+++ /dev/null
-/*
- * Copyright (C) 2000, 2001 Jeff Dike (jdike@karaya.com)
- * Licensed under the GPL
- */
-
-#include "linux/kernel.h"
-#include "asm/errno.h"
-#include "linux/sched.h"
-#include "linux/mm.h"
-#include "linux/spinlock.h"
-#include "linux/config.h"
-#include "linux/init.h"
-#include "linux/ptrace.h"
-#include "asm/semaphore.h"
-#include "asm/pgtable.h"
-#include "asm/pgalloc.h"
-#include "asm/tlbflush.h"
-#include "asm/a.out.h"
-#include "asm/current.h"
-#include "asm/irq.h"
-#include "sysdep/sigcontext.h"
-#include "user_util.h"
-#include "kern_util.h"
-#include "kern.h"
-#include "chan_kern.h"
-#include "mconsole_kern.h"
-#include "mem.h"
-#include "mem_kern.h"
-#include "sysdep/sigcontext.h"
-#include "sysdep/ptrace.h"
-#include "os.h"
-#ifdef CONFIG_MODE_SKAS
-#include "skas.h"
-#endif
-#include "os.h"
-
-/* Note this is constrained to return 0, -EFAULT, -EACCESS, -ENOMEM by segv(). */
-int handle_page_fault(unsigned long address, unsigned long ip,
- int is_write, int is_user, int *code_out)
-{
- struct mm_struct *mm = current->mm;
- struct vm_area_struct *vma;
- pgd_t *pgd;
- pud_t *pud;
- pmd_t *pmd;
- pte_t *pte;
- int err = -EFAULT;
-
- *code_out = SEGV_MAPERR;
-
- /* If the fault was during atomic operation, don't take the fault, just
- * fail. */
- if (in_atomic())
- goto out_nosemaphore;
-
- down_read(&mm->mmap_sem);
- vma = find_vma(mm, address);
- if(!vma)
- goto out;
- else if(vma->vm_start <= address)
- goto good_area;
- else if(!(vma->vm_flags & VM_GROWSDOWN))
- goto out;
- else if(is_user && !ARCH_IS_STACKGROW(address))
- goto out;
- else if(expand_stack(vma, address))
- goto out;
-
-good_area:
- *code_out = SEGV_ACCERR;
- if(is_write && !(vma->vm_flags & VM_WRITE))
- goto out;
-
- /* Don't require VM_READ|VM_EXEC for write faults! */
- if(!is_write && !(vma->vm_flags & (VM_READ | VM_EXEC)))
- goto out;
-
- do {
-survive:
- switch (handle_mm_fault(mm, vma, address, is_write)){
- case VM_FAULT_MINOR:
- current->min_flt++;
- break;
- case VM_FAULT_MAJOR:
- current->maj_flt++;
- break;
- case VM_FAULT_SIGBUS:
- err = -EACCES;
- goto out;
- case VM_FAULT_OOM:
- err = -ENOMEM;
- goto out_of_memory;
- default:
- BUG();
- }
- pgd = pgd_offset(mm, address);
- pud = pud_offset(pgd, address);
- pmd = pmd_offset(pud, address);
- pte = pte_offset_kernel(pmd, address);
- } while(!pte_present(*pte));
- err = 0;
- /* The below warning was added in place of
- * pte_mkyoung(); if (is_write) pte_mkdirty();
- * If it's triggered, we'd see normally a hang here (a clean pte is
- * marked read-only to emulate the dirty bit).
- * However, the generic code can mark a PTE writable but clean on a
- * concurrent read fault, triggering this harmlessly. So comment it out.
- */
-#if 0
- WARN_ON(!pte_young(*pte) || (is_write && !pte_dirty(*pte)));
-#endif
- flush_tlb_page(vma, address);
-out:
- up_read(&mm->mmap_sem);
-out_nosemaphore:
- return(err);
-
-/*
- * 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:
- if (current->pid == 1) {
- up_read(&mm->mmap_sem);
- yield();
- down_read(&mm->mmap_sem);
- goto survive;
- }
- goto out;
-}
-
-void segv_handler(int sig, union uml_pt_regs *regs)
-{
- struct faultinfo * fi = UPT_FAULTINFO(regs);
-
- if(UPT_IS_USER(regs) && !SEGV_IS_FIXABLE(fi)){
- bad_segv(*fi, UPT_IP(regs));
- return;
- }
- segv(*fi, UPT_IP(regs), UPT_IS_USER(regs), regs);
-}
-
-struct kern_handlers handlinfo_kern = {
- .relay_signal = relay_signal,
- .winch = winch,
- .bus_handler = relay_signal,
- .page_fault = segv_handler,
- .sigio_handler = sigio_handler,
- .timer_handler = timer_handler
-};
-/*
- * We give a *copy* of the faultinfo in the regs to segv.
- * This must be done, since nesting SEGVs could overwrite
- * the info in the regs. A pointer to the info then would
- * give us bad data!
- */
-unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, void *sc)
-{
- struct siginfo si;
- void *catcher;
- int err;
- int is_write = FAULT_WRITE(fi);
- unsigned long address = FAULT_ADDRESS(fi);
-
- if(!is_user && (address >= start_vm) && (address < end_vm)){
- flush_tlb_kernel_vm();
- return(0);
- }
- else if(current->mm == NULL)
- panic("Segfault with no mm");
-
- if (SEGV_IS_FIXABLE(&fi) || SEGV_MAYBE_FIXABLE(&fi))
- err = handle_page_fault(address, ip, is_write, is_user, &si.si_code);
- else {
- err = -EFAULT;
- /* A thread accessed NULL, we get a fault, but CR2 is invalid.
- * This code is used in __do_copy_from_user() of TT mode. */
- address = 0;
- }
-
- catcher = current->thread.fault_catcher;
- if(!err)
- return(0);
- else if(catcher != NULL){
- current->thread.fault_addr = (void *) address;
- do_longjmp(catcher, 1);
- }
- else if(current->thread.fault_addr != NULL)
- panic("fault_addr set but no fault catcher");
- else if(!is_user && arch_fixup(ip, sc))
- return(0);
-
- if(!is_user)
- panic("Kernel mode fault at addr 0x%lx, ip 0x%lx",
- address, ip);
-
- if (err == -EACCES) {
- si.si_signo = SIGBUS;
- si.si_errno = 0;
- si.si_code = BUS_ADRERR;
- si.si_addr = (void __user *)address;
- current->thread.arch.faultinfo = fi;
- force_sig_info(SIGBUS, &si, current);
- } else if (err == -ENOMEM) {
- printk("VM: killing process %s\n", current->comm);
- do_exit(SIGKILL);
- } else {
- BUG_ON(err != -EFAULT);
- si.si_signo = SIGSEGV;
- si.si_addr = (void __user *) address;
- current->thread.arch.faultinfo = fi;
- force_sig_info(SIGSEGV, &si, current);
- }
- return(0);
-}
-
-void bad_segv(struct faultinfo fi, unsigned long ip)
-{
- struct siginfo si;
-
- si.si_signo = SIGSEGV;
- si.si_code = SEGV_ACCERR;
- si.si_addr = (void __user *) FAULT_ADDRESS(fi);
- current->thread.arch.faultinfo = fi;
- force_sig_info(SIGSEGV, &si, current);
-}
-
-void relay_signal(int sig, union uml_pt_regs *regs)
-{
- if(arch_handle_signal(sig, regs)) return;
- if(!UPT_IS_USER(regs))
- panic("Kernel mode signal %d", sig);
- current->thread.arch.faultinfo = *UPT_FAULTINFO(regs);
- force_sig(sig, current);
-}
-
-void bus_handler(int sig, union uml_pt_regs *regs)
-{
- if(current->thread.fault_catcher != NULL)
- do_longjmp(current->thread.fault_catcher, 1);
- else relay_signal(sig, regs);
-}
-
-void winch(int sig, union uml_pt_regs *regs)
-{
- do_IRQ(WINCH_IRQ, regs);
-}
-
-void trap_init(void)
-{
-}
git.openpandora.org / pandora-kernel.git / blobdiff