The page size used to map the namespace is arch dependent. For example
architectures like ppc64 use 16MB page size for direct-mapping. If the namespace
size is not aligned to the mapping page size, we can observe kernel crash
during namespace init and destroy.
This is due to kernel doing partial map/unmap of the resource range
BUG: Unable to handle kernel data access at 0xc001000406000000
Faulting instruction address: 0xc000000000090790
NIP [c000000000090790] arch_add_memory+0xc0/0x130
LR [c000000000090744] arch_add_memory+0x74/0x130
Call Trace:
arch_add_memory+0x74/0x130 (unreliable)
memremap_pages+0x74c/0xa30
devm_memremap_pages+0x3c/0xa0
pmem_attach_disk+0x188/0x770
nvdimm_bus_probe+0xd8/0x470
really_probe+0x148/0x570
driver_probe_device+0x19c/0x1d0
device_driver_attach+0xcc/0x100
bind_store+0x134/0x1c0
drv_attr_store+0x44/0x60
sysfs_kf_write+0x74/0xc0
kernfs_fop_write+0x1b4/0x290
__vfs_write+0x3c/0x70
vfs_write+0xd0/0x260
ksys_write+0xdc/0x130
system_call+0x5c/0x68
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com>
---
arch/arm64/mm/flush.c | 11 +++++++++++
arch/powerpc/lib/pmem.c | 21 +++++++++++++++++++--
arch/x86/mm/pageattr.c | 12 ++++++++++++
include/linux/libnvdimm.h | 1 +
4 files changed, 43 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/mm/flush.c b/arch/arm64/mm/flush.c
index ac485163a4a7..90c54c600023 100644
--- a/arch/arm64/mm/flush.c
+++ b/arch/arm64/mm/flush.c
@@ -91,4 +91,15 @@ void arch_invalidate_pmem(void *addr, size_t size)
__inval_dcache_area(addr, size);
}
EXPORT_SYMBOL_GPL(arch_invalidate_pmem);
+
+unsigned long arch_validate_namespace_size(unsigned int ndr_mappings, unsigned
long size)
+{
+ u32 remainder;
+
+ div_u64_rem(size, PAGE_SIZE * ndr_mappings, &remainder);
+ if (remainder)
+ return PAGE_SIZE * ndr_mappings;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(arch_validate_namespace_size);
#endif
diff --git a/arch/powerpc/lib/pmem.c b/arch/powerpc/lib/pmem.c
index 377712e85605..2e661a08dae5 100644
--- a/arch/powerpc/lib/pmem.c
+++ b/arch/powerpc/lib/pmem.c
@@ -17,14 +17,31 @@ void arch_wb_cache_pmem(void *addr, size_t size)
unsigned long start = (unsigned long) addr;
flush_dcache_range(start, start + size);
}
-EXPORT_SYMBOL(arch_wb_cache_pmem);
+EXPORT_SYMBOL_GPL(arch_wb_cache_pmem);
void arch_invalidate_pmem(void *addr, size_t size)
{
unsigned long start = (unsigned long) addr;
flush_dcache_range(start, start + size);
}
-EXPORT_SYMBOL(arch_invalidate_pmem);
+EXPORT_SYMBOL_GPL(arch_invalidate_pmem);
+
+unsigned long arch_validate_namespace_size(unsigned int ndr_mappings, unsigned
long size)
+{
+ u32 remainder;
+ unsigned long linear_map_size;
+
+ if (radix_enabled())
+ linear_map_size = PAGE_SIZE;
+ else
+ linear_map_size = (1UL <<
mmu_psize_defs[mmu_linear_psize].shift);
+
+ div_u64_rem(size, linear_map_size * ndr_mappings, &remainder);
+ if (remainder)
+ return linear_map_size * ndr_mappings;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(arch_validate_namespace_size);
/*
* CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE symbols
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 0d09cc5aad61..023329d7dfac 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -310,6 +310,18 @@ void arch_invalidate_pmem(void *addr, size_t size)
}
EXPORT_SYMBOL_GPL(arch_invalidate_pmem);
+unsigned long arch_validate_namespace_size(unsigned int ndr_mappings, unsigned
long size)
+{
+ u32 remainder;
+
+ div_u64_rem(size, PAGE_SIZE * ndr_mappings, &remainder);
+ if (remainder)
+ return PAGE_SIZE * ndr_mappings;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(arch_validate_namespace_size);
+
+
static void __cpa_flush_all(void *arg)
{
unsigned long cache = (unsigned long)arg;
diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
index b6eddf912568..e2f8387d9ef4 100644
--- a/include/linux/libnvdimm.h
+++ b/include/linux/libnvdimm.h
@@ -291,4 +291,5 @@ static inline void arch_invalidate_pmem(void *addr, size_t
size)
}
#endif
+unsigned long arch_validate_namespace_size(unsigned int ndr_mappings, unsigned
long size);
#endif /* __LIBNVDIMM_H__ */
--
2.21.0
