Added a new version of trap_pfault() that disallows kernel page faults
to the user address space unless pcb_onfault is set. The code is currently commented out because iBCS2 and process debugging parts of the kernel need to be changed/fixed first.
This commit is contained in:
dg
parent
9e65feecc0
commit
e1d31701ee
@ -35,7 +35,7 @@
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* SUCH DAMAGE.
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*
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* from: @(#)trap.c 7.4 (Berkeley) 5/13/91
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* $Id: trap.c,v 1.49 1995/03/16 18:11:31 bde Exp $
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* $Id: trap.c,v 1.50 1995/03/21 07:02:51 davidg Exp $
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*/
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/*
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@ -388,6 +388,126 @@ trap(frame)
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userret(p, &frame, sticks);
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}
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#ifdef notyet
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/*
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* This version doesn't allow a page fault to user space while
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* in the kernel. The rest of the kernel needs to be made "safe"
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* before this can be used. I think the only things remaining
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* to be made safe are the iBCS2 code and the process tracing/
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* debugging code.
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*/
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int
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trap_pfault(frame, usermode)
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struct trapframe *frame;
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int usermode;
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{
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vm_offset_t va;
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struct vmspace *vm = NULL;
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vm_map_t map = 0;
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int rv = 0;
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vm_prot_t ftype;
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int eva;
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struct proc *p = curproc;
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if (frame->tf_err & PGEX_W)
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ftype = VM_PROT_READ | VM_PROT_WRITE;
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else
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ftype = VM_PROT_READ;
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eva = rcr2();
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va = trunc_page((vm_offset_t)eva);
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if (va < VM_MIN_KERNEL_ADDRESS) {
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vm_offset_t v;
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vm_page_t ptepg;
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if ((p == NULL) ||
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(!usermode && va < VM_MAXUSER_ADDRESS &&
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curpcb->pcb_onfault == NULL)) {
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trap_fatal(frame);
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return (-1);
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}
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/*
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* This is a fault on non-kernel virtual memory.
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* vm is initialized above to NULL. If curproc is NULL
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* or curproc->p_vmspace is NULL the fault is fatal.
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*/
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vm = p->p_vmspace;
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if (vm == NULL)
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goto nogo;
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map = &vm->vm_map;
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/*
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* Keep swapout from messing with us during this
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* critical time.
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*/
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++p->p_lock;
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/*
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* Grow the stack if necessary
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*/
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if ((caddr_t)va > vm->vm_maxsaddr
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&& (caddr_t)va < (caddr_t)USRSTACK) {
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if (!grow(p, va)) {
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rv = KERN_FAILURE;
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--p->p_lock;
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goto nogo;
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}
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}
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/*
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* Check if page table is mapped, if not,
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* fault it first
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*/
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v = (vm_offset_t) vtopte(va);
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/* Fault the pte only if needed: */
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*(volatile char *)v += 0;
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pmap_use_pt( vm_map_pmap(map), va);
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/* Fault in the user page: */
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rv = vm_fault(map, va, ftype, FALSE);
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pmap_unuse_pt( vm_map_pmap(map), va);
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--p->p_lock;
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} else {
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/*
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* Don't allow user-mode faults in kernel address space.
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*/
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if (usermode)
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goto nogo;
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/*
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* Since we know that kernel virtual address addresses
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* always have pte pages mapped, we just have to fault
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* the page.
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*/
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rv = vm_fault(kernel_map, va, ftype, FALSE);
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}
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if (rv == KERN_SUCCESS)
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return (0);
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nogo:
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if (!usermode) {
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if (curpcb && curpcb->pcb_onfault) {
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frame->tf_eip = (int)curpcb->pcb_onfault;
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return (0);
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}
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trap_fatal(frame);
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return (-1);
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}
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/* kludge to pass faulting virtual address to sendsig */
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frame->tf_err = eva;
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return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
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}
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#endif
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int
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trap_pfault(frame, usermode)
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struct trapframe *frame;
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@ -35,7 +35,7 @@
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* SUCH DAMAGE.
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*
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* from: @(#)trap.c 7.4 (Berkeley) 5/13/91
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* $Id: trap.c,v 1.49 1995/03/16 18:11:31 bde Exp $
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* $Id: trap.c,v 1.50 1995/03/21 07:02:51 davidg Exp $
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*/
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/*
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@ -388,6 +388,126 @@ trap(frame)
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userret(p, &frame, sticks);
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}
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#ifdef notyet
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/*
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* This version doesn't allow a page fault to user space while
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* in the kernel. The rest of the kernel needs to be made "safe"
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* before this can be used. I think the only things remaining
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* to be made safe are the iBCS2 code and the process tracing/
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* debugging code.
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*/
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int
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trap_pfault(frame, usermode)
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struct trapframe *frame;
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int usermode;
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{
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vm_offset_t va;
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struct vmspace *vm = NULL;
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vm_map_t map = 0;
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int rv = 0;
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vm_prot_t ftype;
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int eva;
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struct proc *p = curproc;
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if (frame->tf_err & PGEX_W)
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ftype = VM_PROT_READ | VM_PROT_WRITE;
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else
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ftype = VM_PROT_READ;
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eva = rcr2();
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va = trunc_page((vm_offset_t)eva);
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if (va < VM_MIN_KERNEL_ADDRESS) {
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vm_offset_t v;
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vm_page_t ptepg;
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if ((p == NULL) ||
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(!usermode && va < VM_MAXUSER_ADDRESS &&
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curpcb->pcb_onfault == NULL)) {
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trap_fatal(frame);
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return (-1);
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}
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/*
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* This is a fault on non-kernel virtual memory.
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* vm is initialized above to NULL. If curproc is NULL
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* or curproc->p_vmspace is NULL the fault is fatal.
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*/
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vm = p->p_vmspace;
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if (vm == NULL)
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goto nogo;
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map = &vm->vm_map;
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/*
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* Keep swapout from messing with us during this
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* critical time.
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*/
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++p->p_lock;
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/*
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* Grow the stack if necessary
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*/
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if ((caddr_t)va > vm->vm_maxsaddr
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&& (caddr_t)va < (caddr_t)USRSTACK) {
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if (!grow(p, va)) {
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rv = KERN_FAILURE;
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--p->p_lock;
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goto nogo;
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}
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}
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/*
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* Check if page table is mapped, if not,
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* fault it first
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*/
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v = (vm_offset_t) vtopte(va);
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/* Fault the pte only if needed: */
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*(volatile char *)v += 0;
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pmap_use_pt( vm_map_pmap(map), va);
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/* Fault in the user page: */
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rv = vm_fault(map, va, ftype, FALSE);
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pmap_unuse_pt( vm_map_pmap(map), va);
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--p->p_lock;
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} else {
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/*
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* Don't allow user-mode faults in kernel address space.
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*/
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if (usermode)
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goto nogo;
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/*
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* Since we know that kernel virtual address addresses
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* always have pte pages mapped, we just have to fault
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* the page.
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*/
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rv = vm_fault(kernel_map, va, ftype, FALSE);
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}
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if (rv == KERN_SUCCESS)
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return (0);
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nogo:
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if (!usermode) {
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if (curpcb && curpcb->pcb_onfault) {
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frame->tf_eip = (int)curpcb->pcb_onfault;
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return (0);
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}
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trap_fatal(frame);
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return (-1);
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}
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/* kludge to pass faulting virtual address to sendsig */
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frame->tf_err = eva;
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return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
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}
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#endif
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int
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trap_pfault(frame, usermode)
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struct trapframe *frame;
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@ -35,7 +35,7 @@
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* SUCH DAMAGE.
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*
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* from: @(#)trap.c 7.4 (Berkeley) 5/13/91
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* $Id: trap.c,v 1.49 1995/03/16 18:11:31 bde Exp $
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* $Id: trap.c,v 1.50 1995/03/21 07:02:51 davidg Exp $
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*/
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/*
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@ -388,6 +388,126 @@ trap(frame)
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userret(p, &frame, sticks);
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}
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#ifdef notyet
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/*
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* This version doesn't allow a page fault to user space while
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* in the kernel. The rest of the kernel needs to be made "safe"
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* before this can be used. I think the only things remaining
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* to be made safe are the iBCS2 code and the process tracing/
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* debugging code.
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*/
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int
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trap_pfault(frame, usermode)
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struct trapframe *frame;
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int usermode;
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{
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vm_offset_t va;
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struct vmspace *vm = NULL;
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vm_map_t map = 0;
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int rv = 0;
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vm_prot_t ftype;
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int eva;
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struct proc *p = curproc;
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if (frame->tf_err & PGEX_W)
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ftype = VM_PROT_READ | VM_PROT_WRITE;
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else
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ftype = VM_PROT_READ;
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eva = rcr2();
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va = trunc_page((vm_offset_t)eva);
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if (va < VM_MIN_KERNEL_ADDRESS) {
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vm_offset_t v;
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vm_page_t ptepg;
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if ((p == NULL) ||
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(!usermode && va < VM_MAXUSER_ADDRESS &&
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curpcb->pcb_onfault == NULL)) {
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trap_fatal(frame);
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return (-1);
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}
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/*
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* This is a fault on non-kernel virtual memory.
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* vm is initialized above to NULL. If curproc is NULL
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* or curproc->p_vmspace is NULL the fault is fatal.
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*/
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vm = p->p_vmspace;
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if (vm == NULL)
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goto nogo;
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map = &vm->vm_map;
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/*
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* Keep swapout from messing with us during this
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* critical time.
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*/
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++p->p_lock;
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/*
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* Grow the stack if necessary
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*/
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if ((caddr_t)va > vm->vm_maxsaddr
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&& (caddr_t)va < (caddr_t)USRSTACK) {
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if (!grow(p, va)) {
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rv = KERN_FAILURE;
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--p->p_lock;
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goto nogo;
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}
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}
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/*
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* Check if page table is mapped, if not,
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* fault it first
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*/
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v = (vm_offset_t) vtopte(va);
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/* Fault the pte only if needed: */
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*(volatile char *)v += 0;
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pmap_use_pt( vm_map_pmap(map), va);
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/* Fault in the user page: */
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rv = vm_fault(map, va, ftype, FALSE);
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pmap_unuse_pt( vm_map_pmap(map), va);
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--p->p_lock;
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} else {
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/*
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* Don't allow user-mode faults in kernel address space.
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*/
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if (usermode)
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goto nogo;
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/*
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* Since we know that kernel virtual address addresses
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* always have pte pages mapped, we just have to fault
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* the page.
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*/
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rv = vm_fault(kernel_map, va, ftype, FALSE);
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}
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if (rv == KERN_SUCCESS)
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return (0);
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nogo:
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if (!usermode) {
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if (curpcb && curpcb->pcb_onfault) {
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frame->tf_eip = (int)curpcb->pcb_onfault;
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return (0);
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}
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trap_fatal(frame);
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return (-1);
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}
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/* kludge to pass faulting virtual address to sendsig */
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frame->tf_err = eva;
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return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
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}
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#endif
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int
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trap_pfault(frame, usermode)
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struct trapframe *frame;
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