1 files changed, 91 insertions, 36 deletions

diff --git a/arch/sparc64/kernel/head.S b/arch/sparc64/kernel/head.S
index 24340496cdd3..f1dcdf8f7433 100644
--- a/arch/sparc64/kernel/head.S
+++ b/arch/sparc64/kernel/head.S
@@ -382,32 +382,79 @@ tlb_fixup_done:
          nop
         /* Not reached... */
 
-/* IMPORTANT NOTE: Whenever making changes here, check
- * trampoline.S as well. -jj */
-        .globl  setup_tba
-setup_tba:      /* i0 = is_starfire */
-        save    %sp, -160, %sp
+        /* This is meant to allow the sharing of this code between
+         * boot processor invocation (via setup_tba() below) and
+         * secondary processor startup (via trampoline.S).  The
+         * former does use this code, the latter does not yet due
+         * to some complexities.  That should be fixed up at some
+         * point.
+         */
+        .globl  setup_trap_table
+setup_trap_table:
+        save    %sp, -192, %sp
+
+        /* Force interrupts to be disabled.  Transferring over to
+         * the Linux trap table is a very delicate operation.
+         * Until we are actually on the Linux trap table, we cannot
+         * get the PAGE_OFFSET linear mappings translated.  We need
+         * that mapping to be setup in order to initialize the firmware
+         * page tables.
+         *
+         * So there is this window of time, from the return from
+         * prom_set_trap_table() until inherit_prom_mappings_post()
+         * (in arch/sparc64/mm/init.c) completes, during which no
+         * firmware address space accesses can be made.
+         */
+        rdpr    %pstate, %o1
+        andn    %o1, PSTATE_IE, %o1
+        wrpr    %o1, 0x0, %pstate
+        wrpr    %g0, 15, %pil
 
-        rdpr    %tba, %g7
-        sethi   %hi(prom_tba), %o1
-        or      %o1, %lo(prom_tba), %o1
-        stx     %g7, [%o1]
+        /* Ok, now make the final valid firmware call to jump over
+         * to the Linux trap table.
+         */
+        call    prom_set_trap_table
+         sethi  %hi(sparc64_ttable_tl0), %o0
+
+        /* Start using proper page size encodings in ctx register.  */
+        sethi   %hi(sparc64_kern_pri_context), %g3
+        ldx     [%g3 + %lo(sparc64_kern_pri_context)], %g2
+        mov     PRIMARY_CONTEXT, %g1
+        stxa    %g2, [%g1] ASI_DMMU
+        membar  #Sync
+
+        /* The Linux trap handlers expect various trap global registers
+         * to be setup with some fixed values.  So here we set these
+         * up very carefully.  These globals are:
+         *
+         * Alternate Globals (PSTATE_AG):
+         *
+         * %g6                  --> current_thread_info()
+         *
+         * MMU Globals (PSTATE_MG):
+         *
+         * %g1                  --> TLB_SFSR
+         * %g2                  --> ((_PAGE_VALID | _PAGE_SZ4MB |
+         *                            _PAGE_CP | _PAGE_CV | _PAGE_P | _PAGE_W)
+         *                           ^ 0xfffff80000000000)
+         * (this %g2 value is used for computing the PAGE_OFFSET kernel
+         *  TLB entries quickly, the virtual address of the fault XOR'd
+         *  with this %g2 value is the PTE to load into the TLB)
+         * %g3                  --> VPTE_BASE_CHEETAH or VPTE_BASE_SPITFIRE
+         *
+         * Interrupt Globals (PSTATE_IG, setup by init_irqwork_curcpu()):
+         *
+         * %g6                  --> __irq_work[smp_processor_id()]
+         */
 
-        /* Setup "Linux" globals 8-) */
         rdpr    %pstate, %o1
         mov     %g6, %o2
-        wrpr    %o1, (PSTATE_AG|PSTATE_IE), %pstate
-        sethi   %hi(sparc64_ttable_tl0), %g1
-        wrpr    %g1, %tba
+        wrpr    %o1, PSTATE_AG, %pstate
         mov     %o2, %g6
 
-        /* Set up MMU globals */
-        wrpr    %o1, (PSTATE_MG|PSTATE_IE), %pstate
-
-        /* Set fixed globals used by dTLB miss handler. */
 #define KERN_HIGHBITS           ((_PAGE_VALID|_PAGE_SZ4MB)^0xfffff80000000000)
 #define KERN_LOWBITS            (_PAGE_CP | _PAGE_CV | _PAGE_P | _PAGE_W)
-
+        wrpr    %o1, PSTATE_MG, %pstate
         mov     TSB_REG, %g1
         stxa    %g0, [%g1] ASI_DMMU
         membar  #Sync
@@ -419,17 +466,17 @@ setup_tba:	/* i0 = is_starfire */
         sllx    %g2, 32, %g2
         or      %g2, KERN_LOWBITS, %g2
 
-        BRANCH_IF_ANY_CHEETAH(g3,g7,cheetah_vpte_base)
-        ba,pt   %xcc, spitfire_vpte_base
+        BRANCH_IF_ANY_CHEETAH(g3,g7,8f)
+        ba,pt   %xcc, 9f
          nop
 
-cheetah_vpte_base:
+8:
         sethi           %uhi(VPTE_BASE_CHEETAH), %g3
         or              %g3, %ulo(VPTE_BASE_CHEETAH), %g3
         ba,pt           %xcc, 2f
          sllx           %g3, 32, %g3
 
-spitfire_vpte_base:
+9:
         sethi           %uhi(VPTE_BASE_SPITFIRE), %g3
         or              %g3, %ulo(VPTE_BASE_SPITFIRE), %g3
         sllx            %g3, 32, %g3
@@ -455,29 +502,37 @@ spitfire_vpte_base:
         sllx    %o2, 32, %o2
         wr      %o2, %asr25
 
-        /* Ok, we're done setting up all the state our trap mechanims needs,
-         * now get back into normal globals and let the PROM know what is up.
-         */
 2:
         wrpr    %g0, %g0, %wstate
-        wrpr    %o1, PSTATE_IE, %pstate
+        wrpr    %o1, 0x0, %pstate
 
         call    init_irqwork_curcpu
          nop
 
-        call    prom_set_trap_table
-         sethi  %hi(sparc64_ttable_tl0), %o0
-
-        /* Start using proper page size encodings in ctx register.  */
-        sethi   %hi(sparc64_kern_pri_context), %g3
-        ldx     [%g3 + %lo(sparc64_kern_pri_context)], %g2
-        mov     PRIMARY_CONTEXT, %g1
-        stxa    %g2, [%g1] ASI_DMMU
-        membar  #Sync
-
+        /* Now we can turn interrupts back on. */
         rdpr    %pstate, %o1
         or      %o1, PSTATE_IE, %o1
         wrpr    %o1, 0, %pstate
+        wrpr    %g0, 0x0, %pil
+
+        ret
+         restore
+
+        .globl  setup_tba
+setup_tba:      /* i0 = is_starfire */
+        save    %sp, -192, %sp
+
+        /* The boot processor is the only cpu which invokes this
+         * routine, the other cpus set things up via trampoline.S.
+         * So save the OBP trap table address here.
+         */
+        rdpr    %tba, %g7
+        sethi   %hi(prom_tba), %o1
+        or      %o1, %lo(prom_tba), %o1
+        stx     %g7, [%o1]
+
+        call    setup_trap_table
+         nop
 
         ret
          restore