PAPR specifies that DTL buffers can not cross AMS environments (aka CMO in the PAPR) and can not cross a memory entitlement granule boundary (4k). This is found in section 14.11.3.2 H_REGISTER_VPA of the PAPR. kmalloc does not guarantee an alignment of the allocation, though, beyond 8 bytes (at least in my understanding). Over-allocate and align the resulting address. Tested both with and without AMS on a p7 partition.
--- Change from v1: removed extraneous #include. Note, I initially put this in a firmware check if-block, but we have also seen some issues with alignment with non-AMS partitions. The wasted memory is unfortunate, though. Cc: Paul Mackerras <pau...@samba.org> Cc: Anton Blanchard <an...@samba.org> Cc: linuxppc-dev@lists.ozlabs.org arch/powerpc/platforms/pseries/setup.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c index 0007241..a67be48 100644 --- a/arch/powerpc/platforms/pseries/setup.c +++ b/arch/powerpc/platforms/pseries/setup.c @@ -293,14 +293,15 @@ static int alloc_dispatch_logs(void) for_each_possible_cpu(cpu) { pp = &paca[cpu]; - dtl = kmalloc_node(DISPATCH_LOG_BYTES, GFP_KERNEL, - cpu_to_node(cpu)); + dtl = kmalloc_node(DISPATCH_LOG_BYTES + DISPATCH_LOG_BYTES - 1, + GFP_KERNEL, cpu_to_node(cpu)); if (!dtl) { pr_warn("Failed to allocate dispatch trace log for cpu %d\n", cpu); pr_warn("Stolen time statistics will be unreliable\n"); break; } + dtl = PTR_ALIGN(dtl, DISPATCH_LOG_BYTES); pp->dtl_ridx = 0; pp->dispatch_log = dtl; -- 1.7.4.1 _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev