| /* |
| * Low level TLB miss handlers for Book3E |
| * |
| * Copyright (C) 2008-2009 |
| * Ben. Herrenschmidt (benh@kernel.crashing.org), IBM Corp. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| */ |
| |
| #include <asm/processor.h> |
| #include <asm/reg.h> |
| #include <asm/page.h> |
| #include <asm/mmu.h> |
| #include <asm/ppc_asm.h> |
| #include <asm/asm-offsets.h> |
| #include <asm/cputable.h> |
| #include <asm/pgtable.h> |
| #include <asm/exception-64e.h> |
| #include <asm/ppc-opcode.h> |
| |
| #ifdef CONFIG_PPC_64K_PAGES |
| #define VPTE_PMD_SHIFT (PTE_INDEX_SIZE+1) |
| #else |
| #define VPTE_PMD_SHIFT (PTE_INDEX_SIZE) |
| #endif |
| #define VPTE_PUD_SHIFT (VPTE_PMD_SHIFT + PMD_INDEX_SIZE) |
| #define VPTE_PGD_SHIFT (VPTE_PUD_SHIFT + PUD_INDEX_SIZE) |
| #define VPTE_INDEX_SIZE (VPTE_PGD_SHIFT + PGD_INDEX_SIZE) |
| |
| |
| /********************************************************************** |
| * * |
| * TLB miss handling for Book3E with TLB reservation and HES support * |
| * * |
| **********************************************************************/ |
| |
| |
| /* Data TLB miss */ |
| START_EXCEPTION(data_tlb_miss) |
| TLB_MISS_PROLOG |
| |
| /* Now we handle the fault proper. We only save DEAR in normal |
| * fault case since that's the only interesting values here. |
| * We could probably also optimize by not saving SRR0/1 in the |
| * linear mapping case but I'll leave that for later |
| */ |
| mfspr r14,SPRN_ESR |
| mfspr r16,SPRN_DEAR /* get faulting address */ |
| srdi r15,r16,60 /* get region */ |
| cmpldi cr0,r15,0xc /* linear mapping ? */ |
| TLB_MISS_STATS_SAVE_INFO |
| beq tlb_load_linear /* yes -> go to linear map load */ |
| |
| /* The page tables are mapped virtually linear. At this point, though, |
| * we don't know whether we are trying to fault in a first level |
| * virtual address or a virtual page table address. We can get that |
| * from bit 0x1 of the region ID which we have set for a page table |
| */ |
| andi. r10,r15,0x1 |
| bne- virt_page_table_tlb_miss |
| |
| std r14,EX_TLB_ESR(r12); /* save ESR */ |
| std r16,EX_TLB_DEAR(r12); /* save DEAR */ |
| |
| /* We need _PAGE_PRESENT and _PAGE_ACCESSED set */ |
| li r11,_PAGE_PRESENT |
| oris r11,r11,_PAGE_ACCESSED@h |
| |
| /* We do the user/kernel test for the PID here along with the RW test |
| */ |
| cmpldi cr0,r15,0 /* Check for user region */ |
| |
| /* We pre-test some combination of permissions to avoid double |
| * faults: |
| * |
| * We move the ESR:ST bit into the position of _PAGE_BAP_SW in the PTE |
| * ESR_ST is 0x00800000 |
| * _PAGE_BAP_SW is 0x00000010 |
| * So the shift is >> 19. This tests for supervisor writeability. |
| * If the page happens to be supervisor writeable and not user |
| * writeable, we will take a new fault later, but that should be |
| * a rare enough case. |
| * |
| * We also move ESR_ST in _PAGE_DIRTY position |
| * _PAGE_DIRTY is 0x00001000 so the shift is >> 11 |
| * |
| * MAS1 is preset for all we need except for TID that needs to |
| * be cleared for kernel translations |
| */ |
| rlwimi r11,r14,32-19,27,27 |
| rlwimi r11,r14,32-16,19,19 |
| beq normal_tlb_miss |
| /* XXX replace the RMW cycles with immediate loads + writes */ |
| 1: mfspr r10,SPRN_MAS1 |
| cmpldi cr0,r15,8 /* Check for vmalloc region */ |
| rlwinm r10,r10,0,16,1 /* Clear TID */ |
| mtspr SPRN_MAS1,r10 |
| beq+ normal_tlb_miss |
| |
| /* We got a crappy address, just fault with whatever DEAR and ESR |
| * are here |
| */ |
| TLB_MISS_STATS_D(MMSTAT_TLB_MISS_NORM_FAULT) |
| TLB_MISS_EPILOG_ERROR |
| b exc_data_storage_book3e |
| |
| /* Instruction TLB miss */ |
| START_EXCEPTION(instruction_tlb_miss) |
| TLB_MISS_PROLOG |
| |
| /* If we take a recursive fault, the second level handler may need |
| * to know whether we are handling a data or instruction fault in |
| * order to get to the right store fault handler. We provide that |
| * info by writing a crazy value in ESR in our exception frame |
| */ |
| li r14,-1 /* store to exception frame is done later */ |
| |
| /* Now we handle the fault proper. We only save DEAR in the non |
| * linear mapping case since we know the linear mapping case will |
| * not re-enter. We could indeed optimize and also not save SRR0/1 |
| * in the linear mapping case but I'll leave that for later |
| * |
| * Faulting address is SRR0 which is already in r16 |
| */ |
| srdi r15,r16,60 /* get region */ |
| cmpldi cr0,r15,0xc /* linear mapping ? */ |
| TLB_MISS_STATS_SAVE_INFO |
| beq tlb_load_linear /* yes -> go to linear map load */ |
| |
| /* We do the user/kernel test for the PID here along with the RW test |
| */ |
| li r11,_PAGE_PRESENT|_PAGE_EXEC /* Base perm */ |
| oris r11,r11,_PAGE_ACCESSED@h |
| |
| cmpldi cr0,r15,0 /* Check for user region */ |
| std r14,EX_TLB_ESR(r12) /* write crazy -1 to frame */ |
| beq normal_tlb_miss |
| |
| li r11,_PAGE_PRESENT|_PAGE_BAP_SX /* Base perm */ |
| oris r11,r11,_PAGE_ACCESSED@h |
| /* XXX replace the RMW cycles with immediate loads + writes */ |
| mfspr r10,SPRN_MAS1 |
| cmpldi cr0,r15,8 /* Check for vmalloc region */ |
| rlwinm r10,r10,0,16,1 /* Clear TID */ |
| mtspr SPRN_MAS1,r10 |
| beq+ normal_tlb_miss |
| |
| /* We got a crappy address, just fault */ |
| TLB_MISS_STATS_I(MMSTAT_TLB_MISS_NORM_FAULT) |
| TLB_MISS_EPILOG_ERROR |
| b exc_instruction_storage_book3e |
| |
| /* |
| * This is the guts of the first-level TLB miss handler for direct |
| * misses. We are entered with: |
| * |
| * r16 = faulting address |
| * r15 = region ID |
| * r14 = crap (free to use) |
| * r13 = PACA |
| * r12 = TLB exception frame in PACA |
| * r11 = PTE permission mask |
| * r10 = crap (free to use) |
| */ |
| normal_tlb_miss: |
| /* So we first construct the page table address. We do that by |
| * shifting the bottom of the address (not the region ID) by |
| * PAGE_SHIFT-3, clearing the bottom 3 bits (get a PTE ptr) and |
| * or'ing the fourth high bit. |
| * |
| * NOTE: For 64K pages, we do things slightly differently in |
| * order to handle the weird page table format used by linux |
| */ |
| ori r10,r15,0x1 |
| #ifdef CONFIG_PPC_64K_PAGES |
| /* For the top bits, 16 bytes per PTE */ |
| rldicl r14,r16,64-(PAGE_SHIFT-4),PAGE_SHIFT-4+4 |
| /* Now create the bottom bits as 0 in position 0x8000 and |
| * the rest calculated for 8 bytes per PTE |
| */ |
| rldicl r15,r16,64-(PAGE_SHIFT-3),64-15 |
| /* Insert the bottom bits in */ |
| rlwimi r14,r15,0,16,31 |
| #else |
| rldicl r14,r16,64-(PAGE_SHIFT-3),PAGE_SHIFT-3+4 |
| #endif |
| sldi r15,r10,60 |
| clrrdi r14,r14,3 |
| or r10,r15,r14 |
| |
| BEGIN_MMU_FTR_SECTION |
| /* Set the TLB reservation and seach for existing entry. Then load |
| * the entry. |
| */ |
| PPC_TLBSRX_DOT(0,r16) |
| ld r14,0(r10) |
| beq normal_tlb_miss_done |
| MMU_FTR_SECTION_ELSE |
| ld r14,0(r10) |
| ALT_MMU_FTR_SECTION_END_IFSET(MMU_FTR_USE_TLBRSRV) |
| |
| finish_normal_tlb_miss: |
| /* Check if required permissions are met */ |
| andc. r15,r11,r14 |
| bne- normal_tlb_miss_access_fault |
| |
| /* Now we build the MAS: |
| * |
| * MAS 0 : Fully setup with defaults in MAS4 and TLBnCFG |
| * MAS 1 : Almost fully setup |
| * - PID already updated by caller if necessary |
| * - TSIZE need change if !base page size, not |
| * yet implemented for now |
| * MAS 2 : Defaults not useful, need to be redone |
| * MAS 3+7 : Needs to be done |
| * |
| * TODO: mix up code below for better scheduling |
| */ |
| clrrdi r11,r16,12 /* Clear low crap in EA */ |
| rlwimi r11,r14,32-19,27,31 /* Insert WIMGE */ |
| mtspr SPRN_MAS2,r11 |
| |
| /* Check page size, if not standard, update MAS1 */ |
| rldicl r11,r14,64-8,64-8 |
| #ifdef CONFIG_PPC_64K_PAGES |
| cmpldi cr0,r11,BOOK3E_PAGESZ_64K |
| #else |
| cmpldi cr0,r11,BOOK3E_PAGESZ_4K |
| #endif |
| beq- 1f |
| mfspr r11,SPRN_MAS1 |
| rlwimi r11,r14,31,21,24 |
| rlwinm r11,r11,0,21,19 |
| mtspr SPRN_MAS1,r11 |
| 1: |
| /* Move RPN in position */ |
| rldicr r11,r14,64-(PTE_RPN_SHIFT-PAGE_SHIFT),63-PAGE_SHIFT |
| clrldi r15,r11,12 /* Clear crap at the top */ |
| rlwimi r15,r14,32-8,22,25 /* Move in U bits */ |
| rlwimi r15,r14,32-2,26,31 /* Move in BAP bits */ |
| |
| /* Mask out SW and UW if !DIRTY (XXX optimize this !) */ |
| andi. r11,r14,_PAGE_DIRTY |
| bne 1f |
| li r11,MAS3_SW|MAS3_UW |
| andc r15,r15,r11 |
| 1: |
| BEGIN_MMU_FTR_SECTION |
| srdi r16,r15,32 |
| mtspr SPRN_MAS3,r15 |
| mtspr SPRN_MAS7,r16 |
| MMU_FTR_SECTION_ELSE |
| mtspr SPRN_MAS7_MAS3,r15 |
| ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_USE_PAIRED_MAS) |
| |
| tlbwe |
| |
| normal_tlb_miss_done: |
| /* We don't bother with restoring DEAR or ESR since we know we are |
| * level 0 and just going back to userland. They are only needed |
| * if you are going to take an access fault |
| */ |
| TLB_MISS_STATS_X(MMSTAT_TLB_MISS_NORM_OK) |
| TLB_MISS_EPILOG_SUCCESS |
| rfi |
| |
| normal_tlb_miss_access_fault: |
| /* We need to check if it was an instruction miss */ |
| andi. r10,r11,_PAGE_EXEC |
| bne 1f |
| ld r14,EX_TLB_DEAR(r12) |
| ld r15,EX_TLB_ESR(r12) |
| mtspr SPRN_DEAR,r14 |
| mtspr SPRN_ESR,r15 |
| TLB_MISS_STATS_D(MMSTAT_TLB_MISS_NORM_FAULT) |
| TLB_MISS_EPILOG_ERROR |
| b exc_data_storage_book3e |
| 1: TLB_MISS_STATS_I(MMSTAT_TLB_MISS_NORM_FAULT) |
| TLB_MISS_EPILOG_ERROR |
| b exc_instruction_storage_book3e |
| |
| |
| /* |
| * This is the guts of the second-level TLB miss handler for direct |
| * misses. We are entered with: |
| * |
| * r16 = virtual page table faulting address |
| * r15 = region (top 4 bits of address) |
| * r14 = crap (free to use) |
| * r13 = PACA |
| * r12 = TLB exception frame in PACA |
| * r11 = crap (free to use) |
| * r10 = crap (free to use) |
| * |
| * Note that this should only ever be called as a second level handler |
| * with the current scheme when using SW load. |
| * That means we can always get the original fault DEAR at |
| * EX_TLB_DEAR-EX_TLB_SIZE(r12) |
| * |
| * It can be re-entered by the linear mapping miss handler. However, to |
| * avoid too much complication, it will restart the whole fault at level |
| * 0 so we don't care too much about clobbers |
| * |
| * XXX That code was written back when we couldn't clobber r14. We can now, |
| * so we could probably optimize things a bit |
| */ |
| virt_page_table_tlb_miss: |
| /* Are we hitting a kernel page table ? */ |
| andi. r10,r15,0x8 |
| |
| /* The cool thing now is that r10 contains 0 for user and 8 for kernel, |
| * and we happen to have the swapper_pg_dir at offset 8 from the user |
| * pgdir in the PACA :-). |
| */ |
| add r11,r10,r13 |
| |
| /* If kernel, we need to clear MAS1 TID */ |
| beq 1f |
| /* XXX replace the RMW cycles with immediate loads + writes */ |
| mfspr r10,SPRN_MAS1 |
| rlwinm r10,r10,0,16,1 /* Clear TID */ |
| mtspr SPRN_MAS1,r10 |
| 1: |
| BEGIN_MMU_FTR_SECTION |
| /* Search if we already have a TLB entry for that virtual address, and |
| * if we do, bail out. |
| */ |
| PPC_TLBSRX_DOT(0,r16) |
| beq virt_page_table_tlb_miss_done |
| END_MMU_FTR_SECTION_IFSET(MMU_FTR_USE_TLBRSRV) |
| |
| /* Now, we need to walk the page tables. First check if we are in |
| * range. |
| */ |
| rldicl. r10,r16,64-(VPTE_INDEX_SIZE+3),VPTE_INDEX_SIZE+3+4 |
| bne- virt_page_table_tlb_miss_fault |
| |
| /* Get the PGD pointer */ |
| ld r15,PACAPGD(r11) |
| cmpldi cr0,r15,0 |
| beq- virt_page_table_tlb_miss_fault |
| |
| /* Get to PGD entry */ |
| rldicl r11,r16,64-VPTE_PGD_SHIFT,64-PGD_INDEX_SIZE-3 |
| clrrdi r10,r11,3 |
| ldx r15,r10,r15 |
| cmpldi cr0,r15,0 |
| beq virt_page_table_tlb_miss_fault |
| |
| #ifndef CONFIG_PPC_64K_PAGES |
| /* Get to PUD entry */ |
| rldicl r11,r16,64-VPTE_PUD_SHIFT,64-PUD_INDEX_SIZE-3 |
| clrrdi r10,r11,3 |
| ldx r15,r10,r15 |
| cmpldi cr0,r15,0 |
| beq virt_page_table_tlb_miss_fault |
| #endif /* CONFIG_PPC_64K_PAGES */ |
| |
| /* Get to PMD entry */ |
| rldicl r11,r16,64-VPTE_PMD_SHIFT,64-PMD_INDEX_SIZE-3 |
| clrrdi r10,r11,3 |
| ldx r15,r10,r15 |
| cmpldi cr0,r15,0 |
| beq virt_page_table_tlb_miss_fault |
| |
| /* Ok, we're all right, we can now create a kernel translation for |
| * a 4K or 64K page from r16 -> r15. |
| */ |
| /* Now we build the MAS: |
| * |
| * MAS 0 : Fully setup with defaults in MAS4 and TLBnCFG |
| * MAS 1 : Almost fully setup |
| * - PID already updated by caller if necessary |
| * - TSIZE for now is base page size always |
| * MAS 2 : Use defaults |
| * MAS 3+7 : Needs to be done |
| * |
| * So we only do MAS 2 and 3 for now... |
| */ |
| clrldi r11,r15,4 /* remove region ID from RPN */ |
| ori r10,r11,1 /* Or-in SR */ |
| |
| BEGIN_MMU_FTR_SECTION |
| srdi r16,r10,32 |
| mtspr SPRN_MAS3,r10 |
| mtspr SPRN_MAS7,r16 |
| MMU_FTR_SECTION_ELSE |
| mtspr SPRN_MAS7_MAS3,r10 |
| ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_USE_PAIRED_MAS) |
| |
| tlbwe |
| |
| BEGIN_MMU_FTR_SECTION |
| virt_page_table_tlb_miss_done: |
| |
| /* We have overriden MAS2:EPN but currently our primary TLB miss |
| * handler will always restore it so that should not be an issue, |
| * if we ever optimize the primary handler to not write MAS2 on |
| * some cases, we'll have to restore MAS2:EPN here based on the |
| * original fault's DEAR. If we do that we have to modify the |
| * ITLB miss handler to also store SRR0 in the exception frame |
| * as DEAR. |
| * |
| * However, one nasty thing we did is we cleared the reservation |
| * (well, potentially we did). We do a trick here thus if we |
| * are not a level 0 exception (we interrupted the TLB miss) we |
| * offset the return address by -4 in order to replay the tlbsrx |
| * instruction there |
| */ |
| subf r10,r13,r12 |
| cmpldi cr0,r10,PACA_EXTLB+EX_TLB_SIZE |
| bne- 1f |
| ld r11,PACA_EXTLB+EX_TLB_SIZE+EX_TLB_SRR0(r13) |
| addi r10,r11,-4 |
| std r10,PACA_EXTLB+EX_TLB_SIZE+EX_TLB_SRR0(r13) |
| 1: |
| END_MMU_FTR_SECTION_IFSET(MMU_FTR_USE_TLBRSRV) |
| /* Return to caller, normal case */ |
| TLB_MISS_STATS_X(MMSTAT_TLB_MISS_PT_OK); |
| TLB_MISS_EPILOG_SUCCESS |
| rfi |
| |
| virt_page_table_tlb_miss_fault: |
| /* If we fault here, things are a little bit tricky. We need to call |
| * either data or instruction store fault, and we need to retreive |
| * the original fault address and ESR (for data). |
| * |
| * The thing is, we know that in normal circumstances, this is |
| * always called as a second level tlb miss for SW load or as a first |
| * level TLB miss for HW load, so we should be able to peek at the |
| * relevant informations in the first exception frame in the PACA. |
| * |
| * However, we do need to double check that, because we may just hit |
| * a stray kernel pointer or a userland attack trying to hit those |
| * areas. If that is the case, we do a data fault. (We can't get here |
| * from an instruction tlb miss anyway). |
| * |
| * Note also that when going to a fault, we must unwind the previous |
| * level as well. Since we are doing that, we don't need to clear or |
| * restore the TLB reservation neither. |
| */ |
| subf r10,r13,r12 |
| cmpldi cr0,r10,PACA_EXTLB+EX_TLB_SIZE |
| bne- virt_page_table_tlb_miss_whacko_fault |
| |
| /* We dig the original DEAR and ESR from slot 0 */ |
| ld r15,EX_TLB_DEAR+PACA_EXTLB(r13) |
| ld r16,EX_TLB_ESR+PACA_EXTLB(r13) |
| |
| /* We check for the "special" ESR value for instruction faults */ |
| cmpdi cr0,r16,-1 |
| beq 1f |
| mtspr SPRN_DEAR,r15 |
| mtspr SPRN_ESR,r16 |
| TLB_MISS_STATS_D(MMSTAT_TLB_MISS_PT_FAULT); |
| TLB_MISS_EPILOG_ERROR |
| b exc_data_storage_book3e |
| 1: TLB_MISS_STATS_I(MMSTAT_TLB_MISS_PT_FAULT); |
| TLB_MISS_EPILOG_ERROR |
| b exc_instruction_storage_book3e |
| |
| virt_page_table_tlb_miss_whacko_fault: |
| /* The linear fault will restart everything so ESR and DEAR will |
| * not have been clobbered, let's just fault with what we have |
| */ |
| TLB_MISS_STATS_X(MMSTAT_TLB_MISS_PT_FAULT); |
| TLB_MISS_EPILOG_ERROR |
| b exc_data_storage_book3e |
| |
| |
| /************************************************************** |
| * * |
| * TLB miss handling for Book3E with hw page table support * |
| * * |
| **************************************************************/ |
| |
| |
| /* Data TLB miss */ |
| START_EXCEPTION(data_tlb_miss_htw) |
| TLB_MISS_PROLOG |
| |
| /* Now we handle the fault proper. We only save DEAR in normal |
| * fault case since that's the only interesting values here. |
| * We could probably also optimize by not saving SRR0/1 in the |
| * linear mapping case but I'll leave that for later |
| */ |
| mfspr r14,SPRN_ESR |
| mfspr r16,SPRN_DEAR /* get faulting address */ |
| srdi r11,r16,60 /* get region */ |
| cmpldi cr0,r11,0xc /* linear mapping ? */ |
| TLB_MISS_STATS_SAVE_INFO |
| beq tlb_load_linear /* yes -> go to linear map load */ |
| |
| /* We do the user/kernel test for the PID here along with the RW test |
| */ |
| cmpldi cr0,r11,0 /* Check for user region */ |
| ld r15,PACAPGD(r13) /* Load user pgdir */ |
| beq htw_tlb_miss |
| |
| /* XXX replace the RMW cycles with immediate loads + writes */ |
| 1: mfspr r10,SPRN_MAS1 |
| cmpldi cr0,r11,8 /* Check for vmalloc region */ |
| rlwinm r10,r10,0,16,1 /* Clear TID */ |
| mtspr SPRN_MAS1,r10 |
| ld r15,PACA_KERNELPGD(r13) /* Load kernel pgdir */ |
| beq+ htw_tlb_miss |
| |
| /* We got a crappy address, just fault with whatever DEAR and ESR |
| * are here |
| */ |
| TLB_MISS_STATS_D(MMSTAT_TLB_MISS_NORM_FAULT) |
| TLB_MISS_EPILOG_ERROR |
| b exc_data_storage_book3e |
| |
| /* Instruction TLB miss */ |
| START_EXCEPTION(instruction_tlb_miss_htw) |
| TLB_MISS_PROLOG |
| |
| /* If we take a recursive fault, the second level handler may need |
| * to know whether we are handling a data or instruction fault in |
| * order to get to the right store fault handler. We provide that |
| * info by keeping a crazy value for ESR in r14 |
| */ |
| li r14,-1 /* store to exception frame is done later */ |
| |
| /* Now we handle the fault proper. We only save DEAR in the non |
| * linear mapping case since we know the linear mapping case will |
| * not re-enter. We could indeed optimize and also not save SRR0/1 |
| * in the linear mapping case but I'll leave that for later |
| * |
| * Faulting address is SRR0 which is already in r16 |
| */ |
| srdi r11,r16,60 /* get region */ |
| cmpldi cr0,r11,0xc /* linear mapping ? */ |
| TLB_MISS_STATS_SAVE_INFO |
| beq tlb_load_linear /* yes -> go to linear map load */ |
| |
| /* We do the user/kernel test for the PID here along with the RW test |
| */ |
| cmpldi cr0,r11,0 /* Check for user region */ |
| ld r15,PACAPGD(r13) /* Load user pgdir */ |
| beq htw_tlb_miss |
| |
| /* XXX replace the RMW cycles with immediate loads + writes */ |
| 1: mfspr r10,SPRN_MAS1 |
| cmpldi cr0,r11,8 /* Check for vmalloc region */ |
| rlwinm r10,r10,0,16,1 /* Clear TID */ |
| mtspr SPRN_MAS1,r10 |
| ld r15,PACA_KERNELPGD(r13) /* Load kernel pgdir */ |
| beq+ htw_tlb_miss |
| |
| /* We got a crappy address, just fault */ |
| TLB_MISS_STATS_I(MMSTAT_TLB_MISS_NORM_FAULT) |
| TLB_MISS_EPILOG_ERROR |
| b exc_instruction_storage_book3e |
| |
| |
| /* |
| * This is the guts of the second-level TLB miss handler for direct |
| * misses. We are entered with: |
| * |
| * r16 = virtual page table faulting address |
| * r15 = PGD pointer |
| * r14 = ESR |
| * r13 = PACA |
| * r12 = TLB exception frame in PACA |
| * r11 = crap (free to use) |
| * r10 = crap (free to use) |
| * |
| * It can be re-entered by the linear mapping miss handler. However, to |
| * avoid too much complication, it will save/restore things for us |
| */ |
| htw_tlb_miss: |
| /* Search if we already have a TLB entry for that virtual address, and |
| * if we do, bail out. |
| * |
| * MAS1:IND should be already set based on MAS4 |
| */ |
| PPC_TLBSRX_DOT(0,r16) |
| beq htw_tlb_miss_done |
| |
| /* Now, we need to walk the page tables. First check if we are in |
| * range. |
| */ |
| rldicl. r10,r16,64-PGTABLE_EADDR_SIZE,PGTABLE_EADDR_SIZE+4 |
| bne- htw_tlb_miss_fault |
| |
| /* Get the PGD pointer */ |
| cmpldi cr0,r15,0 |
| beq- htw_tlb_miss_fault |
| |
| /* Get to PGD entry */ |
| rldicl r11,r16,64-(PGDIR_SHIFT-3),64-PGD_INDEX_SIZE-3 |
| clrrdi r10,r11,3 |
| ldx r15,r10,r15 |
| cmpldi cr0,r15,0 |
| beq htw_tlb_miss_fault |
| |
| #ifndef CONFIG_PPC_64K_PAGES |
| /* Get to PUD entry */ |
| rldicl r11,r16,64-(PUD_SHIFT-3),64-PUD_INDEX_SIZE-3 |
| clrrdi r10,r11,3 |
| ldx r15,r10,r15 |
| cmpldi cr0,r15,0 |
| beq htw_tlb_miss_fault |
| #endif /* CONFIG_PPC_64K_PAGES */ |
| |
| /* Get to PMD entry */ |
| rldicl r11,r16,64-(PMD_SHIFT-3),64-PMD_INDEX_SIZE-3 |
| clrrdi r10,r11,3 |
| ldx r15,r10,r15 |
| cmpldi cr0,r15,0 |
| beq htw_tlb_miss_fault |
| |
| /* Ok, we're all right, we can now create an indirect entry for |
| * a 1M or 256M page. |
| * |
| * The last trick is now that because we use "half" pages for |
| * the HTW (1M IND is 2K and 256M IND is 32K) we need to account |
| * for an added LSB bit to the RPN. For 64K pages, there is no |
| * problem as we already use 32K arrays (half PTE pages), but for |
| * 4K page we need to extract a bit from the virtual address and |
| * insert it into the "PA52" bit of the RPN. |
| */ |
| #ifndef CONFIG_PPC_64K_PAGES |
| rlwimi r15,r16,32-9,20,20 |
| #endif |
| /* Now we build the MAS: |
| * |
| * MAS 0 : Fully setup with defaults in MAS4 and TLBnCFG |
| * MAS 1 : Almost fully setup |
| * - PID already updated by caller if necessary |
| * - TSIZE for now is base ind page size always |
| * MAS 2 : Use defaults |
| * MAS 3+7 : Needs to be done |
| */ |
| #ifdef CONFIG_PPC_64K_PAGES |
| ori r10,r15,(BOOK3E_PAGESZ_64K << MAS3_SPSIZE_SHIFT) |
| #else |
| ori r10,r15,(BOOK3E_PAGESZ_4K << MAS3_SPSIZE_SHIFT) |
| #endif |
| |
| BEGIN_MMU_FTR_SECTION |
| srdi r16,r10,32 |
| mtspr SPRN_MAS3,r10 |
| mtspr SPRN_MAS7,r16 |
| MMU_FTR_SECTION_ELSE |
| mtspr SPRN_MAS7_MAS3,r10 |
| ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_USE_PAIRED_MAS) |
| |
| tlbwe |
| |
| htw_tlb_miss_done: |
| /* We don't bother with restoring DEAR or ESR since we know we are |
| * level 0 and just going back to userland. They are only needed |
| * if you are going to take an access fault |
| */ |
| TLB_MISS_STATS_X(MMSTAT_TLB_MISS_PT_OK) |
| TLB_MISS_EPILOG_SUCCESS |
| rfi |
| |
| htw_tlb_miss_fault: |
| /* We need to check if it was an instruction miss. We know this |
| * though because r14 would contain -1 |
| */ |
| cmpdi cr0,r14,-1 |
| beq 1f |
| mtspr SPRN_DEAR,r16 |
| mtspr SPRN_ESR,r14 |
| TLB_MISS_STATS_D(MMSTAT_TLB_MISS_PT_FAULT) |
| TLB_MISS_EPILOG_ERROR |
| b exc_data_storage_book3e |
| 1: TLB_MISS_STATS_I(MMSTAT_TLB_MISS_PT_FAULT) |
| TLB_MISS_EPILOG_ERROR |
| b exc_instruction_storage_book3e |
| |
| /* |
| * This is the guts of "any" level TLB miss handler for kernel linear |
| * mapping misses. We are entered with: |
| * |
| * |
| * r16 = faulting address |
| * r15 = crap (free to use) |
| * r14 = ESR (data) or -1 (instruction) |
| * r13 = PACA |
| * r12 = TLB exception frame in PACA |
| * r11 = crap (free to use) |
| * r10 = crap (free to use) |
| * |
| * In addition we know that we will not re-enter, so in theory, we could |
| * use a simpler epilog not restoring SRR0/1 etc.. but we'll do that later. |
| * |
| * We also need to be careful about MAS registers here & TLB reservation, |
| * as we know we'll have clobbered them if we interrupt the main TLB miss |
| * handlers in which case we probably want to do a full restart at level |
| * 0 rather than saving / restoring the MAS. |
| * |
| * Note: If we care about performance of that core, we can easily shuffle |
| * a few things around |
| */ |
| tlb_load_linear: |
| /* For now, we assume the linear mapping is contiguous and stops at |
| * linear_map_top. We also assume the size is a multiple of 1G, thus |
| * we only use 1G pages for now. That might have to be changed in a |
| * final implementation, especially when dealing with hypervisors |
| */ |
| ld r11,PACATOC(r13) |
| ld r11,linear_map_top@got(r11) |
| ld r10,0(r11) |
| cmpld cr0,r10,r16 |
| bge tlb_load_linear_fault |
| |
| /* MAS1 need whole new setup. */ |
| li r15,(BOOK3E_PAGESZ_1GB<<MAS1_TSIZE_SHIFT) |
| oris r15,r15,MAS1_VALID@h /* MAS1 needs V and TSIZE */ |
| mtspr SPRN_MAS1,r15 |
| |
| /* Already somebody there ? */ |
| PPC_TLBSRX_DOT(0,r16) |
| beq tlb_load_linear_done |
| |
| /* Now we build the remaining MAS. MAS0 and 2 should be fine |
| * with their defaults, which leaves us with MAS 3 and 7. The |
| * mapping is linear, so we just take the address, clear the |
| * region bits, and or in the permission bits which are currently |
| * hard wired |
| */ |
| clrrdi r10,r16,30 /* 1G page index */ |
| clrldi r10,r10,4 /* clear region bits */ |
| ori r10,r10,MAS3_SR|MAS3_SW|MAS3_SX |
| |
| BEGIN_MMU_FTR_SECTION |
| srdi r16,r10,32 |
| mtspr SPRN_MAS3,r10 |
| mtspr SPRN_MAS7,r16 |
| MMU_FTR_SECTION_ELSE |
| mtspr SPRN_MAS7_MAS3,r10 |
| ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_USE_PAIRED_MAS) |
| |
| tlbwe |
| |
| tlb_load_linear_done: |
| /* We use the "error" epilog for success as we do want to |
| * restore to the initial faulting context, whatever it was. |
| * We do that because we can't resume a fault within a TLB |
| * miss handler, due to MAS and TLB reservation being clobbered. |
| */ |
| TLB_MISS_STATS_X(MMSTAT_TLB_MISS_LINEAR) |
| TLB_MISS_EPILOG_ERROR |
| rfi |
| |
| tlb_load_linear_fault: |
| /* We keep the DEAR and ESR around, this shouldn't have happened */ |
| cmpdi cr0,r14,-1 |
| beq 1f |
| TLB_MISS_EPILOG_ERROR_SPECIAL |
| b exc_data_storage_book3e |
| 1: TLB_MISS_EPILOG_ERROR_SPECIAL |
| b exc_instruction_storage_book3e |
| |
| |
| #ifdef CONFIG_BOOK3E_MMU_TLB_STATS |
| .tlb_stat_inc: |
| 1: ldarx r8,0,r9 |
| addi r8,r8,1 |
| stdcx. r8,0,r9 |
| bne- 1b |
| blr |
| #endif |
