/* * Author : Kavita Bala * Email : kaybee@lcs.mit.edu * Comment : Added the STLB updating routines when the TLB is being updated. * */ /* * Mach Operating System * Copyright (c) 1991,1990,1989 Carnegie Mellon University * All Rights Reserved. * * Permission to use, copy, modify and distribute this software and its * documentation is hereby granted, provided that both the copyright * notice and this permission notice appear in all copies of the * software, derivative works or modified versions, and any portions * thereof, and that both notices appear in supporting documentation. * * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. * * Carnegie Mellon requests users of this software to return to * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 * * any improvements or extensions that they make and grant Carnegie Mellon * the rights to redistribute these changes. */ /* * HISTORY * $Log: tlb.s,v $ * Revision 2.11 92/02/19 15:09:42 elf * Changed #-style comments, for ANSI cpp. * [92/02/19 13:11:31 rpd] * * Revision 2.10 91/05/14 17:39:11 mrt * Correcting copyright * * Revision 2.9 91/02/05 17:52:11 mrt * Added author notices * [91/02/04 11:25:28 mrt] * * Changed to use new Mach copyright * [91/02/02 12:30:12 mrt] * * Revision 2.8 91/01/08 15:52:02 rpd * Removed tlb_probe_and_wire. * [90/11/12 rpd] * * Revision 2.7 90/12/05 23:39:00 af * * * Revision 2.6 90/12/05 20:50:16 af * Save one cycle in tlb_umiss(), idea from dbg. * [90/12/03 af] * * Revision 2.5 90/09/28 16:57:17 jsb * Picked up Larry Allen's fix to tlb_flush_pid. * [90/09/22 rpd] * * Revision 2.4 90/01/22 23:08:34 af * Consolidated conditionals. * [90/01/20 17:10:24 af] * * Fixed ref bits to avoid I/O pages. * [89/12/09 11:04:51 af] * * Added bookeepings for reference bits. Works, but consider * it experimental for now. * [89/12/05 02:19:17 af] * * Revision 2.3 89/12/08 19:48:37 rwd * Added bookeepings for reference bits. Works, but consider * it experimental for now. * [89/12/05 02:19:17 af] * * Revision 2.2 89/11/29 14:15:36 af * Use assembly mnemonics wherever possible. * Fixed KDB support functions. * [89/11/03 16:34:04 af] * * Upgraded for pure kernel. * Added tlb peek/poke functions for KDB's use. * [89/10/12 af] * * Revision 2.3 89/08/28 22:39:52 af * Optimized and polished. Made all functions names prefixed by * this module's name. Compacted mod/unmodtlb into tlb_modify. * Removed debugging code. * [89/08/06 af] * * Revision 2.2 89/07/14 15:29:07 rvb * Cleanup. * [89/07/14 rvb] * * Revision 2.1 89/05/30 12:56:21 rvb * rcs'ed. * * 10-Feb-89 Alessandro Forin (af) at Carnegie-Mellon University * Created. */ /* * File: tlb.s * Author: Alessandro Forin, Carnegie Mellon University * Date: 2/89 * * Assembly functions to manipulate the mips TLB. * */ #include #include #include #include #include #if REF_BITS #include ABS(pmap_reference_bits, K0SEG_BASE + 0x20000) #endif REF_BITS #include /* KB * Include definitions. */ #include ABS(kb_stlb_ptr1, K0SEG_BASE + 0x181000) ABS(kb_stlb_tmp_space_ptr1, K0SEG_BASE + 0x189000) .extern kb_stlb_ptr .set noreorder /* * Object: * tlb_probe_entry LOCAL macro * * Common code to probe for an entry in the tlb * * Arguments: * pid register * addr register * oldpid register * entry register * index register * * Preserves the current pid in 'oldpid', returns the 'index' * of the mapping for the pair ('pid','addr'). If none is * found returns a negative value. * As a byproduct, leaves the appropriate mapping entry * ready for the tlbhi register in 'entry'. * Note that the macro needs a delay cycle to * complete and make 'index' valid. */ #define tlb_probe_entry(pid,addr,oldpid,entry,index) \ mfc0 oldpid,c0_tlbhi; /* save current tlb pid */ \ and addr,TLB_HI_VPN_MASK; /* drop offset from address */ \ sll pid,TLB_HI_PID_SHIFT; /* shift pid in place */ \ or entry,addr,pid; /* tlbhi value to look for */ \ mtc0 entry,c0_tlbhi; /* put args into tlbhi */ \ nop; /* let tlbhi get through pipe */\ tlbp; /* probe for entry */ \ nop; /* pipeline */ \ nop; /* pipeline */ \ mfc0 index,c0_tlbind; /* see what happened */ /* * Object: * tlb_probe EXPORTED function * * Probe the tlb for a valid mapping of (pid,vaddr) * * Arguments: * pid tlbpid_t * vaddr vm_offset_t * * Returns 1 if the tuple is mapped, else 0 */ LEAF(tlb_probe) mfc0 t0,c0_status /* save SR and disable interrupts */ mtc0 zero,c0_status tlb_probe_entry(a0,a1,t1,a0,a0) nop bltz a0,1f /* found any ? */ move v0,zero /* assume not */ li v0,1 1: mtc0 t1,c0_tlbhi /* restore old tlbpid */ j ra mtc0 t0,c0_status /* restore sr and return */ END(tlb_probe) /* kb * Object: * kb_stlb_unmap Yet another Inlined definition * * Arguments: * vaddr_reg register The virtual address with lower 12 bits 0 * pte_reg register The dummy address we are going to map in * tmp[12]_reg register Temporary registers * * These arguments are registers. * * We need a delay slot at the end of all this * This unmaps entries in the STLB. */ #define kb_stlb_unmap(vaddr_reg,tmp1_reg,tmp2_reg) \ li tmp1_reg,kb_stlb_ptr1 ;/*load the STLB Address*/ \ srl vaddr_reg,vaddr_reg,KB_STLB_SHIFT_VADDR; \ /*stlb_unmap is only if pid is 0 so the vaddr*/ \ /*has got to be in k2seg*/ \ /*shift by 10 so that the lower 2b are 0*/ \ andi vaddr_reg,KB_STLB_INDEX_CTXT_MASK; \ addu tmp1_reg,tmp1_reg,vaddr_reg; \ /*tmp1_reg has address where I want to insert*/ \ sw zero,0(tmp1_reg) ; \ sw zero,4(tmp1_reg) /* kb * Object: * kb_stlb_zero Inlined definition * * Arguments: * tmp[12]_reg register Temporary registers * * These arguments are registers. * * We need a delay slot at the end of all this * * Initialize the STLB to all zeros (all zeros means the valid bit is * set to INVALID). */ #define kb_stlb_zero(tmp1_reg, tmp2_reg) \ li tmp1_reg,kb_stlb_ptr1 ;/*load the STLB Address*/ \ addi tmp2_reg,zero,KB_STLB_BYTE_SIZE; \ 9: \ sw zero,0(tmp1_reg) ; \ add tmp1_reg,4 ; \ bne tmp1_reg,tmp2_reg,9b; \ nop /* * Object: * tlb_zero EXPORTED function * * Invalidate the i-th TLB entry. * * Arguments: * i unsigned * * Puts some special neutral mapping at entry i. * Uses a virtual address in the k1seg, which will * not be looked for translation. Uses zero for * the physical page, for cosmetic reasons. */ LEAF(tlb_zero) mfc0 t0,c0_status /* save SR and disable interrupts */ mtc0 zero,c0_status li t2,K1SEG_BASE&TLB_HI_VPN_MASK /* neutral vaddr */ mfc0 t1,c0_tlbhi /* save current tlbpid */ sll a0,TLB_IND_INX_SHIFT /* shift pid in place */ mtc0 t2,c0_tlbhi /* set VPN and TLBPID */ mtc0 zero,c0_tlblo /* set PPN and protection */ mtc0 a0,c0_tlbind /* set INDEX */ nop tlbwi /* drop it in */ nop mtc0 t1,c0_tlbhi /* restore old tlbpid */ j ra mtc0 t0,c0_status /* restore SR and return */ END(tlb_zero) /* * Object: * tlb_map EXPORTED function * * Insert a mapping in a tlb line * * Arguments: * line unsigned * pid tlbpid_t * vaddr vm_offset_t * pte pt_entry_t * * Builds a tlb entry for (pid,vaddr,pte) and inserts * it at the given tlb line. Valid lines are indexed * from 0 to TLB_SIZE, but validity is not checked for. * Address does not need to be rounded. * Note that no check is made against conflicting mappings. */ LEAF(tlb_map) mfc0 t0,c0_status /* save SR and disable interrupts */ mtc0 zero,c0_status sll a0,TLB_IND_INX_SHIFT /* shift line index in place */ mfc0 t1,c0_tlbhi /* save current tlbpid */ sll t6,a1,TLB_HI_PID_SHIFT /* line up pid bits */ and a2,TLB_HI_VPN_MASK /* chop offset bits */ or t6,a2 /* kb */ mtc0 t6,c0_tlbhi /* set VPN and TLBPID */ mtc0 a3,c0_tlblo /* set PPN and access bits */ mtc0 a0,c0_tlbind /* set INDEX to wired entry */ #if REF_BITS lui a1,0xf000 /* I/O page ? */ tlbwi /* drop it in */ and a1,a3 bne a1,zero,1f li a1,pmap_reference_bits srl a3,VA_PAGEOFF addu a1,a3 /* reference bit address */ sb zero,0(a1) /* set ref bit */ 1: #else REF_BITS /* The entry was NOT already there */ move t4,a2 /* KB nop replaced, nothing added */ tlbwi /* drop it in */ li t2,kb_stlb_ptr1 /* KB nop replaced, nothing added */ bne a1,zero,kb_tlb_map_done /* 1 */ or a3,KB_STLB_L2_MASK /* 2 */ srl a2,a2,KB_STLB_SHIFT_VADDR /* 3 */ andi a2,a2,KB_STLB_INDEX_CTXT_MASK /* 4 */ addu t2,a2 /* 5 */ sw a3,0(t2) /* 6 */ sw t4,4(t2) /* 7 */ #endif REF_BITS kb_tlb_map_done: mtc0 t1,c0_tlbhi /* restore old tlbpid */ j ra mtc0 t0,c0_status /* restore SR and return */ END(tlbwired) /* * Object: * tlb_map_random EXPORTED function * * Insert a mapping someplace in the tlb * * Arguments: * pid tlbpid_t * vaddr vm_offset_t * pte pt_eptry_t * * Like tlb_map(), but uses one of the lines indexed by * the random register (randomly :-). * This one also checks against existing mapping * that would cause conflict and overrides them. * Returns whether this happened (1) or not (0). */ LEAF(tlb_map_random) mfc0 t0,c0_status /* save SR and disable interrupts */ mtc0 zero,c0_status mfc0 t1,c0_tlbhi and a1,TLB_HI_VPN_MASK sll a0,TLB_HI_PID_SHIFT or t2,a1,a0 mtc0 t2,c0_tlbhi li t4,kb_stlb_ptr1 /* kb replaced nop, nothing added */ tlbp move t2,a1 /* kb replaced nop, nothing added */ srl a1,a1,KB_STLB_SHIFT_VADDR /* kb replaced nop, nothing added */ mfc0 t3,c0_tlbind move v0,zero /* assume no conflicts */ bltz t3,1f /* not found */ mtc0 a2,c0_tlblo /* pte for new entry (BDSLOT) */ andi a1,KB_STLB_INDEX_CTXT_MASK tlbwi /* re-use line */ addu t4,t4,a1 b 2f li v0,1 /* overridden */ 1: #if REF_BITS lui a1,0xf000 /* I/O page ? */ tlbwr /* use random slot */ and a1,a2 bne a1,zero,2f li a1,pmap_reference_bits srl a2,VA_PAGEOFF addu a1,a2 /* reference bit address */ sb zero,0(a1) /* set ref bit (no misses!) */ #else REF_BITS andi a1, KB_STLB_INDEX_CTXT_MASK /* kb replaced nop, nothing added */ tlbwr /* use random slot */ addu t4,t4,a1 /* KB replaced nop, nothing added */ #endif REF_BITS 2: bne a0,zero,kb_tlb_map_random_done /* 1 */ and a2,~KB_STLB_L2_MASK /* This is not a L2 entry */ /* 2 */ sw a2,0(t4) /* 3 */ sw t2,4(t4) /* 4 */ kb_tlb_map_random_done: mtc0 t1,c0_tlbhi /* restore tlbpid */ j ra mtc0 t0,c0_status /* restore SR and return */ END(tlb_map_random) /* * Object: * tlb_modify EXPORTED function * * Set or clear the writeable bit of an entry * * Arguments: * pid tlbpid_t * vaddr vm_offset_t * writeable boolean_t * * Probes first for a mapping, if found changes it * to be writeable or not as requested. * [Protection is independent of user/kernel mode.] */ LEAF(tlb_modify) mfc0 t0,c0_status /* save SR and disable interrupts */ mtc0 zero,c0_status tlb_probe_entry(a0,a1,t1,t2,t3) nop bltz t3,3f /* kb changed this*/ move v0,zero /* assume probe failed (BDSLOT) */ tlbr /* load entry in TLBLO/TLBHI */ nop nop mfc0 t2,c0_tlblo bne a2,zero,1f /* make it writeable ? */ or t2,TLB_LO_D /* set writeable bit (BDSLOT) */ and t2,~TLB_LO_D /* clear writeable bit */ 1: mtc0 t2,c0_tlblo /* change entry */ nop tlbwi nop 3: bne a0,zero,2f nop kb_stlb_unmap(a1,t3,t4) /* kb Unmap the entry from the STLB */ nop 2: mtc0 t1,c0_tlbhi /* restore old tlbpid */ j ra mtc0 t0,c0_status /* restore SR and return */ END(tlb_modify) /* * Object: * tlb_unmap EXPORTED function * * Remove the mapping for address vaddr with id pid. * * Arguments: * pid tlbpid_t * vaddr vm_offset_t * * Probes to see if there is any such mapping. Note that * interrupts must be disabled in this and the other * tlb operations since an interrupt could cause * a miss which could alter the content of the * tlbhi register. */ /* * kb */ LEAF(tlb_unmap) mfc0 t0,c0_status /* save SR and disable interrupts */ mtc0 zero,c0_status tlb_probe_entry(a0,a1,t1,t2,t3) move v0,zero /* assume not there */ bltz t3,1f /* probe failed */ li t2,K1SEG_BASE&TLB_HI_VPN_MASK /* invalid vaddr (not 0!) */ mtc0 t2,c0_tlbhi /* invalidate entry */ mtc0 zero,c0_tlblo /* cosmetic */ nop tlbwi nop 1: bne a0,zero,2f /*Check if the pid is for kernel*/ nop kb_stlb_unmap (a1,t2,t3) /*unmap the entry from the STLB*/ nop 2: mtc0 t1,c0_tlbhi /* restore old tlbpid */ j ra mtc0 t0,c0_status /* restore SR and return */ END(tlb_unmap) /* * Object: * tlb_flush EXPORTED function * * Flush all tlb lines in the given range (inclusive) * * Arguments: * from_line unsigned * to_line unsigned * * Zeroes all entries in the given range of lines. * Could be done with tlb_zero, but this is slightly * faster. Besides, one would probably expect this * function anyways. */ LEAF(tlb_flush) mfc0 t0,c0_status /* save SR and disable interrupts */ mtc0 zero,c0_status li t2,K1SEG_BASE&TLB_HI_VPN_MASK /* set up to invalidate entries */ mfc0 t1,c0_tlbhi /* save current tlbpid */ mtc0 zero,c0_tlblo /* setup neutral mapping */ mtc0 t2,c0_tlbhi sll t2,a0,TLB_IND_INX_SHIFT 1: mtc0 t2,c0_tlbind /* set index */ addu a0,1 /* bump to next entry */ tlbwi /* invalidate */ bne a0,a1,1b /* more to do */ sll t2,a0,TLB_IND_INX_SHIFT /* prepare index (BDSLOT) */ mtc0 t1,c0_tlbhi /* restore tlbpid */ j ra mtc0 t0,c0_status /* restore SR and return */ END(flush_tlb) /* * Object: * tlb_flush_pid EXPORTED function * * Flush all the entries with the given pid * * Arguments: * pid tlbpid_t * from_line unsigned * to_line unsigned * * Makes sure no entries for the given pid are in the tlb. * Walks through all entries in the given range (inclusive). * */ /* kb * tlb_flush_pid is called once in pmap.c * and it blows the TLB out for that pid. So we blow the STLB out here * if the pid is 0. If the pid is not zero don't remove anything. */ LEAF(tlb_flush_pid) mfc0 t0,c0_status /* save SR and disable interrupts */ mtc0 zero,c0_status li t2,K1SEG_BASE&TLB_HI_VPN_MASK /* set up to invalidate entries */ mfc0 t1,c0_tlbhi /* save current tlbpid */ sll t3,a1,TLB_IND_INX_SHIFT /* starting index */ sll a0,TLB_HI_PID_SHIFT /* lined up pid to check against */ 1: mtc0 t3,c0_tlbind /* set index */ addu a1,1 /* bump to next entry */ tlbr /* read the entry */ nop nop mfc0 t4,c0_tlbhi mtc0 zero,c0_tlblo /* assume a match */ and t4,TLB_HI_PID_MASK /* does the pid match ? */ bne t4,a0,2f mtc0 t2,c0_tlbhi /* yep, flush it */ nop tlbwi /* invalidate */ 2: bne a1,a2,1b /* more to do */ sll t3,a1,TLB_IND_INX_SHIFT /* prepare next index (BDSLOT) */ bne a0,zero,kb_tlb_flush_pid_done nop kb_stlb_zero (t2,t3) /* arguments just give it * a bunch of temporary registers * that it can use*/ kb_tlb_flush_pid_done: mtc0 t1,c0_tlbhi /* restore tlbpid */ j ra mtc0 t0,c0_status /* restore SR and return */ END(flush_tlbpid) /* * Object: * tlb_set_context EXPORTED function * * Setup the tlb to use the given pmap * * Arguments: * pmap pmap_t * * Changes the current TLBPID, sets the CONTEXT register * for use by the tlb_umiss handler. * Used at initialization and context switching. */ LEAF(tlb_set_context) mfc0 t0,c0_status /* save SR and disable interrupts */ mtc0 zero,c0_status lw t2,PMAP_PTEBASE(a0) /* get page table base */ lw t1,PMAP_PID(a0) /* get new tlbpid */ mtc0 t2,c0_tlbcxt /* tlb_umiss is happy now */ sll t1,TLB_HI_PID_SHIFT /* line up pid bits */ and t1,TLB_HI_PID_MASK /* sanity */ mtc0 t1,c0_tlbhi /* assert new pid */ sw a0,active_pmap /* assert new pmap */ j ra mtc0 t0,c0_status /* restore SR and return */ END(set_tlb_context) #if 0 /* * Object: * tlb_probe_and_wire EXPORTED function * * Wire an (existing) tlb entry * * Arguments: * a0 * entry tlbhi_t * pte pt_entry_t * index unsigned * * Probe for 'entry' (a formatted TLBHI value) in the TLB. * If a line exists for it, remove it. * Insert the entry at line index. * * Calling sequence * a0 -- preserved * a1 -- entry clobbered * a2 -- pte clobbered * a3 -- index clobbered * v0 -- clobbered * * Side effects: Changes the TLBPID. */ LEAF(tlb_probe_and_wire) mtc0 a2,c0_tlbhi /* probe (vaddr,0) */ nop tlbp nop nop mfc0 v0,c0_tlbind /* get index */ nop bltz v0,1f /* nope, missing */ nop beq v0,a3,1f /* already in place ? */ li v0,K1SEG_BASE&TLB_HI_VPN_MASK mtc0 v0,c0_tlbhi /* invalidate old one */ mtc0 zero,c0_tlblo nop tlbwi nop nop /* fall through */ 1: /* Entry not (anymore) in tlb, wire it */ mtc0 a3,c0_tlbind mtc0 a1,c0_tlblo mtc0 a2,c0_tlbhi #if REF_BITS /* * NOTE: this function is currently only used for stack pages * If this changes, beware of I/O pages (see tlb_map()) */ srl a1,VA_PAGEOFF tlbwi li a2,pmap_reference_bits addu a2,a1 /* reference bit address */ j ra sb zero,0(a2) /* set ref bit (no misses!) */ #else REF_BITS nop tlbwi j ra nop #endif REF_BITS END(tlb_probe_and_wire) #endif 0 #if MACH_KDB /* * Object: * tlb_read_tlbhi EXPORTED function * * Returns the TLBHI register * * Arguments: * none * */ LEAF(tlb_read_tlbhi) mfc0 v0,c0_tlbhi j ra nop END(tlb_read_tlbhi) /* * Object: * tlb_read_tlblo EXPORTED function * * Returns the TLBLO register * * Arguments: * none * */ LEAF(tlb_read_tlblo) mfc0 v0,c0_tlblo j ra nop END(tlb_read_tlblo) /* * Object: * tlb_read_line EXPORTED function * * Read the i-th tlb line * * Arguments: * line unsigned * * Side effect: Changes both TLBHI and TLBLO */ LEAF(tlb_read_line) sll a0,TLB_IND_INX_SHIFT mtc0 a0,c0_tlbind nop tlbr j ra nop END(tlb_read_line) /* * Object: * tlb_write_line EXPORTED function * * Write a tlb line * * Arguments: * line int * hi tlbhi_t * lo tlblo_t * * Extra special values recognized for 'line': * -1 use the current tlbind value * -2 use a random line * -3 only set tlbhi/lo */ LEAF(tlb_write_line) bgez a0,std_write li t0,-1 beq a0,t0,2f sub t0,1 beq a0,t0,1f sub t0,1 bne a0,t0,3f nop mtc0 a1,c0_tlbhi /* only set hi/lo */ j ra mtc0 a2,c0_tlblo 1: mtc0 a1,c0_tlbhi /* write random line */ mtc0 a2,c0_tlblo b 3f tlbwr std_write: /* write specific line */ sll a0,TLB_IND_INX_SHIFT mtc0 a0,c0_tlbind 2: mtc0 a1,c0_tlbhi /* write current line */ mtc0 a2,c0_tlblo nop tlbwi 3: j ra nop END(tlb_write_line) #endif MACH_KDB