Nicholas Piggin <npig...@gmail.com> writes:
> create_physical_mapping expects physical addresses, but creating and
> splitting these mappings after boot is supplying virtual (effective)
> addresses. This can be irritated by booting with mem= to limit memory
> then probing an unused physical memory range:
>
> echo <addr> > /sys/devices/system/memory/probe
>
> This mostly works by accident, firstly because __va(__va(x)) == __va(x)
> so the virtual address does not get corrupted. Secondly because pfn_pte
> masks out the upper bits of the pfn beyond the physical address limit,
> so a pfn constructed with a 0xc000000000000000 virtual linear address
> will be masked back to the correct physical address in the pte.
>
Good catch. Did this result in any error?
Reviewed-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com>
> Cc: Reza Arbab <ar...@linux.vnet.ibm.com>
> Fixes: 6cc27341b21a8 ("powerpc/mm: add radix__create_section_mapping()")
> Signed-off-by: Nicholas Piggin <npig...@gmail.com>
> ---
> arch/powerpc/mm/book3s64/radix_pgtable.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c
> b/arch/powerpc/mm/book3s64/radix_pgtable.c
> index b4ca9e95e678..c5cc16ab1954 100644
> --- a/arch/powerpc/mm/book3s64/radix_pgtable.c
> +++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
> @@ -902,7 +902,7 @@ int __meminit radix__create_section_mapping(unsigned long
> start, unsigned long e
> return -1;
> }
>
> - return create_physical_mapping(start, end, nid);
> + return create_physical_mapping(__pa(start), __pa(end), nid);
While we are here, should we change the prototype to take phys_addr_t ?
> }
>
> int __meminit radix__remove_section_mapping(unsigned long start, unsigned
> long end)
> --
> 2.22.0
