static void translate(unsigned virt_addr, unsigned* phys_addr, bool write)
{
unsigned virt_page;
unsigned offset;
virt_page = virt_addr / PAGESIZE;
offset = virt_addr & (PAGESIZE - 1);
if (!page_table[virt_page].inmemory)
pagefault(virt_page);
page_table[virt_page].referenced = 1;
if (write)
page_table[virt_page].modified = 1;
*phys_addr = page_table[virt_page].page * PAGESIZE + offset;
}
void pagetable_walk_64(const maddr_t & cr3, const vaddr_t & vaddr,
maddr_t & maddr, vaddr_t * page_end)
{
// cr3 has the pml4 physical address between bits 51 and 12
// each page entry contain the next physical address between the same bits
static const uint64_t addr_mask = 0x000FFFFFFFFFF000ULL;
maddr_t pml4_entry;
maddr_t pdpt_base;
maddr_t pdpt_entry;
maddr_t pd_base;
maddr_t pd_entry;
maddr_t pt_base;
maddr_t pt_entry;
maddr_t page;
/* While this could technically be valid under x86 architecture, it is
* certainly invalid under a sensible Xen setup, and implies a failure to
* parse a {P,V}CPU correctly.
*/
if ( ! cr3 )
throw pagefault(vaddr, cr3, 5);
memory.read64((cr3 & addr_mask) + pm4l_offset(vaddr),
pml4_entry);
// PDPT present?
if ( ! present(pml4_entry) )
throw pagefault(vaddr, cr3, 4);
pdpt_base = pml4_entry & addr_mask;
// Page Size bit set? (512G superpage)
if ( page_size(pml4_entry) )
{
maddr = offset_512G(pdpt_base, vaddr);
if ( page_end )
*page_end = roundup_512G(vaddr);
return;
}
memory.read64(pdpt_base + pdpt_offset(vaddr),
pdpt_entry);
// PD present?
if ( ! present(pdpt_entry) )
throw pagefault(vaddr, cr3, 3);
pd_base = pdpt_entry & addr_mask;
// Page Size bit set? (1G superpage)
if ( page_size(pdpt_entry) )
{
maddr = offset_1G(pd_base, vaddr);
if ( page_end )
*page_end = roundup_1G(vaddr);
return;
}
memory.read64(pd_base + pd_offset(vaddr),
pd_entry);
// PT present?
if ( ! present(pd_entry) )
throw pagefault(vaddr, cr3, 2);
pt_base = pd_entry & addr_mask;
// Page Size bit set? (2M superpage)
if ( page_size(pd_entry) )
{
maddr = offset_2M(pt_base, vaddr);
if ( page_end )
*page_end = roundup_2M(vaddr);
return;
}
memory.read64(pt_base + pt_offset(vaddr),
pt_entry);
// Page present?
if ( ! present(pt_entry) )
throw pagefault(vaddr, cr3, 1);
page = pt_entry & addr_mask;
maddr = offset_4K(page, vaddr);
if ( page_end )
*page_end = roundup_4K(vaddr);
}
int pagefault(int argc, char * argv){
return pagefault(argc, argv);
}
/*===========================================================================*
* exception *
*===========================================================================*/
PUBLIC void exception_handler(int is_nested, struct exception_frame * frame)
{
/* An exception or unexpected interrupt has occurred. */
struct ex_s {
char *msg;
int signum;
int minprocessor;
};
static struct ex_s ex_data[] = {
{ "Divide error", SIGFPE, 86 },
{ "Debug exception", SIGTRAP, 86 },
{ "Nonmaskable interrupt", SIGBUS, 86 },
{ "Breakpoint", SIGEMT, 86 },
{ "Overflow", SIGFPE, 86 },
{ "Bounds check", SIGFPE, 186 },
{ "Invalid opcode", SIGILL, 186 },
{ "Coprocessor not available", SIGFPE, 186 },
{ "Double fault", SIGBUS, 286 },
{ "Coprocessor segment overrun", SIGSEGV, 286 },
{ "Invalid TSS", SIGSEGV, 286 },
{ "Segment not present", SIGSEGV, 286 },
{ "Stack exception", SIGSEGV, 286 }, /* STACK_FAULT already used */
{ "General protection", SIGSEGV, 286 },
{ "Page fault", SIGSEGV, 386 }, /* not close */
{ NULL, SIGILL, 0 }, /* probably software trap */
{ "Coprocessor error", SIGFPE, 386 },
{ "Alignment check", SIGBUS, 386 },
{ "Machine check", SIGBUS, 386 },
{ "SIMD exception", SIGFPE, 386 },
};
register struct ex_s *ep;
struct proc *saved_proc;
/* Save proc_ptr, because it may be changed by debug statements. */
saved_proc = proc_ptr;
ep = &ex_data[frame->vector];
if (frame->vector == 2) { /* spurious NMI on some machines */
printf("got spurious NMI\n");
return;
}
/*
* handle special cases for nested problems as they might be tricky or filter
* them out quickly if the traps are not nested
*/
if (is_nested) {
/*
* if a problem occured while copying a message from userspace because
* of a wrong pointer supplied by userland, handle it the only way we
* can handle it ...
*/
if (((void*)frame->eip >= (void*)copy_msg_to_user &&
(void*)frame->eip <= (void*)__copy_msg_to_user_end) ||
((void*)frame->eip >= (void*)copy_msg_from_user &&
(void*)frame->eip <= (void*)__copy_msg_from_user_end)) {
switch(frame->vector) {
/* these error are expected */
case PAGE_FAULT_VECTOR:
case PROTECTION_VECTOR:
frame->eip = (reg_t) __user_copy_msg_pointer_failure;
return;
default:
panic("Copy involving a user pointer failed unexpectedly!");
}
}
}
if(frame->vector == PAGE_FAULT_VECTOR) {
pagefault(saved_proc, frame, is_nested);
return;
}
/* If an exception occurs while running a process, the is_nested variable
* will be zero. Exceptions in interrupt handlers or system traps will make
* is_nested non-zero.
*/
if (is_nested == 0 && ! iskernelp(saved_proc)) {
#if 0
{
printf(
"vec_nr= %d, trap_errno= 0x%lx, eip= 0x%lx, cs= 0x%x, eflags= 0x%lx\n",
frame->vector, (unsigned long)frame->errcode,
(unsigned long)frame->eip, frame->cs,
(unsigned long)frame->eflags);
printseg("cs: ", 1, saved_proc, frame->cs);
printseg("ds: ", 0, saved_proc, saved_proc->p_reg.ds);
if(saved_proc->p_reg.ds != saved_proc->p_reg.ss) {
printseg("ss: ", 0, saved_proc, saved_proc->p_reg.ss);
}
proc_stacktrace(saved_proc);
}
#endif
cause_sig(proc_nr(saved_proc), ep->signum);
return;
}
/* Exception in system code. This is not supposed to happen. */
if (ep->msg == NULL || machine.processor < ep->minprocessor)
printf("\nIntel-reserved exception %d\n", frame->vector);
else
printf("\n%s\n", ep->msg);
printf("is_nested = %d ", is_nested);
printf("vec_nr= %d, trap_errno= 0x%x, eip= 0x%x, "
"cs= 0x%x, eflags= 0x%x trap_esp 0x%08x\n",
frame->vector, frame->errcode, frame->eip,
frame->cs, frame->eflags, frame);
printf("KERNEL registers :\n");
printf(
"\t%%eax 0x%08x %%ebx 0x%08x %%ecx 0x%08x %%edx 0x%08x\n"
"\t%%esp 0x%08x %%ebp 0x%08x %%esi 0x%08x %%edi 0x%08x\n",
((u32_t *)frame)[-1],
((u32_t *)frame)[-2],
((u32_t *)frame)[-3],
((u32_t *)frame)[-4],
((u32_t *)frame)[-5],
((u32_t *)frame)[-6],
((u32_t *)frame)[-7],
((u32_t *)frame)[-8]
);
printseg("ker cs: ", 1, NULL, frame->cs);
printseg("ker ds: ", 0, NULL, DS_SELECTOR);
/* TODO should we enable this only when compiled for some debug mode? */
if (saved_proc) {
printf("scheduled was: process %d (%s), ", proc_nr(saved_proc), saved_proc->p_name);
printf("pc = %u:0x%x\n", (unsigned) saved_proc->p_reg.cs,
(unsigned) saved_proc->p_reg.pc);
proc_stacktrace(saved_proc);
panic("Unhandled kernel exception");
}
else {
/* in an early stage of boot process we don't have processes yet */
panic("exception in kernel while booting");
}
}
/*===========================================================================*
* exception *
*===========================================================================*/
PUBLIC void exception_handler(int is_nested, struct exception_frame * frame)
{
/* An exception or unexpected interrupt has occurred. */
register struct ex_s *ep;
struct proc *saved_proc;
/* Save proc_ptr, because it may be changed by debug statements. */
saved_proc = get_cpulocal_var(proc_ptr);
ep = &ex_data[frame->vector];
if (frame->vector == 2) { /* spurious NMI on some machines */
printf("got spurious NMI\n");
return;
}
/*
* handle special cases for nested problems as they might be tricky or filter
* them out quickly if the traps are not nested
*/
if (is_nested) {
/*
* if a problem occured while copying a message from userspace because
* of a wrong pointer supplied by userland, handle it the only way we
* can handle it ...
*/
if (((void*)frame->eip >= (void*)copy_msg_to_user &&
(void*)frame->eip <= (void*)__copy_msg_to_user_end) ||
((void*)frame->eip >= (void*)copy_msg_from_user &&
(void*)frame->eip <= (void*)__copy_msg_from_user_end)) {
switch(frame->vector) {
/* these error are expected */
case PAGE_FAULT_VECTOR:
case PROTECTION_VECTOR:
frame->eip = (reg_t) __user_copy_msg_pointer_failure;
return;
default:
panic("Copy involving a user pointer failed unexpectedly!");
}
}
/* Pass any error resulting from restoring FPU state, as a FPU
* exception to the process.
*/
if (((void*)frame->eip >= (void*)fxrstor &&
(void *)frame->eip <= (void*)__fxrstor_end) ||
((void*)frame->eip >= (void*)frstor &&
(void *)frame->eip <= (void*)__frstor_end)) {
frame->eip = (reg_t) __frstor_failure;
return;
}
}
if(frame->vector == PAGE_FAULT_VECTOR) {
pagefault(saved_proc, frame, is_nested);
return;
}
/* If an exception occurs while running a process, the is_nested variable
* will be zero. Exceptions in interrupt handlers or system traps will make
* is_nested non-zero.
*/
if (is_nested == 0 && ! iskernelp(saved_proc)) {
#if 0
{
printf(
"vec_nr= %d, trap_errno= 0x%lx, eip= 0x%lx, cs= 0x%x, eflags= 0x%lx\n",
frame->vector, (unsigned long)frame->errcode,
(unsigned long)frame->eip, frame->cs,
(unsigned long)frame->eflags);
printseg("cs: ", 1, saved_proc, frame->cs);
printseg("ds: ", 0, saved_proc, saved_proc->p_reg.ds);
if(saved_proc->p_reg.ds != saved_proc->p_reg.ss) {
printseg("ss: ", 0, saved_proc, saved_proc->p_reg.ss);
}
proc_stacktrace(saved_proc);
}
#endif
cause_sig(proc_nr(saved_proc), ep->signum);
return;
}
/* Exception in system code. This is not supposed to happen. */
inkernel_disaster(saved_proc, frame, ep, is_nested);
panic("return from inkernel_disaster");
}
