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Diffstat (limited to 'arch/cris/arch-v32/mm/mmu.S')
| -rw-r--r-- | arch/cris/arch-v32/mm/mmu.S | 211 |
1 files changed, 0 insertions, 211 deletions
diff --git a/arch/cris/arch-v32/mm/mmu.S b/arch/cris/arch-v32/mm/mmu.S deleted file mode 100644 index f24965703f6d..000000000000 --- a/arch/cris/arch-v32/mm/mmu.S +++ /dev/null @@ -1,211 +0,0 @@ -; SPDX-License-Identifier: GPL-2.0 -; WARNING : The refill handler has been modified, see below !!! - -/* - * Copyright (C) 2003 Axis Communications AB - * - * Authors: Mikael Starvik (starvik@axis.com) - * - * Code for the fault low-level handling routines. - * - */ - -#include <asm/page.h> -#include <asm/pgtable.h> - -; Save all register. Must save in same order as struct pt_regs. -.macro SAVE_ALL - subq 12, $sp - move $erp, [$sp] - subq 4, $sp - move $srp, [$sp] - subq 4, $sp - move $ccs, [$sp] - subq 4, $sp - move $spc, [$sp] - subq 4, $sp - move $mof, [$sp] - subq 4, $sp - move $srs, [$sp] - subq 4, $sp - move.d $acr, [$sp] - subq 14*4, $sp - movem $r13, [$sp] - subq 4, $sp - move.d $r10, [$sp] -.endm - -; Bus fault handler. Extracts relevant information and calls mm subsystem -; to handle the fault. -.macro MMU_BUS_FAULT_HANDLER handler, mmu, we, ex - .globl \handler - .type \handler,"function" -\handler: - SAVE_ALL - move \mmu, $srs ; Select MMU support register bank - move.d $sp, $r11 ; regs - moveq 1, $r12 ; protection fault - moveq \we, $r13 ; write exception? - orq \ex << 1, $r13 ; execute? - move $s3, $r10 ; rw_mm_cause - and.d ~8191, $r10 ; Get faulting page start address - - jsr do_page_fault - nop - ba ret_from_intr - nop - .size \handler, . - \handler -.endm - -; Refill handler. Three cases may occur: -; 1. PMD and PTE exists in mm subsystem but not in TLB -; 2. PMD exists but not PTE -; 3. PMD doesn't exist -; The code below handles case 1 and calls the mm subsystem for case 2 and 3. -; Do not touch this code without very good reasons and extensive testing. -; Note that the code is optimized to minimize stalls (makes the code harder -; to read). -; -; WARNING !!! -; Modified by Mikael Asker 060725: added a workaround for strange TLB -; behavior. If the same PTE is present in more than one set, the TLB -; doesn't recognize it and we get stuck in a loop of refill exceptions. -; The workaround detects such loops and exits them by flushing -; the TLB contents. The problem and workaround were verified -; in VCS by Mikael Starvik. -; -; Each page is 8 KB. Each PMD holds 8192/4 PTEs (each PTE is 4 bytes) so each -; PMD holds 16 MB of virtual memory. -; Bits 0-12 : Offset within a page -; Bits 13-23 : PTE offset within a PMD -; Bits 24-31 : PMD offset within the PGD - -.macro MMU_REFILL_HANDLER handler, mmu - .data -1: .dword 0 ; refill_count - ; == 0 <=> last_refill_cause is invalid -2: .dword 0 ; last_refill_cause - .text - .globl \handler - .type \handler, "function" -\handler: - subq 4, $sp -; (The pipeline stalls for one cycle; $sp used as address in the next cycle.) - move $srs, [$sp] - subq 4, $sp - move \mmu, $srs ; Select MMU support register bank - move.d $acr, [$sp] - subq 12, $sp - move.d 1b, $acr ; Point to refill_count - movem $r2, [$sp] - - test.d [$acr] ; refill_count == 0 ? - beq 5f ; yes, last_refill_cause is invalid - move.d $acr, $r1 - - ; last_refill_cause is valid, investigate cause - addq 4, $r1 ; Point to last_refill_cause - move $s3, $r0 ; Get rw_mm_cause - move.d [$r1], $r2 ; Get last_refill_cause - cmp.d $r0, $r2 ; rw_mm_cause == last_refill_cause ? - beq 6f ; yes, increment count - moveq 1, $r2 - - ; rw_mm_cause != last_refill_cause - move.d $r2, [$acr] ; refill_count = 1 - move.d $r0, [$r1] ; last_refill_cause = rw_mm_cause - -3: ; Probably not in a loop, continue normal processing - move.d current_pgd, $acr ; PGD - ; Look up PMD in PGD - lsrq 24, $r0 ; Get PMD index into PGD (bit 24-31) - move.d [$acr], $acr ; PGD for the current process - addi $r0.d, $acr, $acr - move $s3, $r0 ; rw_mm_cause - move.d [$acr], $acr ; Get PMD - beq 8f - ; Look up PTE in PMD - lsrq PAGE_SHIFT, $r0 - and.w PAGE_MASK, $acr ; Remove PMD flags - and.d 0x7ff, $r0 ; Get PTE index into PMD (bit 13-23) - addi $r0.d, $acr, $acr - move.d [$acr], $acr ; Get PTE - beq 9f - movem [$sp], $r2 ; Restore r0-r2 in delay slot - addq 12, $sp - ; Store in TLB - move $acr, $s5 -4: ; Return - move.d [$sp+], $acr - move [$sp], $srs - addq 4, $sp - rete - rfe - -5: ; last_refill_cause is invalid - moveq 1, $r2 - addq 4, $r1 ; Point to last_refill_cause - move.d $r2, [$acr] ; refill_count = 1 - move $s3, $r0 ; Get rw_mm_cause - ba 3b ; Continue normal processing - move.d $r0,[$r1] ; last_refill_cause = rw_mm_cause - -6: ; rw_mm_cause == last_refill_cause - move.d [$acr], $r2 ; Get refill_count - cmpq 4, $r2 ; refill_count > 4 ? - bhi 7f ; yes - addq 1, $r2 ; refill_count++ - ba 3b ; Continue normal processing - move.d $r2, [$acr] - -7: ; refill_count > 4, error - move.d $acr, $r0 ; Save pointer to refill_count - clear.d [$r0] ; refill_count = 0 - - ;; rewind the short stack - movem [$sp], $r2 ; Restore r0-r2 - addq 12, $sp - move.d [$sp+], $acr - move [$sp], $srs - addq 4, $sp - ;; Keep it simple (slow), save all the regs. - SAVE_ALL - jsr __flush_tlb_all - nop - ba ret_from_intr ; Return - nop - -8: ; PMD missing, let the mm subsystem fix it up. - movem [$sp], $r2 ; Restore r0-r2 -9: ; PTE missing, let the mm subsystem fix it up. - addq 12, $sp - move.d [$sp+], $acr - move [$sp], $srs - addq 4, $sp - SAVE_ALL - move \mmu, $srs - move.d $sp, $r11 ; regs - clear.d $r12 ; Not a protection fault - move.w PAGE_MASK, $acr - move $s3, $r10 ; rw_mm_cause - btstq 9, $r10 ; Check if write access - smi $r13 - and.w PAGE_MASK, $r10 ; Get VPN (virtual address) - jsr do_page_fault - and.w $acr, $r10 - ; Return - ba ret_from_intr - nop - .size \handler, . - \handler -.endm - - ; This is the MMU bus fault handlers. - -MMU_REFILL_HANDLER i_mmu_refill, 1 -MMU_BUS_FAULT_HANDLER i_mmu_invalid, 1, 0, 0 -MMU_BUS_FAULT_HANDLER i_mmu_access, 1, 0, 0 -MMU_BUS_FAULT_HANDLER i_mmu_execute, 1, 0, 1 -MMU_REFILL_HANDLER d_mmu_refill, 2 -MMU_BUS_FAULT_HANDLER d_mmu_invalid, 2, 0, 0 -MMU_BUS_FAULT_HANDLER d_mmu_access, 2, 0, 0 -MMU_BUS_FAULT_HANDLER d_mmu_write, 2, 1, 0 |