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powerpc/cell: Make ptcal more reliable

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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>
This commit is contained in:
Gerhard Stenzel 2009-05-13 05:50:46 +00:00 committed by Benjamin Herrenschmidt
parent 49a8496525
commit 37cd8ed90f
1 changed files with 14 additions and 3 deletions
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17
arch/powerpc/platforms/cell/ras.c
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@ -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,