[SPARC64]: Fix boot failures on SunBlade-150

[linux-2.6-omap-h63xx.git] / arch / sparc64 / kernel / head.S

diff --git a/arch/sparc64/kernel/head.S b/arch/sparc64/kernel/head.S
index 4c942f71184daa9d69345404794dc82be834fa2c..b49dcd4504b029e1684730a554fe5cd0684dc92b 100644 (file)
--- a/arch/sparc64/kernel/head.S
+++ b/arch/sparc64/kernel/head.S
@@ -28,19 +28,14 @@
 #include <asm/mmu.h>
        
 /* This section from from _start to sparc64_boot_end should fit into
- * 0x0000.0000.0040.4000 to 0x0000.0000.0040.8000 and will be sharing space
- * with bootup_user_stack, which is from 0x0000.0000.0040.4000 to
- * 0x0000.0000.0040.6000 and empty_bad_page, which is from
- * 0x0000.0000.0040.6000 to 0x0000.0000.0040.8000. 
+ * 0x0000000000404000 to 0x0000000000408000.
  */
-
        .text
        .globl  start, _start, stext, _stext
 _start:
 start:
 _stext:
 stext:
-bootup_user_stack:
 ! 0x0000000000404000
        b       sparc64_boot
         flushw                                 /* Flush register file.      */
@@ -392,31 +387,30 @@ tlb_fixup_done:
         * former does use this code, the latter does not yet due
         * to some complexities.  That should be fixed up at some
         * point.
+        *
+        * There used to be enormous complexity wrt. transferring
+        * over from the firwmare's trap table to the Linux kernel's.
+        * For example, there was a chicken & egg problem wrt. building
+        * the OBP page tables, yet needing to be on the Linux kernel
+        * trap table (to translate PAGE_OFFSET addresses) in order to
+        * do that.
+        *
+        * We now handle OBP tlb misses differently, via linear lookups
+        * into the prom_trans[] array.  So that specific problem no
+        * longer exists.  Yet, unfortunately there are still some issues
+        * preventing trampoline.S from using this code... ho hum.
         */
        .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.
-        */
+       /* Force interrupts to be disabled. */
        rdpr    %pstate, %o1
        andn    %o1, PSTATE_IE, %o1
        wrpr    %o1, 0x0, %pstate
        wrpr    %g0, 15, %pil
 
-       /* Ok, now make the final valid firmware call to jump over
-        * to the Linux trap table.
-        */
+       /* Make the firmware call to jump over to the Linux trap table.  */
        call    prom_set_trap_table
         sethi  %hi(sparc64_ttable_tl0), %o0
 
@@ -540,15 +534,21 @@ setup_tba:        /* i0 = is_starfire */
 
        ret
         restore
+sparc64_boot_end:
+
+#include "systbls.S"
+#include "ktlb.S"
+#include "etrap.S"
+#include "rtrap.S"
+#include "winfixup.S"
+#include "entry.S"
 
 /*
- * The following skips make sure the trap table in ttable.S is aligned
+ * The following skip makes sure the trap table in ttable.S is aligned
  * on a 32K boundary as required by the v9 specs for TBA register.
  */
-sparc64_boot_end:
-       .skip   0x2000 + _start - sparc64_boot_end
-bootup_user_stack_end:
-       .skip   0x2000
+1:
+       .skip   0x4000 + _start - 1b
 
 #ifdef CONFIG_SBUS
 /* This is just a hack to fool make depend config.h discovering
@@ -560,15 +560,6 @@ bootup_user_stack_end:
 ! 0x0000000000408000
 
 #include "ttable.S"
-#include "systbls.S"
-#include "ktlb.S"
-#include "etrap.S"
-#include "rtrap.S"
-#include "winfixup.S"
-#include "entry.S"
-
-       /* This is just anal retentiveness on my part... */
-       .align  16384
 
        .data
        .align  8