/*
* Task entrypoint. A double fault switches into this code. All double
* faults are fatal, so just print out something useful and panic. It
* would be nice at some point to hook into the pthreads code so that
* the current thread information could be dumped too.
*/
void
double_fault_handler(void)
{
oskit_addr_t addr;
struct x86_desc *sd;
extern void tss_dump(struct x86_tss *);
while (1) {
addr = get_cr2();
/* This seems to keep netboot from going nuts */
clear_ts();
printf("\nDOUBLE FAULT: possible stack overflow at %#x\n",
addr);
/*
* Read the back_link field of the current TSS and use that
* to index into the GDT and obtain the previous TSS segment
* descriptor. Use the base fields of that descriptor to get
* the linear address of the x86_tss struct. Finally, pass
* lintokv of that address to tss_dump to get useful info!
*/
sd = &base_gdt[task_tss.back_link / 8];
addr = ((sd->base_high << 24) | (sd->base_med << 16) |
sd->base_low);
tss_dump((struct x86_tss *)lintokv(addr));
tss_dump_stack_trace((struct x86_tss *)lintokv(addr), 64);
panic("DOUBLE FAULT panic");
}
}
/*
* Look for FPU and initialize it.
* Called on each CPU.
*/
void
init_fpu()
{
unsigned short status, control;
#ifdef MACH_HYP
clear_ts();
#else /* MACH_HYP */
unsigned int native = 0;
if (machine_slot[cpu_number()].cpu_type >= CPU_TYPE_I486)
native = CR0_NE;
/*
* Check for FPU by initializing it,
* then trying to read the correct bit patterns from
* the control and status registers.
*/
set_cr0((get_cr0() & ~(CR0_EM|CR0_TS)) | native); /* allow use of FPU */
#endif /* MACH_HYP */
fninit();
status = fnstsw();
fnstcw(&control);
if ((status & 0xff) == 0 &&
(control & 0x103f) == 0x3f)
{
/*
* We have a FPU of some sort.
* Compare -infinity against +infinity
* to check whether we have a 287 or a 387.
*/
volatile double fp_infinity, fp_one, fp_zero;
fp_one = 1.0;
fp_zero = 0.0;
fp_infinity = fp_one / fp_zero;
if (fp_infinity == -fp_infinity) {
/*
* We have an 80287.
*/
fp_kind = FP_287;
asm volatile(".byte 0xdb; .byte 0xe4"); /* fnsetpm */
}
else {
/*
* We have a 387.
*/
if (CPU_HAS_FEATURE(CPU_FEATURE_FXSR)) {
kern_return_t
pal_efi_call_in_32bit_mode(uint32_t func,
struct pal_efi_registers *efi_reg,
void *stack_contents,
size_t stack_contents_size, /* 16-byte multiple */
uint32_t *efi_status)
{
DBG("pal_efi_call_in_32bit_mode(0x%08x, %p, %p, %lu, %p)\n",
func, efi_reg, stack_contents, stack_contents_size, efi_status);
if (func == 0) {
return KERN_INVALID_ADDRESS;
}
if ((efi_reg == NULL)
|| (stack_contents == NULL)
|| (stack_contents_size % 16 != 0)) {
return KERN_INVALID_ARGUMENT;
}
if (!gPEEFISystemTable || !gPEEFIRuntimeServices) {
return KERN_NOT_SUPPORTED;
}
DBG("pal_efi_call_in_32bit_mode() efi_reg:\n");
DBG(" rcx: 0x%016llx\n", efi_reg->rcx);
DBG(" rdx: 0x%016llx\n", efi_reg->rdx);
DBG(" r8: 0x%016llx\n", efi_reg->r8);
DBG(" r9: 0x%016llx\n", efi_reg->r9);
DBG(" rax: 0x%016llx\n", efi_reg->rax);
DBG("pal_efi_call_in_32bit_mode() stack:\n");
#if PAL_DEBUG
size_t i;
for (i = 0; i < stack_contents_size; i += sizeof(uint32_t)) {
uint32_t *p = (uint32_t *) ((uintptr_t)stack_contents + i);
DBG(" %p: 0x%08x\n", p, *p);
}
#endif
#ifdef __x86_64__
/*
* Ensure no interruptions.
* Taking a spinlock for serialization is technically unnecessary
* because the EFIRuntime kext should serialize.
*/
boolean_t istate = ml_set_interrupts_enabled(FALSE);
simple_lock(&pal_efi_lock);
/*
* Switch to special page tables with the entire high kernel space
* double-mapped into the bottom 4GB.
*
* NB: We assume that all data passed exchanged with RuntimeServices is
* located in the 4GB of KVA based at VM_MIN_ADDRESS. In particular, kexts
* loaded the basement (below VM_MIN_ADDRESS) cannot pass static data.
* Kernel stack and heap space is OK.
*/
MARK_CPU_IDLE(cpu_number());
pal_efi_saved_cr3 = get_cr3_raw();
pal_efi_saved_cr0 = get_cr0();
IDPML4[KERNEL_PML4_INDEX] = IdlePML4[KERNEL_PML4_INDEX];
IDPML4[0] = IdlePML4[KERNEL_PML4_INDEX];
clear_ts();
set_cr3_raw((uint64_t) ID_MAP_VTOP(IDPML4));
swapgs(); /* Save kernel's GS base */
/* Set segment state ready for compatibility mode */
set_gs(NULL_SEG);
set_fs(NULL_SEG);
set_es(KERNEL_DS);
set_ds(KERNEL_DS);
set_ss(KERNEL_DS);
_pal_efi_call_in_32bit_mode_asm(func,
efi_reg,
stack_contents,
stack_contents_size);
/* Restore NULL segment state */
set_ss(NULL_SEG);
set_es(NULL_SEG);
set_ds(NULL_SEG);
swapgs(); /* Restore kernel's GS base */
/* Restore the 64-bit user GS base we just destroyed */
wrmsr64(MSR_IA32_KERNEL_GS_BASE,
current_cpu_datap()->cpu_uber.cu_user_gs_base);
/* End of mapping games */
set_cr3_raw(pal_efi_saved_cr3);
set_cr0(pal_efi_saved_cr0);
MARK_CPU_ACTIVE(cpu_number());
simple_unlock(&pal_efi_lock);
ml_set_interrupts_enabled(istate);
#else
_pal_efi_call_in_32bit_mode_asm(func,
efi_reg,
stack_contents,
stack_contents_size);
#endif
*efi_status = (uint32_t)efi_reg->rax;
DBG("pal_efi_call_in_32bit_mode() efi_status: 0x%x\n", *efi_status);
return KERN_SUCCESS;
}
