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Diffstat (limited to 'arch/powerpc/mm/tlb_low_64e.S')
| -rw-r--r-- | arch/powerpc/mm/tlb_low_64e.S | 769 |
1 files changed, 769 insertions, 0 deletions
diff --git a/arch/powerpc/mm/tlb_low_64e.S b/arch/powerpc/mm/tlb_low_64e.S new file mode 100644 index 000000000000..f288279e679d --- /dev/null +++ b/arch/powerpc/mm/tlb_low_64e.S @@ -0,0 +1,769 @@ +/* + * Low leve 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 + /* 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 */ + 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 |