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authorDavid S. Miller <davem@davemloft.net>2006-01-31 21:29:18 -0500
committerDavid S. Miller <davem@sunset.davemloft.net>2006-03-20 04:11:13 -0500
commit74bf4312fff083ab25c3f357cc653ada7995e5f6 (patch)
treec23dea461e32485f4cd7ca4b8c33c632655eb906 /arch/sparc64/kernel/dtlb_miss.S
parent30d4d1ffed7098afe2641536d67eef150499da02 (diff)
[SPARC64]: Move away from virtual page tables, part 1.
We now use the TSB hardware assist features of the UltraSPARC MMUs. SMP is currently knowingly broken, we need to find another place to store the per-cpu base pointers. We hid them away in the TSB base register, and that obviously will not work any more :-) Another known broken case is non-8KB base page size. Also noticed that flush_tlb_all() is not referenced anywhere, only the internal __flush_tlb_all() (local cpu only) is used by the sparc64 port, so we can get rid of flush_tlb_all(). The kernel gets it's own 8KB TSB (swapper_tsb) and each address space gets it's own private 8K TSB. Later we can add code to dynamically increase the size of per-process TSB as the RSS grows. An 8KB TSB is good enough for up to about a 4MB RSS, after which the TSB starts to incur many capacity and conflict misses. We even accumulate OBP translations into the kernel TSB. Another area for refinement is large page size support. We could use a secondary address space TSB to handle those. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/sparc64/kernel/dtlb_miss.S')
-rw-r--r--arch/sparc64/kernel/dtlb_miss.S39
1 files changed, 39 insertions, 0 deletions
diff --git a/arch/sparc64/kernel/dtlb_miss.S b/arch/sparc64/kernel/dtlb_miss.S
new file mode 100644
index 000000000000..d0f1565cb564
--- /dev/null
+++ b/arch/sparc64/kernel/dtlb_miss.S
@@ -0,0 +1,39 @@
1/* DTLB ** ICACHE line 1: Context 0 check and TSB load */
2 ldxa [%g0] ASI_DMMU_TSB_8KB_PTR, %g1 ! Get TSB 8K pointer
3 ldxa [%g0] ASI_DMMU, %g6 ! Get TAG TARGET
4 srlx %g6, 48, %g5 ! Get context
5 brz,pn %g5, kvmap_dtlb ! Context 0 processing
6 nop ! Delay slot (fill me)
7 ldda [%g1] ASI_NUCLEUS_QUAD_LDD, %g4 ! Load TSB entry
8 nop ! Push branch to next I$ line
9 cmp %g4, %g6 ! Compare TAG
10
11/* DTLB ** ICACHE line 2: TSB compare and TLB load */
12 bne,pn %xcc, tsb_miss_dtlb ! Miss
13 mov FAULT_CODE_DTLB, %g3
14 stxa %g5, [%g0] ASI_DTLB_DATA_IN ! Load TLB
15 retry ! Trap done
16 nop
17 nop
18 nop
19 nop
20
21/* DTLB ** ICACHE line 3: */
22 nop
23 nop
24 nop
25 nop
26 nop
27 nop
28 nop
29 nop
30
31/* DTLB ** ICACHE line 4: */
32 nop
33 nop
34 nop
35 nop
36 nop
37 nop
38 nop
39 nop