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authorVineet Gupta <vgupta@synopsys.com>2017-08-03 17:45:44 +0530
committerVineet Gupta <vgupta@synopsys.com>2017-08-04 13:56:35 +0530
commitb5ddb6d54729d814356937572d6c9b599f10c29f (patch)
tree122ddb43a2f0a0472237e20114ea78b1db5ff7a3 /arch/arc/mm/cache.c
parent7d79cee2c6540ea64dd917a14e2fd63d4ac3d3c0 (diff)
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ARCv2: PAE40: set MSB even if !CONFIG_ARC_HAS_PAE40 but PAE exists in SoC
PAE40 confiuration in hardware extends some of the address registers for TLB/cache ops to 2 words. So far kernel was NOT setting the higher word if feature was not enabled in software which is wrong. Those need to be set to 0 in such case. Normally this would be done in the cache flush / tlb ops, however since these registers only exist conditionally, this would have to be conditional to a flag being set on boot which is expensive/ugly - specially for the more common case of PAE exists but not in use. Optimize that by zero'ing them once at boot - nobody will write to them afterwards Cc: stable@vger.kernel.org #4.4+ Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Diffstat (limited to 'arch/arc/mm/cache.c')
-rw-r--r--arch/arc/mm/cache.c34
1 files changed, 28 insertions, 6 deletions
diff --git a/arch/arc/mm/cache.c b/arch/arc/mm/cache.c
index 874913b3e826..7db283b46ebd 100644
--- a/arch/arc/mm/cache.c
+++ b/arch/arc/mm/cache.c
@@ -1123,6 +1123,13 @@ noinline void __init arc_ioc_setup(void)
__dc_enable();
}
+/*
+ * Cache related boot time checks/setups only needed on master CPU:
+ * - Geometry checks (kernel build and hardware agree: e.g. L1_CACHE_BYTES)
+ * Assume SMP only, so all cores will have same cache config. A check on
+ * one core suffices for all
+ * - IOC setup / dma callbacks only need to be done once
+ */
void __init arc_cache_init_master(void)
{
unsigned int __maybe_unused cpu = smp_processor_id();
@@ -1202,12 +1209,27 @@ void __ref arc_cache_init(void)
printk(arc_cache_mumbojumbo(0, str, sizeof(str)));
- /*
- * Only master CPU needs to execute rest of function:
- * - Assume SMP so all cores will have same cache config so
- * any geomtry checks will be same for all
- * - IOC setup / dma callbacks only need to be setup once
- */
if (!cpu)
arc_cache_init_master();
+
+ /*
+ * In PAE regime, TLB and cache maintenance ops take wider addresses
+ * And even if PAE is not enabled in kernel, the upper 32-bits still need
+ * to be zeroed to keep the ops sane.
+ * As an optimization for more common !PAE enabled case, zero them out
+ * once at init, rather than checking/setting to 0 for every runtime op
+ */
+ if (is_isa_arcv2() && pae40_exist_but_not_enab()) {
+
+ if (IS_ENABLED(CONFIG_ARC_HAS_ICACHE))
+ write_aux_reg(ARC_REG_IC_PTAG_HI, 0);
+
+ if (IS_ENABLED(CONFIG_ARC_HAS_DCACHE))
+ write_aux_reg(ARC_REG_DC_PTAG_HI, 0);
+
+ if (l2_line_sz) {
+ write_aux_reg(ARC_REG_SLC_RGN_END1, 0);
+ write_aux_reg(ARC_REG_SLC_RGN_START1, 0);
+ }
+ }
}