	if (altmap)
+		page += vmem_altmap_offset(altmap);
+
+	ret = __remove_pages(page_zone(page), start_pfn, nr_pages);
 	if (ret)
 		return ret;
 
-- 
2.9.4

[PATCH v4 4/6] powerpc/mm: Add devmap support for ppc64

[Oliver O'Halloran]

Add support for the devmap bit on PTEs and PMDs for PPC64 Book3S.  This
is used to differentiate device backed memory from transparent huge
pages since they are handled in more or less the same manner by the core
mm code.

Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
---
v1 -> v2: Properly differentiate THP and PMD Devmap entries. The
mm core assumes that pmd_trans_huge() and pmd_devmap() are mutually
exclusive and v1 had pmd_trans_huge() being true on a devmap pmd.

v2 -> v3:
	Remove setting of _PAGE_SPECIAL in pmd_mkdevmap()
	Make pud_pfn() a BUILD_BUG()
	Remove unnecessary _PAGE_DEVMAP check in hash__pmd_trans_huge()

v3 -> v4:
	Moved pud_pfn() outside #ifdef THP. This is required to work
	around a build breakage.
---
 arch/powerpc/include/asm/book3s/64/pgtable.h | 45 ++++++++++++++++++++++++++++
 arch/powerpc/include/asm/book3s/64/radix.h   |  2 +-
 arch/powerpc/mm/hugetlbpage.c                |  2 +-
 arch/powerpc/mm/pgtable-book3s64.c           |  4 +--
 arch/powerpc/mm/pgtable-hash64.c             |  4 ++-
 arch/powerpc/mm/pgtable-radix.c              |  3 +-
 arch/powerpc/mm/pgtable_64.c                 |  2 +-
 7 files changed, 55 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 85bc9875c3be..c0737c86a362 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -5,6 +5,7 @@
 
 #ifndef __ASSEMBLY__
 #include <linux/mmdebug.h>
+#include <linux/bug.h>
 #endif
 
 /*
@@ -79,6 +80,9 @@
 
 #define _PAGE_SOFT_DIRTY	_RPAGE_SW3 /* software: software dirty tracking */
 #define _PAGE_SPECIAL		_RPAGE_SW2 /* software: special page */
+#define _PAGE_DEVMAP		_RPAGE_SW1 /* software: ZONE_DEVICE page */
+#define __HAVE_ARCH_PTE_DEVMAP
+
 /*
  * Drivers request for cache inhibited pte mapping using _PAGE_NO_CACHE
  * Instead of fixing all of them, add an alternate define which
@@ -599,6 +603,16 @@ static inline pte_t pte_mkhuge(pte_t pte)
 	return pte;
 }
 
+static inline pte_t pte_mkdevmap(pte_t pte)
+{
+	return __pte(pte_val(pte) | _PAGE_SPECIAL|_PAGE_DEVMAP);
+}
+
+static inline int pte_devmap(pte_t pte)
+{
+	return !!(pte_raw(pte) & cpu_to_be64(_PAGE_DEVMAP));
+}
+
 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 {
 	/* FIXME!! check whether this need to be a conditional */
@@ -1146,6 +1160,37 @@ static inline bool arch_needs_pgtable_deposit(void)
 	return true;
 }
 
+
+static inline pmd_t pmd_mkdevmap(pmd_t pmd)
+{
+	return __pmd(pmd_val(pmd) | (_PAGE_PTE | _PAGE_DEVMAP));
+}
+
+static inline int pmd_devmap(pmd_t pmd)
+{
+	return pte_devmap(pmd_pte(pmd));
+}
+
+static inline int pud_devmap(pud_t pud)
+{
+	return 0;
+}
+
+static inline int pgd_devmap(pgd_t pgd)
+{
+	return 0;
+}
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
+static inline const int pud_pfn(pud_t pud)
+{
+	/*
+	 * Currently all calls to pud_pfn() are gated around a pud_devmap()
+	 * check so this should never be used. If it grows another user we
+	 * want to know about it.
+	 */
+	BUILD_BUG();
+	return 0;
+}
 #endif /* __ASSEMBLY__ */
 #endif /* _ASM_POWERPC_BOOK3S_64_PGTABLE_H_ */
diff --git a/arch/powerpc/include/asm/book3s/64/radix.h b/arch/powerpc/include/asm/book3s/64/radix.h
index ac16d1943022..ba43754e96d2 100644
--- a/arch/powerpc/include/asm/book3s/64/radix.h
+++ b/arch/powerpc/include/asm/book3s/64/radix.h
@@ -252,7 +252,7 @@ static inline int radix__pgd_bad(pgd_t pgd)
 
 static inline int radix__pmd_trans_huge(pmd_t pmd)
 {
-	return !!(pmd_val(pmd) & _PAGE_PTE);
+	return (pmd_val(pmd) & (_PAGE_PTE | _PAGE_DEVMAP)) == _PAGE_PTE;
 }
 
 static inline pmd_t radix__pmd_mkhuge(pmd_t pmd)
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index ceeab69cf7fc..5c4645e73cc8 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -945,7 +945,7 @@ pte_t *__find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
 			if (pmd_none(pmd))
 				return NULL;
 
-			if (pmd_trans_huge(pmd)) {
+			if (pmd_trans_huge(pmd) || pmd_devmap(pmd)) {
 				if (is_thp)
 					*is_thp = true;
 				ret_pte = (pte_t *) pmdp;
diff --git a/arch/powerpc/mm/pgtable-book3s64.c b/arch/powerpc/mm/pgtable-book3s64.c
index 5fcb3dd74c13..31eed8fa8e99 100644
--- a/arch/powerpc/mm/pgtable-book3s64.c
+++ b/arch/powerpc/mm/pgtable-book3s64.c
@@ -32,7 +32,7 @@ int pmdp_set_access_flags(struct vm_area_struct *vma, unsigned long address,
 {
 	int changed;
 #ifdef CONFIG_DEBUG_VM
-	WARN_ON(!pmd_trans_huge(*pmdp));
+	WARN_ON(!pmd_trans_huge(*pmdp) && !pmd_devmap(*pmdp));
 	assert_spin_locked(&vma->vm_mm->page_table_lock);
 #endif
 	changed = !pmd_same(*(pmdp), entry);
@@ -59,7 +59,7 @@ void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 #ifdef CONFIG_DEBUG_VM
 	WARN_ON(pte_present(pmd_pte(*pmdp)) && !pte_protnone(pmd_pte(*pmdp)));
 	assert_spin_locked(&mm->page_table_lock);
-	WARN_ON(!pmd_trans_huge(pmd));
+	WARN_ON(!(pmd_trans_huge(pmd) || pmd_devmap(pmd)));
 #endif
 	trace_hugepage_set_pmd(addr, pmd_val(pmd));
 	return set_pte_at(mm, addr, pmdp_ptep(pmdp), pmd_pte(pmd));
diff --git a/arch/powerpc/mm/pgtable-hash64.c b/arch/powerpc/mm/pgtable-hash64.c
index 8b85a14b08ea..7456cde4dbce 100644
--- a/arch/powerpc/mm/pgtable-hash64.c
+++ b/arch/powerpc/mm/pgtable-hash64.c
@@ -109,7 +109,7 @@ unsigned long hash__pmd_hugepage_update(struct mm_struct *mm, unsigned long addr
 	unsigned long old;
 
 #ifdef CONFIG_DEBUG_VM
-	WARN_ON(!pmd_trans_huge(*pmdp));
+	WARN_ON(!hash__pmd_trans_huge(*pmdp) && !pmd_devmap(*pmdp));
 	assert_spin_locked(&mm->page_table_lock);
 #endif
 
@@ -141,6 +141,7 @@ pmd_t hash__pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long addres
 
 	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 	VM_BUG_ON(pmd_trans_huge(*pmdp));
+	VM_BUG_ON(pmd_devmap(*pmdp));
 
 	pmd = *pmdp;
 	pmd_clear(pmdp);
@@ -221,6 +222,7 @@ void hash__pmdp_huge_split_prepare(struct vm_area_struct *vma,
 {
 	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 	VM_BUG_ON(REGION_ID(address) != USER_REGION_ID);
+	VM_BUG_ON(pmd_devmap(*pmdp));
 
 	/*
 	 * We can't mark the pmd none here, because that will cause a race
diff --git a/arch/powerpc/mm/pgtable-radix.c b/arch/powerpc/mm/pgtable-radix.c
index 6c062f92b9e4..5bf40e7ff448 100644
--- a/arch/powerpc/mm/pgtable-radix.c
+++ b/arch/powerpc/mm/pgtable-radix.c
@@ -691,7 +691,7 @@ unsigned long radix__pmd_hugepage_update(struct mm_struct *mm, unsigned long add
 	unsigned long old;
 
 #ifdef CONFIG_DEBUG_VM
-	WARN_ON(!radix__pmd_trans_huge(*pmdp));
+	WARN_ON(!radix__pmd_trans_huge(*pmdp) && !pmd_devmap(*pmdp));
 	assert_spin_locked(&mm->page_table_lock);
 #endif
 
@@ -709,6 +709,7 @@ pmd_t radix__pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long addre
 
 	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 	VM_BUG_ON(radix__pmd_trans_huge(*pmdp));
+	VM_BUG_ON(pmd_devmap(*pmdp));
 	/*
 	 * khugepaged calls this for normal pmd
 	 */
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index 8d2d6742a465..b792ea537b1c 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -323,7 +323,7 @@ struct page *pud_page(pud_t pud)
  */
 struct page *pmd_page(pmd_t pmd)
 {
-	if (pmd_trans_huge(pmd) || pmd_huge(pmd))
+	if (pmd_trans_huge(pmd) || pmd_huge(pmd) || pmd_devmap(pmd))
 		return pte_page(pmd_pte(pmd));
 	return virt_to_page(pmd_page_vaddr(pmd));
 }
-- 
2.9.4

[PATCH v4 5/6] powerpc/mm: Wire up hpte_removebolted for powernv

[Oliver O'Halloran]

From: Anton Blanchard <anton@samba.org>

Adds support for removing bolted (i.e kernel linear mapping) mappings on
powernv. This is needed to support memory hot unplug operations which
are required for the teardown of DAX/PMEM devices.

Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: Rashmica Gupta <rashmica.g@gmail.com>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
---
v1 -> v2: Fixed the commit author
          Added VM_WARN_ON() if we attempt to remove an unbolted hpte
---
 arch/powerpc/mm/hash_native_64.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/arch/powerpc/mm/hash_native_64.c b/arch/powerpc/mm/hash_native_64.c
index 65bb8f33b399..b534d041cfe8 100644
--- a/arch/powerpc/mm/hash_native_64.c
+++ b/arch/powerpc/mm/hash_native_64.c
@@ -407,6 +407,38 @@ static void native_hpte_updateboltedpp(unsigned long newpp, unsigned long ea,
 	tlbie(vpn, psize, psize, ssize, 0);
 }
 
+/*
+ * Remove a bolted kernel entry. Memory hotplug uses this.
+ *
+ * No need to lock here because we should be the only user.
+ */
+static int native_hpte_removebolted(unsigned long ea, int psize, int ssize)
+{
+	unsigned long vpn;
+	unsigned long vsid;
+	long slot;
+	struct hash_pte *hptep;
+
+	vsid = get_kernel_vsid(ea, ssize);
+	vpn = hpt_vpn(ea, vsid, ssize);
+
+	slot = native_hpte_find(vpn, psize, ssize);
+	if (slot == -1)
+		return -ENOENT;
+
+	hptep = htab_address + slot;
+
+	VM_WARN_ON(!(be64_to_cpu(hptep->v) & HPTE_V_BOLTED));
+
+	/* Invalidate the hpte */
+	hptep->v = 0;
+
+	/* Invalidate the TLB */
+	tlbie(vpn, psize, psize, ssize, 0);
+	return 0;
+}
+
+
 static void native_hpte_invalidate(unsigned long slot, unsigned long vpn,
 				   int bpsize, int apsize, int ssize, int local)
 {
@@ -725,6 +757,7 @@ void __init hpte_init_native(void)
 	mmu_hash_ops.hpte_invalidate	= native_hpte_invalidate;
 	mmu_hash_ops.hpte_updatepp	= native_hpte_updatepp;
 	mmu_hash_ops.hpte_updateboltedpp = native_hpte_updateboltedpp;
+	mmu_hash_ops.hpte_removebolted = native_hpte_removebolted;
 	mmu_hash_ops.hpte_insert	= native_hpte_insert;
 	mmu_hash_ops.hpte_remove	= native_hpte_remove;
 	mmu_hash_ops.hpte_clear_all	= native_hpte_clear;
-- 
2.9.4

[PATCH v4 6/6] powerpc/mm: Enable ZONE_DEVICE on powerpc

[Oliver O'Halloran]

Flip the switch. Running around and screaming "IT'S ALIVE" is optional,
but recommended.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
---
v3: Only select when building for 64bit Book3-S
---
 arch/powerpc/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index d556f9557f04..4526c9ba09b6 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -131,6 +131,7 @@ config PPC
 	select ARCH_HAS_SG_CHAIN
 	select ARCH_HAS_TICK_BROADCAST		if GENERIC_CLOCKEVENTS_BROADCAST
 	select ARCH_HAS_UBSAN_SANITIZE_ALL
+	select ARCH_HAS_ZONE_DEVICE		if PPC_BOOK3S_64
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select ARCH_MIGHT_HAVE_PC_PARPORT
 	select ARCH_MIGHT_HAVE_PC_SERIO
-- 
2.9.4

Re: [PATCH v4 1/6] mm, x86: Add ARCH_HAS_ZONE_DEVICE to Kconfig

[Michael Ellerman]

Oliver O'Halloran <oohall@gmail.com> writes:

> Currently ZONE_DEVICE depends on X86_64 and this will get unwieldly as
> new architectures (and platforms) get ZONE_DEVICE support. Move to an
> arch selected Kconfig option to save us the trouble.
>
> Cc: linux-mm@kvack.org
> Acked-by: Ingo Molnar <mingo@kernel.org>
> Acked-by: Balbir Singh <bsingharora@gmail.com>
> Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
> ---
> Andew, the rest of the series should be going in via the ppc tree, but
> since there's nothing ppc specific about this patch do you want to
> take it via mm?

Except without this patch none of the rest of the series can be tested
on powerpc, because the code doesn't go live until ARCH_HAS_ZONE_DEVICE
is wired up for powerpc.

So it'd be better if the series stayed together, wherever it goes. I'll
pick it up unless Andrew objects.

cheers

Re: [v4,1/6] mm, x86: Add ARCH_HAS_ZONE_DEVICE to Kconfig

[Michael Ellerman]

On Wed, 2017-06-28 at 01:32:31 UTC, Oliver O'Halloran wrote:
> Currently ZONE_DEVICE depends on X86_64 and this will get unwieldly as
> new architectures (and platforms) get ZONE_DEVICE support. Move to an
> arch selected Kconfig option to save us the trouble.
> 
> Cc: linux-mm@kvack.org
> Acked-by: Ingo Molnar <mingo@kernel.org>
> Acked-by: Balbir Singh <bsingharora@gmail.com>
> Signed-off-by: Oliver O'Halloran <oohall@gmail.com>

Series applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/65f7d049788763969180c72ef98dab

cheers