aboutsummaryrefslogtreecommitdiffstats
path: root/arch/arc/mm/tlb.c
diff options
context:
space:
mode:
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/tlb.c
parentARCv2: PAE40: Explicitly set MSB counterpart of SLC region ops addresses (diff)
downloadlinux-dev-b5ddb6d54729d814356937572d6c9b599f10c29f.tar.xz
linux-dev-b5ddb6d54729d814356937572d6c9b599f10c29f.zip
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 '')
-rw-r--r--arch/arc/mm/tlb.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/arch/arc/mm/tlb.c b/arch/arc/mm/tlb.c
index d0126fdfe2d8..b181f3ee38aa 100644
--- a/arch/arc/mm/tlb.c
+++ b/arch/arc/mm/tlb.c
@@ -104,6 +104,8 @@
/* A copy of the ASID from the PID reg is kept in asid_cache */
DEFINE_PER_CPU(unsigned int, asid_cache) = MM_CTXT_FIRST_CYCLE;
+static int __read_mostly pae_exists;
+
/*
* Utility Routine to erase a J-TLB entry
* Caller needs to setup Index Reg (manually or via getIndex)
@@ -784,7 +786,7 @@ void read_decode_mmu_bcr(void)
mmu->u_dtlb = mmu4->u_dtlb * 4;
mmu->u_itlb = mmu4->u_itlb * 4;
mmu->sasid = mmu4->sasid;
- mmu->pae = mmu4->pae;
+ pae_exists = mmu->pae = mmu4->pae;
}
}
@@ -809,6 +811,11 @@ char *arc_mmu_mumbojumbo(int cpu_id, char *buf, int len)
return buf;
}
+int pae40_exist_but_not_enab(void)
+{
+ return pae_exists && !is_pae40_enabled();
+}
+
void arc_mmu_init(void)
{
char str[256];
@@ -859,6 +866,9 @@ void arc_mmu_init(void)
/* swapper_pg_dir is the pgd for the kernel, used by vmalloc */
write_aux_reg(ARC_REG_SCRATCH_DATA0, swapper_pg_dir);
#endif
+
+ if (pae40_exist_but_not_enab())
+ write_aux_reg(ARC_REG_TLBPD1HI, 0);
}
/*