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
Kernel should also ensure that namespace size is also mulitple of subsection
size.
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com>
---
Changes from v2:
* Use SUBSECTION_SIZE instead of PAGE_SIZE. Namespace size should be multiple
of SUBSECTION size.
arch/arm64/mm/flush.c | 6 ++++++
arch/powerpc/lib/pmem.c | 11 +++++++++++
arch/x86/mm/pageattr.c | 7 +++++++
include/linux/libnvdimm.h | 1 +
4 files changed, 25 insertions(+)
diff --git a/arch/arm64/mm/flush.c b/arch/arm64/mm/flush.c
index ac485163a4a7..5d82484ac8ca 100644
--- a/arch/arm64/mm/flush.c
+++ b/arch/arm64/mm/flush.c
@@ -91,4 +91,10 @@ void arch_invalidate_pmem(void *addr, size_t size)
__inval_dcache_area(addr, size);
}
EXPORT_SYMBOL_GPL(arch_invalidate_pmem);
+
+unsigned long arch_namespace_align_size(void)
+{
+ return (1UL << SUBSECTION_SHIFT);
+}
+EXPORT_SYMBOL_GPL(arch_namespace_align_size);
#endif
diff --git a/arch/powerpc/lib/pmem.c b/arch/powerpc/lib/pmem.c
index 0666a8d29596..b94e7d4876d1 100644
--- a/arch/powerpc/lib/pmem.c
+++ b/arch/powerpc/lib/pmem.c
@@ -26,6 +26,17 @@ void arch_invalidate_pmem(void *addr, size_t size)
}
EXPORT_SYMBOL_GPL(arch_invalidate_pmem);
+unsigned long arch_namespace_align_size(void)
+{
+ unsigned long sub_section_size = (1UL << SUBSECTION_SHIFT);
+
+ if (radix_enabled())
+ return sub_section_size;
+ return max(sub_section_size, (1UL <<
mmu_psize_defs[mmu_linear_psize].shift));
+
+}
+EXPORT_SYMBOL_GPL(arch_namespace_align_size);
+
/*
* CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE symbols
*/
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 1b99ad05b117..0bcd22e11dd0 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -310,6 +310,13 @@ void arch_invalidate_pmem(void *addr, size_t size)
}
EXPORT_SYMBOL_GPL(arch_invalidate_pmem);
+unsigned long arch_namespace_align_size(void)
+{
+ return (1UL << SUBSECTION_SHIFT);
+}
+EXPORT_SYMBOL_GPL(arch_namespace_align_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 9df091bd30ba..f2a33f2e3ba8 100644
--- a/include/linux/libnvdimm.h
+++ b/include/linux/libnvdimm.h
@@ -284,4 +284,5 @@ static inline void arch_invalidate_pmem(void *addr, size_t
size)
}
#endif
+unsigned long arch_namespace_align_size(void);
#endif /* __LIBNVDIMM_H__ */
--
2.24.1
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