The "ibm,arch-vec-5-platform-support" property is a list of pairs of
bytes representing the options and values supported by the platform
firmware. At boot time, Linux scans this list and activates the
available features it recognizes : Radix and XIVE.
A recent change modified the number of entries to loop on and 8 bytes,
4 pairs of { options, values } entries are always scanned. This is
fine on KVM but not on PowerVM which can advertises less. As a
consequence on this platform, Linux reads extra entries pointing to
random data, interprets these as available features and tries to
activate them, leading to a firmware crash in
ibm,client-architecture-support.
Fix that by using the property length of "ibm,arch-vec-5-platform-support".
Cc: stable@xxxxxxxxxxxxxxx # v4.20+
Fixes: ab91239942a9 ("powerpc/prom: Remove VLA in prom_check_platform_support()")
Signed-off-by: Cédric Le Goater <clg@xxxxxxxx>
---
arch/powerpc/kernel/prom_init.c | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index e9d4eb6144e1..ccf77b985c8f 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -1331,14 +1331,10 @@ static void __init prom_check_platform_support(void)
if (prop_len > sizeof(vec))
prom_printf("WARNING: ibm,arch-vec-5-platform-support longer than expected (len: %d)\n",
prop_len);
- prom_getprop(prom.chosen, "ibm,arch-vec-5-platform-support",
- &vec, sizeof(vec));
- for (i = 0; i < sizeof(vec); i += 2) {
- prom_debug("%d: index = 0x%x val = 0x%x\n", i / 2
- , vec[i]
- , vec[i + 1]);
- prom_parse_platform_support(vec[i], vec[i + 1],
- &supported);
+ prom_getprop(prom.chosen, "ibm,arch-vec-5-platform-support", &vec, sizeof(vec));
+ for (i = 0; i < prop_len; i += 2) {
+ prom_debug("%d: index = 0x%x val = 0x%x\n", i / 2, vec[i], vec[i + 1]);
+ prom_parse_platform_support(vec[i], vec[i + 1], &supported);
}
}
--
2.26.2
