[PATCH AUTOSEL for 4.9 28/54] powerpc/mm: Fix memory hotplug BUG() on radix

From: alexander . levin
Date: Wed Nov 22 2017 - 18:20:00 EST


From: Reza Arbab <arbab@xxxxxxxxxxxxxxxxxx>

[ Upstream commit 32b53c012e0bfe20b2745962a89db0dc72ef3270 ]

Memory hotplug is leading to hash page table calls, even on radix:

arch_add_memory
create_section_mapping
htab_bolt_mapping
BUG_ON(!ppc_md.hpte_insert);

To fix, refactor {create,remove}_section_mapping() into hash__ and
radix__ variants. Leave the radix versions stubbed for now.

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Acked-by: Balbir Singh <bsingharora@xxxxxxxxx>
Signed-off-by: Reza Arbab <arbab@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
---
arch/powerpc/include/asm/book3s/64/hash.h | 4 ++++
arch/powerpc/mm/hash_utils_64.c | 4 ++--
arch/powerpc/mm/pgtable-book3s64.c | 18 ++++++++++++++++++
3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h
index f61cad3de4e6..4c935f7504f7 100644
--- a/arch/powerpc/include/asm/book3s/64/hash.h
+++ b/arch/powerpc/include/asm/book3s/64/hash.h
@@ -201,6 +201,10 @@ extern int __meminit hash__vmemmap_create_mapping(unsigned long start,
unsigned long phys);
extern void hash__vmemmap_remove_mapping(unsigned long start,
unsigned long page_size);
+
+int hash__create_section_mapping(unsigned long start, unsigned long end);
+int hash__remove_section_mapping(unsigned long start, unsigned long end);
+
#endif /* !__ASSEMBLY__ */
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_BOOK3S_64_HASH_H */
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 78dabf065ba9..bd666287c5ed 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -747,7 +747,7 @@ static unsigned long __init htab_get_table_size(void)
}

#ifdef CONFIG_MEMORY_HOTPLUG
-int create_section_mapping(unsigned long start, unsigned long end)
+int hash__create_section_mapping(unsigned long start, unsigned long end)
{
int rc = htab_bolt_mapping(start, end, __pa(start),
pgprot_val(PAGE_KERNEL), mmu_linear_psize,
@@ -761,7 +761,7 @@ int create_section_mapping(unsigned long start, unsigned long end)
return rc;
}

-int remove_section_mapping(unsigned long start, unsigned long end)
+int hash__remove_section_mapping(unsigned long start, unsigned long end)
{
int rc = htab_remove_mapping(start, end, mmu_linear_psize,
mmu_kernel_ssize);
diff --git a/arch/powerpc/mm/pgtable-book3s64.c b/arch/powerpc/mm/pgtable-book3s64.c
index f4f437cbabf1..0fad7f6742ff 100644
--- a/arch/powerpc/mm/pgtable-book3s64.c
+++ b/arch/powerpc/mm/pgtable-book3s64.c
@@ -125,3 +125,21 @@ void mmu_cleanup_all(void)
else if (mmu_hash_ops.hpte_clear_all)
mmu_hash_ops.hpte_clear_all();
}
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+int create_section_mapping(unsigned long start, unsigned long end)
+{
+ if (radix_enabled())
+ return -ENODEV;
+
+ return hash__create_section_mapping(start, end);
+}
+
+int remove_section_mapping(unsigned long start, unsigned long end)
+{
+ if (radix_enabled())
+ return -ENODEV;
+
+ return hash__remove_section_mapping(start, end);
+}
+#endif /* CONFIG_MEMORY_HOTPLUG */
--
2.11.0