/*
* 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 handle_segv(int pid)
{
struct ptrace_faultinfo fault;
int err;
err = ptrace(PTRACE_FAULTINFO, pid, 0, &fault);
if(err)
panic("handle_segv - PTRACE_FAULTINFO failed, errno = %d\n",
errno);
segv(fault.addr, 0, FAULT_WRITE(fault.is_write), 1, NULL);
}
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);
}
int copy_sc_from_user_skas(int pid, union uml_pt_regs *regs, void *from_ptr)
{
struct sigcontext sc, *from = from_ptr;
unsigned long fpregs[FP_FRAME_SIZE];
int err;
err = copy_from_user_proc(&sc, from, sizeof(sc));
err |= copy_from_user_proc(fpregs, sc.fpstate, sizeof(fpregs));
if(err)
return(err);
regs->skas.regs[GS] = sc.gs;
regs->skas.regs[FS] = sc.fs;
regs->skas.regs[ES] = sc.es;
regs->skas.regs[DS] = sc.ds;
regs->skas.regs[EDI] = sc.edi;
regs->skas.regs[ESI] = sc.esi;
regs->skas.regs[EBP] = sc.ebp;
regs->skas.regs[UESP] = sc.esp;
regs->skas.regs[EBX] = sc.ebx;
regs->skas.regs[EDX] = sc.edx;
regs->skas.regs[ECX] = sc.ecx;
regs->skas.regs[EAX] = sc.eax;
regs->skas.regs[EIP] = sc.eip;
regs->skas.regs[CS] = sc.cs;
regs->skas.regs[EFL] = sc.eflags;
regs->skas.regs[SS] = sc.ss;
regs->skas.fault_addr = sc.cr2;
regs->skas.fault_type = FAULT_WRITE(sc.err);
regs->skas.trap_type = sc.trapno;
err = ptrace(PTRACE_SETFPREGS, pid, 0, fpregs);
if(err < 0){
printk("copy_sc_to_user - PTRACE_SETFPREGS failed, "
"errno = %d\n", errno);
return(1);
}
return(0);
}
/*
* 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;
}
