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Fix a kernel page fault when accessing user memory. We were

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combining too much conditions and as such ended up with the
kernel map instead of the corresponding process map. While
here, remove code to allow access to the stackgap and restyle
slightly to improve readability.

This fix specifically fixes the procfs failure we're having
when reading the process map (cat /proc/curproc/map)
This commit is contained in:
Marcel Moolenaar 2002-05-19 22:28:57 +00:00
parent dae7ca35a3
commit 424f97a066
1 changed files with 38 additions and 57 deletions
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95
sys/ia64/ia64/trap.c
View File

@ -519,58 +519,43 @@ trap(int vector, int imm, struct trapframe *framep)
case IA64_VEC_INST_ACCESS_RIGHTS:
case IA64_VEC_DATA_ACCESS_RIGHTS:
{
vm_offset_t va = framep->tf_cr_ifa;
struct vmspace *vm = NULL;
vm_offset_t va;
struct vmspace *vm;
vm_map_t map;
vm_prot_t ftype = 0;
vm_prot_t ftype;
int rv;
rv = 0;
va = framep->tf_cr_ifa;
/*
* If it was caused by fuswintr or suswintr,
* just punt. Note that we check the faulting
* address against the address accessed by
* [fs]uswintr, in case another fault happens
* when they are running.
* If it was caused by fuswintr or suswintr, just punt. Note
* that we check the faulting address against the address
* accessed by [fs]uswintr, in case another fault happens when
* they are running.
*/
if (!user &&
td != NULL &&
td->td_pcb->pcb_onfault == (unsigned long)fswintrberr &&
td->td_pcb->pcb_accessaddr == va) {
if (!user && td != NULL && td->td_pcb->pcb_accessaddr == va &&
td->td_pcb->pcb_onfault == (unsigned long)fswintrberr) {
framep->tf_cr_iip = td->td_pcb->pcb_onfault;
framep->tf_cr_ipsr &= ~IA64_PSR_RI;
td->td_pcb->pcb_onfault = 0;
goto out;
}
/*
* It is only a kernel address space fault iff:
* 1. !user and
* 2. pcb_onfault not set or
* 3. pcb_onfault set but kernel space data fault
* The last can occur during an exec() copyin where the
* argument space is lazy-allocated.
*
* For the purposes of the Linux emulator, we allow
* kernel accesses to a small region of the
* user stack which the emulator uses to
* translate syscall arguments.
*/
if (!user
&& ((va >= VM_MIN_KERNEL_ADDRESS)
|| (td == NULL)
|| (td->td_pcb->pcb_onfault == 0))) {
if (va >= trunc_page(PS_STRINGS
- szsigcode
- SPARE_USRSPACE)
&& va < round_page(PS_STRINGS
- szsigcode)) {
vm = p->p_vmspace;
map = &vm->vm_map;
} else {
map = kernel_map;
}
va = trunc_page((vm_offset_t)va);
if (va >= VM_MIN_KERNEL_ADDRESS) {
/*
* Don't allow user-mode faults for kernel virtual
* addresses
*/
if (user)
goto no_fault_in;
map = kernel_map;
} else {
vm = p->p_vmspace;
vm = (p != NULL) ? p->p_vmspace : NULL;
if (vm == NULL)
goto no_fault_in;
map = &vm->vm_map;
}
@ -580,51 +565,47 @@ trap(int vector, int imm, struct trapframe *framep)
ftype = VM_PROT_WRITE;
else
ftype = VM_PROT_READ;
va = trunc_page((vm_offset_t)va);
if (map != kernel_map) {
/*
* Keep swapout from messing with us
* during this critical time.
* Keep swapout from messing with us during this
* critical time.
*/
PROC_LOCK(p);
++p->p_lock;
PROC_UNLOCK(p);
/* Fault in the user page: */
rv = vm_fault(map, va, ftype,
(ftype & VM_PROT_WRITE)
? VM_FAULT_DIRTY
: VM_FAULT_NORMAL);
rv = vm_fault(map, va, ftype, (ftype & VM_PROT_WRITE)
? VM_FAULT_DIRTY : VM_FAULT_NORMAL);
PROC_LOCK(p);
--p->p_lock;
PROC_UNLOCK(p);
} else {
/*
* Don't have to worry about process
* locking or stacks in the kernel.
* Don't have to worry about process locking or
* stacks in the kernel.
*/
rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
}
if (rv == KERN_SUCCESS)
goto out;
no_fault_in:
if (!user) {
/* Check for copyin/copyout fault */
if (td != NULL &&
td->td_pcb->pcb_onfault != 0) {
framep->tf_cr_iip =
td->td_pcb->pcb_onfault;
/* Check for copyin/copyout fault. */
if (td != NULL && td->td_pcb->pcb_onfault != 0) {
framep->tf_cr_iip = td->td_pcb->pcb_onfault;
framep->tf_cr_ipsr &= ~IA64_PSR_RI;
td->td_pcb->pcb_onfault = 0;
goto out;
}
goto dopanic;
}
ucode = va;
i = SIGSEGV;
ucode = va;
i = (rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV;
break;
}