From 5f97f7f9400de47ae837170bb274e90ad3934386 Mon Sep 17 00:00:00 2001 From: Haavard Skinnemoen Date: Mon, 25 Sep 2006 23:32:13 -0700 Subject: [PATCH] avr32 architecture This adds support for the Atmel AVR32 architecture as well as the AT32AP7000 CPU and the AT32STK1000 development board. AVR32 is a new high-performance 32-bit RISC microprocessor core, designed for cost-sensitive embedded applications, with particular emphasis on low power consumption and high code density. The AVR32 architecture is not binary compatible with earlier 8-bit AVR architectures. The AVR32 architecture, including the instruction set, is described by the AVR32 Architecture Manual, available from http://www.atmel.com/dyn/resources/prod_documents/doc32000.pdf The Atmel AT32AP7000 is the first CPU implementing the AVR32 architecture. It features a 7-stage pipeline, 16KB instruction and data caches and a full Memory Management Unit. It also comes with a large set of integrated peripherals, many of which are shared with the AT91 ARM-based controllers from Atmel. Full data sheet is available from http://www.atmel.com/dyn/resources/prod_documents/doc32003.pdf while the CPU core implementation including caches and MMU is documented by the AVR32 AP Technical Reference, available from http://www.atmel.com/dyn/resources/prod_documents/doc32001.pdf Information about the AT32STK1000 development board can be found at http://www.atmel.com/dyn/products/tools_card.asp?tool_id=3918 including a BSP CD image with an earlier version of this patch, development tools (binaries and source/patches) and a root filesystem image suitable for booting from SD card. Alternatively, there's a preliminary "getting started" guide available at http://avr32linux.org/twiki/bin/view/Main/GettingStarted which provides links to the sources and patches you will need in order to set up a cross-compiling environment for avr32-linux. This patch, as well as the other patches included with the BSP and the toolchain patches, is actively supported by Atmel Corporation. [dmccr@us.ibm.com: Fix more pxx_page macro locations] [bunk@stusta.de: fix `make defconfig'] Signed-off-by: Haavard Skinnemoen Signed-off-by: Adrian Bunk Signed-off-by: Dave McCracken Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/avr32/mm/fault.c | 315 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 315 insertions(+) create mode 100644 arch/avr32/mm/fault.c (limited to 'arch/avr32/mm/fault.c') diff --git a/arch/avr32/mm/fault.c b/arch/avr32/mm/fault.c new file mode 100644 index 0000000..6785572 --- /dev/null +++ b/arch/avr32/mm/fault.c @@ -0,0 +1,315 @@ +/* + * Copyright (C) 2004-2006 Atmel Corporation + * + * Based on linux/arch/sh/mm/fault.c: + * Copyright (C) 1999 Niibe Yutaka + * + * 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. + */ + +#include +#include +#include + +#include +#include +#include +#include +#include + +#ifdef DEBUG +static void dump_code(unsigned long pc) +{ + char *p = (char *)pc; + char val; + int i; + + + printk(KERN_DEBUG "Code:"); + for (i = 0; i < 16; i++) { + if (__get_user(val, p + i)) + break; + printk(" %02x", val); + } + printk("\n"); +} +#endif + +#ifdef CONFIG_KPROBES +ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain); + +/* Hook to register for page fault notifications */ +int register_page_fault_notifier(struct notifier_block *nb) +{ + return atomic_notifier_chain_register(¬ify_page_fault_chain, nb); +} + +int unregister_page_fault_notifier(struct notifier_block *nb) +{ + return atomic_notifier_chain_unregister(¬ify_page_fault_chain, nb); +} + +static inline int notify_page_fault(enum die_val val, struct pt_regs *regs, + int trap, int sig) +{ + struct die_args args = { + .regs = regs, + .trapnr = trap, + }; + return atomic_notifier_call_chain(¬ify_page_fault_chain, val, &args); +} +#else +static inline int notify_page_fault(enum die_val val, struct pt_regs *regs, + int trap, int sig) +{ + return NOTIFY_DONE; +} +#endif + +/* + * This routine handles page faults. It determines the address and the + * problem, and then passes it off to one of the appropriate routines. + * + * ecr is the Exception Cause Register. Possible values are: + * 5: Page not found (instruction access) + * 6: Protection fault (instruction access) + * 12: Page not found (read access) + * 13: Page not found (write access) + * 14: Protection fault (read access) + * 15: Protection fault (write access) + */ +asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs) +{ + struct task_struct *tsk; + struct mm_struct *mm; + struct vm_area_struct *vma; + const struct exception_table_entry *fixup; + unsigned long address; + unsigned long page; + int writeaccess = 0; + + if (notify_page_fault(DIE_PAGE_FAULT, regs, + ecr, SIGSEGV) == NOTIFY_STOP) + return; + + address = sysreg_read(TLBEAR); + + tsk = current; + mm = tsk->mm; + + /* + * If we're in an interrupt or have no user context, we must + * not take the fault... + */ + if (in_atomic() || !mm || regs->sr & SYSREG_BIT(GM)) + goto no_context; + + local_irq_enable(); + + down_read(&mm->mmap_sem); + + vma = find_vma(mm, address); + if (!vma) + goto bad_area; + if (vma->vm_start <= address) + goto good_area; + if (!(vma->vm_flags & VM_GROWSDOWN)) + goto bad_area; + if (expand_stack(vma, address)) + goto bad_area; + + /* + * Ok, we have a good vm_area for this memory access, so we + * can handle it... + */ +good_area: + //pr_debug("good area: vm_flags = 0x%lx\n", vma->vm_flags); + switch (ecr) { + case ECR_PROTECTION_X: + case ECR_TLB_MISS_X: + if (!(vma->vm_flags & VM_EXEC)) + goto bad_area; + break; + case ECR_PROTECTION_R: + case ECR_TLB_MISS_R: + if (!(vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC))) + goto bad_area; + break; + case ECR_PROTECTION_W: + case ECR_TLB_MISS_W: + if (!(vma->vm_flags & VM_WRITE)) + goto bad_area; + writeaccess = 1; + break; + default: + panic("Unhandled case %lu in do_page_fault!", ecr); + } + + /* + * If for any reason at all we couldn't handle the fault, make + * sure we exit gracefully rather than endlessly redo the + * fault. + */ +survive: + switch (handle_mm_fault(mm, vma, address, writeaccess)) { + case VM_FAULT_MINOR: + tsk->min_flt++; + break; + case VM_FAULT_MAJOR: + tsk->maj_flt++; + break; + case VM_FAULT_SIGBUS: + goto do_sigbus; + case VM_FAULT_OOM: + goto out_of_memory; + default: + BUG(); + } + + up_read(&mm->mmap_sem); + return; + + /* + * Something tried to access memory that isn't in our memory + * map. Fix it, but check if it's kernel or user first... + */ +bad_area: + pr_debug("Bad area [%s:%u]: addr %08lx, ecr %lu\n", + tsk->comm, tsk->pid, address, ecr); + + up_read(&mm->mmap_sem); + + if (user_mode(regs)) { + /* Hmm...we have to pass address and ecr somehow... */ + /* tsk->thread.address = address; + tsk->thread.error_code = ecr; */ +#ifdef DEBUG + show_regs(regs); + dump_code(regs->pc); + + page = sysreg_read(PTBR); + printk("ptbr = %08lx", page); + if (page) { + page = ((unsigned long *)page)[address >> 22]; + printk(" pgd = %08lx", page); + if (page & _PAGE_PRESENT) { + page &= PAGE_MASK; + address &= 0x003ff000; + page = ((unsigned long *)__va(page))[address >> PAGE_SHIFT]; + printk(" pte = %08lx\n", page); + } + } +#endif + pr_debug("Sending SIGSEGV to PID %d...\n", + tsk->pid); + force_sig(SIGSEGV, tsk); + return; + } + +no_context: + pr_debug("No context\n"); + + /* Are we prepared to handle this kernel fault? */ + fixup = search_exception_tables(regs->pc); + if (fixup) { + regs->pc = fixup->fixup; + pr_debug("Found fixup at %08lx\n", fixup->fixup); + return; + } + + /* + * Oops. The kernel tried to access some bad page. We'll have + * to terminate things with extreme prejudice. + */ + if (address < PAGE_SIZE) + printk(KERN_ALERT + "Unable to handle kernel NULL pointer dereference"); + else + printk(KERN_ALERT + "Unable to handle kernel paging request"); + printk(" at virtual address %08lx\n", address); + printk(KERN_ALERT "pc = %08lx\n", regs->pc); + + page = sysreg_read(PTBR); + printk(KERN_ALERT "ptbr = %08lx", page); + if (page) { + page = ((unsigned long *)page)[address >> 22]; + printk(" pgd = %08lx", page); + if (page & _PAGE_PRESENT) { + page &= PAGE_MASK; + address &= 0x003ff000; + page = ((unsigned long *)__va(page))[address >> PAGE_SHIFT]; + printk(" pte = %08lx\n", page); + } + } + die("\nOops", regs, ecr); + do_exit(SIGKILL); + + /* + * We ran out of memory, or some other thing happened to us + * that made us unable to handle the page fault gracefully. + */ +out_of_memory: + printk("Out of memory\n"); + up_read(&mm->mmap_sem); + if (current->pid == 1) { + yield(); + down_read(&mm->mmap_sem); + goto survive; + } + printk("VM: Killing process %s\n", tsk->comm); + if (user_mode(regs)) + do_exit(SIGKILL); + goto no_context; + +do_sigbus: + up_read(&mm->mmap_sem); + + /* + * Send a sigbus, regardless of whether we were in kernel or + * user mode. + */ + /* address, error_code, trap_no, ... */ +#ifdef DEBUG + show_regs(regs); + dump_code(regs->pc); +#endif + pr_debug("Sending SIGBUS to PID %d...\n", tsk->pid); + force_sig(SIGBUS, tsk); + + /* Kernel mode? Handle exceptions or die */ + if (!user_mode(regs)) + goto no_context; +} + +asmlinkage void do_bus_error(unsigned long addr, int write_access, + struct pt_regs *regs) +{ + printk(KERN_ALERT + "Bus error at physical address 0x%08lx (%s access)\n", + addr, write_access ? "write" : "read"); + printk(KERN_INFO "DTLB dump:\n"); + dump_dtlb(); + die("Bus Error", regs, write_access); + do_exit(SIGKILL); +} + +/* + * This functionality is currently not possible to implement because + * we're using segmentation to ensure a fixed mapping of the kernel + * virtual address space. + * + * It would be possible to implement this, but it would require us to + * disable segmentation at startup and load the kernel mappings into + * the TLB like any other pages. There will be lots of trickery to + * avoid recursive invocation of the TLB miss handler, though... + */ +#ifdef CONFIG_DEBUG_PAGEALLOC +void kernel_map_pages(struct page *page, int numpages, int enable) +{ + +} +EXPORT_SYMBOL(kernel_map_pages); +#endif -- cgit v1.1