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authorGerhard Stenzel <stenzel@de.ibm.com>2009-05-13 05:50:46 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-05-15 16:43:42 +1000
commit37cd8ed90fc5b11941110d2d0cea6807f86d4787 (patch)
parent49a849652513235a244dfbf5e58c54f796bd1148 (diff)
powerpc/cell: Make ptcal more reliable
There have been a series of checkstops on QS21 related to ptcal being set up incorrectly. On systems that only have memory on a single node, ptcal fails when it gets a pointer to memory on the remote node. Moreover, agressive prefetching in memcpy and other functions may accidentally touch the first cache line of the page that we reserve for ptcal, which causes an ECC checkstop. We now allocate pages only from the specified node, moves the ptcal area into the middle of the allocated page to avoid potential prefetch problems and prints the address of the ptcal area to facilitate diagnostics. Signed-off-by: Gerhard Stenzel <gerhard.stenzel@de.ibm.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
1 files changed, 14 insertions, 3 deletions
diff --git a/arch/powerpc/platforms/cell/ras.c b/arch/powerpc/platforms/cell/ras.c
index 5f961c464cc4..296b5268754e 100644
--- a/arch/powerpc/platforms/cell/ras.c
+++ b/arch/powerpc/platforms/cell/ras.c
@@ -122,12 +122,23 @@ static int __init cbe_ptcal_enable_on_node(int nid, int order)
area->nid = nid;
area->order = order;
- area->pages = alloc_pages_node(area->nid, GFP_KERNEL, area->order);
+ area->pages = alloc_pages_node(area->nid, GFP_KERNEL | GFP_THISNODE,
+ area->order);
- if (!area->pages)
+ if (!area->pages) {
+ printk(KERN_WARNING "%s: no page on node %d\n",
+ __func__, area->nid);
goto out_free_area;
+ }
- addr = __pa(page_address(area->pages));
+ /*
+ * We move the ptcal area to the middle of the allocated
+ * page, in order to avoid prefetches in memcpy and similar
+ * functions stepping on it.
+ */
+ addr = __pa(page_address(area->pages)) + (PAGE_SIZE >> 1);
+ printk(KERN_DEBUG "%s: enabling PTCAL on node %d address=0x%016lx\n",
+ __func__, area->nid, addr);
ret = -EIO;
if (rtas_call(ptcal_start_tok, 3, 1, NULL, area->nid,