1 /* head.S: Initial boot code for the Sparc64 port of Linux.
3 * Copyright (C) 1996, 1997, 2007 David S. Miller (davem@davemloft.net)
4 * Copyright (C) 1996 David Sitsky (David.Sitsky@anu.edu.au)
5 * Copyright (C) 1997, 1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
6 * Copyright (C) 1997 Miguel de Icaza (miguel@nuclecu.unam.mx)
9 #include <linux/version.h>
10 #include <linux/errno.h>
11 #include <linux/threads.h>
12 #include <linux/init.h>
13 #include <asm/thread_info.h>
15 #include <asm/pstate.h>
16 #include <asm/ptrace.h>
17 #include <asm/spitfire.h>
19 #include <asm/pgtable.h>
20 #include <asm/errno.h>
21 #include <asm/signal.h>
22 #include <asm/processor.h>
27 #include <asm/ttable.h>
29 #include <asm/cpudata.h>
31 #include <asm/estate.h>
32 #include <asm/sfafsr.h>
33 #include <asm/unistd.h>
35 /* This section from from _start to sparc64_boot_end should fit into
36 * 0x0000000000404000 to 0x0000000000408000.
39 .globl start, _start, stext, _stext
46 flushw /* Flush register file. */
48 /* This stuff has to be in sync with SILO and other potential boot loaders
49 * Fields should be kept upward compatible and whenever any change is made,
50 * HdrS version should be incremented.
52 .global root_flags, ram_flags, root_dev
53 .global sparc_ramdisk_image, sparc_ramdisk_size
54 .global sparc_ramdisk_image64
57 .word LINUX_VERSION_CODE
61 * 0x0300 : Supports being located at other than 0x4000
62 * 0x0202 : Supports kernel params string
63 * 0x0201 : Supports reboot_command
65 .half 0x0301 /* HdrS version */
79 sparc_ramdisk_image64:
83 /* PROM cif handler code address is in %o4. */
87 /* We need to remap the kernel. Use position independant
88 * code to remap us to KERNBASE.
90 * SILO can invoke us with 32-bit address masking enabled,
91 * so make sure that's clear.
94 andn %g1, PSTATE_AM, %g1
95 wrpr %g1, 0x0, %pstate
98 .globl prom_finddev_name, prom_chosen_path, prom_root_node
99 .globl prom_getprop_name, prom_mmu_name, prom_peer_name
100 .globl prom_callmethod_name, prom_translate_name, prom_root_compatible
101 .globl prom_map_name, prom_unmap_name, prom_mmu_ihandle_cache
102 .globl prom_boot_mapped_pc, prom_boot_mapping_mode
103 .globl prom_boot_mapping_phys_high, prom_boot_mapping_phys_low
104 .globl prom_compatible_name, prom_cpu_path, prom_cpu_compatible
105 .globl is_sun4v, sun4v_chip_type, prom_set_trap_table_name
108 prom_compatible_name:
120 prom_callmethod_name:
128 prom_set_trap_table_name:
129 .asciz "SUNW,set-trap-table"
133 .asciz "SUNW,UltraSPARC-T"
135 prom_root_compatible:
141 prom_mmu_ihandle_cache:
145 prom_boot_mapping_mode:
148 prom_boot_mapping_phys_high:
150 prom_boot_mapping_phys_low:
155 .word SUN4V_CHIP_INVALID
159 mov (1b - prom_peer_name), %l1
163 /* prom_root_node = prom_peer(0) */
164 stx %l1, [%sp + 2047 + 128 + 0x00] ! service, "peer"
166 stx %l3, [%sp + 2047 + 128 + 0x08] ! num_args, 1
167 stx %l3, [%sp + 2047 + 128 + 0x10] ! num_rets, 1
168 stx %l2, [%sp + 2047 + 128 + 0x18] ! arg1, 0
169 stx %g0, [%sp + 2047 + 128 + 0x20] ! ret1
171 add %sp, (2047 + 128), %o0 ! argument array
173 ldx [%sp + 2047 + 128 + 0x20], %l4 ! prom root node
174 mov (1b - prom_root_node), %l1
178 mov (1b - prom_getprop_name), %l1
179 mov (1b - prom_compatible_name), %l2
180 mov (1b - prom_root_compatible), %l5
185 /* prom_getproperty(prom_root_node, "compatible",
186 * &prom_root_compatible, 64)
188 stx %l1, [%sp + 2047 + 128 + 0x00] ! service, "getprop"
190 stx %l3, [%sp + 2047 + 128 + 0x08] ! num_args, 4
192 stx %l3, [%sp + 2047 + 128 + 0x10] ! num_rets, 1
193 stx %l4, [%sp + 2047 + 128 + 0x18] ! arg1, prom_root_node
194 stx %l2, [%sp + 2047 + 128 + 0x20] ! arg2, "compatible"
195 stx %l5, [%sp + 2047 + 128 + 0x28] ! arg3, &prom_root_compatible
197 stx %l3, [%sp + 2047 + 128 + 0x30] ! arg4, size
198 stx %g0, [%sp + 2047 + 128 + 0x38] ! ret1
200 add %sp, (2047 + 128), %o0 ! argument array
202 mov (1b - prom_finddev_name), %l1
203 mov (1b - prom_chosen_path), %l2
204 mov (1b - prom_boot_mapped_pc), %l3
209 sub %sp, (192 + 128), %sp
211 /* chosen_node = prom_finddevice("/chosen") */
212 stx %l1, [%sp + 2047 + 128 + 0x00] ! service, "finddevice"
214 stx %l3, [%sp + 2047 + 128 + 0x08] ! num_args, 1
215 stx %l3, [%sp + 2047 + 128 + 0x10] ! num_rets, 1
216 stx %l2, [%sp + 2047 + 128 + 0x18] ! arg1, "/chosen"
217 stx %g0, [%sp + 2047 + 128 + 0x20] ! ret1
219 add %sp, (2047 + 128), %o0 ! argument array
221 ldx [%sp + 2047 + 128 + 0x20], %l4 ! chosen device node
223 mov (1b - prom_getprop_name), %l1
224 mov (1b - prom_mmu_name), %l2
225 mov (1b - prom_mmu_ihandle_cache), %l5
230 /* prom_mmu_ihandle_cache = prom_getint(chosen_node, "mmu") */
231 stx %l1, [%sp + 2047 + 128 + 0x00] ! service, "getprop"
233 stx %l3, [%sp + 2047 + 128 + 0x08] ! num_args, 4
235 stx %l3, [%sp + 2047 + 128 + 0x10] ! num_rets, 1
236 stx %l4, [%sp + 2047 + 128 + 0x18] ! arg1, chosen_node
237 stx %l2, [%sp + 2047 + 128 + 0x20] ! arg2, "mmu"
238 stx %l5, [%sp + 2047 + 128 + 0x28] ! arg3, &prom_mmu_ihandle_cache
240 stx %l3, [%sp + 2047 + 128 + 0x30] ! arg4, sizeof(arg3)
241 stx %g0, [%sp + 2047 + 128 + 0x38] ! ret1
243 add %sp, (2047 + 128), %o0 ! argument array
245 mov (1b - prom_callmethod_name), %l1
246 mov (1b - prom_translate_name), %l2
249 lduw [%l5], %l5 ! prom_mmu_ihandle_cache
251 stx %l1, [%sp + 2047 + 128 + 0x00] ! service, "call-method"
253 stx %l3, [%sp + 2047 + 128 + 0x08] ! num_args, 3
255 stx %l3, [%sp + 2047 + 128 + 0x10] ! num_rets, 5
256 stx %l2, [%sp + 2047 + 128 + 0x18] ! arg1: "translate"
257 stx %l5, [%sp + 2047 + 128 + 0x20] ! arg2: prom_mmu_ihandle_cache
261 stx %l3, [%sp + 2047 + 128 + 0x28] ! arg3: vaddr, our PC
262 stx %g0, [%sp + 2047 + 128 + 0x30] ! res1
263 stx %g0, [%sp + 2047 + 128 + 0x38] ! res2
264 stx %g0, [%sp + 2047 + 128 + 0x40] ! res3
265 stx %g0, [%sp + 2047 + 128 + 0x48] ! res4
266 stx %g0, [%sp + 2047 + 128 + 0x50] ! res5
268 add %sp, (2047 + 128), %o0 ! argument array
270 ldx [%sp + 2047 + 128 + 0x40], %l1 ! translation mode
271 mov (1b - prom_boot_mapping_mode), %l4
274 mov (1b - prom_boot_mapping_phys_high), %l4
276 ldx [%sp + 2047 + 128 + 0x48], %l2 ! physaddr high
278 ldx [%sp + 2047 + 128 + 0x50], %l3 ! physaddr low
284 /* Leave service as-is, "call-method" */
286 stx %l3, [%sp + 2047 + 128 + 0x08] ! num_args, 7
288 stx %l3, [%sp + 2047 + 128 + 0x10] ! num_rets, 1
289 mov (1b - prom_map_name), %l3
291 stx %l3, [%sp + 2047 + 128 + 0x18] ! arg1: "map"
292 /* Leave arg2 as-is, prom_mmu_ihandle_cache */
294 stx %l3, [%sp + 2047 + 128 + 0x28] ! arg3: mode (-1 default)
295 /* 4MB align the kernel image size. */
296 set (_end - KERNBASE), %l3
297 set ((4 * 1024 * 1024) - 1), %l4
300 stx %l3, [%sp + 2047 + 128 + 0x30] ! arg4: roundup(ksize, 4MB)
301 sethi %hi(KERNBASE), %l3
302 stx %l3, [%sp + 2047 + 128 + 0x38] ! arg5: vaddr (KERNBASE)
303 stx %g0, [%sp + 2047 + 128 + 0x40] ! arg6: empty
304 mov (1b - prom_boot_mapping_phys_low), %l3
307 stx %l3, [%sp + 2047 + 128 + 0x48] ! arg7: phys addr
309 add %sp, (2047 + 128), %o0 ! argument array
311 add %sp, (192 + 128), %sp
313 sethi %hi(prom_root_compatible), %g1
314 or %g1, %lo(prom_root_compatible), %g1
315 sethi %hi(prom_sun4v_name), %g7
316 or %g7, %lo(prom_sun4v_name), %g7
327 sethi %hi(is_sun4v), %g1
328 or %g1, %lo(is_sun4v), %g1
332 /* cpu_node = prom_finddevice("/cpu") */
333 mov (1b - prom_finddev_name), %l1
334 mov (1b - prom_cpu_path), %l2
337 sub %sp, (192 + 128), %sp
339 stx %l1, [%sp + 2047 + 128 + 0x00] ! service, "finddevice"
341 stx %l3, [%sp + 2047 + 128 + 0x08] ! num_args, 1
342 stx %l3, [%sp + 2047 + 128 + 0x10] ! num_rets, 1
343 stx %l2, [%sp + 2047 + 128 + 0x18] ! arg1, "/cpu"
344 stx %g0, [%sp + 2047 + 128 + 0x20] ! ret1
346 add %sp, (2047 + 128), %o0 ! argument array
348 ldx [%sp + 2047 + 128 + 0x20], %l4 ! cpu device node
350 mov (1b - prom_getprop_name), %l1
351 mov (1b - prom_compatible_name), %l2
352 mov (1b - prom_cpu_compatible), %l5
357 /* prom_getproperty(cpu_node, "compatible",
358 * &prom_cpu_compatible, 64)
360 stx %l1, [%sp + 2047 + 128 + 0x00] ! service, "getprop"
362 stx %l3, [%sp + 2047 + 128 + 0x08] ! num_args, 4
364 stx %l3, [%sp + 2047 + 128 + 0x10] ! num_rets, 1
365 stx %l4, [%sp + 2047 + 128 + 0x18] ! arg1, cpu_node
366 stx %l2, [%sp + 2047 + 128 + 0x20] ! arg2, "compatible"
367 stx %l5, [%sp + 2047 + 128 + 0x28] ! arg3, &prom_cpu_compatible
369 stx %l3, [%sp + 2047 + 128 + 0x30] ! arg4, size
370 stx %g0, [%sp + 2047 + 128 + 0x38] ! ret1
372 add %sp, (2047 + 128), %o0 ! argument array
374 add %sp, (192 + 128), %sp
376 sethi %hi(prom_cpu_compatible), %g1
377 or %g1, %lo(prom_cpu_compatible), %g1
378 sethi %hi(prom_niagara_prefix), %g7
379 or %g7, %lo(prom_niagara_prefix), %g7
390 sethi %hi(prom_cpu_compatible), %g1
391 or %g1, %lo(prom_cpu_compatible), %g1
395 mov SUN4V_CHIP_NIAGARA1, %g4
398 mov SUN4V_CHIP_NIAGARA2, %g4
400 mov SUN4V_CHIP_UNKNOWN, %g4
401 5: sethi %hi(sun4v_chip_type), %g2
402 or %g2, %lo(sun4v_chip_type), %g2
406 BRANCH_IF_SUN4V(g1, jump_to_sun4u_init)
407 BRANCH_IF_CHEETAH_BASE(g1,g7,cheetah_boot)
408 BRANCH_IF_CHEETAH_PLUS_OR_FOLLOWON(g1,g7,cheetah_plus_boot)
409 ba,pt %xcc, spitfire_boot
413 /* Preserve OBP chosen DCU and DCR register settings. */
414 ba,pt %xcc, cheetah_generic_boot
418 mov DCR_BPE | DCR_RPE | DCR_SI | DCR_IFPOE | DCR_MS, %g1
421 sethi %uhi(DCU_ME|DCU_RE|DCU_HPE|DCU_SPE|DCU_SL|DCU_WE), %g7
422 or %g7, %ulo(DCU_ME|DCU_RE|DCU_HPE|DCU_SPE|DCU_SL|DCU_WE), %g7
424 or %g7, DCU_DM | DCU_IM | DCU_DC | DCU_IC, %g7
425 stxa %g7, [%g0] ASI_DCU_CONTROL_REG
428 cheetah_generic_boot:
429 mov TSB_EXTENSION_P, %g3
430 stxa %g0, [%g3] ASI_DMMU
431 stxa %g0, [%g3] ASI_IMMU
434 mov TSB_EXTENSION_S, %g3
435 stxa %g0, [%g3] ASI_DMMU
438 mov TSB_EXTENSION_N, %g3
439 stxa %g0, [%g3] ASI_DMMU
440 stxa %g0, [%g3] ASI_IMMU
443 ba,a,pt %xcc, jump_to_sun4u_init
446 /* Typically PROM has already enabled both MMU's and both on-chip
447 * caches, but we do it here anyway just to be paranoid.
449 mov (LSU_CONTROL_IC|LSU_CONTROL_DC|LSU_CONTROL_IM|LSU_CONTROL_DM), %g1
450 stxa %g1, [%g0] ASI_LSU_CONTROL
455 * Make sure we are in privileged mode, have address masking,
456 * using the ordinary globals and have enabled floating
459 * Again, typically PROM has left %pil at 13 or similar, and
460 * (PSTATE_PRIV | PSTATE_PEF | PSTATE_IE) in %pstate.
462 wrpr %g0, (PSTATE_PRIV|PSTATE_PEF|PSTATE_IE), %pstate
469 .section .text.init.refok
471 BRANCH_IF_SUN4V(g1, sun4v_init)
474 mov PRIMARY_CONTEXT, %g7
475 stxa %g0, [%g7] ASI_DMMU
478 mov SECONDARY_CONTEXT, %g7
479 stxa %g0, [%g7] ASI_DMMU
482 ba,pt %xcc, sun4u_continue
487 mov PRIMARY_CONTEXT, %g7
488 stxa %g0, [%g7] ASI_MMU
491 mov SECONDARY_CONTEXT, %g7
492 stxa %g0, [%g7] ASI_MMU
494 ba,pt %xcc, niagara_tlb_fixup
498 BRANCH_IF_ANY_CHEETAH(g1, g7, cheetah_tlb_fixup)
500 ba,pt %xcc, spitfire_tlb_fixup
504 mov 3, %g2 /* Set TLB type to hypervisor. */
505 sethi %hi(tlb_type), %g1
506 stw %g2, [%g1 + %lo(tlb_type)]
508 /* Patch copy/clear ops. */
509 sethi %hi(sun4v_chip_type), %g1
510 lduw [%g1 + %lo(sun4v_chip_type)], %g1
511 cmp %g1, SUN4V_CHIP_NIAGARA1
512 be,pt %xcc, niagara_patch
513 cmp %g1, SUN4V_CHIP_NIAGARA2
514 be,pt %xcc, niagara2_patch
517 call generic_patch_copyops
519 call generic_patch_bzero
521 call generic_patch_pageops
526 call niagara2_patch_copyops
528 call niagara_patch_bzero
530 call niagara2_patch_pageops
536 call niagara_patch_copyops
538 call niagara_patch_bzero
540 call niagara_patch_pageops
544 /* Patch TLB/cache ops. */
545 call hypervisor_patch_cachetlbops
548 ba,pt %xcc, tlb_fixup_done
552 mov 2, %g2 /* Set TLB type to cheetah+. */
553 BRANCH_IF_CHEETAH_PLUS_OR_FOLLOWON(g1,g7,1f)
555 mov 1, %g2 /* Set TLB type to cheetah. */
557 1: sethi %hi(tlb_type), %g1
558 stw %g2, [%g1 + %lo(tlb_type)]
560 /* Patch copy/page operations to cheetah optimized versions. */
561 call cheetah_patch_copyops
563 call cheetah_patch_copy_page
565 call cheetah_patch_cachetlbops
568 ba,pt %xcc, tlb_fixup_done
572 /* Set TLB type to spitfire. */
574 sethi %hi(tlb_type), %g1
575 stw %g2, [%g1 + %lo(tlb_type)]
578 sethi %hi(init_thread_union), %g6
579 or %g6, %lo(init_thread_union), %g6
580 ldx [%g6 + TI_TASK], %g4
585 sllx %g1, THREAD_SHIFT, %g1
586 sub %g1, (STACKFRAME_SZ + STACK_BIAS), %g1
590 /* Set per-cpu pointer initially to zero, this makes
591 * the boot-cpu use the in-kernel-image per-cpu areas
592 * before setup_per_cpu_area() is invoked.
600 sethi %hi(__bss_start), %o0
601 or %o0, %lo(__bss_start), %o0
603 or %o1, %lo(_end), %o1
607 #ifdef CONFIG_LOCKDEP
608 /* We have this call this super early, as even prom_init can grab
609 * spinlocks and thus call into the lockdep code.
615 mov %l6, %o1 ! OpenPROM stack
617 mov %l7, %o0 ! OpenPROM cif handler
619 /* Initialize current_thread_info()->cpu as early as possible.
620 * In order to do that accurately we have to patch up the get_cpuid()
621 * assembler sequences. And that, in turn, requires that we know
622 * if we are on a Starfire box or not. While we're here, patch up
623 * the sun4v sequences as well.
625 call check_if_starfire
633 call hard_smp_processor_id
638 call boot_cpu_id_too_large
643 /* If we boot on a non-zero cpu, all of the per-cpu
644 * variable references we make before setting up the
645 * per-cpu areas will use a bogus offset. Put a
646 * compensating factor into __per_cpu_base to handle
649 * What the per-cpu code calculates is:
651 * __per_cpu_base + (cpu << __per_cpu_shift)
653 * These two variables are zero initially, so to
654 * make it all cancel out to zero we need to put
655 * "0 - (cpu << 0)" into __per_cpu_base so that the
656 * above formula evaluates to zero.
658 * We cannot even perform a printk() until this stuff
659 * is setup as that calls cpu_clock() which uses
663 sethi %hi(__per_cpu_base), %o2
664 stx %o1, [%o2 + %lo(__per_cpu_base)]
668 sth %o0, [%g6 + TI_CPU]
670 call prom_init_report
680 /* This is meant to allow the sharing of this code between
681 * boot processor invocation (via setup_tba() below) and
682 * secondary processor startup (via trampoline.S). The
683 * former does use this code, the latter does not yet due
684 * to some complexities. That should be fixed up at some
687 * There used to be enormous complexity wrt. transferring
688 * over from the firwmare's trap table to the Linux kernel's.
689 * For example, there was a chicken & egg problem wrt. building
690 * the OBP page tables, yet needing to be on the Linux kernel
691 * trap table (to translate PAGE_OFFSET addresses) in order to
694 * We now handle OBP tlb misses differently, via linear lookups
695 * into the prom_trans[] array. So that specific problem no
696 * longer exists. Yet, unfortunately there are still some issues
697 * preventing trampoline.S from using this code... ho hum.
699 .globl setup_trap_table
703 /* Force interrupts to be disabled. */
705 andn %l0, PSTATE_IE, %o1
706 wrpr %o1, 0x0, %pstate
710 /* Make the firmware call to jump over to the Linux trap table. */
711 sethi %hi(is_sun4v), %o0
712 lduw [%o0 + %lo(is_sun4v)], %o0
716 TRAP_LOAD_TRAP_BLOCK(%g2, %g3)
717 add %g2, TRAP_PER_CPU_FAULT_INFO, %g2
718 stxa %g2, [%g0] ASI_SCRATCHPAD
720 /* Compute physical address:
722 * paddr = kern_base + (mmfsa_vaddr - KERNBASE)
724 sethi %hi(KERNBASE), %g3
726 sethi %hi(kern_base), %g3
727 ldx [%g3 + %lo(kern_base)], %g3
729 sethi %hi(sparc64_ttable_tl0), %o0
731 set prom_set_trap_table_name, %g2
732 stx %g2, [%sp + 2047 + 128 + 0x00]
734 stx %g2, [%sp + 2047 + 128 + 0x08]
736 stx %g2, [%sp + 2047 + 128 + 0x10]
737 stx %o0, [%sp + 2047 + 128 + 0x18]
738 stx %o1, [%sp + 2047 + 128 + 0x20]
739 sethi %hi(p1275buf), %g2
740 or %g2, %lo(p1275buf), %g2
741 ldx [%g2 + 0x08], %o1
743 add %sp, (2047 + 128), %o0
748 1: sethi %hi(sparc64_ttable_tl0), %o0
749 set prom_set_trap_table_name, %g2
750 stx %g2, [%sp + 2047 + 128 + 0x00]
752 stx %g2, [%sp + 2047 + 128 + 0x08]
754 stx %g2, [%sp + 2047 + 128 + 0x10]
755 stx %o0, [%sp + 2047 + 128 + 0x18]
756 sethi %hi(p1275buf), %g2
757 or %g2, %lo(p1275buf), %g2
758 ldx [%g2 + 0x08], %o1
760 add %sp, (2047 + 128), %o0
762 /* Start using proper page size encodings in ctx register. */
763 2: sethi %hi(sparc64_kern_pri_context), %g3
764 ldx [%g3 + %lo(sparc64_kern_pri_context)], %g2
766 mov PRIMARY_CONTEXT, %g1
768 661: stxa %g2, [%g1] ASI_DMMU
769 .section .sun4v_1insn_patch, "ax"
771 stxa %g2, [%g1] ASI_MMU
776 BRANCH_IF_SUN4V(o2, 1f)
778 /* Kill PROM timer */
779 sethi %hi(0x80000000), %o2
781 wr %o2, 0, %tick_cmpr
783 BRANCH_IF_ANY_CHEETAH(o2, o3, 1f)
788 /* Disable STICK_INT interrupts. */
790 sethi %hi(0x80000000), %o2
795 wrpr %g0, %g0, %wstate
797 call init_irqwork_curcpu
800 /* Now we can restore interrupt state. */
811 /* The boot processor is the only cpu which invokes this
812 * routine, the other cpus set things up via trampoline.S.
813 * So save the OBP trap table address here.
816 sethi %hi(prom_tba), %o1
817 or %o1, %lo(prom_tba), %o1
820 call setup_trap_table
829 #include "winfixup.S"
830 #include "fpu_traps.S"
832 #include "getsetcc.S"
834 #include "spiterrs.S"
836 #include "misctrap.S"
837 #include "syscalls.S"
840 #include "sun4v_tlb_miss.S"
841 #include "sun4v_ivec.S"
846 * The following skip makes sure the trap table in ttable.S is aligned
847 * on a 32K boundary as required by the v9 specs for TBA register.
849 * We align to a 32K boundary, then we have the 32K kernel TSB,
850 * the 64K kernel 4MB TSB, and then the 32K aligned trap table.
853 .skip 0x4000 + _start - 1b
861 .globl swapper_4m_tsb
867 /* Some care needs to be exercised if you try to move the
868 * location of the trap table relative to other things. For
869 * one thing there are br* instructions in some of the
870 * trap table entires which branch back to code in ktlb.S
871 * Those instructions can only handle a signed 16-bit
874 * There is a binutils bug (bugzilla #4558) which causes
875 * the relocation overflow checks for such instructions to
876 * not be done correctly. So bintuils will not notice the
877 * error and will instead write junk into the relocation and
878 * you'll have an unbootable kernel.
888 .globl prom_tba, tlb_type
890 tlb_type: .word 0 /* Must NOT end up in BSS */
891 .section ".fixup",#alloc,#execinstr
893 .globl __ret_efault, __retl_efault
896 restore %g0, -EFAULT, %o0