[SPARC64]: Initial sun4v TLB miss handling infrastructure.

Things are a little tricky because, unlike sun4u, we have
to:

1) do a hypervisor trap to do the TLB load.
2) do the TSB lookup calculations by hand

Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 332 insertions, 16 deletions

diff --git a/arch/sparc64/kernel/head.S b/arch/sparc64/kernel/head.S
index 7840271d7aae..03fc0b5b1d98 100644
--- a/arch/sparc64/kernel/head.S
+++ b/arch/sparc64/kernel/head.S
@@ -474,6 +474,7 @@ setup_tba:
 sparc64_boot_end:
 
 #include "systbls.S"
+#include "sun4v_tlb_miss.S"
 #include "ktlb.S"
 #include "tsb.S"
 #include "etrap.S"
diff --git a/arch/sparc64/kernel/ktlb.S b/arch/sparc64/kernel/ktlb.S
index c1335432124e..2e55084a0c12 100644
--- a/arch/sparc64/kernel/ktlb.S
+++ b/arch/sparc64/kernel/ktlb.S
@@ -16,12 +16,16 @@
         .text
         .align          32
 
-        .globl          kvmap_itlb
 kvmap_itlb:
         /* g6: TAG TARGET */
         mov             TLB_TAG_ACCESS, %g4
         ldxa            [%g4] ASI_IMMU, %g4
 
+        /* sun4v_itlb_miss branches here with the missing virtual
+         * address already loaded into %g4
+         */
+kvmap_itlb_4v:
+
 kvmap_itlb_nonlinear:
         /* Catch kernel NULL pointer calls.  */
         sethi           %hi(PAGE_SIZE), %g5
@@ -94,11 +98,15 @@ kvmap_dtlb_obp:
          nop
 
         .align          32
-        .globl          kvmap_dtlb
 kvmap_dtlb:
         /* %g6: TAG TARGET */
         mov             TLB_TAG_ACCESS, %g4
         ldxa            [%g4] ASI_DMMU, %g4
+
+        /* sun4v_dtlb_miss branches here with the missing virtual
+         * address already loaded into %g4
+         */
+kvmap_dtlb_4v:
         brgez,pn        %g4, kvmap_dtlb_nonlinear
          nop
 
diff --git a/arch/sparc64/kernel/sun4v_tlb_miss.S b/arch/sparc64/kernel/sun4v_tlb_miss.S
new file mode 100644
index 000000000000..58ea5dd8573c
--- /dev/null
+++ b/arch/sparc64/kernel/sun4v_tlb_miss.S
@@ -0,0 +1,219 @@
+/* sun4v_tlb_miss.S: Sun4v TLB miss handlers.
+ *
+ * Copyright (C) 2006 <davem@davemloft.net>
+ */
+
+        .text
+        .align  32
+
+sun4v_itlb_miss:
+        /* Load CPU ID into %g3.  */
+        mov     SCRATCHPAD_CPUID, %g1
+        ldxa    [%g1] ASI_SCRATCHPAD, %g3
+        
+        /* Load UTSB reg into %g1.  */
+        ldxa    [%g1 + %g1] ASI_SCRATCHPAD, %g1
+
+        /* Load &trap_block[smp_processor_id()] into %g2.  */
+        sethi   %hi(trap_block), %g2
+        or      %g2, %lo(trap_block), %g2
+        sllx    %g3, TRAP_BLOCK_SZ_SHIFT, %g3
+        add     %g2, %g3, %g2
+
+        /* Create a TAG TARGET, "(vaddr>>22) | (ctx << 48)", in %g6.
+         * Branch if kernel TLB miss.  The kernel TSB and user TSB miss
+         * code wants the missing virtual address in %g4, so that value
+         * cannot be modified through the entirety of this handler.
+         */
+        ldx     [%g2 + TRAP_PER_CPU_FAULT_INFO + HV_FAULT_I_ADDR_OFFSET], %g4
+        ldx     [%g2 + TRAP_PER_CPU_FAULT_INFO + HV_FAULT_I_CTX_OFFSET], %g5
+        srlx    %g4, 22, %g3
+        sllx    %g5, 48, %g6
+        or      %g6, %g3, %g6
+        brz,pn  %g5, kvmap_itlb_4v
+         nop
+
+        /* Create TSB pointer.  This is something like:
+         *
+         * index_mask = (512 << (tsb_reg & 0x7UL)) - 1UL;
+         * tsb_base = tsb_reg & ~0x7UL;
+         */
+        and     %g1, 0x7, %g3
+        andn    %g1, 0x7, %g1
+        mov     512, %g7
+        sllx    %g7, %g3, %g7
+        sub     %g7, 1, %g7
+
+        /* TSB index mask is in %g7, tsb base is in %g1.  Compute
+         * the TSB entry pointer into %g1:
+         *
+         * tsb_index = ((vaddr >> PAGE_SHIFT) & tsb_mask);
+         * tsb_ptr = tsb_base + (tsb_index * 16);
+         */
+        srlx    %g4, PAGE_SHIFT, %g3
+        and     %g3, %g7, %g3
+        sllx    %g3, 4, %g3
+        add     %g1, %g3, %g1
+
+        /* Load TSB tag/pte into %g2/%g3 and compare the tag.  */
+        ldda    [%g1] ASI_QUAD_LDD_PHYS, %g2
+        cmp     %g2, %g6
+        sethi   %hi(_PAGE_EXEC), %g7
+        bne,a,pn %xcc, tsb_miss_page_table_walk
+         mov    FAULT_CODE_ITLB, %g3
+        andcc   %g3, %g7, %g0
+        be,a,pn %xcc, tsb_do_fault
+         mov    FAULT_CODE_ITLB, %g3
+
+        /* We have a valid entry, make hypervisor call to load
+         * I-TLB and return from trap.
+         *
+         * %g3: PTE
+         * %g4: vaddr
+         * %g6: TAG TARGET (only "CTX << 48" part matters)
+         */
+sun4v_itlb_load:
+        mov     %o0, %g1                ! save %o0
+        mov     %o1, %g2                ! save %o1
+        mov     %o2, %g5                ! save %o2
+        mov     %o3, %g7                ! save %o3
+        mov     %g4, %o0                ! vaddr
+        srlx    %g6, 48, %o1            ! ctx
+        mov     %g3, %o2                ! PTE
+        mov     HV_MMU_IMMU, %o3        ! flags
+        ta      HV_MMU_MAP_ADDR_TRAP
+        mov     %g1, %o0                ! restore %o0
+        mov     %g2, %o1                ! restore %o1
+        mov     %g5, %o2                ! restore %o2
+        mov     %g7, %o3                ! restore %o3
+
+        retry
+
+sun4v_dtlb_miss:
+        /* Load CPU ID into %g3.  */
+        mov     SCRATCHPAD_CPUID, %g1
+        ldxa    [%g1] ASI_SCRATCHPAD, %g3
+        
+        /* Load UTSB reg into %g1.  */
+        ldxa    [%g1 + %g1] ASI_SCRATCHPAD, %g1
+
+        /* Load &trap_block[smp_processor_id()] into %g2.  */
+        sethi   %hi(trap_block), %g2
+        or      %g2, %lo(trap_block), %g2
+        sllx    %g3, TRAP_BLOCK_SZ_SHIFT, %g3
+        add     %g2, %g3, %g2
+
+        /* Create a TAG TARGET, "(vaddr>>22) | (ctx << 48)", in %g6.
+         * Branch if kernel TLB miss.  The kernel TSB and user TSB miss
+         * code wants the missing virtual address in %g4, so that value
+         * cannot be modified through the entirety of this handler.
+         */
+        ldx     [%g2 + TRAP_PER_CPU_FAULT_INFO + HV_FAULT_D_ADDR_OFFSET], %g4
+        ldx     [%g2 + TRAP_PER_CPU_FAULT_INFO + HV_FAULT_D_CTX_OFFSET], %g5
+        srlx    %g4, 22, %g3
+        sllx    %g5, 48, %g6
+        or      %g6, %g3, %g6
+        brz,pn  %g5, kvmap_dtlb_4v
+         nop
+
+        /* Create TSB pointer.  This is something like:
+         *
+         * index_mask = (512 << (tsb_reg & 0x7UL)) - 1UL;
+         * tsb_base = tsb_reg & ~0x7UL;
+         */
+        and     %g1, 0x7, %g3
+        andn    %g1, 0x7, %g1
+        mov     512, %g7
+        sllx    %g7, %g3, %g7
+        sub     %g7, 1, %g7
+
+        /* TSB index mask is in %g7, tsb base is in %g1.  Compute
+         * the TSB entry pointer into %g1:
+         *
+         * tsb_index = ((vaddr >> PAGE_SHIFT) & tsb_mask);
+         * tsb_ptr = tsb_base + (tsb_index * 16);
+         */
+        srlx    %g4, PAGE_SHIFT, %g3
+        and     %g3, %g7, %g3
+        sllx    %g3, 4, %g3
+        add     %g1, %g3, %g1
+
+        /* Load TSB tag/pte into %g2/%g3 and compare the tag.  */
+        ldda    [%g1] ASI_QUAD_LDD_PHYS, %g2
+        cmp     %g2, %g6
+        bne,a,pn %xcc, tsb_miss_page_table_walk
+         mov    FAULT_CODE_ITLB, %g3
+
+        /* We have a valid entry, make hypervisor call to load
+         * D-TLB and return from trap.
+         *
+         * %g3: PTE
+         * %g4: vaddr
+         * %g6: TAG TARGET (only "CTX << 48" part matters)
+         */
+sun4v_dtlb_load:
+        mov     %o0, %g1                ! save %o0
+        mov     %o1, %g2                ! save %o1
+        mov     %o2, %g5                ! save %o2
+        mov     %o3, %g7                ! save %o3
+        mov     %g4, %o0                ! vaddr
+        srlx    %g6, 48, %o1            ! ctx
+        mov     %g3, %o2                ! PTE
+        mov     HV_MMU_DMMU, %o3        ! flags
+        ta      HV_MMU_MAP_ADDR_TRAP
+        mov     %g1, %o0                ! restore %o0
+        mov     %g2, %o1                ! restore %o1
+        mov     %g5, %o2                ! restore %o2
+        mov     %g7, %o3                ! restore %o3
+
+        retry
+
+sun4v_dtlb_prot:
+        /* Load CPU ID into %g3.  */
+        mov     SCRATCHPAD_CPUID, %g1
+        ldxa    [%g1] ASI_SCRATCHPAD, %g3
+        
+        /* Load &trap_block[smp_processor_id()] into %g2.  */
+        sethi   %hi(trap_block), %g2
+        or      %g2, %lo(trap_block), %g2
+        sllx    %g3, TRAP_BLOCK_SZ_SHIFT, %g3
+        add     %g2, %g3, %g2
+
+        ldx     [%g2 + TRAP_PER_CPU_FAULT_INFO + HV_FAULT_D_ADDR_OFFSET], %g5
+        rdpr    %tl, %g1
+        cmp     %g1, 1
+        bgu,pn          %xcc, winfix_trampoline
+         nop
+        ba,pt           %xcc, sparc64_realfault_common
+         mov            FAULT_CODE_DTLB | FAULT_CODE_WRITE, %g4
+
+#define BRANCH_ALWAYS   0x10680000
+#define NOP             0x01000000
+#define SUN4V_DO_PATCH(OLD, NEW)        \
+        sethi   %hi(NEW), %g1; \
+        or      %g1, %lo(NEW), %g1; \
+        sethi   %hi(OLD), %g2; \
+        or      %g2, %lo(OLD), %g2; \
+        sub     %g1, %g2, %g1; \
+        sethi   %hi(BRANCH_ALWAYS), %g3; \
+        srl     %g1, 2, %g1; \
+        or      %g3, %lo(BRANCH_ALWAYS), %g3; \
+        or      %g3, %g1, %g3; \
+        stw     %g3, [%g2]; \
+        sethi   %hi(NOP), %g3; \
+        or      %g3, %lo(NOP), %g3; \
+        stw     %g3, [%g2 + 0x4]; \
+        flush   %g2;
+
+        .globl  sun4v_patch_tlb_handlers
+        .type   sun4v_patch_tlb_handlers,#function
+sun4v_patch_tlb_handlers:
+        SUN4V_DO_PATCH(tl0_iamiss, sun4v_itlb_miss)
+        SUN4V_DO_PATCH(tl1_iamiss, sun4v_itlb_miss)
+        SUN4V_DO_PATCH(tl0_damiss, sun4v_dtlb_miss)
+        SUN4V_DO_PATCH(tl1_damiss, sun4v_dtlb_miss)
+        SUN4V_DO_PATCH(tl0_daprot, sun4v_dtlb_prot)
+        SUN4V_DO_PATCH(tl1_daprot, sun4v_dtlb_prot)
+        retl
+         nop
+        .size   sun4v_patch_tlb_handlers,.-sun4v_patch_tlb_handlers
diff --git a/arch/sparc64/kernel/tsb.S b/arch/sparc64/kernel/tsb.S
index 96e63168d8b2..818bc9e9135a 100644
--- a/arch/sparc64/kernel/tsb.S
+++ b/arch/sparc64/kernel/tsb.S
@@ -18,30 +18,33 @@
          * %g4: available temporary
          * %g5: available temporary
          * %g6: TAG TARGET
-         * %g7: physical address base of the linux page
+         * %g7: available temporary, will be loaded by us with
+         *      the physical address base of the linux page
          *      tables for the current address space
          */
-        .globl          tsb_miss_dtlb
 tsb_miss_dtlb:
         mov             TLB_TAG_ACCESS, %g4
         ldxa            [%g4] ASI_DMMU, %g4
         ba,pt           %xcc, tsb_miss_page_table_walk
          nop
 
-        .globl          tsb_miss_itlb
 tsb_miss_itlb:
         mov             TLB_TAG_ACCESS, %g4
         ldxa            [%g4] ASI_IMMU, %g4
         ba,pt           %xcc, tsb_miss_page_table_walk
          nop
 
+        /* The sun4v TLB miss handlers jump directly here instead
+         * of tsb_miss_{d,i}tlb with the missing virtual address
+         * already loaded into %g4.
+         */
 tsb_miss_page_table_walk:
         TRAP_LOAD_PGD_PHYS(%g7, %g5)
 
         USER_PGTABLE_WALK_TL1(%g4, %g7, %g5, %g2, tsb_do_fault)
 
 tsb_reload:
-        TSB_LOCK_TAG(%g1, %g2, %g4)
+        TSB_LOCK_TAG(%g1, %g2, %g7)
 
         /* Load and check PTE.  */
         ldxa            [%g5] ASI_PHYS_USE_EC, %g5
@@ -52,9 +55,9 @@ tsb_reload:
          * bother putting it into the TSB.
          */
         srlx            %g5, 32, %g2
-        sethi           %hi(_PAGE_ALL_SZ_BITS >> 32), %g4
+        sethi           %hi(_PAGE_ALL_SZ_BITS >> 32), %g7
+        and             %g2, %g7, %g2
         sethi           %hi(_PAGE_SZBITS >> 32), %g7
-        and             %g2, %g4, %g2
         cmp             %g2, %g7
         bne,a,pn        %xcc, tsb_tlb_reload
          TSB_STORE(%g1, %g0)
@@ -68,12 +71,54 @@ tsb_tlb_reload:
          nop
 
 tsb_dtlb_load:
-        stxa            %g5, [%g0] ASI_DTLB_DATA_IN
+
+661:    stxa            %g5, [%g0] ASI_DTLB_DATA_IN
         retry
+        .section        .gl_2insn_patch, "ax"
+        .word           661b
+        nop
+        nop
+        .previous
+
+        /* For sun4v the ASI_DTLB_DATA_IN store and the retry
+         * instruction get nop'd out and we get here to branch
+         * to the sun4v tlb load code.  The registers are setup
+         * as follows:
+         *
+         * %g4: vaddr
+         * %g5: PTE
+         * %g6: TAG
+         *
+         * The sun4v TLB load wants the PTE in %g3 so we fix that
+         * up here.
+         */
+        ba,pt           %xcc, sun4v_dtlb_load
+         mov            %g5, %g3
 
 tsb_itlb_load:
-        stxa            %g5, [%g0] ASI_ITLB_DATA_IN
+
+661:    stxa            %g5, [%g0] ASI_ITLB_DATA_IN
         retry
+        .section        .gl_2insn_patch, "ax"
+        .word           661b
+        nop
+        nop
+        .previous
+
+        /* For sun4v the ASI_ITLB_DATA_IN store and the retry
+         * instruction get nop'd out and we get here to branch
+         * to the sun4v tlb load code.  The registers are setup
+         * as follows:
+         *
+         * %g4: vaddr
+         * %g5: PTE
+         * %g6: TAG
+         *
+         * The sun4v TLB load wants the PTE in %g3 so we fix that
+         * up here.
+         */
+        ba,pt           %xcc, sun4v_itlb_load
+         mov            %g5, %g3
 
         /* No valid entry in the page tables, do full fault
          * processing.
@@ -95,10 +140,17 @@ tsb_do_fault:
          nop
 
 tsb_do_dtlb_fault:
-        rdpr    %tl, %g4
-        cmp     %g4, 1
-        mov     TLB_TAG_ACCESS, %g4
+        rdpr    %tl, %g3
+        cmp     %g3, 1
+
+661:    mov     TLB_TAG_ACCESS, %g4
         ldxa    [%g4] ASI_DMMU, %g5
+        .section .gl_2insn_patch, "ax"
+        .word   661b
+        mov     %g4, %g5
+        nop
+        .previous
+
         be,pt   %xcc, sparc64_realfault_common
          mov    FAULT_CODE_DTLB, %g4
         ba,pt   %xcc, winfix_trampoline
@@ -196,12 +248,23 @@ __tsb_context_switch:
         add     %g2, %g1, %g2
         stx     %o0, [%g2 + TRAP_PER_CPU_PGD_PADDR]
 
-        mov     TSB_REG, %g1
+661:    mov     TSB_REG, %g1
         stxa    %o1, [%g1] ASI_DMMU
+        .section .gl_2insn_patch, "ax"
+        .word   661b
+        mov     SCRATCHPAD_UTSBREG1, %g1
+        stxa    %o1, [%g1] ASI_SCRATCHPAD
+        .previous
+
         membar  #Sync
 
-        stxa    %o1, [%g1] ASI_IMMU
+661:    stxa    %o1, [%g1] ASI_IMMU
         membar  #Sync
+        .section .gl_2insn_patch, "ax"
+        .word   661b
+        nop
+        nop
+        .previous
 
         brz     %o2, 9f
          nop
diff --git a/arch/sparc64/kernel/vmlinux.lds.S b/arch/sparc64/kernel/vmlinux.lds.S
index 686bf6b3b03f..a09a8a2383dd 100644
--- a/arch/sparc64/kernel/vmlinux.lds.S
+++ b/arch/sparc64/kernel/vmlinux.lds.S
@@ -71,6 +71,9 @@ SECTIONS
   __con_initcall_end = .;
   SECURITY_INIT
   . = ALIGN(4);
+  __tsb_ldquad_phys_patch = .;
+  .tsb_ldquad_phys_patch : { *(.tsb_ldquad_phys_patch) }
+  __tsb_ldquad_phys_patch_end = .;
   __tsb_phys_patch = .;
   .tsb_phys_patch : { *(.tsb_phys_patch) }
   __tsb_phys_patch_end = .;
diff --git a/arch/sparc64/mm/init.c b/arch/sparc64/mm/init.c
index ab50cd9618f3..e9aac424877f 100644
--- a/arch/sparc64/mm/init.c
+++ b/arch/sparc64/mm/init.c
@@ -1050,8 +1050,25 @@ unsigned long __init find_ecache_flush_span(unsigned long size)
 
 static void __init tsb_phys_patch(void)
 {
+        struct tsb_ldquad_phys_patch_entry *pquad;
         struct tsb_phys_patch_entry *p;
 
+        pquad = &__tsb_ldquad_phys_patch;
+        while (pquad < &__tsb_ldquad_phys_patch_end) {
+                unsigned long addr = pquad->addr;
+
+                if (tlb_type == hypervisor)
+                        *(unsigned int *) addr = pquad->sun4v_insn;
+                else
+                        *(unsigned int *) addr = pquad->sun4u_insn;
+                wmb();
+                __asm__ __volatile__("flush     %0"
+                                     : /* no outputs */
+                                     : "r" (addr));
+
+                pquad++;
+        }
+
         p = &__tsb_phys_patch;
         while (p < &__tsb_phys_patch_end) {
                 unsigned long addr = p->addr;
@@ -1069,6 +1086,7 @@ static void __init tsb_phys_patch(void)
 /* paging_init() sets up the page tables */
 
 extern void cheetah_ecache_flush_init(void);
+extern void sun4v_patch_tlb_handlers(void);
 
 static unsigned long last_valid_pfn;
 pgd_t swapper_pg_dir[2048];
@@ -1078,9 +1096,13 @@ void __init paging_init(void)
         unsigned long end_pfn, pages_avail, shift;
         unsigned long real_end, i;
 
-        if (tlb_type == cheetah_plus)
+        if (tlb_type == cheetah_plus ||
+            tlb_type == hypervisor)
                 tsb_phys_patch();
 
+        if (tlb_type == hypervisor)
+                sun4v_patch_tlb_handlers();
+
         /* Find available physical memory... */
         read_obp_memory("available", &pavail[0], &pavail_ents);