===
/* Validate blk_sz is a power of 2 and not less than section size */
if ((block_sz & (block_sz - 1)) || (block_sz < MIN_MEMORY_BLOCK_SIZE)) {
WARN_ON(1);
block_sz = MIN_MEMORY_BLOCK_SIZE;
}
===
This splits memory nodes into set of smaller blocks with
a size which is a power of two. This makes sure the start
address of every node is aligned to the node size.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alexander Graf <agraf@suse.de>
---
hw/ppc/spapr.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
@@ -691,8 +691,18 @@ static int spapr_populate_memory(sPAPREnvironment *spapr, void *fdt)
mem_start += spapr->rma_size;
node_size -= spapr->rma_size;
}
- spapr_populate_memory_node(fdt, i, mem_start, node_size);
- mem_start += node_size;
+ for ( ; node_size; ) {
+ hwaddr sizetmp = pow2floor(node_size);
+
+ /* mem_start != 0 here */
+ if (ffsl(mem_start) < ffsl(sizetmp)) {
+ sizetmp = 1ULL << (ffsl(mem_start) - 1);
+ }
+
+ spapr_populate_memory_node(fdt, i, mem_start, sizetmp);
+ node_size -= sizetmp;
+ mem_start += sizetmp;
+ }
}
return 0;
From: Alexey Kardashevskiy <aik@ozlabs.ru> Linux kernel expects nodes to have power-of-two size and does WARN_ON if this is not the case: [ 0.041456] WARNING: at drivers/base/memory.c:115 which is: