linux/arch/sparc64/kernel/dtlb_miss.S
David S. Miller 517af33237 [SPARC64]: Access TSB with physical addresses when possible.
This way we don't need to lock the TSB into the TLB.
The trick is that every TSB load/store is registered into
a special instruction patch section.  The default uses
virtual addresses, and the patch instructions use physical
address load/stores.

We can't do this on all chips because only cheetah+ and later
have the physical variant of the atomic quad load.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:11:32 -08:00

40 lines
744 B
ArmAsm

/* DTLB ** ICACHE line 1: Context 0 check and TSB load */
ldxa [%g0] ASI_DMMU_TSB_8KB_PTR, %g1 ! Get TSB 8K pointer
ldxa [%g0] ASI_DMMU, %g6 ! Get TAG TARGET
srlx %g6, 48, %g5 ! Get context
brz,pn %g5, kvmap_dtlb ! Context 0 processing
nop ! Delay slot (fill me)
TSB_LOAD_QUAD(%g1, %g4) ! Load TSB entry
nop ! Push branch to next I$ line
cmp %g4, %g6 ! Compare TAG
/* DTLB ** ICACHE line 2: TSB compare and TLB load */
bne,pn %xcc, tsb_miss_dtlb ! Miss
mov FAULT_CODE_DTLB, %g3
stxa %g5, [%g0] ASI_DTLB_DATA_IN ! Load TLB
retry ! Trap done
nop
nop
nop
nop
/* DTLB ** ICACHE line 3: */
nop
nop
nop
nop
nop
nop
nop
nop
/* DTLB ** ICACHE line 4: */
nop
nop
nop
nop
nop
nop
nop
nop