diff mbox series

[SRU,F,2/8] powerpc/pseries: Fix of_read_drc_info_cell() to point at next record

Message ID 20240308122820.316586-3-frank.heimes@canonical.com
State New
Headers show
Series Problems with HVCS and hotplugging (LP: 2056373) | expand

Commit Message

Frank Heimes March 8, 2024, 12:28 p.m. UTC 
From: Tyrel Datwyler <tyreld@linux.ibm.com>

BugLink: https://bugs.launchpad.net/bugs/2056373

The expectation is that when calling of_read_drc_info_cell()
repeatedly to parse multiple drc-info records that the in/out curval
parameter points at the start of the next record on return. However,
the current behavior has curval still pointing at the final value of
the record just parsed. The result of which is that if the
ibm,drc-info property contains multiple properties the parsed value
of the drc_type for any record after the first has the power_domain
value of the previous record appended to the type string.

eg: observed the following 0xffffffff prepended to PHB

  drc-info: type: \xff\xff\xff\xffPHB, prefix: PHB , index_start: 0x20000001
  drc-info: suffix_start: 1, sequential_elems: 3072, sequential_inc: 1
  drc-info: power-domain: 0xffffffff, last_index: 0x20000c00

In practice PHBs are the only type of connector in the ibm,drc-info
property that has multiple records. So, it breaks PHB hotplug, but by
chance not PCI, CPU, slot, or memory because they happen to only ever
be a single record.

Fix by incrementing curval past the power_domain value to point at
drc_type string of next record.

Fixes: e83636ac3334 ("pseries/drc-info: Search DRC properties for CPU indexes")
Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Acked-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200307024547.5748-1-tyreld@linux.ibm.com
(cherry picked from commit c5e76fa05b2df519b9f08571cc57e623c1569faa)
Signed-off-by: Frank Heimes <frank.heimes@canonical.com>
---
 arch/powerpc/platforms/pseries/of_helpers.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/arch/powerpc/platforms/pseries/of_helpers.c b/arch/powerpc/platforms/pseries/of_helpers.c
index 66dfd8256712..23241c71ef37 100644
--- a/arch/powerpc/platforms/pseries/of_helpers.c
+++ b/arch/powerpc/platforms/pseries/of_helpers.c
@@ -88,7 +88,7 @@  int of_read_drc_info_cell(struct property **prop, const __be32 **curval,
 		return -EINVAL;
 
 	/* Should now know end of current entry */
-	(*curval) = (void *)p2;
+	(*curval) = (void *)(++p2);
 	data->last_drc_index = data->drc_index_start +
 		((data->num_sequential_elems - 1) * data->sequential_inc);