/* * Exception handling for Microblaze * * Rewriten interrupt handling * * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu> * Copyright (C) 2008-2009 PetaLogix * * uClinux customisation (C) 2005 John Williams * * MMU code derived from arch/ppc/kernel/head_4xx.S: * Copyright (C) 1995-1996 Gary Thomas <gdt@linuxppc.org> * Initial PowerPC version. * Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu> * Rewritten for PReP * Copyright (C) 1996 Paul Mackerras <paulus@cs.anu.edu.au> * Low-level exception handers, MMU support, and rewrite. * Copyright (C) 1997 Dan Malek <dmalek@jlc.net> * PowerPC 8xx modifications. * Copyright (C) 1998-1999 TiVo, Inc. * PowerPC 403GCX modifications. * Copyright (C) 1999 Grant Erickson <grant@lcse.umn.edu> * PowerPC 403GCX/405GP modifications. * Copyright 2000 MontaVista Software Inc. * PPC405 modifications * PowerPC 403GCX/405GP modifications. * Author: MontaVista Software, Inc. * frank_rowand@mvista.com or source@mvista.com * debbie_chu@mvista.com * * Original code * Copyright (C) 2004 Xilinx, Inc. * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 as published * by the Free Software Foundation. */ /* * Here are the handlers which don't require enabling translation * and calling other kernel code thus we can keep their design very simple * and do all processing in real mode. All what they need is a valid current * (that is an issue for the CONFIG_REGISTER_TASK_PTR case) * This handlers use r3,r4,r5,r6 and optionally r[current] to work therefore * these registers are saved/restored * The handlers which require translation are in entry.S --KAA * * Microblaze HW Exception Handler * - Non self-modifying exception handler for the following exception conditions * - Unalignment * - Instruction bus error * - Data bus error * - Illegal instruction opcode * - Divide-by-zero * * - Privileged instruction exception (MMU) * - Data storage exception (MMU) * - Instruction storage exception (MMU) * - Data TLB miss exception (MMU) * - Instruction TLB miss exception (MMU) * * Note we disable interrupts during exception handling, otherwise we will * possibly get multiple re-entrancy if interrupt handles themselves cause * exceptions. JW */ #include <asm/exceptions.h> #include <asm/unistd.h> #include <asm/page.h> #include <asm/entry.h> #include <asm/current.h> #include <linux/linkage.h> #include <asm/mmu.h> #include <asm/pgtable.h> #include <asm/signal.h> #include <asm/registers.h> #include <asm/asm-offsets.h> #undef DEBUG /* Helpful Macros */ #define NUM_TO_REG(num) r ## num #ifdef CONFIG_MMU #define RESTORE_STATE \ lwi r5, r1, 0; \ mts rmsr, r5; \ nop; \ lwi r3, r1, PT_R3; \ lwi r4, r1, PT_R4; \ lwi r5, r1, PT_R5; \ lwi r6, r1, PT_R6; \ lwi r11, r1, PT_R11; \ lwi r31, r1, PT_R31; \ lwi r1, r1, PT_R1; #endif /* CONFIG_MMU */ #define LWREG_NOP \ bri ex_handler_unhandled; \ nop; #define SWREG_NOP \ bri ex_handler_unhandled; \ nop; /* FIXME this is weird - for noMMU kernel is not possible to use brid * instruction which can shorten executed time */ /* r3 is the source */ #define R3_TO_LWREG_V(regnum) \ swi r3, r1, 4 * regnum; \ bri ex_handler_done; /* r3 is the source */ #define R3_TO_LWREG(regnum) \ or NUM_TO_REG (regnum), r0, r3; \ bri ex_handler_done; /* r3 is the target */ #define SWREG_TO_R3_V(regnum) \ lwi r3, r1, 4 * regnum; \ bri ex_sw_tail; /* r3 is the target */ #define SWREG_TO_R3(regnum) \ or r3, r0, NUM_TO_REG (regnum); \ bri ex_sw_tail; #ifdef CONFIG_MMU #define R3_TO_LWREG_VM_V(regnum) \ brid ex_lw_end_vm; \ swi r3, r7, 4 * regnum; #define R3_TO_LWREG_VM(regnum) \ brid ex_lw_end_vm; \ or NUM_TO_REG (regnum), r0, r3; #define SWREG_TO_R3_VM_V(regnum) \ brid ex_sw_tail_vm; \ lwi r3, r7, 4 * regnum; #define SWREG_TO_R3_VM(regnum) \ brid ex_sw_tail_vm; \ or r3, r0, NUM_TO_REG (regnum); /* Shift right instruction depending on available configuration */ #if CONFIG_XILINX_MICROBLAZE0_USE_BARREL > 0 #define BSRLI(rD, rA, imm) \ bsrli rD, rA, imm #else #define BSRLI(rD, rA, imm) BSRLI ## imm (rD, rA) /* Only the used shift constants defined here - add more if needed */ #define BSRLI2(rD, rA) \ srl rD, rA; /* << 1 */ \ srl rD, rD; /* << 2 */ #define BSRLI10(rD, rA) \ srl rD, rA; /* << 1 */ \ srl rD, rD; /* << 2 */ \ srl rD, rD; /* << 3 */ \ srl rD, rD; /* << 4 */ \ srl rD, rD; /* << 5 */ \ srl rD, rD; /* << 6 */ \ srl rD, rD; /* << 7 */ \ srl rD, rD; /* << 8 */ \ srl rD, rD; /* << 9 */ \ srl rD, rD /* << 10 */ #define BSRLI20(rD, rA) \ BSRLI10(rD, rA); \ BSRLI10(rD, rD) #endif #endif /* CONFIG_MMU */ .extern other_exception_handler /* Defined in exception.c */ /* * hw_exception_handler - Handler for exceptions * * Exception handler notes: * - Handles all exceptions * - Does not handle unaligned exceptions during load into r17, r1, r0. * - Does not handle unaligned exceptions during store from r17 (cannot be * done) and r1 (slows down common case) * * Relevant register structures * * EAR - |----|----|----|----|----|----|----|----| * - < ## 32 bit faulting address ## > * * ESR - |----|----|----|----|----| - | - |-----|-----| * - W S REG EXC * * * STACK FRAME STRUCTURE (for NO_MMU) * --------------------------------- * * +-------------+ + 0 * | MSR | * +-------------+ + 4 * | r1 | * | . | * | . | * | . | * | . | * | r18 | * +-------------+ + 76 * | . | * | . | * * MMU kernel uses the same 'pt_pool_space' pointed space * which is used for storing register values - noMMu style was, that values were * stored in stack but in case of failure you lost information about register. * Currently you can see register value in memory in specific place. * In compare to with previous solution the speed should be the same. * * MMU exception handler has different handling compare to no MMU kernel. * Exception handler use jump table for directing of what happen. For MMU kernel * is this approach better because MMU relate exception are handled by asm code * in this file. In compare to with MMU expect of unaligned exception * is everything handled by C code. */ /* * every of these handlers is entered having R3/4/5/6/11/current saved on stack * and clobbered so care should be taken to restore them if someone is going to * return from exception */ /* wrappers to restore state before coming to entry.S */ #ifdef CONFIG_MMU .section .data .align 4 pt_pool_space: .space PT_SIZE #ifdef DEBUG /* Create space for exception counting. */ .section .data .global exception_debug_table .align 4 exception_debug_table: /* Look at exception vector table. There is 32 exceptions * word size */ .space (32 * 4) #endif /* DEBUG */ .section .rodata .align 4 _MB_HW_ExceptionVectorTable: /* 0 - Undefined */ .long TOPHYS(ex_handler_unhandled) /* 1 - Unaligned data access exception */ .long TOPHYS(handle_unaligned_ex) /* 2 - Illegal op-code exception */ .long TOPHYS(full_exception_trapw) /* 3 - Instruction bus error exception */ .long TOPHYS(full_exception_trapw) /* 4 - Data bus error exception */ .long TOPHYS(full_exception_trapw) /* 5 - Divide by zero exception */ .long TOPHYS(full_exception_trapw) /* 6 - Floating point unit exception */ .long TOPHYS(full_exception_trapw) /* 7 - Privileged instruction exception */ .long TOPHYS(full_exception_trapw) /* 8 - 15 - Undefined */ .long TOPHYS(ex_handler_unhandled) .long TOPHYS(ex_handler_unhandled) .long TOPHYS(ex_handler_unhandled) .long TOPHYS(ex_handler_unhandled) .long TOPHYS(ex_handler_unhandled) .long TOPHYS(ex_handler_unhandled) .long TOPHYS(ex_handler_unhandled) .long TOPHYS(ex_handler_unhandled) /* 16 - Data storage exception */ .long TOPHYS(handle_data_storage_exception) /* 17 - Instruction storage exception */ .long TOPHYS(handle_instruction_storage_exception) /* 18 - Data TLB miss exception */ .long TOPHYS(handle_data_tlb_miss_exception) /* 19 - Instruction TLB miss exception */ .long TOPHYS(handle_instruction_tlb_miss_exception) /* 20 - 31 - Undefined */ .long TOPHYS(ex_handler_unhandled) .long TOPHYS(ex_handler_unhandled) .long TOPHYS(ex_handler_unhandled) .long TOPHYS(ex_handler_unhandled) .long TOPHYS(ex_handler_unhandled) .long TOPHYS(ex_handler_unhandled) .long TOPHYS(ex_handler_unhandled) .long TOPHYS(ex_handler_unhandled) .long TOPHYS(ex_handler_unhandled) .long TOPHYS(ex_handler_unhandled) .long TOPHYS(ex_handler_unhandled) .long TOPHYS(ex_handler_unhandled) #endif .global _hw_exception_handler .section .text .align 4 .ent _hw_exception_handler _hw_exception_handler: #ifndef CONFIG_MMU addik r1, r1, -(EX_HANDLER_STACK_SIZ); /* Create stack frame */ #else swi r1, r0, TOPHYS(pt_pool_space + PT_R1); /* GET_SP */ /* Save date to kernel memory. Here is the problem * when you came from user space */ ori r1, r0, TOPHYS(pt_pool_space); #endif swi r3, r1, PT_R3 swi r4, r1, PT_R4 swi r5, r1, PT_R5 swi r6, r1, PT_R6 #ifdef CONFIG_MMU swi r11, r1, PT_R11 swi r31, r1, PT_R31 lwi r31, r0, TOPHYS(PER_CPU(CURRENT_SAVE)) /* get saved current */ #endif mfs r5, rmsr; nop swi r5, r1, 0; mfs r4, resr nop mfs r3, rear; nop #ifndef CONFIG_MMU andi r5, r4, 0x1000; /* Check ESR[DS] */ beqi r5, not_in_delay_slot; /* Branch if ESR[DS] not set */ mfs r17, rbtr; /* ESR[DS] set - return address in BTR */ nop not_in_delay_slot: swi r17, r1, PT_R17 #endif andi r5, r4, 0x1F; /* Extract ESR[EXC] */ #ifdef CONFIG_MMU /* Calculate exception vector offset = r5 << 2 */ addk r6, r5, r5; /* << 1 */ addk r6, r6, r6; /* << 2 */ #ifdef DEBUG /* counting which exception happen */ lwi r5, r0, TOPHYS(exception_debug_table) addi r5, r5, 1 swi r5, r0, TOPHYS(exception_debug_table) lwi r5, r6, TOPHYS(exception_debug_table) addi r5, r5, 1 swi r5, r6, TOPHYS(exception_debug_table) #endif /* end */ /* Load the HW Exception vector */ lwi r6, r6, TOPHYS(_MB_HW_ExceptionVectorTable) bra r6 full_exception_trapw: RESTORE_STATE bri full_exception_trap #else /* Exceptions enabled here. This will allow nested exceptions */ mfs r6, rmsr; nop swi r6, r1, 0; /* RMSR_OFFSET */ ori r6, r6, 0x100; /* Turn ON the EE bit */ andi r6, r6, ~2; /* Disable interrupts */ mts rmsr, r6; nop xori r6, r5, 1; /* 00001 = Unaligned Exception */ /* Jump to unalignment exception handler */ beqi r6, handle_unaligned_ex; handle_other_ex: /* Handle Other exceptions here */ /* Save other volatiles before we make procedure calls below */ swi r7, r1, PT_R7 swi r8, r1, PT_R8 swi r9, r1, PT_R9 swi r10, r1, PT_R10 swi r11, r1, PT_R11 swi r12, r1, PT_R12 swi r14, r1, PT_R14 swi r15, r1, PT_R15 swi r18, r1, PT_R18 or r5, r1, r0 andi r6, r4, 0x1F; /* Load ESR[EC] */ lwi r7, r0, PER_CPU(KM) /* MS: saving current kernel mode to regs */ swi r7, r1, PT_MODE mfs r7, rfsr nop addk r8, r17, r0; /* Load exception address */ bralid r15, full_exception; /* Branch to the handler */ nop; mts rfsr, r0; /* Clear sticky fsr */ nop /* * Trigger execution of the signal handler by enabling * interrupts and calling an invalid syscall. */ mfs r5, rmsr; nop ori r5, r5, 2; mts rmsr, r5; /* enable interrupt */ nop addi r12, r0, __NR_syscalls; brki r14, 0x08; mfs r5, rmsr; /* disable interrupt */ nop andi r5, r5, ~2; mts rmsr, r5; nop lwi r7, r1, PT_R7 lwi r8, r1, PT_R8 lwi r9, r1, PT_R9 lwi r10, r1, PT_R10 lwi r11, r1, PT_R11 lwi r12, r1, PT_R12 lwi r14, r1, PT_R14 lwi r15, r1, PT_R15 lwi r18, r1, PT_R18 bri ex_handler_done; /* Complete exception handling */ #endif /* 0x01 - Unaligned data access exception * This occurs when a word access is not aligned on a word boundary, * or when a 16-bit access is not aligned on a 16-bit boundary. * This handler perform the access, and returns, except for MMU when * the unaligned address is last on a 4k page or the physical address is * not found in the page table, in which case unaligned_data_trap is called. */ handle_unaligned_ex: /* Working registers already saved: R3, R4, R5, R6 * R4 = ESR * R3 = EAR */ #ifdef CONFIG_MMU andi r6, r4, 0x1000 /* Check ESR[DS] */ beqi r6, _no_delayslot /* Branch if ESR[DS] not set */ mfs r17, rbtr; /* ESR[DS] set - return address in BTR */ nop _no_delayslot: /* jump to high level unaligned handler */ RESTORE_STATE; bri unaligned_data_trap #endif andi r6, r4, 0x3E0; /* Mask and extract the register operand */ srl r6, r6; /* r6 >> 5 */ srl r6, r6; srl r6, r6; srl r6, r6; srl r6, r6; /* Store the register operand in a temporary location */ sbi r6, r0, TOPHYS(ex_reg_op); andi r6, r4, 0x400; /* Extract ESR[S] */ bnei r6, ex_sw; ex_lw: andi r6, r4, 0x800; /* Extract ESR[W] */ beqi r6, ex_lhw; lbui r5, r3, 0; /* Exception address in r3 */ /* Load a word, byte-by-byte from destination address and save it in tmp space */ sbi r5, r0, TOPHYS(ex_tmp_data_loc_0); lbui r5, r3, 1; sbi r5, r0, TOPHYS(ex_tmp_data_loc_1); lbui r5, r3, 2; sbi r5, r0, TOPHYS(ex_tmp_data_loc_2); lbui r5, r3, 3; sbi r5, r0, TOPHYS(ex_tmp_data_loc_3); /* Get the destination register value into r4 */ lwi r4, r0, TOPHYS(ex_tmp_data_loc_0); bri ex_lw_tail; ex_lhw: lbui r5, r3, 0; /* Exception address in r3 */ /* Load a half-word, byte-by-byte from destination address and save it in tmp space */ sbi r5, r0, TOPHYS(ex_tmp_data_loc_0); lbui r5, r3, 1; sbi r5, r0, TOPHYS(ex_tmp_data_loc_1); /* Get the destination register value into r4 */ lhui r4, r0, TOPHYS(ex_tmp_data_loc_0); ex_lw_tail: /* Get the destination register number into r5 */ lbui r5, r0, TOPHYS(ex_reg_op); /* Form load_word jump table offset (lw_table + (8 * regnum)) */ addik r6, r0, TOPHYS(lw_table); addk r5, r5, r5; addk r5, r5, r5; addk r5, r5, r5; addk r5, r5, r6; bra r5; ex_lw_end: /* Exception handling of load word, ends */ ex_sw: /* Get the destination register number into r5 */ lbui r5, r0, TOPHYS(ex_reg_op); /* Form store_word jump table offset (sw_table + (8 * regnum)) */ addik r6, r0, TOPHYS(sw_table); add r5, r5, r5; add r5, r5, r5; add r5, r5, r5; add r5, r5, r6; bra r5; ex_sw_tail: mfs r6, resr; nop andi r6, r6, 0x800; /* Extract ESR[W] */ beqi r6, ex_shw; /* Get the word - delay slot */ swi r4, r0, TOPHYS(ex_tmp_data_loc_0); /* Store the word, byte-by-byte into destination address */ lbui r4, r0, TOPHYS(ex_tmp_data_loc_0); sbi r4, r3, 0; lbui r4, r0, TOPHYS(ex_tmp_data_loc_1); sbi r4, r3, 1; lbui r4, r0, TOPHYS(ex_tmp_data_loc_2); sbi r4, r3, 2; lbui r4, r0, TOPHYS(ex_tmp_data_loc_3); sbi r4, r3, 3; bri ex_handler_done; ex_shw: /* Store the lower half-word, byte-by-byte into destination address */ swi r4, r0, TOPHYS(ex_tmp_data_loc_0); lbui r4, r0, TOPHYS(ex_tmp_data_loc_2); sbi r4, r3, 0; lbui r4, r0, TOPHYS(ex_tmp_data_loc_3); sbi r4, r3, 1; ex_sw_end: /* Exception handling of store word, ends. */ ex_handler_done: #ifndef CONFIG_MMU lwi r5, r1, 0 /* RMSR */ mts rmsr, r5 nop lwi r3, r1, PT_R3 lwi r4, r1, PT_R4 lwi r5, r1, PT_R5 lwi r6, r1, PT_R6 lwi r17, r1, PT_R17 rted r17, 0 addik r1, r1, (EX_HANDLER_STACK_SIZ); /* Restore stack frame */ #else RESTORE_STATE; rted r17, 0 nop #endif #ifdef CONFIG_MMU /* Exception vector entry code. This code runs with address translation * turned off (i.e. using physical addresses). */ /* Exception vectors. */ /* 0x10 - Data Storage Exception * This happens for just a few reasons. U0 set (but we don't do that), * or zone protection fault (user violation, write to protected page). * If this is just an update of modified status, we do that quickly * and exit. Otherwise, we call heavyweight functions to do the work. */ handle_data_storage_exception: /* Working registers already saved: R3, R4, R5, R6 * R3 = ESR */ mfs r11, rpid nop /* If we are faulting a kernel address, we have to use the * kernel page tables. */ ori r5, r0, CONFIG_KERNEL_START cmpu r5, r3, r5 bgti r5, ex3 /* First, check if it was a zone fault (which means a user * tried to access a kernel or read-protected page - always * a SEGV). All other faults here must be stores, so no * need to check ESR_S as well. */ andi r4, r4, ESR_DIZ /* ESR_Z - zone protection */ bnei r4, ex2 ori r4, r0, swapper_pg_dir mts rpid, r0 /* TLB will have 0 TID */ nop bri ex4 /* Get the PGD for the current thread. */ ex3: /* First, check if it was a zone fault (which means a user * tried to access a kernel or read-protected page - always * a SEGV). All other faults here must be stores, so no * need to check ESR_S as well. */ andi r4, r4, ESR_DIZ /* ESR_Z */ bnei r4, ex2 /* get current task address */ addi r4 ,CURRENT_TASK, TOPHYS(0); lwi r4, r4, TASK_THREAD+PGDIR ex4: tophys(r4,r4) /* Create L1 (pgdir/pmd) address */ BSRLI(r5,r3, PGDIR_SHIFT - 2) andi r5, r5, PAGE_SIZE - 4 /* Assume pgdir aligned on 4K boundary, no need for "andi r4,r4,0xfffff003" */ or r4, r4, r5 lwi r4, r4, 0 /* Get L1 entry */ andi r5, r4, PAGE_MASK /* Extract L2 (pte) base address */ beqi r5, ex2 /* Bail if no table */ tophys(r5,r5) BSRLI(r6,r3,PTE_SHIFT) /* Compute PTE address */ andi r6, r6, PAGE_SIZE - 4 or r5, r5, r6 lwi r4, r5, 0 /* Get Linux PTE */ andi r6, r4, _PAGE_RW /* Is it writeable? */ beqi r6, ex2 /* Bail if not */ /* Update 'changed' */ ori r4, r4, _PAGE_DIRTY|_PAGE_ACCESSED|_PAGE_HWWRITE swi r4, r5, 0 /* Update Linux page table */ /* Most of the Linux PTE is ready to load into the TLB LO. * We set ZSEL, where only the LS-bit determines user access. * We set execute, because we don't have the granularity to * properly set this at the page level (Linux problem). * If shared is set, we cause a zero PID->TID load. * Many of these bits are software only. Bits we don't set * here we (properly should) assume have the appropriate value. */ /* Ignore memory coherent, just LSB on ZSEL is used + EX/WR */ andi r4, r4, PAGE_MASK | TLB_EX | TLB_WR | \ TLB_ZSEL(1) | TLB_ATTR_MASK ori r4, r4, _PAGE_HWEXEC /* make it executable */ /* find the TLB index that caused the fault. It has to be here*/ mts rtlbsx, r3 nop mfs r5, rtlbx /* DEBUG: TBD */ nop mts rtlblo, r4 /* Load TLB LO */ nop /* Will sync shadow TLBs */ /* Done...restore registers and get out of here. */ mts rpid, r11 nop bri 4 RESTORE_STATE; rted r17, 0 nop ex2: /* The bailout. Restore registers to pre-exception conditions * and call the heavyweights to help us out. */ mts rpid, r11 nop bri 4 RESTORE_STATE; bri page_fault_data_trap /* 0x11 - Instruction Storage Exception * This is caused by a fetch from non-execute or guarded pages. */ handle_instruction_storage_exception: /* Working registers already saved: R3, R4, R5, R6 * R3 = ESR */ RESTORE_STATE; bri page_fault_instr_trap /* 0x12 - Data TLB Miss Exception * As the name implies, translation is not in the MMU, so search the * page tables and fix it. The only purpose of this function is to * load TLB entries from the page table if they exist. */ handle_data_tlb_miss_exception: /* Working registers already saved: R3, R4, R5, R6 * R3 = EAR, R4 = ESR */ mfs r11, rpid nop /* If we are faulting a kernel address, we have to use the * kernel page tables. */ ori r6, r0, CONFIG_KERNEL_START cmpu r4, r3, r6 bgti r4, ex5 ori r4, r0, swapper_pg_dir mts rpid, r0 /* TLB will have 0 TID */ nop bri ex6 /* Get the PGD for the current thread. */ ex5: /* get current task address */ addi r4 ,CURRENT_TASK, TOPHYS(0); lwi r4, r4, TASK_THREAD+PGDIR ex6: tophys(r4,r4) /* Create L1 (pgdir/pmd) address */ BSRLI(r5,r3, PGDIR_SHIFT - 2) andi r5, r5, PAGE_SIZE - 4 /* Assume pgdir aligned on 4K boundary, no need for "andi r4,r4,0xfffff003" */ or r4, r4, r5 lwi r4, r4, 0 /* Get L1 entry */ andi r5, r4, PAGE_MASK /* Extract L2 (pte) base address */ beqi r5, ex7 /* Bail if no table */ tophys(r5,r5) BSRLI(r6,r3,PTE_SHIFT) /* Compute PTE address */ andi r6, r6, PAGE_SIZE - 4 or r5, r5, r6 lwi r4, r5, 0 /* Get Linux PTE */ andi r6, r4, _PAGE_PRESENT beqi r6, ex7 ori r4, r4, _PAGE_ACCESSED swi r4, r5, 0 /* Most of the Linux PTE is ready to load into the TLB LO. * We set ZSEL, where only the LS-bit determines user access. * We set execute, because we don't have the granularity to * properly set this at the page level (Linux problem). * If shared is set, we cause a zero PID->TID load. * Many of these bits are software only. Bits we don't set * here we (properly should) assume have the appropriate value. */ brid finish_tlb_load andi r4, r4, PAGE_MASK | TLB_EX | TLB_WR | \ TLB_ZSEL(1) | TLB_ATTR_MASK ex7: /* The bailout. Restore registers to pre-exception conditions * and call the heavyweights to help us out. */ mts rpid, r11 nop bri 4 RESTORE_STATE; bri page_fault_data_trap /* 0x13 - Instruction TLB Miss Exception * Nearly the same as above, except we get our information from * different registers and bailout to a different point. */ handle_instruction_tlb_miss_exception: /* Working registers already saved: R3, R4, R5, R6 * R3 = ESR */ mfs r11, rpid nop /* If we are faulting a kernel address, we have to use the * kernel page tables. */ ori r4, r0, CONFIG_KERNEL_START cmpu r4, r3, r4 bgti r4, ex8 ori r4, r0, swapper_pg_dir mts rpid, r0 /* TLB will have 0 TID */ nop bri ex9 /* Get the PGD for the current thread. */ ex8: /* get current task address */ addi r4 ,CURRENT_TASK, TOPHYS(0); lwi r4, r4, TASK_THREAD+PGDIR ex9: tophys(r4,r4) /* Create L1 (pgdir/pmd) address */ BSRLI(r5,r3, PGDIR_SHIFT - 2) andi r5, r5, PAGE_SIZE - 4 /* Assume pgdir aligned on 4K boundary, no need for "andi r4,r4,0xfffff003" */ or r4, r4, r5 lwi r4, r4, 0 /* Get L1 entry */ andi r5, r4, PAGE_MASK /* Extract L2 (pte) base address */ beqi r5, ex10 /* Bail if no table */ tophys(r5,r5) BSRLI(r6,r3,PTE_SHIFT) /* Compute PTE address */ andi r6, r6, PAGE_SIZE - 4 or r5, r5, r6 lwi r4, r5, 0 /* Get Linux PTE */ andi r6, r4, _PAGE_PRESENT beqi r6, ex10 ori r4, r4, _PAGE_ACCESSED swi r4, r5, 0 /* Most of the Linux PTE is ready to load into the TLB LO. * We set ZSEL, where only the LS-bit determines user access. * We set execute, because we don't have the granularity to * properly set this at the page level (Linux problem). * If shared is set, we cause a zero PID->TID load. * Many of these bits are software only. Bits we don't set * here we (properly should) assume have the appropriate value. */ brid finish_tlb_load andi r4, r4, PAGE_MASK | TLB_EX | TLB_WR | \ TLB_ZSEL(1) | TLB_ATTR_MASK ex10: /* The bailout. Restore registers to pre-exception conditions * and call the heavyweights to help us out. */ mts rpid, r11 nop bri 4 RESTORE_STATE; bri page_fault_instr_trap /* Both the instruction and data TLB miss get to this point to load the TLB. * r3 - EA of fault * r4 - TLB LO (info from Linux PTE) * r5, r6 - available to use * PID - loaded with proper value when we get here * Upon exit, we reload everything and RFI. * A common place to load the TLB. */ .section .data .align 4 .global tlb_skip tlb_skip: .long MICROBLAZE_TLB_SKIP tlb_index: /* MS: storing last used tlb index */ .long MICROBLAZE_TLB_SIZE/2 .previous finish_tlb_load: /* MS: load the last used TLB index. */ lwi r5, r0, TOPHYS(tlb_index) addik r5, r5, 1 /* MS: inc tlb_index -> use next one */ /* MS: FIXME this is potential fault, because this is mask not count */ andi r5, r5, MICROBLAZE_TLB_SIZE - 1 ori r6, r0, 1 cmp r31, r5, r6 blti r31, ex12 lwi r5, r0, TOPHYS(tlb_skip) ex12: /* MS: save back current TLB index */ swi r5, r0, TOPHYS(tlb_index) ori r4, r4, _PAGE_HWEXEC /* make it executable */ mts rtlbx, r5 /* MS: save current TLB */ nop mts rtlblo, r4 /* MS: save to TLB LO */ nop /* Create EPN. This is the faulting address plus a static * set of bits. These are size, valid, E, U0, and ensure * bits 20 and 21 are zero. */ andi r3, r3, PAGE_MASK #ifdef CONFIG_MICROBLAZE_64K_PAGES ori r3, r3, TLB_VALID | TLB_PAGESZ(PAGESZ_64K) #elif CONFIG_MICROBLAZE_16K_PAGES ori r3, r3, TLB_VALID | TLB_PAGESZ(PAGESZ_16K) #else ori r3, r3, TLB_VALID | TLB_PAGESZ(PAGESZ_4K) #endif mts rtlbhi, r3 /* Load TLB HI */ nop /* Done...restore registers and get out of here. */ mts rpid, r11 nop bri 4 RESTORE_STATE; rted r17, 0 nop /* extern void giveup_fpu(struct task_struct *prev) * * The MicroBlaze processor may have an FPU, so this should not just * return: TBD. */ .globl giveup_fpu; .align 4; giveup_fpu: bralid r15,0 /* TBD */ nop /* At present, this routine just hangs. - extern void abort(void) */ .globl abort; .align 4; abort: br r0 .globl set_context; .align 4; set_context: mts rpid, r5 /* Shadow TLBs are automatically */ nop bri 4 /* flushed by changing PID */ rtsd r15,8 nop #endif .end _hw_exception_handler #ifdef CONFIG_MMU /* Unaligned data access exception last on a 4k page for MMU. * When this is called, we are in virtual mode with exceptions enabled * and registers 1-13,15,17,18 saved. * * R3 = ESR * R4 = EAR * R7 = pointer to saved registers (struct pt_regs *regs) * * This handler perform the access, and returns via ret_from_exc. */ .global _unaligned_data_exception .ent _unaligned_data_exception _unaligned_data_exception: andi r8, r3, 0x3E0; /* Mask and extract the register operand */ BSRLI(r8,r8,2); /* r8 >> 2 = register operand * 8 */ andi r6, r3, 0x400; /* Extract ESR[S] */ bneid r6, ex_sw_vm; andi r6, r3, 0x800; /* Extract ESR[W] - delay slot */ ex_lw_vm: beqid r6, ex_lhw_vm; load1: lbui r5, r4, 0; /* Exception address in r4 - delay slot */ /* Load a word, byte-by-byte from destination address and save it in tmp space*/ addik r6, r0, ex_tmp_data_loc_0; sbi r5, r6, 0; load2: lbui r5, r4, 1; sbi r5, r6, 1; load3: lbui r5, r4, 2; sbi r5, r6, 2; load4: lbui r5, r4, 3; sbi r5, r6, 3; brid ex_lw_tail_vm; /* Get the destination register value into r3 - delay slot */ lwi r3, r6, 0; ex_lhw_vm: /* Load a half-word, byte-by-byte from destination address and * save it in tmp space */ addik r6, r0, ex_tmp_data_loc_0; sbi r5, r6, 0; load5: lbui r5, r4, 1; sbi r5, r6, 1; lhui r3, r6, 0; /* Get the destination register value into r3 */ ex_lw_tail_vm: /* Form load_word jump table offset (lw_table_vm + (8 * regnum)) */ addik r5, r8, lw_table_vm; bra r5; ex_lw_end_vm: /* Exception handling of load word, ends */ brai ret_from_exc; ex_sw_vm: /* Form store_word jump table offset (sw_table_vm + (8 * regnum)) */ addik r5, r8, sw_table_vm; bra r5; ex_sw_tail_vm: addik r5, r0, ex_tmp_data_loc_0; beqid r6, ex_shw_vm; swi r3, r5, 0; /* Get the word - delay slot */ /* Store the word, byte-by-byte into destination address */ lbui r3, r5, 0; store1: sbi r3, r4, 0; lbui r3, r5, 1; store2: sbi r3, r4, 1; lbui r3, r5, 2; store3: sbi r3, r4, 2; lbui r3, r5, 3; brid ret_from_exc; store4: sbi r3, r4, 3; /* Delay slot */ ex_shw_vm: /* Store the lower half-word, byte-by-byte into destination address */ #ifdef __MICROBLAZEEL__ lbui r3, r5, 0; store5: sbi r3, r4, 0; lbui r3, r5, 1; brid ret_from_exc; store6: sbi r3, r4, 1; /* Delay slot */ #else lbui r3, r5, 2; store5: sbi r3, r4, 0; lbui r3, r5, 3; brid ret_from_exc; store6: sbi r3, r4, 1; /* Delay slot */ #endif ex_sw_end_vm: /* Exception handling of store word, ends. */ /* We have to prevent cases that get/put_user macros get unaligned pointer * to bad page area. We have to find out which origin instruction caused it * and called fixup for that origin instruction not instruction in unaligned * handler */ ex_unaligned_fixup: ori r5, r7, 0 /* setup pointer to pt_regs */ lwi r6, r7, PT_PC; /* faulting address is one instruction above */ addik r6, r6, -4 /* for finding proper fixup */ swi r6, r7, PT_PC; /* a save back it to PT_PC */ addik r7, r0, SIGSEGV /* call bad_page_fault for finding aligned fixup, fixup address is saved * in PT_PC which is used as return address from exception */ addik r15, r0, ret_from_exc-8 /* setup return address */ brid bad_page_fault nop /* We prevent all load/store because it could failed any attempt to access */ .section __ex_table,"a"; .word load1,ex_unaligned_fixup; .word load2,ex_unaligned_fixup; .word load3,ex_unaligned_fixup; .word load4,ex_unaligned_fixup; .word load5,ex_unaligned_fixup; .word store1,ex_unaligned_fixup; .word store2,ex_unaligned_fixup; .word store3,ex_unaligned_fixup; .word store4,ex_unaligned_fixup; .word store5,ex_unaligned_fixup; .word store6,ex_unaligned_fixup; .previous; .end _unaligned_data_exception #endif /* CONFIG_MMU */ .global ex_handler_unhandled ex_handler_unhandled: /* FIXME add handle function for unhandled exception - dump register */ bri 0 /* * hw_exception_handler Jump Table * - Contains code snippets for each register that caused the unalign exception * - Hence exception handler is NOT self-modifying * - Separate table for load exceptions and store exceptions. * - Each table is of size: (8 * 32) = 256 bytes */ .section .text .align 4 lw_table: lw_r0: R3_TO_LWREG (0); lw_r1: LWREG_NOP; lw_r2: R3_TO_LWREG (2); lw_r3: R3_TO_LWREG_V (3); lw_r4: R3_TO_LWREG_V (4); lw_r5: R3_TO_LWREG_V (5); lw_r6: R3_TO_LWREG_V (6); lw_r7: R3_TO_LWREG (7); lw_r8: R3_TO_LWREG (8); lw_r9: R3_TO_LWREG (9); lw_r10: R3_TO_LWREG (10); lw_r11: R3_TO_LWREG (11); lw_r12: R3_TO_LWREG (12); lw_r13: R3_TO_LWREG (13); lw_r14: R3_TO_LWREG (14); lw_r15: R3_TO_LWREG (15); lw_r16: R3_TO_LWREG (16); lw_r17: LWREG_NOP; lw_r18: R3_TO_LWREG (18); lw_r19: R3_TO_LWREG (19); lw_r20: R3_TO_LWREG (20); lw_r21: R3_TO_LWREG (21); lw_r22: R3_TO_LWREG (22); lw_r23: R3_TO_LWREG (23); lw_r24: R3_TO_LWREG (24); lw_r25: R3_TO_LWREG (25); lw_r26: R3_TO_LWREG (26); lw_r27: R3_TO_LWREG (27); lw_r28: R3_TO_LWREG (28); lw_r29: R3_TO_LWREG (29); lw_r30: R3_TO_LWREG (30); #ifdef CONFIG_MMU lw_r31: R3_TO_LWREG_V (31); #else lw_r31: R3_TO_LWREG (31); #endif sw_table: sw_r0: SWREG_TO_R3 (0); sw_r1: SWREG_NOP; sw_r2: SWREG_TO_R3 (2); sw_r3: SWREG_TO_R3_V (3); sw_r4: SWREG_TO_R3_V (4); sw_r5: SWREG_TO_R3_V (5); sw_r6: SWREG_TO_R3_V (6); sw_r7: SWREG_TO_R3 (7); sw_r8: SWREG_TO_R3 (8); sw_r9: SWREG_TO_R3 (9); sw_r10: SWREG_TO_R3 (10); sw_r11: SWREG_TO_R3 (11); sw_r12: SWREG_TO_R3 (12); sw_r13: SWREG_TO_R3 (13); sw_r14: SWREG_TO_R3 (14); sw_r15: SWREG_TO_R3 (15); sw_r16: SWREG_TO_R3 (16); sw_r17: SWREG_NOP; sw_r18: SWREG_TO_R3 (18); sw_r19: SWREG_TO_R3 (19); sw_r20: SWREG_TO_R3 (20); sw_r21: SWREG_TO_R3 (21); sw_r22: SWREG_TO_R3 (22); sw_r23: SWREG_TO_R3 (23); sw_r24: SWREG_TO_R3 (24); sw_r25: SWREG_TO_R3 (25); sw_r26: SWREG_TO_R3 (26); sw_r27: SWREG_TO_R3 (27); sw_r28: SWREG_TO_R3 (28); sw_r29: SWREG_TO_R3 (29); sw_r30: SWREG_TO_R3 (30); #ifdef CONFIG_MMU sw_r31: SWREG_TO_R3_V (31); #else sw_r31: SWREG_TO_R3 (31); #endif #ifdef CONFIG_MMU lw_table_vm: lw_r0_vm: R3_TO_LWREG_VM (0); lw_r1_vm: R3_TO_LWREG_VM_V (1); lw_r2_vm: R3_TO_LWREG_VM_V (2); lw_r3_vm: R3_TO_LWREG_VM_V (3); lw_r4_vm: R3_TO_LWREG_VM_V (4); lw_r5_vm: R3_TO_LWREG_VM_V (5); lw_r6_vm: R3_TO_LWREG_VM_V (6); lw_r7_vm: R3_TO_LWREG_VM_V (7); lw_r8_vm: R3_TO_LWREG_VM_V (8); lw_r9_vm: R3_TO_LWREG_VM_V (9); lw_r10_vm: R3_TO_LWREG_VM_V (10); lw_r11_vm: R3_TO_LWREG_VM_V (11); lw_r12_vm: R3_TO_LWREG_VM_V (12); lw_r13_vm: R3_TO_LWREG_VM_V (13); lw_r14_vm: R3_TO_LWREG_VM_V (14); lw_r15_vm: R3_TO_LWREG_VM_V (15); lw_r16_vm: R3_TO_LWREG_VM_V (16); lw_r17_vm: R3_TO_LWREG_VM_V (17); lw_r18_vm: R3_TO_LWREG_VM_V (18); lw_r19_vm: R3_TO_LWREG_VM_V (19); lw_r20_vm: R3_TO_LWREG_VM_V (20); lw_r21_vm: R3_TO_LWREG_VM_V (21); lw_r22_vm: R3_TO_LWREG_VM_V (22); lw_r23_vm: R3_TO_LWREG_VM_V (23); lw_r24_vm: R3_TO_LWREG_VM_V (24); lw_r25_vm: R3_TO_LWREG_VM_V (25); lw_r26_vm: R3_TO_LWREG_VM_V (26); lw_r27_vm: R3_TO_LWREG_VM_V (27); lw_r28_vm: R3_TO_LWREG_VM_V (28); lw_r29_vm: R3_TO_LWREG_VM_V (29); lw_r30_vm: R3_TO_LWREG_VM_V (30); lw_r31_vm: R3_TO_LWREG_VM_V (31); sw_table_vm: sw_r0_vm: SWREG_TO_R3_VM (0); sw_r1_vm: SWREG_TO_R3_VM_V (1); sw_r2_vm: SWREG_TO_R3_VM_V (2); sw_r3_vm: SWREG_TO_R3_VM_V (3); sw_r4_vm: SWREG_TO_R3_VM_V (4); sw_r5_vm: SWREG_TO_R3_VM_V (5); sw_r6_vm: SWREG_TO_R3_VM_V (6); sw_r7_vm: SWREG_TO_R3_VM_V (7); sw_r8_vm: SWREG_TO_R3_VM_V (8); sw_r9_vm: SWREG_TO_R3_VM_V (9); sw_r10_vm: SWREG_TO_R3_VM_V (10); sw_r11_vm: SWREG_TO_R3_VM_V (11); sw_r12_vm: SWREG_TO_R3_VM_V (12); sw_r13_vm: SWREG_TO_R3_VM_V (13); sw_r14_vm: SWREG_TO_R3_VM_V (14); sw_r15_vm: SWREG_TO_R3_VM_V (15); sw_r16_vm: SWREG_TO_R3_VM_V (16); sw_r17_vm: SWREG_TO_R3_VM_V (17); sw_r18_vm: SWREG_TO_R3_VM_V (18); sw_r19_vm: SWREG_TO_R3_VM_V (19); sw_r20_vm: SWREG_TO_R3_VM_V (20); sw_r21_vm: SWREG_TO_R3_VM_V (21); sw_r22_vm: SWREG_TO_R3_VM_V (22); sw_r23_vm: SWREG_TO_R3_VM_V (23); sw_r24_vm: SWREG_TO_R3_VM_V (24); sw_r25_vm: SWREG_TO_R3_VM_V (25); sw_r26_vm: SWREG_TO_R3_VM_V (26); sw_r27_vm: SWREG_TO_R3_VM_V (27); sw_r28_vm: SWREG_TO_R3_VM_V (28); sw_r29_vm: SWREG_TO_R3_VM_V (29); sw_r30_vm: SWREG_TO_R3_VM_V (30); sw_r31_vm: SWREG_TO_R3_VM_V (31); #endif /* CONFIG_MMU */ /* Temporary data structures used in the handler */ .section .data .align 4 ex_tmp_data_loc_0: .byte 0 ex_tmp_data_loc_1: .byte 0 ex_tmp_data_loc_2: .byte 0 ex_tmp_data_loc_3: .byte 0 ex_reg_op: .byte 0