On Thu, May 12, 2016 at 03:47:09PM +1000, Alexey Kardashevskiy wrote: >The pnv_pci_init_ioda_phb() helper allocates a blob to store auxilary >data such PE and M32/M64 segment allocation maps; this single blob has few >partitions, size of each is derived from the PE number - >phb->ioda.total_pe_num. > >It was assumed that the minimum PE number is 8, however it is 4 for NPU >so the pe_alloc part was missing in the allocated blob. >It was invisible till recently as we were not tracking used M64 segments >and NPUs do not use M32 segments so the phb->ioda.m32_segmap >(which was pointing to the same address as phb->ioda.pe_alloc) >has never been written to leaving the pe_alloc memory intact. > >After 401203ac2d "powerpc/powernv: Track M64 segment consumption" >the pe_alloc gets corrupted and PE allocation cannot work. >This fixes the issue by enforcing the minimum PE number to 8. >
As I said offline yesterday, the issue exists from day-1 when NPU PHB is supported. I don't think it's related to 401203ac2d. Without the logic tracking M64 segments, the PE# bitmap still can be corrupted when writting to M32 segment map. It's confusing to mention a unrelated commit in the changelog. Since the issue exists from day-1 when NPU PHB is supported, is a stable tag needed? >Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru> With above parts fixed: Reviewed-by: Gavin Shan <gws...@linux.vnet.ibm.com> >--- > arch/powerpc/platforms/powernv/pci-ioda.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > >diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c >b/arch/powerpc/platforms/powernv/pci-ioda.c >index 6cda2a8..d0d32c2 100644 >--- a/arch/powerpc/platforms/powernv/pci-ioda.c >+++ b/arch/powerpc/platforms/powernv/pci-ioda.c >@@ -3507,7 +3507,8 @@ static void __init pnv_pci_init_ioda_phb(struct >device_node *np, > PNV_IODA1_DMA32_SEGSIZE; > > /* Allocate aux data & arrays. We don't have IO ports on PHB3 */ >- size = _ALIGN_UP(phb->ioda.total_pe_num / 8, sizeof(unsigned long)); >+ size = _ALIGN_UP(max_t(unsigned, phb->ioda.total_pe_num, 8) / 8, >+ sizeof(unsigned long)); > m64map_off = size; > size += phb->ioda.total_pe_num * sizeof(phb->ioda.m64_segmap[0]); > m32map_off = size; >-- >2.5.0.rc3 > _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
