Cédric Le Goater <c...@kaod.org> writes: > 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: sta...@vger.kernel.org # v4.20+ > Fixes: ab91239942a9 ("powerpc/prom: Remove VLA in > prom_check_platform_support()") > Signed-off-by: Cédric Le Goater <c...@kaod.org>
Reviewed-by: Fabiano Rosas <faro...@linux.ibm.com> > --- > 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); > } > }