| Message ID | 20190722174700.11483-2-npiggin@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | assorted virtual / physical address fixes | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch next (f3365d1a959d5c6527efe3d38276acc9b58e3f3f) |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 8 lines checked |
Nicholas Piggin <npiggin@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 hit by booting with limited memory then probing > new physical memory sections. > > Cc: Reza Arbab <arbab@linux.vnet.ibm.com> > Fixes: 6cc27341b21a8 ("powerpc/mm: add radix__create_section_mapping()") > Signed-off-by: Nicholas Piggin <npiggin@gmail.com> This is not catastrophic because create_physical_mapping() just uses start/end to construct virtual addresses anyway, and __va(__va(x)) == __va(x) ? Although we do pass those through as region_start/end which then go to memblock_alloc_try_nid(). But I guess that doesn't happen after boot, which is the case you're talking about. So I think looks good, change log could use a bit more detail though :) cheers > 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); > } > > int __meminit radix__remove_section_mapping(unsigned long start, unsigned long end) > -- > 2.20.1
Michael Ellerman's on July 23, 2019 8:52 pm: > Nicholas Piggin <npiggin@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 hit by booting with limited memory then probing >> new physical memory sections. >> >> Cc: Reza Arbab <arbab@linux.vnet.ibm.com> >> Fixes: 6cc27341b21a8 ("powerpc/mm: add radix__create_section_mapping()") >> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> > > This is not catastrophic because create_physical_mapping() just uses > start/end to construct virtual addresses anyway, and __va(__va(x)) == __va(x) ? A bit more subtle, it calls __map_kernel_page with the pa as well. pfn_pte ends up masking the top 0xc bits out with PTE_RPN_MASK, which is what saves us. Hmm, so we really should also have a VM_BUG_ON in pfn_pte if it's given a pfn with the top PAGE_SHIFT bit or PTE_RPN_MASK bits set. I'll add that as a patch 5. > Although we do pass those through as region_start/end which then go to > memblock_alloc_try_nid(). But I guess that doesn't happen after boot, > which is the case you're talking about. > > So I think looks good, change log could use a bit more detail though :) Thanks for taking a look. I'll resend after a bit more testing and some changelog improvement. Thanks, Nick
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); } int __meminit radix__remove_section_mapping(unsigned long start, unsigned long end)
create_physical_mapping expects physical addresses, but creating and splitting these mappings after boot is supplying virtual (effective) addresses. This can be hit by booting with limited memory then probing new physical memory sections. Cc: Reza Arbab <arbab@linux.vnet.ibm.com> Fixes: 6cc27341b21a8 ("powerpc/mm: add radix__create_section_mapping()") Signed-off-by: Nicholas Piggin <npiggin@gmail.com> --- arch/powerpc/mm/book3s64/radix_pgtable.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)