diff options
Diffstat (limited to 'arch/unicore32/mm/fault.c')
| -rw-r--r-- | arch/unicore32/mm/fault.c | 479 |
1 files changed, 479 insertions, 0 deletions
diff --git a/arch/unicore32/mm/fault.c b/arch/unicore32/mm/fault.c new file mode 100644 index 000000000000..283aa4b50b7a --- /dev/null +++ b/arch/unicore32/mm/fault.c @@ -0,0 +1,479 @@ +/* + * linux/arch/unicore32/mm/fault.c + * + * Code specific to PKUnity SoC and UniCore ISA + * + * Copyright (C) 2001-2010 GUAN Xue-tao + * + * 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 <linux/module.h> +#include <linux/signal.h> +#include <linux/mm.h> +#include <linux/hardirq.h> +#include <linux/init.h> +#include <linux/kprobes.h> +#include <linux/uaccess.h> +#include <linux/page-flags.h> +#include <linux/sched.h> +#include <linux/io.h> + +#include <asm/system.h> +#include <asm/pgtable.h> +#include <asm/tlbflush.h> + +/* + * Fault status register encodings. We steal bit 31 for our own purposes. + */ +#define FSR_LNX_PF (1 << 31) + +static inline int fsr_fs(unsigned int fsr) +{ + /* xyabcde will be abcde+xy */ + return (fsr & 31) + ((fsr & (3 << 5)) >> 5); +} + +/* + * This is useful to dump out the page tables associated with + * 'addr' in mm 'mm'. + */ +void show_pte(struct mm_struct *mm, unsigned long addr) +{ + pgd_t *pgd; + + if (!mm) + mm = &init_mm; + + printk(KERN_ALERT "pgd = %p\n", mm->pgd); + pgd = pgd_offset(mm, addr); + printk(KERN_ALERT "[%08lx] *pgd=%08lx", addr, pgd_val(*pgd)); + + do { + pmd_t *pmd; + pte_t *pte; + + if (pgd_none(*pgd)) + break; + + if (pgd_bad(*pgd)) { + printk("(bad)"); + break; + } + + pmd = pmd_offset((pud_t *) pgd, addr); + if (PTRS_PER_PMD != 1) + printk(", *pmd=%08lx", pmd_val(*pmd)); + + if (pmd_none(*pmd)) + break; + + if (pmd_bad(*pmd)) { + printk("(bad)"); + break; + } + + /* We must not map this if we have highmem enabled */ + if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT))) + break; + + pte = pte_offset_map(pmd, addr); + printk(", *pte=%08lx", pte_val(*pte)); + pte_unmap(pte); + } while (0); + + printk("\n"); +} + +/* + * Oops. The kernel tried to access some page that wasn't present. + */ +static void __do_kernel_fault(struct mm_struct *mm, unsigned long addr, + unsigned int fsr, struct pt_regs *regs) +{ + /* + * Are we prepared to handle this kernel fault? + */ + if (fixup_exception(regs)) + return; + + /* + * No handler, we'll have to terminate things with extreme prejudice. + */ + bust_spinlocks(1); + printk(KERN_ALERT + "Unable to handle kernel %s at virtual address %08lx\n", + (addr < PAGE_SIZE) ? "NULL pointer dereference" : + "paging request", addr); + + show_pte(mm, addr); + die("Oops", regs, fsr); + bust_spinlocks(0); + do_exit(SIGKILL); +} + +/* + * Something tried to access memory that isn't in our memory map.. + * User mode accesses just cause a SIGSEGV + */ +static void __do_user_fault(struct task_struct *tsk, unsigned long addr, + unsigned int fsr, unsigned int sig, int code, + struct pt_regs *regs) +{ + struct siginfo si; + + tsk->thread.address = addr; + tsk->thread.error_code = fsr; + tsk->thread.trap_no = 14; + si.si_signo = sig; + si.si_errno = 0; + si.si_code = code; + si.si_addr = (void __user *)addr; + force_sig_info(sig, &si, tsk); +} + +void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs) +{ + struct task_struct *tsk = current; + struct mm_struct *mm = tsk->active_mm; + + /* + * If we are in kernel mode at this point, we + * have no context to handle this fault with. + */ + if (user_mode(regs)) + __do_user_fault(tsk, addr, fsr, SIGSEGV, SEGV_MAPERR, regs); + else + __do_kernel_fault(mm, addr, fsr, regs); +} + +#define VM_FAULT_BADMAP 0x010000 +#define VM_FAULT_BADACCESS 0x020000 + +/* + * Check that the permissions on the VMA allow for the fault which occurred. + * If we encountered a write fault, we must have write permission, otherwise + * we allow any permission. + */ +static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma) +{ + unsigned int mask = VM_READ | VM_WRITE | VM_EXEC; + + if (!(fsr ^ 0x12)) /* write? */ + mask = VM_WRITE; + if (fsr & FSR_LNX_PF) + mask = VM_EXEC; + + return vma->vm_flags & mask ? false : true; +} + +static int __do_pf(struct mm_struct *mm, unsigned long addr, unsigned int fsr, + struct task_struct *tsk) +{ + struct vm_area_struct *vma; + int fault; + + vma = find_vma(mm, addr); + fault = VM_FAULT_BADMAP; + if (unlikely(!vma)) + goto out; + if (unlikely(vma->vm_start > addr)) + goto check_stack; + + /* + * Ok, we have a good vm_area for this + * memory access, so we can handle it. + */ +good_area: + if (access_error(fsr, vma)) { + fault = VM_FAULT_BADACCESS; + goto out; + } + + /* + * If for any reason at all we couldn't handle the fault, make + * sure we exit gracefully rather than endlessly redo the fault. + */ + fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, + (!(fsr ^ 0x12)) ? FAULT_FLAG_WRITE : 0); + if (unlikely(fault & VM_FAULT_ERROR)) + return fault; + if (fault & VM_FAULT_MAJOR) + tsk->maj_flt++; + else + tsk->min_flt++; + return fault; + +check_stack: + if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr)) + goto good_area; +out: + return fault; +} + +static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs) +{ + struct task_struct *tsk; + struct mm_struct *mm; + int fault, sig, code; + + 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) + goto no_context; + + /* + * As per x86, we may deadlock here. However, since the kernel only + * validly references user space from well defined areas of the code, + * we can bug out early if this is from code which shouldn't. + */ + if (!down_read_trylock(&mm->mmap_sem)) { + if (!user_mode(regs) + && !search_exception_tables(regs->UCreg_pc)) + goto no_context; + down_read(&mm->mmap_sem); + } else { + /* + * The above down_read_trylock() might have succeeded in + * which case, we'll have missed the might_sleep() from + * down_read() + */ + might_sleep(); +#ifdef CONFIG_DEBUG_VM + if (!user_mode(regs) && + !search_exception_tables(regs->UCreg_pc)) + goto no_context; +#endif + } + + fault = __do_pf(mm, addr, fsr, tsk); + up_read(&mm->mmap_sem); + + /* + * Handle the "normal" case first - VM_FAULT_MAJOR / VM_FAULT_MINOR + */ + if (likely(!(fault & + (VM_FAULT_ERROR | VM_FAULT_BADMAP | VM_FAULT_BADACCESS)))) + return 0; + + if (fault & VM_FAULT_OOM) { + /* + * We ran out of memory, call the OOM killer, and return to + * userspace (which will retry the fault, or kill us if we + * got oom-killed) + */ + pagefault_out_of_memory(); + return 0; + } + + /* + * If we are in kernel mode at this point, we + * have no context to handle this fault with. + */ + if (!user_mode(regs)) + goto no_context; + + if (fault & VM_FAULT_SIGBUS) { + /* + * We had some memory, but were unable to + * successfully fix up this page fault. + */ + sig = SIGBUS; + code = BUS_ADRERR; + } else { + /* + * Something tried to access memory that + * isn't in our memory map.. + */ + sig = SIGSEGV; + code = fault == VM_FAULT_BADACCESS ? SEGV_ACCERR : SEGV_MAPERR; + } + + __do_user_fault(tsk, addr, fsr, sig, code, regs); + return 0; + +no_context: + __do_kernel_fault(mm, addr, fsr, regs); + return 0; +} + +/* + * First Level Translation Fault Handler + * + * We enter here because the first level page table doesn't contain + * a valid entry for the address. + * + * If the address is in kernel space (>= TASK_SIZE), then we are + * probably faulting in the vmalloc() area. + * + * If the init_task's first level page tables contains the relevant + * entry, we copy the it to this task. If not, we send the process + * a signal, fixup the exception, or oops the kernel. + * + * NOTE! We MUST NOT take any locks for this case. We may be in an + * interrupt or a critical region, and should only copy the information + * from the master page table, nothing more. + */ +static int do_ifault(unsigned long addr, unsigned int fsr, struct pt_regs *regs) +{ + unsigned int index; + pgd_t *pgd, *pgd_k; + pmd_t *pmd, *pmd_k; + + if (addr < TASK_SIZE) + return do_pf(addr, fsr, regs); + + if (user_mode(regs)) + goto bad_area; + + index = pgd_index(addr); + + pgd = cpu_get_pgd() + index; + pgd_k = init_mm.pgd + index; + + if (pgd_none(*pgd_k)) + goto bad_area; + + pmd_k = pmd_offset((pud_t *) pgd_k, addr); + pmd = pmd_offset((pud_t *) pgd, addr); + + if (pmd_none(*pmd_k)) + goto bad_area; + + set_pmd(pmd, *pmd_k); + flush_pmd_entry(pmd); + return 0; + +bad_area: + do_bad_area(addr, fsr, regs); + return 0; +} + +/* + * This abort handler always returns "fault". + */ +static int do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs) +{ + return 1; +} + +static int do_good(unsigned long addr, unsigned int fsr, struct pt_regs *regs) +{ + unsigned int res1, res2; + + printk("dabt exception but no error!\n"); + + __asm__ __volatile__( + "mff %0,f0\n" + "mff %1,f1\n" + : "=r"(res1), "=r"(res2) + : + : "memory"); + + printk(KERN_EMERG "r0 :%08x r1 :%08x\n", res1, res2); + panic("shut up\n"); + return 0; +} + +static struct fsr_info { + int (*fn) (unsigned long addr, unsigned int fsr, struct pt_regs *regs); + int sig; + int code; + const char *name; +} fsr_info[] = { + /* + * The following are the standard Unicore-I and UniCore-II aborts. + */ + { do_good, SIGBUS, 0, "no error" }, + { do_bad, SIGBUS, BUS_ADRALN, "alignment exception" }, + { do_bad, SIGBUS, BUS_OBJERR, "external exception" }, + { do_bad, SIGBUS, 0, "burst operation" }, + { do_bad, SIGBUS, 0, "unknown 00100" }, + { do_ifault, SIGSEGV, SEGV_MAPERR, "2nd level pt non-exist"}, + { do_bad, SIGBUS, 0, "2nd lvl large pt non-exist" }, + { do_bad, SIGBUS, 0, "invalid pte" }, + { do_pf, SIGSEGV, SEGV_MAPERR, "page miss" }, + { do_bad, SIGBUS, 0, "middle page miss" }, + { do_bad, SIGBUS, 0, "large page miss" }, + { do_pf, SIGSEGV, SEGV_MAPERR, "super page (section) miss" }, + { do_bad, SIGBUS, 0, "unknown 01100" }, + { do_bad, SIGBUS, 0, "unknown 01101" }, + { do_bad, SIGBUS, 0, "unknown 01110" }, + { do_bad, SIGBUS, 0, "unknown 01111" }, + { do_bad, SIGBUS, 0, "addr: up 3G or IO" }, + { do_pf, SIGSEGV, SEGV_ACCERR, "read unreadable addr" }, + { do_pf, SIGSEGV, SEGV_ACCERR, "write unwriteable addr"}, + { do_pf, SIGSEGV, SEGV_ACCERR, "exec unexecutable addr"}, + { do_bad, SIGBUS, 0, "unknown 10100" }, + { do_bad, SIGBUS, 0, "unknown 10101" }, + { do_bad, SIGBUS, 0, "unknown 10110" }, + { do_bad, SIGBUS, 0, "unknown 10111" }, + { do_bad, SIGBUS, 0, "unknown 11000" }, + { do_bad, SIGBUS, 0, "unknown 11001" }, + { do_bad, SIGBUS, 0, "unknown 11010" }, + { do_bad, SIGBUS, 0, "unknown 11011" }, + { do_bad, SIGBUS, 0, "unknown 11100" }, + { do_bad, SIGBUS, 0, "unknown 11101" }, + { do_bad, SIGBUS, 0, "unknown 11110" }, + { do_bad, SIGBUS, 0, "unknown 11111" } +}; + +void __init hook_fault_code(int nr, + int (*fn) (unsigned long, unsigned int, struct pt_regs *), + int sig, int code, const char *name) +{ + if (nr < 0 || nr >= ARRAY_SIZE(fsr_info)) + BUG(); + + fsr_info[nr].fn = fn; + fsr_info[nr].sig = sig; + fsr_info[nr].code = code; + fsr_info[nr].name = name; +} + +/* + * Dispatch a data abort to the relevant handler. + */ +asmlinkage void do_DataAbort(unsigned long addr, unsigned int fsr, + struct pt_regs *regs) +{ + const struct fsr_info *inf = fsr_info + fsr_fs(fsr); + struct siginfo info; + + if (!inf->fn(addr, fsr & ~FSR_LNX_PF, regs)) + return; + + printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n", + inf->name, fsr, addr); + + info.si_signo = inf->sig; + info.si_errno = 0; + info.si_code = inf->code; + info.si_addr = (void __user *)addr; + uc32_notify_die("", regs, &info, fsr, 0); +} + +asmlinkage void do_PrefetchAbort(unsigned long addr, + unsigned int ifsr, struct pt_regs *regs) +{ + const struct fsr_info *inf = fsr_info + fsr_fs(ifsr); + struct siginfo info; + + if (!inf->fn(addr, ifsr | FSR_LNX_PF, regs)) + return; + + printk(KERN_ALERT "Unhandled prefetch abort: %s (0x%03x) at 0x%08lx\n", + inf->name, ifsr, addr); + + info.si_signo = inf->sig; + info.si_errno = 0; + info.si_code = inf->code; + info.si_addr = (void __user *)addr; + uc32_notify_die("", regs, &info, ifsr, 0); +} |