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595 lines
15 KiB
595 lines
15 KiB
/* $Id: fault.c,v 1.122 2001/11/17 07:19:26 davem Exp $
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* fault.c: Page fault handlers for the Sparc.
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*
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* Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
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* Copyright (C) 1996 Eddie C. Dost (ecd@skynet.be)
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* Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
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*/
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#include <asm/head.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/sched.h>
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#include <linux/ptrace.h>
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#include <linux/mman.h>
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#include <linux/threads.h>
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#include <linux/kernel.h>
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#include <linux/signal.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/smp_lock.h>
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#include <linux/interrupt.h>
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#include <linux/module.h>
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#include <asm/system.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include <asm/memreg.h>
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#include <asm/openprom.h>
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#include <asm/oplib.h>
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#include <asm/smp.h>
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#include <asm/traps.h>
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#include <asm/kdebug.h>
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#include <asm/uaccess.h>
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#define ELEMENTS(arr) (sizeof (arr)/sizeof (arr[0]))
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extern int prom_node_root;
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/* At boot time we determine these two values necessary for setting
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* up the segment maps and page table entries (pte's).
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*/
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int num_segmaps, num_contexts;
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int invalid_segment;
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/* various Virtual Address Cache parameters we find at boot time... */
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int vac_size, vac_linesize, vac_do_hw_vac_flushes;
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int vac_entries_per_context, vac_entries_per_segment;
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int vac_entries_per_page;
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/* Nice, simple, prom library does all the sweating for us. ;) */
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int prom_probe_memory (void)
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{
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register struct linux_mlist_v0 *mlist;
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register unsigned long bytes, base_paddr, tally;
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register int i;
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i = 0;
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mlist= *prom_meminfo()->v0_available;
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bytes = tally = mlist->num_bytes;
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base_paddr = (unsigned long) mlist->start_adr;
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sp_banks[0].base_addr = base_paddr;
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sp_banks[0].num_bytes = bytes;
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while (mlist->theres_more != (void *) 0){
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i++;
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mlist = mlist->theres_more;
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bytes = mlist->num_bytes;
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tally += bytes;
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if (i > SPARC_PHYS_BANKS-1) {
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printk ("The machine has more banks than "
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"this kernel can support\n"
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"Increase the SPARC_PHYS_BANKS "
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"setting (currently %d)\n",
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SPARC_PHYS_BANKS);
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i = SPARC_PHYS_BANKS-1;
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break;
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}
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sp_banks[i].base_addr = (unsigned long) mlist->start_adr;
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sp_banks[i].num_bytes = mlist->num_bytes;
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}
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i++;
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sp_banks[i].base_addr = 0xdeadbeef;
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sp_banks[i].num_bytes = 0;
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/* Now mask all bank sizes on a page boundary, it is all we can
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* use anyways.
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*/
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for(i=0; sp_banks[i].num_bytes != 0; i++)
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sp_banks[i].num_bytes &= PAGE_MASK;
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return tally;
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}
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/* Traverse the memory lists in the prom to see how much physical we
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* have.
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*/
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unsigned long
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probe_memory(void)
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{
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int total;
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total = prom_probe_memory();
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/* Oh man, much nicer, keep the dirt in promlib. */
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return total;
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}
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extern void sun4c_complete_all_stores(void);
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/* Whee, a level 15 NMI interrupt memory error. Let's have fun... */
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asmlinkage void sparc_lvl15_nmi(struct pt_regs *regs, unsigned long serr,
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unsigned long svaddr, unsigned long aerr,
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unsigned long avaddr)
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{
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sun4c_complete_all_stores();
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printk("FAULT: NMI received\n");
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printk("SREGS: Synchronous Error %08lx\n", serr);
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printk(" Synchronous Vaddr %08lx\n", svaddr);
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printk(" Asynchronous Error %08lx\n", aerr);
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printk(" Asynchronous Vaddr %08lx\n", avaddr);
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if (sun4c_memerr_reg)
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printk(" Memory Parity Error %08lx\n", *sun4c_memerr_reg);
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printk("REGISTER DUMP:\n");
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show_regs(regs);
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prom_halt();
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}
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static void unhandled_fault(unsigned long, struct task_struct *,
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struct pt_regs *) __attribute__ ((noreturn));
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static void unhandled_fault(unsigned long address, struct task_struct *tsk,
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struct pt_regs *regs)
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{
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if((unsigned long) address < PAGE_SIZE) {
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printk(KERN_ALERT
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"Unable to handle kernel NULL pointer dereference\n");
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} else {
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printk(KERN_ALERT "Unable to handle kernel paging request "
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"at virtual address %08lx\n", address);
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}
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printk(KERN_ALERT "tsk->{mm,active_mm}->context = %08lx\n",
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(tsk->mm ? tsk->mm->context : tsk->active_mm->context));
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printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %08lx\n",
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(tsk->mm ? (unsigned long) tsk->mm->pgd :
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(unsigned long) tsk->active_mm->pgd));
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die_if_kernel("Oops", regs);
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}
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asmlinkage int lookup_fault(unsigned long pc, unsigned long ret_pc,
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unsigned long address)
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{
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struct pt_regs regs;
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unsigned long g2;
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unsigned int insn;
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int i;
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i = search_extables_range(ret_pc, &g2);
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switch (i) {
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case 3:
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/* load & store will be handled by fixup */
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return 3;
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case 1:
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/* store will be handled by fixup, load will bump out */
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/* for _to_ macros */
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insn = *((unsigned int *) pc);
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if ((insn >> 21) & 1)
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return 1;
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break;
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case 2:
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/* load will be handled by fixup, store will bump out */
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/* for _from_ macros */
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insn = *((unsigned int *) pc);
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if (!((insn >> 21) & 1) || ((insn>>19)&0x3f) == 15)
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return 2;
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break;
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default:
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break;
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};
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memset(®s, 0, sizeof (regs));
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regs.pc = pc;
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regs.npc = pc + 4;
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__asm__ __volatile__(
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"rd %%psr, %0\n\t"
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"nop\n\t"
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"nop\n\t"
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"nop\n" : "=r" (regs.psr));
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unhandled_fault(address, current, ®s);
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/* Not reached */
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return 0;
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}
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extern unsigned long safe_compute_effective_address(struct pt_regs *,
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unsigned int);
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static unsigned long compute_si_addr(struct pt_regs *regs, int text_fault)
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{
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unsigned int insn;
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if (text_fault)
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return regs->pc;
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if (regs->psr & PSR_PS) {
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insn = *(unsigned int *) regs->pc;
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} else {
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__get_user(insn, (unsigned int *) regs->pc);
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}
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return safe_compute_effective_address(regs, insn);
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}
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asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write,
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unsigned long address)
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{
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struct vm_area_struct *vma;
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struct task_struct *tsk = current;
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struct mm_struct *mm = tsk->mm;
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unsigned int fixup;
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unsigned long g2;
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siginfo_t info;
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int from_user = !(regs->psr & PSR_PS);
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if(text_fault)
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address = regs->pc;
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/*
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* We fault-in kernel-space virtual memory on-demand. The
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* 'reference' page table is init_mm.pgd.
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*
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* NOTE! We MUST NOT take any locks for this case. We may
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* be in an interrupt or a critical region, and should
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* only copy the information from the master page table,
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* nothing more.
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*/
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if (!ARCH_SUN4C_SUN4 && address >= TASK_SIZE)
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goto vmalloc_fault;
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info.si_code = SEGV_MAPERR;
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/*
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* If we're in an interrupt or have no user
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* context, we must not take the fault..
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*/
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if (in_atomic() || !mm)
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goto no_context;
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down_read(&mm->mmap_sem);
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/*
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* The kernel referencing a bad kernel pointer can lock up
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* a sun4c machine completely, so we must attempt recovery.
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*/
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if(!from_user && address >= PAGE_OFFSET)
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goto bad_area;
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vma = find_vma(mm, address);
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if(!vma)
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goto bad_area;
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if(vma->vm_start <= address)
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goto good_area;
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if(!(vma->vm_flags & VM_GROWSDOWN))
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goto bad_area;
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if(expand_stack(vma, address))
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goto bad_area;
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/*
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* Ok, we have a good vm_area for this memory access, so
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* we can handle it..
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*/
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good_area:
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info.si_code = SEGV_ACCERR;
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if(write) {
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if(!(vma->vm_flags & VM_WRITE))
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goto bad_area;
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} else {
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/* Allow reads even for write-only mappings */
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if(!(vma->vm_flags & (VM_READ | VM_EXEC)))
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goto bad_area;
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}
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/*
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* If for any reason at all we couldn't handle the fault,
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* make sure we exit gracefully rather than endlessly redo
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* the fault.
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*/
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switch (handle_mm_fault(mm, vma, address, write)) {
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case VM_FAULT_SIGBUS:
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goto do_sigbus;
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case VM_FAULT_OOM:
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goto out_of_memory;
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case VM_FAULT_MAJOR:
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current->maj_flt++;
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break;
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case VM_FAULT_MINOR:
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default:
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current->min_flt++;
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break;
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}
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up_read(&mm->mmap_sem);
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return;
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/*
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* Something tried to access memory that isn't in our memory map..
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* Fix it, but check if it's kernel or user first..
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*/
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bad_area:
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up_read(&mm->mmap_sem);
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bad_area_nosemaphore:
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/* User mode accesses just cause a SIGSEGV */
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if(from_user) {
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#if 0
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printk("Fault whee %s [%d]: segfaults at %08lx pc=%08lx\n",
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tsk->comm, tsk->pid, address, regs->pc);
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#endif
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info.si_signo = SIGSEGV;
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info.si_errno = 0;
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/* info.si_code set above to make clear whether
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this was a SEGV_MAPERR or SEGV_ACCERR fault. */
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info.si_addr = (void __user *)compute_si_addr(regs, text_fault);
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info.si_trapno = 0;
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force_sig_info (SIGSEGV, &info, tsk);
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return;
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}
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/* Is this in ex_table? */
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no_context:
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g2 = regs->u_regs[UREG_G2];
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if (!from_user && (fixup = search_extables_range(regs->pc, &g2))) {
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if (fixup > 10) { /* Values below are reserved for other things */
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extern const unsigned __memset_start[];
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extern const unsigned __memset_end[];
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extern const unsigned __csum_partial_copy_start[];
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extern const unsigned __csum_partial_copy_end[];
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#ifdef DEBUG_EXCEPTIONS
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printk("Exception: PC<%08lx> faddr<%08lx>\n", regs->pc, address);
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printk("EX_TABLE: insn<%08lx> fixup<%08x> g2<%08lx>\n",
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regs->pc, fixup, g2);
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#endif
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if ((regs->pc >= (unsigned long)__memset_start &&
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regs->pc < (unsigned long)__memset_end) ||
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(regs->pc >= (unsigned long)__csum_partial_copy_start &&
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regs->pc < (unsigned long)__csum_partial_copy_end)) {
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regs->u_regs[UREG_I4] = address;
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regs->u_regs[UREG_I5] = regs->pc;
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}
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regs->u_regs[UREG_G2] = g2;
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regs->pc = fixup;
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regs->npc = regs->pc + 4;
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return;
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}
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}
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unhandled_fault (address, tsk, regs);
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do_exit(SIGKILL);
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/*
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* We ran out of memory, or some other thing happened to us that made
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* us unable to handle the page fault gracefully.
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*/
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out_of_memory:
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up_read(&mm->mmap_sem);
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printk("VM: killing process %s\n", tsk->comm);
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if (from_user)
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do_exit(SIGKILL);
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goto no_context;
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do_sigbus:
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up_read(&mm->mmap_sem);
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info.si_signo = SIGBUS;
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info.si_errno = 0;
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info.si_code = BUS_ADRERR;
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info.si_addr = (void __user *) compute_si_addr(regs, text_fault);
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info.si_trapno = 0;
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force_sig_info (SIGBUS, &info, tsk);
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if (!from_user)
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goto no_context;
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vmalloc_fault:
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{
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/*
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* Synchronize this task's top level page-table
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* with the 'reference' page table.
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*/
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int offset = pgd_index(address);
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pgd_t *pgd, *pgd_k;
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pmd_t *pmd, *pmd_k;
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pgd = tsk->active_mm->pgd + offset;
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pgd_k = init_mm.pgd + offset;
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if (!pgd_present(*pgd)) {
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if (!pgd_present(*pgd_k))
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goto bad_area_nosemaphore;
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pgd_val(*pgd) = pgd_val(*pgd_k);
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return;
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}
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pmd = pmd_offset(pgd, address);
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pmd_k = pmd_offset(pgd_k, address);
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if (pmd_present(*pmd) || !pmd_present(*pmd_k))
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goto bad_area_nosemaphore;
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*pmd = *pmd_k;
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return;
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}
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}
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asmlinkage void do_sun4c_fault(struct pt_regs *regs, int text_fault, int write,
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unsigned long address)
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{
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extern void sun4c_update_mmu_cache(struct vm_area_struct *,
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unsigned long,pte_t);
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extern pte_t *sun4c_pte_offset_kernel(pmd_t *,unsigned long);
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struct task_struct *tsk = current;
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struct mm_struct *mm = tsk->mm;
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pgd_t *pgdp;
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pte_t *ptep;
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if (text_fault) {
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address = regs->pc;
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} else if (!write &&
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!(regs->psr & PSR_PS)) {
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unsigned int insn, __user *ip;
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ip = (unsigned int __user *)regs->pc;
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if (!get_user(insn, ip)) {
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if ((insn & 0xc1680000) == 0xc0680000)
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write = 1;
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}
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}
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if (!mm) {
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/* We are oopsing. */
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do_sparc_fault(regs, text_fault, write, address);
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BUG(); /* P3 Oops already, you bitch */
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}
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pgdp = pgd_offset(mm, address);
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ptep = sun4c_pte_offset_kernel((pmd_t *) pgdp, address);
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if (pgd_val(*pgdp)) {
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if (write) {
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if ((pte_val(*ptep) & (_SUN4C_PAGE_WRITE|_SUN4C_PAGE_PRESENT))
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== (_SUN4C_PAGE_WRITE|_SUN4C_PAGE_PRESENT)) {
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unsigned long flags;
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*ptep = __pte(pte_val(*ptep) | _SUN4C_PAGE_ACCESSED |
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_SUN4C_PAGE_MODIFIED |
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_SUN4C_PAGE_VALID |
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_SUN4C_PAGE_DIRTY);
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local_irq_save(flags);
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if (sun4c_get_segmap(address) != invalid_segment) {
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sun4c_put_pte(address, pte_val(*ptep));
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local_irq_restore(flags);
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return;
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}
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local_irq_restore(flags);
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}
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} else {
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if ((pte_val(*ptep) & (_SUN4C_PAGE_READ|_SUN4C_PAGE_PRESENT))
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== (_SUN4C_PAGE_READ|_SUN4C_PAGE_PRESENT)) {
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unsigned long flags;
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*ptep = __pte(pte_val(*ptep) | _SUN4C_PAGE_ACCESSED |
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_SUN4C_PAGE_VALID);
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local_irq_save(flags);
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if (sun4c_get_segmap(address) != invalid_segment) {
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sun4c_put_pte(address, pte_val(*ptep));
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local_irq_restore(flags);
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return;
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}
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local_irq_restore(flags);
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}
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}
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}
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/* This conditional is 'interesting'. */
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if (pgd_val(*pgdp) && !(write && !(pte_val(*ptep) & _SUN4C_PAGE_WRITE))
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&& (pte_val(*ptep) & _SUN4C_PAGE_VALID))
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/* Note: It is safe to not grab the MMAP semaphore here because
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* we know that update_mmu_cache() will not sleep for
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* any reason (at least not in the current implementation)
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* and therefore there is no danger of another thread getting
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* on the CPU and doing a shrink_mmap() on this vma.
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*/
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sun4c_update_mmu_cache (find_vma(current->mm, address), address,
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*ptep);
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else
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do_sparc_fault(regs, text_fault, write, address);
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}
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/* This always deals with user addresses. */
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inline void force_user_fault(unsigned long address, int write)
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{
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struct vm_area_struct *vma;
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struct task_struct *tsk = current;
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struct mm_struct *mm = tsk->mm;
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siginfo_t info;
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info.si_code = SEGV_MAPERR;
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#if 0
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printk("wf<pid=%d,wr=%d,addr=%08lx>\n",
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tsk->pid, write, address);
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#endif
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down_read(&mm->mmap_sem);
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vma = find_vma(mm, address);
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if(!vma)
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goto bad_area;
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if(vma->vm_start <= address)
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goto good_area;
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if(!(vma->vm_flags & VM_GROWSDOWN))
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goto bad_area;
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if(expand_stack(vma, address))
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goto bad_area;
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good_area:
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info.si_code = SEGV_ACCERR;
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if(write) {
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if(!(vma->vm_flags & VM_WRITE))
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goto bad_area;
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} else {
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if(!(vma->vm_flags & (VM_READ | VM_EXEC)))
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goto bad_area;
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}
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switch (handle_mm_fault(mm, vma, address, write)) {
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case VM_FAULT_SIGBUS:
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case VM_FAULT_OOM:
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goto do_sigbus;
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}
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up_read(&mm->mmap_sem);
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return;
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bad_area:
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up_read(&mm->mmap_sem);
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#if 0
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printk("Window whee %s [%d]: segfaults at %08lx\n",
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tsk->comm, tsk->pid, address);
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#endif
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info.si_signo = SIGSEGV;
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info.si_errno = 0;
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/* info.si_code set above to make clear whether
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this was a SEGV_MAPERR or SEGV_ACCERR fault. */
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info.si_addr = (void __user *) address;
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info.si_trapno = 0;
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force_sig_info (SIGSEGV, &info, tsk);
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return;
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do_sigbus:
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up_read(&mm->mmap_sem);
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info.si_signo = SIGBUS;
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info.si_errno = 0;
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info.si_code = BUS_ADRERR;
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info.si_addr = (void __user *) address;
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info.si_trapno = 0;
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force_sig_info (SIGBUS, &info, tsk);
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}
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void window_overflow_fault(void)
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{
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unsigned long sp;
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sp = current_thread_info()->rwbuf_stkptrs[0];
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if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
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force_user_fault(sp + 0x38, 1);
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force_user_fault(sp, 1);
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}
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void window_underflow_fault(unsigned long sp)
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{
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if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
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force_user_fault(sp + 0x38, 0);
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force_user_fault(sp, 0);
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}
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void window_ret_fault(struct pt_regs *regs)
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{
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unsigned long sp;
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sp = regs->u_regs[UREG_FP];
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if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
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force_user_fault(sp + 0x38, 0);
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force_user_fault(sp, 0);
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}
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