/* $Id: head.S,v 1.43 1997/07/07 03:05:25 davem Exp $ * head.S: Initial boot code for the Sparc64 port of Linux. * * Copyright (C) 1996,1997 David S. Miller (davem@caip.rutgers.edu) * Copyright (C) 1996 David Sitsky (David.Sitsky@anu.edu.au) * Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz) * Copyright (C) 1997 Miguel de Icaza (miguel@nuclecu.unam.mx) */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* 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 bootup_kernel_stack, which is from * 0x0000.0000.0040.6000 to 0x0000.0000.0040.8000. */ .text .globl start, _start, stext, _stext _start: start: _stext: stext: bootup_user_stack: ! 0x0000000000404000 b sparc64_boot flushw /* Flush register file. */ /* This stuff has to be in sync with SILO and other potential boot loaders * Fields should be kept upward compatible and whenever any change is made, * HdrS version should be incremented. */ .global root_flags, ram_flags, root_dev .global ramdisk_image, ramdisk_size .globl silo_args .ascii "HdrS" .word LINUX_VERSION_CODE .half 0x0202 /* HdrS version */ root_flags: .half 1 root_dev: .half 0 ram_flags: .half 0 ramdisk_image: .word 0 ramdisk_size: .word 0 .xword reboot_command .xword bootstr_len /* We must be careful, 32-bit OpenBOOT will get confused if it * tries to save away a register window to a 64-bit kernel * stack address. Flush all windows, disable interrupts, * remap if necessary, jump onto kernel trap table, then kernel * stack, or else we die. * * PROM entry point is on %o4 */ sparc64_boot: /* Typically PROM has already enabled both MMU's and both on-chip * caches, but we do it here anyway just to be paranoid. */ mov (LSU_CONTROL_IC|LSU_CONTROL_DC|LSU_CONTROL_IM|LSU_CONTROL_DM), %g1 stxa %g1, [%g0] ASI_LSU_CONTROL /* * Make sure we are in privileged mode, have address masking, * using the ordinary globals and have enabled floating * point. * * Again, typically PROM has left %pil at 13 or similar, and * (PSTATE_PRIV | PSTATE_PEF | PSTATE_IE) in %pstate. */ wrpr %g0, (PSTATE_PRIV|PSTATE_PEF|PSTATE_IE), %pstate create_mappings: /* %g5 holds the tlb data */ sethi %uhi(_PAGE_VALID | _PAGE_SZ4MB), %g5 sllx %g5, 32, %g5 or %g5, (_PAGE_CP | _PAGE_CV | _PAGE_P | _PAGE_L | _PAGE_W | _PAGE_G), %g5 /* Base of physical memory cannot reliably be assumed to be * at 0x0! Figure out where it happens to be. -DaveM */ /* Put PADDR tlb data mask into %g3. */ sethi %uhi(_PAGE_PADDR), %g3 or %g3, %ulo(_PAGE_PADDR), %g3 sllx %g3, 32, %g3 sethi %hi(_PAGE_PADDR), %g7 or %g7, %lo(_PAGE_PADDR), %g7 or %g3, %g7, %g3 /* Walk through entire ITLB, looking for entry which maps * our %pc currently, stick PADDR from there into %g5 tlb data. */ clr %l0 /* TLB entry walker. */ set 0x1fff, %l2 /* Page mask. */ rd %pc, %l3 andn %l3, %l2, %g2 /* vaddr comparator */ 1: /* Yes, the nops seem to be necessary for now, don't ask me why. -DaveM */ ldxa [%l0] ASI_ITLB_TAG_READ, %g1 nop nop nop andn %g1, %l2, %g1 /* Get vaddr */ cmp %g1, %g2 be,a,pn %xcc, got_tlbentry ldxa [%l0] ASI_ITLB_DATA_ACCESS, %g1 cmp %l0, (63 << 3) blu,pt %xcc, 1b add %l0, (1 << 3), %l0 got_tlbentry: /* Nops here again, perhaps Cheetah/Blackbird are better behaved... */ nop nop nop and %g1, %g3, %g1 /* Mask to just get paddr bits. */ sub %g1, %g2, %g1 /* Get rid of %pc offset to get base. */ /* NOTE: We hold on to %g1 paddr base as we need it below to lock * NOTE: the PROM cif code into the TLB. */ or %g5, %g1, %g5 /* Or it into TAG being built. */ clr %l0 /* TLB entry walker. */ sethi %hi(KERNBASE), %g3 /* 4M lower limit */ sethi %hi(KERNBASE<<1), %g7 /* 8M upper limit */ mov TLB_TAG_ACCESS, %l7 1: /* Yes, the nops seem to be necessary for now, don't ask me why. -DaveM */ ldxa [%l0] ASI_ITLB_TAG_READ, %g1 nop nop nop andn %g1, %l2, %g1 /* Get vaddr */ cmp %g1, %g3 blu,pn %xcc, 2f cmp %g1, %g7 bgeu,pn %xcc, 2f nop stxa %g0, [%l7] ASI_IMMU stxa %g0, [%l0] ASI_ITLB_DATA_ACCESS 2: cmp %l0, (63 << 3) blu,pt %xcc, 1b add %l0, (1 << 3), %l0 nop; nop; nop clr %l0 /* TLB entry walker. */ 1: /* Yes, the nops seem to be necessary for now, don't ask me why. -DaveM */ ldxa [%l0] ASI_DTLB_TAG_READ, %g1 nop nop nop andn %g1, %l2, %g1 /* Get vaddr */ cmp %g1, %g3 blu,pn %xcc, 2f cmp %g1, %g7 bgeu,pn %xcc, 2f nop stxa %g0, [%l7] ASI_DMMU stxa %g0, [%l0] ASI_DTLB_DATA_ACCESS 2: cmp %l0, (63 << 3) blu,pt %xcc, 1b add %l0, (1 << 3), %l0 nop; nop; nop /* PROM never puts any TLB entries into the MMU with the lock bit * set. So we gladly use tlb entry 63 for KERNBASE. */ sethi %hi(KERNBASE), %g3 mov (63 << 3), %g7 stxa %g3, [%l7] ASI_DMMU /* KERNBASE into TLB TAG */ stxa %g5, [%g7] ASI_DTLB_DATA_ACCESS /* TTE into TLB DATA */ membar #Sync stxa %g3, [%l7] ASI_IMMU /* KERNBASE into TLB TAG */ stxa %g5, [%g7] ASI_ITLB_DATA_ACCESS /* TTE into TLB DATA */ membar #Sync flush %g3 membar #Sync ba,pt %xcc, 1f nop 1: set sun4u_init, %g2 jmpl %g2 + %g0, %g0 nop sun4u_init: /* Set ctx 0 */ mov PRIMARY_CONTEXT, %g7 stxa %g0, [%g7] ASI_DMMU membar #Sync mov SECONDARY_CONTEXT, %g7 stxa %g0, [%g7] ASI_DMMU membar #Sync sethi %uhi(PAGE_OFFSET), %g4 sllx %g4, 32, %g4 /* We are now safely (we hope) in Nucleus context (0), rewrite * the KERNBASE TTE's so they no longer have the global bit set. * Don't forget to setup TAG_ACCESS first 8-) */ mov TLB_TAG_ACCESS, %g2 stxa %g3, [%g2] ASI_IMMU stxa %g3, [%g2] ASI_DMMU mov (63 << 3), %g7 ldxa [%g7] ASI_ITLB_DATA_ACCESS, %g1 andn %g1, (_PAGE_G), %g1 stxa %g1, [%g7] ASI_ITLB_DATA_ACCESS membar #Sync ldxa [%g7] ASI_DTLB_DATA_ACCESS, %g1 andn %g1, (_PAGE_G), %g1 stxa %g1, [%g7] ASI_DTLB_DATA_ACCESS membar #Sync /* Kill instruction prefetch queues. */ flush %g3 membar #Sync sethi %hi(init_task_union), %g6 or %g6, %lo(init_task_union), %g6 mov %sp, %l6 mov %o4, %l7 #if 0 /* We don't do it like this anymore, but for historical hack value * I leave this snippet here to show how crazy we can be sometimes. 8-) */ /* Setup "Linux Current Register", thanks Sun 8-) */ wr %g0, 0x1, %pcr wr %g6, 0x0, %pic #endif mov 1, %g5 sllx %g5, (PAGE_SHIFT + 1), %g5 sub %g5, (REGWIN_SZ + STACK_BIAS), %g5 add %g6, %g5, %sp mov 0, %fp wrpr %g0, 0, %wstate wrpr %g0, 0x0, %tl /* Clear the bss */ sethi %hi(8191), %l2 or %l2, %lo(8191), %l2 sethi %hi(__bss_start), %l0 or %l0, %lo(__bss_start), %l0 sethi %hi(_end), %l1 or %l1, %lo(_end), %l1 add %l1, %l2, %l1 andn %l1, %l2, %l1 add %l2, 1, %l2 add %l0, %g0, %o0 1: mov %l2, %o1 call __bzero add %l0, %l2, %l0 cmp %l0, %l1 blu,pt %xcc, 1b add %l0, %g0, %o0 /* Now clear empty_zero_page */ mov %l2, %o1 call __bzero mov %g3, %o0 mov %l6, %o1 ! OpenPROM stack call prom_init mov %l7, %o0 ! OpenPROM cif handler /* Off we go.... */ call start_kernel nop /* Not reached... */ .globl setup_tba setup_tba: save %sp, -160, %sp rdpr %tba, %g7 sethi %hi(prom_tba), %o1 or %o1, %lo(prom_tba), %o1 stx %g7, [%o1] /* Setup "Linux" globals 8-) */ rdpr %pstate, %o1 mov %g6, %o2 wrpr %o1, (PSTATE_AG|PSTATE_IE), %pstate sethi %hi(sparc64_ttable_tl0), %g5 wrpr %g5, %tba mov %o2, %g6 /* Set up MMU globals */ wrpr %o1, (PSTATE_MG|PSTATE_IE), %pstate /* PGD/PMD offset mask, used by TLB miss handlers. */ sethi %hi(0x1ff8), %g2 or %g2, %lo(0x1ff8), %g2 /* Kernel PGDIR used by TLB miss handlers. */ mov %i0, %g6 /* To catch bootup bugs, this is user PGDIR for TLB miss handlers. */ clr %g7 /* Setup Interrupt globals */ wrpr %o1, (PSTATE_IG|PSTATE_IE), %pstate sethi %hi(ivector_to_mask), %g5 or %g5, %lo(ivector_to_mask), %g1 /* IVECTOR table */ mov 0x40, %g2 /* INTR data 0 register */ /* 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 it up. */ wrpr %g0, %g0, %wstate wrpr %o1, PSTATE_IE, %pstate /* Zap TSB BASE to zero with TSB_size==1. */ mov TSB_REG, %o4 mov 1, %o5 stxa %o5, [%o4] ASI_DMMU stxa %o5, [%o4] ASI_IMMU membar #Sync sethi %hi(sparc64_ttable_tl0), %g5 call prom_set_trap_table mov %g5, %o0 rdpr %pstate, %o1 or %o1, PSTATE_IE, %o1 wrpr %o1, 0, %pstate ret restore sparc64_boot_end: .skip 0x2000 + _start - sparc64_boot_end bootup_user_stack_end: bootup_kernel_stack: .skip 0x2000 ! 0x0000000000408000 #include "ttable.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 .globl prom_tba prom_tba: .xword 0 .section ".fixup",#alloc,#execinstr .globl __ret_efault __ret_efault: ret restore %g0, -EFAULT, %o0