[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>

7 files changed, 143 insertions, 47 deletions

diff --git a/arch/sparc64/kernel/dtlb_miss.S b/arch/sparc64/kernel/dtlb_miss.S
index d0f1565cb564..2ef6f6e6e72b 100644
--- a/arch/sparc64/kernel/dtlb_miss.S
+++ b/arch/sparc64/kernel/dtlb_miss.S
@@ -4,7 +4,7 @@
         srlx    %g6, 48, %g5                    ! Get context
         brz,pn  %g5, kvmap_dtlb                 ! Context 0 processing
          nop                                    ! Delay slot (fill me)
-        ldda    [%g1] ASI_NUCLEUS_QUAD_LDD, %g4 ! Load TSB entry
+        TSB_LOAD_QUAD(%g1, %g4)                 ! Load TSB entry
         nop                                     ! Push branch to next I$ line
         cmp     %g4, %g6                        ! Compare TAG
 
diff --git a/arch/sparc64/kernel/itlb_miss.S b/arch/sparc64/kernel/itlb_miss.S
index 6b6c8fee04bd..97facce27aad 100644
--- a/arch/sparc64/kernel/itlb_miss.S
+++ b/arch/sparc64/kernel/itlb_miss.S
@@ -4,7 +4,7 @@
         srlx    %g6, 48, %g5                    ! Get context
         brz,pn  %g5, kvmap_itlb                 ! Context 0 processing
          nop                                    ! Delay slot (fill me)
-        ldda    [%g1] ASI_NUCLEUS_QUAD_LDD, %g4 ! Load TSB entry
+        TSB_LOAD_QUAD(%g1, %g4)                 ! Load TSB entry
         cmp     %g4, %g6                        ! Compare TAG
         sethi   %hi(_PAGE_EXEC), %g4            ! Setup exec check
 
diff --git a/arch/sparc64/kernel/ktlb.S b/arch/sparc64/kernel/ktlb.S
index 2b5e71b68882..9b415ab6db6b 100644
--- a/arch/sparc64/kernel/ktlb.S
+++ b/arch/sparc64/kernel/ktlb.S
@@ -44,14 +44,14 @@ kvmap_itlb_tsb_miss:
 kvmap_itlb_vmalloc_addr:
         KERN_PGTABLE_WALK(%g4, %g5, %g2, kvmap_itlb_longpath)
 
-        TSB_LOCK_TAG(%g1, %g2, %g4)
+        KTSB_LOCK_TAG(%g1, %g2, %g4)
 
         /* Load and check PTE.  */
         ldxa            [%g5] ASI_PHYS_USE_EC, %g5
         brgez,a,pn      %g5, kvmap_itlb_longpath
-         stx            %g0, [%g1]
+         KTSB_STORE(%g1, %g0)
 
-        TSB_WRITE(%g1, %g5, %g6)
+        KTSB_WRITE(%g1, %g5, %g6)
 
         /* fallthrough to TLB load */
 
@@ -69,9 +69,9 @@ kvmap_itlb_longpath:
 kvmap_itlb_obp:
         OBP_TRANS_LOOKUP(%g4, %g5, %g2, %g3, kvmap_itlb_longpath)
 
-        TSB_LOCK_TAG(%g1, %g2, %g4)
+        KTSB_LOCK_TAG(%g1, %g2, %g4)
 
-        TSB_WRITE(%g1, %g5, %g6)
+        KTSB_WRITE(%g1, %g5, %g6)
 
         ba,pt           %xcc, kvmap_itlb_load
          nop
@@ -79,9 +79,9 @@ kvmap_itlb_obp:
 kvmap_dtlb_obp:
         OBP_TRANS_LOOKUP(%g4, %g5, %g2, %g3, kvmap_dtlb_longpath)
 
-        TSB_LOCK_TAG(%g1, %g2, %g4)
+        KTSB_LOCK_TAG(%g1, %g2, %g4)
 
-        TSB_WRITE(%g1, %g5, %g6)
+        KTSB_WRITE(%g1, %g5, %g6)
 
         ba,pt           %xcc, kvmap_dtlb_load
          nop
@@ -114,14 +114,14 @@ kvmap_linear_patch:
 kvmap_dtlb_vmalloc_addr:
         KERN_PGTABLE_WALK(%g4, %g5, %g2, kvmap_dtlb_longpath)
 
-        TSB_LOCK_TAG(%g1, %g2, %g4)
+        KTSB_LOCK_TAG(%g1, %g2, %g4)
 
         /* Load and check PTE.  */
         ldxa            [%g5] ASI_PHYS_USE_EC, %g5
         brgez,a,pn      %g5, kvmap_dtlb_longpath
-         stx            %g0, [%g1]
+         KTSB_STORE(%g1, %g0)
 
-        TSB_WRITE(%g1, %g5, %g6)
+        KTSB_WRITE(%g1, %g5, %g6)
 
         /* fallthrough to TLB load */
 
diff --git a/arch/sparc64/kernel/tsb.S b/arch/sparc64/kernel/tsb.S
index e1dd37f5e535..ff6a79beb98d 100644
--- a/arch/sparc64/kernel/tsb.S
+++ b/arch/sparc64/kernel/tsb.S
@@ -53,7 +53,7 @@ tsb_reload:
         /* Load and check PTE.  */
         ldxa            [%g5] ASI_PHYS_USE_EC, %g5
         brgez,a,pn      %g5, tsb_do_fault
-         stx            %g0, [%g1]
+         TSB_STORE(%g1, %g0)
 
         /* If it is larger than the base page size, don't
          * bother putting it into the TSB.
@@ -64,7 +64,7 @@ tsb_reload:
         and             %g2, %g4, %g2
         cmp             %g2, %g7
         bne,a,pn        %xcc, tsb_tlb_reload
-         stx            %g0, [%g1]
+         TSB_STORE(%g1, %g0)
 
         TSB_WRITE(%g1, %g5, %g6)
 
@@ -131,13 +131,13 @@ winfix_trampoline:
 
         /* Insert an entry into the TSB.
          *
-         * %o0: TSB entry pointer
+         * %o0: TSB entry pointer (virt or phys address)
          * %o1: tag
          * %o2: pte
          */
         .align  32
-        .globl  tsb_insert
-tsb_insert:
+        .globl  __tsb_insert
+__tsb_insert:
         rdpr    %pstate, %o5
         wrpr    %o5, PSTATE_IE, %pstate
         TSB_LOCK_TAG(%o0, %g2, %g3)
@@ -146,6 +146,31 @@ tsb_insert:
         retl
          nop
 
+        /* Flush the given TSB entry if it has the matching
+         * tag.
+         *
+         * %o0: TSB entry pointer (virt or phys address)
+         * %o1: tag
+         */
+        .align  32
+        .globl  tsb_flush
+tsb_flush:
+        sethi   %hi(TSB_TAG_LOCK_HIGH), %g2
+1:      TSB_LOAD_TAG(%o0, %g1)
+        srlx    %g1, 32, %o3
+        andcc   %o3, %g2, %g0
+        bne,pn  %icc, 1b
+         membar #LoadLoad
+        cmp     %g1, %o1
+        bne,pt  %xcc, 2f
+         clr    %o3
+        TSB_CAS_TAG(%o0, %g1, %o3)
+        cmp     %g1, %o3
+        bne,pn  %xcc, 1b
+         nop
+2:      retl
+         TSB_MEMBAR
+
         /* Reload MMU related context switch state at
          * schedule() time.
          *
diff --git a/arch/sparc64/kernel/vmlinux.lds.S b/arch/sparc64/kernel/vmlinux.lds.S
index 467d13a0d5c1..71b943f1c9b1 100644
--- a/arch/sparc64/kernel/vmlinux.lds.S
+++ b/arch/sparc64/kernel/vmlinux.lds.S
@@ -70,6 +70,10 @@ SECTIONS
   .con_initcall.init : { *(.con_initcall.init) }
   __con_initcall_end = .;
   SECURITY_INIT
+  . = ALIGN(4);
+  __tsb_phys_patch = .;
+  .tsb_phys_patch : { *(.tsb_phys_patch) }
+  __tsb_phys_patch_end = .;
   . = ALIGN(8192); 
   __initramfs_start = .;
   .init.ramfs : { *(.init.ramfs) }
diff --git a/arch/sparc64/mm/init.c b/arch/sparc64/mm/init.c
index 2c21d85de78f..4893f3e2c336 100644
--- a/arch/sparc64/mm/init.c
+++ b/arch/sparc64/mm/init.c
@@ -39,6 +39,7 @@
 #include <asm/tlb.h>
 #include <asm/spitfire.h>
 #include <asm/sections.h>
+#include <asm/tsb.h>
 
 extern void device_scan(void);
 
@@ -244,6 +245,16 @@ static __inline__ void clear_dcache_dirty_cpu(struct page *page, unsigned long c
                              : "g1", "g7");
 }
 
+static inline void tsb_insert(struct tsb *ent, unsigned long tag, unsigned long pte)
+{
+        unsigned long tsb_addr = (unsigned long) ent;
+
+        if (tlb_type == cheetah_plus)
+                tsb_addr = __pa(tsb_addr);
+
+        __tsb_insert(tsb_addr, tag, pte);
+}
+
 void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t pte)
 {
         struct mm_struct *mm;
@@ -1040,6 +1051,24 @@ unsigned long __init find_ecache_flush_span(unsigned long size)
         return ~0UL;
 }
 
+static void __init tsb_phys_patch(void)
+{
+        struct tsb_phys_patch_entry *p;
+
+        p = &__tsb_phys_patch;
+        while (p < &__tsb_phys_patch_end) {
+                unsigned long addr = p->addr;
+
+                *(unsigned int *) addr = p->insn;
+                wmb();
+                __asm__ __volatile__("flush     %0"
+                                     : /* no outputs */
+                                     : "r" (addr));
+
+                p++;
+        }
+}
+
 /* paging_init() sets up the page tables */
 
 extern void cheetah_ecache_flush_init(void);
@@ -1052,6 +1081,9 @@ void __init paging_init(void)
         unsigned long end_pfn, pages_avail, shift;
         unsigned long real_end, i;
 
+        if (tlb_type == cheetah_plus)
+                tsb_phys_patch();
+
         /* Find available physical memory... */
         read_obp_memory("available", &pavail[0], &pavail_ents);
 
diff --git a/arch/sparc64/mm/tsb.c b/arch/sparc64/mm/tsb.c
index 1c4e5c2dfc53..787533f01049 100644
--- a/arch/sparc64/mm/tsb.c
+++ b/arch/sparc64/mm/tsb.c
@@ -20,12 +20,9 @@ static inline unsigned long tsb_hash(unsigned long vaddr, unsigned long nentries
         return vaddr & (nentries - 1);
 }
 
-static inline int tag_compare(struct tsb *entry, unsigned long vaddr, unsigned long context)
+static inline int tag_compare(unsigned long tag, unsigned long vaddr, unsigned long context)
 {
-        if (context == ~0UL)
-                return 1;
-
-        return (entry->tag == ((vaddr >> 22) | (context << 48)));
+        return (tag == ((vaddr >> 22) | (context << 48)));
 }
 
 /* TSB flushes need only occur on the processor initiating the address
@@ -41,7 +38,7 @@ void flush_tsb_kernel_range(unsigned long start, unsigned long end)
                 unsigned long hash = tsb_hash(v, KERNEL_TSB_NENTRIES);
                 struct tsb *ent = &swapper_tsb[hash];
 
-                if (tag_compare(ent, v, 0)) {
+                if (tag_compare(ent->tag, v, 0)) {
                         ent->tag = 0UL;
                         membar_storeload_storestore();
                 }
@@ -52,24 +49,31 @@ void flush_tsb_user(struct mmu_gather *mp)
 {
         struct mm_struct *mm = mp->mm;
         struct tsb *tsb = mm->context.tsb;
-        unsigned long ctx = ~0UL;
         unsigned long nentries = mm->context.tsb_nentries;
+        unsigned long ctx, base;
         int i;
 
-        if (CTX_VALID(mm->context))
-                ctx = CTX_HWBITS(mm->context);
+        if (unlikely(!CTX_VALID(mm->context)))
+                return;
+
+        ctx = CTX_HWBITS(mm->context);
 
+        if (tlb_type == cheetah_plus)
+                base = __pa(tsb);
+        else
+                base = (unsigned long) tsb;
+        
         for (i = 0; i < mp->tlb_nr; i++) {
                 unsigned long v = mp->vaddrs[i];
-                struct tsb *ent;
+                unsigned long tag, ent, hash;
 
                 v &= ~0x1UL;
 
-                ent = &tsb[tsb_hash(v, nentries)];
-                if (tag_compare(ent, v, ctx)) {
-                        ent->tag = 0UL;
-                        membar_storeload_storestore();
-                }
+                hash = tsb_hash(v, nentries);
+                ent = base + (hash * sizeof(struct tsb));
+                tag = (v >> 22UL) | (ctx << 48UL);
+
+                tsb_flush(ent, tag);
         }
 }
 
@@ -84,6 +88,7 @@ static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_bytes)
         tte = (_PAGE_VALID | _PAGE_L | _PAGE_CP |
                _PAGE_CV    | _PAGE_P | _PAGE_W);
         tsb_paddr = __pa(mm->context.tsb);
+        BUG_ON(tsb_paddr & (tsb_bytes - 1UL));
 
         /* Use the smallest page size that can map the whole TSB
          * in one TLB entry.
@@ -144,13 +149,23 @@ static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_bytes)
                 BUG();
         };
 
-        tsb_reg |= base;
-        tsb_reg |= (tsb_paddr & (page_sz - 1UL));
-        tte |= (tsb_paddr & ~(page_sz - 1UL));
+        if (tlb_type == cheetah_plus) {
+                /* Physical mapping, no locked TLB entry for TSB.  */
+                tsb_reg |= tsb_paddr;
+
+                mm->context.tsb_reg_val = tsb_reg;
+                mm->context.tsb_map_vaddr = 0;
+                mm->context.tsb_map_pte = 0;
+        } else {
+                tsb_reg |= base;
+                tsb_reg |= (tsb_paddr & (page_sz - 1UL));
+                tte |= (tsb_paddr & ~(page_sz - 1UL));
+
+                mm->context.tsb_reg_val = tsb_reg;
+                mm->context.tsb_map_vaddr = base;
+                mm->context.tsb_map_pte = tte;
+        }
 
-        mm->context.tsb_reg_val = tsb_reg;
-        mm->context.tsb_map_vaddr = base;
-        mm->context.tsb_map_pte = tte;
 }
 
 /* The page tables are locked against modifications while this
@@ -168,13 +183,21 @@ static void copy_tsb(struct tsb *old_tsb, unsigned long old_size,
         for (i = 0; i < old_nentries; i++) {
                 register unsigned long tag asm("o4");
                 register unsigned long pte asm("o5");
-                unsigned long v;
-                unsigned int hash;
-
-                __asm__ __volatile__(
-                        "ldda [%2] %3, %0"
-                        : "=r" (tag), "=r" (pte)
-                        : "r" (&old_tsb[i]), "i" (ASI_NUCLEUS_QUAD_LDD));
+                unsigned long v, hash;
+
+                if (tlb_type == cheetah_plus) {
+                        __asm__ __volatile__(
+                                "ldda [%2] %3, %0"
+                                : "=r" (tag), "=r" (pte)
+                                : "r" (__pa(&old_tsb[i])),
+                                  "i" (ASI_QUAD_LDD_PHYS));
+                } else {
+                        __asm__ __volatile__(
+                                "ldda [%2] %3, %0"
+                                : "=r" (tag), "=r" (pte)
+                                : "r" (&old_tsb[i]),
+                                  "i" (ASI_NUCLEUS_QUAD_LDD));
+                }
 
                 if (!tag || (tag & (1UL << TSB_TAG_LOCK_BIT)))
                         continue;
@@ -198,8 +221,20 @@ static void copy_tsb(struct tsb *old_tsb, unsigned long old_size,
                 v |= (i & (512UL - 1UL)) << 13UL;
 
                 hash = tsb_hash(v, new_nentries);
-                new_tsb[hash].tag = tag;
-                new_tsb[hash].pte = pte;
+                if (tlb_type == cheetah_plus) {
+                        __asm__ __volatile__(
+                                "stxa   %0, [%1] %2\n\t"
+                                "stxa   %3, [%4] %2"
+                                : /* no outputs */
+                                : "r" (tag),
+                                  "r" (__pa(&new_tsb[hash].tag)),
+                                  "i" (ASI_PHYS_USE_EC),
+                                  "r" (pte),
+                                  "r" (__pa(&new_tsb[hash].pte)));
+                } else {
+                        new_tsb[hash].tag = tag;
+                        new_tsb[hash].pte = pte;
+                }
         }
 }