From: Vineet Gupta vgupta@synopsys.com
[ Upstream commit 99bd5fcc505d65ea9c60619202f0b2d926eabbe9 ]
HSDK currently panics when built for HIGHMEM/ARC_HAS_PAE40 because ioc is enabled with default which doesn't work for the 2 non contiguous memory nodes. So get PAE working by disabling ioc instead.
Tested with !PAE40 by forcing @ioc_enable=0 and running the glibc testsuite over ssh
Signed-off-by: Vineet Gupta vgupta@synopsys.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arc/mm/cache.c | 31 ++++++++++++++++--------------- 1 file changed, 16 insertions(+), 15 deletions(-)
diff --git a/arch/arc/mm/cache.c b/arch/arc/mm/cache.c index 4135abec3fb09..63e6e65046992 100644 --- a/arch/arc/mm/cache.c +++ b/arch/arc/mm/cache.c @@ -113,10 +113,24 @@ static void read_decode_cache_bcr_arcv2(int cpu) }
READ_BCR(ARC_REG_CLUSTER_BCR, cbcr); - if (cbcr.c) + if (cbcr.c) { ioc_exists = 1; - else + + /* + * As for today we don't support both IOC and ZONE_HIGHMEM enabled + * simultaneously. This happens because as of today IOC aperture covers + * only ZONE_NORMAL (low mem) and any dma transactions outside this + * region won't be HW coherent. + * If we want to use both IOC and ZONE_HIGHMEM we can use + * bounce_buffer to handle dma transactions to HIGHMEM. + * Also it is possible to modify dma_direct cache ops or increase IOC + * aperture size if we are planning to use HIGHMEM without PAE. + */ + if (IS_ENABLED(CONFIG_HIGHMEM) || is_pae40_enabled()) + ioc_enable = 0; + } else { ioc_enable = 0; + }
/* HS 2.0 didn't have AUX_VOL */ if (cpuinfo_arc700[cpu].core.family > 0x51) { @@ -1158,19 +1172,6 @@ noinline void __init arc_ioc_setup(void) if (!ioc_enable) return;
- /* - * As for today we don't support both IOC and ZONE_HIGHMEM enabled - * simultaneously. This happens because as of today IOC aperture covers - * only ZONE_NORMAL (low mem) and any dma transactions outside this - * region won't be HW coherent. - * If we want to use both IOC and ZONE_HIGHMEM we can use - * bounce_buffer to handle dma transactions to HIGHMEM. - * Also it is possible to modify dma_direct cache ops or increase IOC - * aperture size if we are planning to use HIGHMEM without PAE. - */ - if (IS_ENABLED(CONFIG_HIGHMEM)) - panic("IOC and HIGHMEM can't be used simultaneously"); - /* Flush + invalidate + disable L1 dcache */ __dc_disable();