| Message ID | 1553892336-29596-1-git-send-email-vgupta@synopsys.com |
|---|---|
| State | New |
| Headers | show |
| Series | ARC: PAE40: don't panic and instead turn off hw ioc | expand |
Hi Vineet, On Fri, 2019-03-29 at 13:45 -0700, Vineet Gupta wrote: > HSDK currently panics when built for HIGHMEM/ARC_HAS_PAE40 because ioc > is enabled with default which doesn't for the 2 non contiguous memory > nodes. > > So get PAE working with ioc disabled instead > > Tested with !PAE40 by forcing @ioc_enable=0 and running the glibc > testsuite over ssh > > Signed-off-by: Vineet Gupta <vgupta@synopsys.com> > --- > 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 4135abec3fb0..63e6e6504699 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()) As for today PAE40 couldn't be enabled without HIGHMEM for ARC, so probably we can simplify this to ----------------------------->8---------------------------------- if (IS_ENABLED(CONFIG_HIGHMEM)) ioc_enable = 0; ----------------------------->8---------------------------------- > + 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(); >
On 4/1/19 11:04 AM, Eugeniy Paltsev wrote: >> + if (IS_ENABLED(CONFIG_HIGHMEM) || is_pae40_enabled()) > As for today PAE40 couldn't be enabled without HIGHMEM for ARC, so probably we can > simplify this to > > ----------------------------->8---------------------------------- > if (IS_ENABLED(CONFIG_HIGHMEM)) > ioc_enable = 0; That is true, but mentioning both sort of documents the requirements. Also these checks are compile time only so don't add any extra code whatsoever. -Vineet
On Mon, 2019-04-01 at 11:08 -0700, Vineet Gupta wrote: > On 4/1/19 11:04 AM, Eugeniy Paltsev wrote: > > > + if (IS_ENABLED(CONFIG_HIGHMEM) || is_pae40_enabled()) > > > > As for today PAE40 couldn't be enabled without HIGHMEM for ARC, so probably we can > > simplify this to > > > > ----------------------------->8---------------------------------- > > if (IS_ENABLED(CONFIG_HIGHMEM)) > > ioc_enable = 0; > > That is true, but mentioning both sort of documents the requirements. > Also these checks are compile time only so don't add any extra code whatsoever. OK, I'm fine with it. Let's check both conditions explicitly. > -Vineet >
diff --git a/arch/arc/mm/cache.c b/arch/arc/mm/cache.c index 4135abec3fb0..63e6e6504699 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();
HSDK currently panics when built for HIGHMEM/ARC_HAS_PAE40 because ioc is enabled with default which doesn't for the 2 non contiguous memory nodes. So get PAE working with ioc disabled instead Tested with !PAE40 by forcing @ioc_enable=0 and running the glibc testsuite over ssh Signed-off-by: Vineet Gupta <vgupta@synopsys.com> --- arch/arc/mm/cache.c | 31 ++++++++++++++++--------------- 1 file changed, 16 insertions(+), 15 deletions(-)