From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- arch/parisc/mm/fault.c | 351 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 351 insertions(+) create mode 100644 arch/parisc/mm/fault.c (limited to 'arch/parisc/mm/fault.c') diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c new file mode 100644 index 000000000..e5120e653 --- /dev/null +++ b/arch/parisc/mm/fault.c @@ -0,0 +1,351 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * + * Copyright (C) 1995, 1996, 1997, 1998 by Ralf Baechle + * Copyright 1999 SuSE GmbH (Philipp Rumpf, prumpf@tux.org) + * Copyright 1999 Hewlett Packard Co. + * + */ + +#include +#include +#include +#include +#include + +#include +#include + +/* Various important other fields */ +#define bit22set(x) (x & 0x00000200) +#define bits23_25set(x) (x & 0x000001c0) +#define isGraphicsFlushRead(x) ((x & 0xfc003fdf) == 0x04001a80) + /* extended opcode is 0x6a */ + +#define BITSSET 0x1c0 /* for identifying LDCW */ + + +DEFINE_PER_CPU(struct exception_data, exception_data); + +int show_unhandled_signals = 1; + +/* + * parisc_acctyp(unsigned int inst) -- + * Given a PA-RISC memory access instruction, determine if the + * the instruction would perform a memory read or memory write + * operation. + * + * This function assumes that the given instruction is a memory access + * instruction (i.e. you should really only call it if you know that + * the instruction has generated some sort of a memory access fault). + * + * Returns: + * VM_READ if read operation + * VM_WRITE if write operation + * VM_EXEC if execute operation + */ +static unsigned long +parisc_acctyp(unsigned long code, unsigned int inst) +{ + if (code == 6 || code == 16) + return VM_EXEC; + + switch (inst & 0xf0000000) { + case 0x40000000: /* load */ + case 0x50000000: /* new load */ + return VM_READ; + + case 0x60000000: /* store */ + case 0x70000000: /* new store */ + return VM_WRITE; + + case 0x20000000: /* coproc */ + case 0x30000000: /* coproc2 */ + if (bit22set(inst)) + return VM_WRITE; + + case 0x0: /* indexed/memory management */ + if (bit22set(inst)) { + /* + * Check for the 'Graphics Flush Read' instruction. + * It resembles an FDC instruction, except for bits + * 20 and 21. Any combination other than zero will + * utilize the block mover functionality on some + * older PA-RISC platforms. The case where a block + * move is performed from VM to graphics IO space + * should be treated as a READ. + * + * The significance of bits 20,21 in the FDC + * instruction is: + * + * 00 Flush data cache (normal instruction behavior) + * 01 Graphics flush write (IO space -> VM) + * 10 Graphics flush read (VM -> IO space) + * 11 Graphics flush read/write (VM <-> IO space) + */ + if (isGraphicsFlushRead(inst)) + return VM_READ; + return VM_WRITE; + } else { + /* + * Check for LDCWX and LDCWS (semaphore instructions). + * If bits 23 through 25 are all 1's it is one of + * the above two instructions and is a write. + * + * Note: With the limited bits we are looking at, + * this will also catch PROBEW and PROBEWI. However, + * these should never get in here because they don't + * generate exceptions of the type: + * Data TLB miss fault/data page fault + * Data memory protection trap + */ + if (bits23_25set(inst) == BITSSET) + return VM_WRITE; + } + return VM_READ; /* Default */ + } + return VM_READ; /* Default */ +} + +#undef bit22set +#undef bits23_25set +#undef isGraphicsFlushRead +#undef BITSSET + + +#if 0 +/* This is the treewalk to find a vma which is the highest that has + * a start < addr. We're using find_vma_prev instead right now, but + * we might want to use this at some point in the future. Probably + * not, but I want it committed to CVS so I don't lose it :-) + */ + while (tree != vm_avl_empty) { + if (tree->vm_start > addr) { + tree = tree->vm_avl_left; + } else { + prev = tree; + if (prev->vm_next == NULL) + break; + if (prev->vm_next->vm_start > addr) + break; + tree = tree->vm_avl_right; + } + } +#endif + +int fixup_exception(struct pt_regs *regs) +{ + const struct exception_table_entry *fix; + + /* If we only stored 32bit addresses in the exception table we can drop + * out if we faulted on a 64bit address. */ + if ((sizeof(regs->iaoq[0]) > sizeof(fix->insn)) + && (regs->iaoq[0] >> 32)) + return 0; + + fix = search_exception_tables(regs->iaoq[0]); + if (fix) { + struct exception_data *d; + d = this_cpu_ptr(&exception_data); + d->fault_ip = regs->iaoq[0]; + d->fault_space = regs->isr; + d->fault_addr = regs->ior; + + regs->iaoq[0] = ((fix->fixup) & ~3); + /* + * NOTE: In some cases the faulting instruction + * may be in the delay slot of a branch. We + * don't want to take the branch, so we don't + * increment iaoq[1], instead we set it to be + * iaoq[0]+4, and clear the B bit in the PSW + */ + regs->iaoq[1] = regs->iaoq[0] + 4; + regs->gr[0] &= ~PSW_B; /* IPSW in gr[0] */ + + return 1; + } + + return 0; +} + +/* + * Print out info about fatal segfaults, if the show_unhandled_signals + * sysctl is set: + */ +static inline void +show_signal_msg(struct pt_regs *regs, unsigned long code, + unsigned long address, struct task_struct *tsk, + struct vm_area_struct *vma) +{ + if (!unhandled_signal(tsk, SIGSEGV)) + return; + + if (!printk_ratelimit()) + return; + + pr_warn("\n"); + pr_warn("do_page_fault() command='%s' type=%lu address=0x%08lx", + tsk->comm, code, address); + print_vma_addr(KERN_CONT " in ", regs->iaoq[0]); + if (vma) + pr_warn(" vm_start = 0x%08lx, vm_end = 0x%08lx\n", + vma->vm_start, vma->vm_end); + + show_regs(regs); +} + +void do_page_fault(struct pt_regs *regs, unsigned long code, + unsigned long address) +{ + struct vm_area_struct *vma, *prev_vma; + struct task_struct *tsk; + struct mm_struct *mm; + unsigned long acc_type; + int fault; + unsigned int flags; + + if (in_atomic()) + goto no_context; + + tsk = current; + mm = tsk->mm; + if (!mm) + goto no_context; + + flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + if (user_mode(regs)) + flags |= FAULT_FLAG_USER; + + acc_type = parisc_acctyp(code, regs->iir); + if (acc_type & VM_WRITE) + flags |= FAULT_FLAG_WRITE; +retry: + down_read(&mm->mmap_sem); + vma = find_vma_prev(mm, address, &prev_vma); + if (!vma || address < vma->vm_start) + goto check_expansion; +/* + * Ok, we have a good vm_area for this memory access. We still need to + * check the access permissions. + */ + +good_area: + + if ((vma->vm_flags & acc_type) != acc_type) + goto bad_area; + + /* + * 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, address, flags); + + if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + return; + + if (unlikely(fault & VM_FAULT_ERROR)) { + /* + * We hit a shared mapping outside of the file, or some + * other thing happened to us that made us unable to + * handle the page fault gracefully. + */ + if (fault & VM_FAULT_OOM) + goto out_of_memory; + else if (fault & VM_FAULT_SIGSEGV) + goto bad_area; + else if (fault & VM_FAULT_SIGBUS) + goto bad_area; + BUG(); + } + if (flags & FAULT_FLAG_ALLOW_RETRY) { + if (fault & VM_FAULT_MAJOR) + current->maj_flt++; + else + current->min_flt++; + if (fault & VM_FAULT_RETRY) { + flags &= ~FAULT_FLAG_ALLOW_RETRY; + + /* + * No need to up_read(&mm->mmap_sem) as we would + * have already released it in __lock_page_or_retry + * in mm/filemap.c. + */ + + goto retry; + } + } + up_read(&mm->mmap_sem); + return; + +check_expansion: + vma = prev_vma; + if (vma && (expand_stack(vma, address) == 0)) + goto good_area; + +/* + * Something tried to access memory that isn't in our memory map.. + */ +bad_area: + up_read(&mm->mmap_sem); + + if (user_mode(regs)) { + struct siginfo si; + + show_signal_msg(regs, code, address, tsk, vma); + + switch (code) { + case 15: /* Data TLB miss fault/Data page fault */ + /* send SIGSEGV when outside of vma */ + if (!vma || + address < vma->vm_start || address > vma->vm_end) { + si.si_signo = SIGSEGV; + si.si_code = SEGV_MAPERR; + break; + } + + /* send SIGSEGV for wrong permissions */ + if ((vma->vm_flags & acc_type) != acc_type) { + si.si_signo = SIGSEGV; + si.si_code = SEGV_ACCERR; + break; + } + + /* probably address is outside of mapped file */ + /* fall through */ + case 17: /* NA data TLB miss / page fault */ + case 18: /* Unaligned access - PCXS only */ + si.si_signo = SIGBUS; + si.si_code = (code == 18) ? BUS_ADRALN : BUS_ADRERR; + break; + case 16: /* Non-access instruction TLB miss fault */ + case 26: /* PCXL: Data memory access rights trap */ + default: + si.si_signo = SIGSEGV; + si.si_code = (code == 26) ? SEGV_ACCERR : SEGV_MAPERR; + break; + } + si.si_errno = 0; + si.si_addr = (void __user *) address; + force_sig_info(si.si_signo, &si, current); + return; + } + +no_context: + + if (!user_mode(regs) && fixup_exception(regs)) { + return; + } + + parisc_terminate("Bad Address (null pointer deref?)", regs, code, address); + + out_of_memory: + up_read(&mm->mmap_sem); + if (!user_mode(regs)) + goto no_context; + pagefault_out_of_memory(); +} -- cgit v1.2.3-54-g00ecf