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SubjectRe: [RFC 3/3] s390/mm: Define arch_get_addressable_range()
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On 11/25/20 10:57 PM, David Hildenbrand wrote:
> On 23.11.20 03:28, Anshuman Khandual wrote:
>> This overrides arch_get_addressable_range() on s390 platform and drops
>> now redudant similar check in vmem_add_mapping().
>>
>> Cc: Heiko Carstens <hca@linux.ibm.com>
>> Cc: Vasily Gorbik <gor@linux.ibm.com>
>> Cc: David Hildenbrand <david@redhat.com>
>> Cc: linux-s390@vger.kernel.org
>> Cc: linux-kernel@vger.kernel.org
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
>> ---
>> arch/s390/include/asm/mmu.h | 2 ++
>> arch/s390/mm/vmem.c | 16 ++++++++++++----
>> 2 files changed, 14 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/s390/include/asm/mmu.h b/arch/s390/include/asm/mmu.h
>> index e12ff0f29d1a..f92d3926b188 100644
>> --- a/arch/s390/include/asm/mmu.h
>> +++ b/arch/s390/include/asm/mmu.h
>> @@ -55,4 +55,6 @@ static inline int tprot(unsigned long addr)
>> return rc;
>> }
>>
>> +#define arch_get_addressable_range arch_get_addressable_range
>> +struct range arch_get_addressable_range(bool need_mapping);
>> #endif
>> diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
>> index b239f2ba93b0..e03ad0ed13a7 100644
>> --- a/arch/s390/mm/vmem.c
>> +++ b/arch/s390/mm/vmem.c
>> @@ -532,14 +532,22 @@ void vmem_remove_mapping(unsigned long start, unsigned long size)
>> mutex_unlock(&vmem_mutex);
>> }
>>
>> +struct range arch_get_addressable_range(bool need_mapping)
>> +{
>> + struct range memhp_range;
>> +
>> + memhp_range.start = 0;
>> + if (need_mapping)
>> + memhp_range.end = VMEM_MAX_PHYS;
>> + else
>> + memhp_range.end = (1ULL << (MAX_PHYSMEM_BITS + 1)) - 1;
>> + return memhp_range;
>> +}
>> +
>> int vmem_add_mapping(unsigned long start, unsigned long size)
>> {
>> int ret;
>>
>> - if (start + size > VMEM_MAX_PHYS ||
>> - start + size < start)
>> - return -ERANGE;
>> -
>> mutex_lock(&vmem_mutex);
>> ret = vmem_add_range(start, size);
>> if (ret)
>>
>
> Note that vmem_add_mapping() is also called from extmem
> (arch/s390/mm/extmem.c).

Right, probably something like this should be able to take care of
the range check, it lost out earlier.

diff --git a/arch/s390/mm/extmem.c b/arch/s390/mm/extmem.c
index 5060956b8e7d..c61620ae5ee6 100644
--- a/arch/s390/mm/extmem.c
+++ b/arch/s390/mm/extmem.c
@@ -337,6 +337,11 @@ __segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long
goto out_free_resource;
}

+ if (seg->end + 1 > VMEM_MAX_PHYS || seg->end + 1 < seg->start) {
+ rc = -ERANGE;
+ goto out_resource;
+ }
+
rc = vmem_add_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
if (rc)
goto out_resource;
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