[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>

1 files changed, 89 insertions, 5 deletions

diff --git a/include/asm-sparc64/tsb.h b/include/asm-sparc64/tsb.h
index f384565212fe..44709cde5617 100644
--- a/include/asm-sparc64/tsb.h
+++ b/include/asm-sparc64/tsb.h
@@ -44,7 +44,89 @@
 
 #define TSB_MEMBAR      membar  #StoreStore
 
+/* Some cpus support physical address quad loads.  We want to use
+ * those if possible so we don't need to hard-lock the TSB mapping
+ * into the TLB.  We encode some instruction patching in order to
+ * support this.
+ *
+ * The kernel TSB is locked into the TLB by virtue of being in the
+ * kernel image, so we don't play these games for swapper_tsb access.
+ */
+#ifndef __ASSEMBLY__
+struct tsb_phys_patch_entry {
+        unsigned int    addr;
+        unsigned int    insn;
+};
+extern struct tsb_phys_patch_entry __tsb_phys_patch, __tsb_phys_patch_end;
+#endif
+#define TSB_LOAD_QUAD(TSB, REG) \
+661:    ldda            [TSB] ASI_NUCLEUS_QUAD_LDD, REG; \
+        .section        .tsb_phys_patch, "ax"; \
+        .word           661b; \
+        ldda            [TSB] ASI_QUAD_LDD_PHYS, REG; \
+        .previous
+
+#define TSB_LOAD_TAG_HIGH(TSB, REG) \
+661:    lduwa           [TSB] ASI_N, REG; \
+        .section        .tsb_phys_patch, "ax"; \
+        .word           661b; \
+        lduwa           [TSB] ASI_PHYS_USE_EC, REG; \
+        .previous
+
+#define TSB_LOAD_TAG(TSB, REG) \
+661:    ldxa            [TSB] ASI_N, REG; \
+        .section        .tsb_phys_patch, "ax"; \
+        .word           661b; \
+        ldxa            [TSB] ASI_PHYS_USE_EC, REG; \
+        .previous
+
+#define TSB_CAS_TAG_HIGH(TSB, REG1, REG2) \
+661:    casa            [TSB] ASI_N, REG1, REG2; \
+        .section        .tsb_phys_patch, "ax"; \
+        .word           661b; \
+        casa            [TSB] ASI_PHYS_USE_EC, REG1, REG2; \
+        .previous
+
+#define TSB_CAS_TAG(TSB, REG1, REG2) \
+661:    casxa           [TSB] ASI_N, REG1, REG2; \
+        .section        .tsb_phys_patch, "ax"; \
+        .word           661b; \
+        casxa           [TSB] ASI_PHYS_USE_EC, REG1, REG2; \
+        .previous
+
+#define TSB_STORE(ADDR, VAL) \
+661:    stxa            VAL, [ADDR] ASI_N; \
+        .section        .tsb_phys_patch, "ax"; \
+        .word           661b; \
+        stxa            VAL, [ADDR] ASI_PHYS_USE_EC; \
+        .previous
+
 #define TSB_LOCK_TAG(TSB, REG1, REG2)   \
+99:     TSB_LOAD_TAG_HIGH(TSB, REG1);   \
+        sethi   %hi(TSB_TAG_LOCK_HIGH), REG2;\
+        andcc   REG1, REG2, %g0;        \
+        bne,pn  %icc, 99b;              \
+         nop;                           \
+        TSB_CAS_TAG_HIGH(TSB, REG1, REG2);      \
+        cmp     REG1, REG2;             \
+        bne,pn  %icc, 99b;              \
+         nop;                           \
+        TSB_MEMBAR
+
+#define TSB_WRITE(TSB, TTE, TAG) \
+        add     TSB, 0x8, TSB;   \
+        TSB_STORE(TSB, TTE);     \
+        sub     TSB, 0x8, TSB;   \
+        TSB_MEMBAR;              \
+        TSB_STORE(TSB, TAG);
+
+#define KTSB_LOAD_QUAD(TSB, REG) \
+        ldda            [TSB] ASI_NUCLEUS_QUAD_LDD, REG;
+
+#define KTSB_STORE(ADDR, VAL) \
+        stxa            VAL, [ADDR] ASI_N;
+
+#define KTSB_LOCK_TAG(TSB, REG1, REG2)  \
 99:     lduwa   [TSB] ASI_N, REG1;      \
         sethi   %hi(TSB_TAG_LOCK_HIGH), REG2;\
         andcc   REG1, REG2, %g0;        \
@@ -56,10 +138,12 @@
          nop;                           \
         TSB_MEMBAR
 
-#define TSB_WRITE(TSB, TTE, TAG)           \
-        stx             TTE, [TSB + 0x08]; \
-        TSB_MEMBAR;                        \
-        stx             TAG, [TSB + 0x00];
+#define KTSB_WRITE(TSB, TTE, TAG) \
+        add     TSB, 0x8, TSB;   \
+        stxa    TTE, [TSB] ASI_N;     \
+        sub     TSB, 0x8, TSB;   \
+        TSB_MEMBAR;              \
+        stxa    TAG, [TSB] ASI_N;
 
         /* Do a kernel page table walk.  Leaves physical PTE pointer in
          * REG1.  Jumps to FAIL_LABEL on early page table walk termination.
@@ -157,7 +241,7 @@
         and             REG2, (KERNEL_TSB_NENTRIES - 1), REG2; \
         sllx            REG2, 4, REG2; \
         add             REG1, REG2, REG2; \
-        ldda            [REG2] ASI_NUCLEUS_QUAD_LDD, REG3; \
+        KTSB_LOAD_QUAD(REG2, REG3); \
         cmp             REG3, TAG; \
         be,a,pt         %xcc, OK_LABEL; \
          mov            REG4, REG1;