/*
* 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);
}
static 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);
}
static void show_segv_info(struct uml_pt_regs *regs)
{
struct task_struct *tsk = current;
struct faultinfo *fi = UPT_FAULTINFO(regs);
if (!unhandled_signal(tsk, SIGSEGV))
return;
if (!printk_ratelimit())
return;
printk("%s%s[%d]: segfault at %lx ip %p sp %p error %x",
task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
tsk->comm, task_pid_nr(tsk), FAULT_ADDRESS(*fi),
(void *)UPT_IP(regs), (void *)UPT_SP(regs),
fi->error_code);
print_vma_addr(KERN_CONT " in ", UPT_IP(regs));
printk(KERN_CONT "\n");
}
void segv_handler(int sig, union uml_pt_regs *regs)
{
int index, max;
struct faultinfo * fi = UPT_FAULTINFO(regs);
if(UPT_IS_USER(regs) && !SEGV_IS_FIXABLE(fi)){
bad_segv(*fi, UPT_IP(regs));
return;
}
max = sizeof(segfault_record)/sizeof(segfault_record[0]);
index = next_trap_index(max);
nsegfaults++;
segfault_record[index].address = FAULT_ADDRESS(*fi);
segfault_record[index].pid = os_getpid();
segfault_record[index].is_write = FAULT_WRITE(*fi);
segfault_record[index].sp = UPT_SP(regs);
segfault_record[index].is_user = UPT_IS_USER(regs);
segv(*fi, UPT_IP(regs), UPT_IS_USER(regs), regs);
}
void relay_signal(int sig, struct siginfo *si, struct uml_pt_regs *regs)
{
struct faultinfo *fi;
struct siginfo clean_si;
if (!UPT_IS_USER(regs)) {
if (sig == SIGBUS)
printk(KERN_ERR "Bus error - the host /dev/shm or /tmp "
"mount likely just ran out of space\n");
panic("Kernel mode signal %d", sig);
}
arch_examine_signal(sig, regs);
memset(&clean_si, 0, sizeof(clean_si));
clean_si.si_signo = si->si_signo;
clean_si.si_errno = si->si_errno;
clean_si.si_code = si->si_code;
switch (sig) {
case SIGILL:
case SIGFPE:
case SIGSEGV:
case SIGBUS:
case SIGTRAP:
fi = UPT_FAULTINFO(regs);
clean_si.si_addr = (void __user *) FAULT_ADDRESS(*fi);
current->thread.arch.faultinfo = *fi;
#ifdef __ARCH_SI_TRAPNO
clean_si.si_trapno = si->si_trapno;
#endif
break;
default:
printk(KERN_ERR "Attempted to relay unknown signal %d (si_code = %d)\n",
sig, si->si_code);
}
force_sig_info(sig, &clean_si, current);
}
/*
* 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,
struct uml_pt_regs *regs)
{
struct siginfo si;
jmp_buf *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) {
show_regs(container_of(regs, struct pt_regs, regs));
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.
* XXX tt mode is gone, so maybe this isn't needed any more
*/
address = 0;
}
catcher = current->thread.fault_catcher;
if (!err)
return 0;
else if (catcher != NULL) {
current->thread.fault_addr = (void *) address;
UML_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, regs))
return 0;
if (!is_user) {
show_regs(container_of(regs, struct pt_regs, regs));
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(KERN_INFO "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;
}
