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#include <mini-os/os.h>
#include <mini-os/traps.h>
#include <mini-os/hypervisor.h>
#include <mini-os/mm.h>
#include <mini-os/lib.h>
#include <mini-os/sched.h>
/*
* These are assembler stubs in entry.S.
* They are the actual entry points for virtual exceptions.
*/
void divide_error(void);
void debug(void);
void int3(void);
void overflow(void);
void bounds(void);
void invalid_op(void);
void device_not_available(void);
void coprocessor_segment_overrun(void);
void invalid_TSS(void);
void segment_not_present(void);
void stack_segment(void);
void general_protection(void);
void page_fault(void);
void coprocessor_error(void);
void simd_coprocessor_error(void);
void alignment_check(void);
void spurious_interrupt_bug(void);
void machine_check(void);
void dump_regs(struct pt_regs *regs)
{
printk("Thread: %s\n", current->name);
#ifdef __i386__
printk("EIP: %x, EFLAGS %x.\n", regs->eip, regs->eflags);
printk("EBX: %08x ECX: %08x EDX: %08x\n",
regs->ebx, regs->ecx, regs->edx);
printk("ESI: %08x EDI: %08x EBP: %08x EAX: %08x\n",
regs->esi, regs->edi, regs->ebp, regs->eax);
printk("DS: %04x ES: %04x orig_eax: %08x, eip: %08x\n",
regs->xds, regs->xes, regs->orig_eax, regs->eip);
printk("CS: %04x EFLAGS: %08x esp: %08x ss: %04x\n",
regs->xcs, regs->eflags, regs->esp, regs->xss);
#else
printk("RIP: %04lx:[<%016lx>] ", regs->cs & 0xffff, regs->rip);
printk("\nRSP: %04lx:%016lx EFLAGS: %08lx\n",
regs->ss, regs->rsp, regs->eflags);
printk("RAX: %016lx RBX: %016lx RCX: %016lx\n",
regs->rax, regs->rbx, regs->rcx);
printk("RDX: %016lx RSI: %016lx RDI: %016lx\n",
regs->rdx, regs->rsi, regs->rdi);
printk("RBP: %016lx R08: %016lx R09: %016lx\n",
regs->rbp, regs->r8, regs->r9);
printk("R10: %016lx R11: %016lx R12: %016lx\n",
regs->r10, regs->r11, regs->r12);
printk("R13: %016lx R14: %016lx R15: %016lx\n",
regs->r13, regs->r14, regs->r15);
#endif
}
static void do_trap(int trapnr, char *str, struct pt_regs * regs, unsigned long error_code)
{
printk("FATAL: Unhandled Trap %d (%s), error code=0x%lx\n", trapnr, str, error_code);
printk("Regs address %p\n", regs);
dump_regs(regs);
do_exit();
}
#define DO_ERROR(trapnr, str, name) \
void do_##name(struct pt_regs * regs, unsigned long error_code) \
{ \
do_trap(trapnr, str, regs, error_code); \
}
#define DO_ERROR_INFO(trapnr, str, name, sicode, siaddr) \
void do_##name(struct pt_regs * regs, unsigned long error_code) \
{ \
do_trap(trapnr, str, regs, error_code); \
}
DO_ERROR_INFO( 0, "divide error", divide_error, FPE_INTDIV, regs->eip)
DO_ERROR( 3, "int3", int3)
DO_ERROR( 4, "overflow", overflow)
DO_ERROR( 5, "bounds", bounds)
DO_ERROR_INFO( 6, "invalid operand", invalid_op, ILL_ILLOPN, regs->eip)
DO_ERROR( 7, "device not available", device_not_available)
DO_ERROR( 9, "coprocessor segment overrun", coprocessor_segment_overrun)
DO_ERROR(10, "invalid TSS", invalid_TSS)
DO_ERROR(11, "segment not present", segment_not_present)
DO_ERROR(12, "stack segment", stack_segment)
DO_ERROR_INFO(17, "alignment check", alignment_check, BUS_ADRALN, 0)
DO_ERROR(18, "machine check", machine_check)
void page_walk(unsigned long virt_address)
{
pgentry_t *tab = (pgentry_t *)start_info.pt_base, page;
unsigned long addr = virt_address;
printk("Pagetable walk from virt %lx, base %lx:\n", virt_address, start_info.pt_base);
#if defined(__x86_64__)
page = tab[l4_table_offset(addr)];
tab = pte_to_virt(page);
printk(" L4 = %"PRIpte" (%p) [offset = %lx]\n", page, tab, l4_table_offset(addr));
#endif
page = tab[l3_table_offset(addr)];
tab = pte_to_virt(page);
printk(" L3 = %"PRIpte" (%p) [offset = %lx]\n", page, tab, l3_table_offset(addr));
page = tab[l2_table_offset(addr)];
tab = pte_to_virt(page);
printk(" L2 = %"PRIpte" (%p) [offset = %lx]\n", page, tab, l2_table_offset(addr));
page = tab[l1_table_offset(addr)];
printk(" L1 = %"PRIpte" [offset = %lx]\n", page, l1_table_offset(addr));
}
static int handle_cow(unsigned long addr) {
pgentry_t *tab = (pgentry_t *)start_info.pt_base, page;
unsigned long new_page;
int rc;
#if defined(__x86_64__)
page = tab[l4_table_offset(addr)];
if (!(page & _PAGE_PRESENT))
return 0;
tab = pte_to_virt(page);
#endif
page = tab[l3_table_offset(addr)];
if (!(page & _PAGE_PRESENT))
return 0;
tab = pte_to_virt(page);
page = tab[l2_table_offset(addr)];
if (!(page & _PAGE_PRESENT))
return 0;
tab = pte_to_virt(page);
page = tab[l1_table_offset(addr)];
if (!(page & _PAGE_PRESENT))
return 0;
/* Only support CoW for the zero page. */
if (PHYS_PFN(page) != mfn_zero)
return 0;
new_page = alloc_pages(0);
memset((void*) new_page, 0, PAGE_SIZE);
rc = HYPERVISOR_update_va_mapping(addr & PAGE_MASK, __pte(virt_to_mach(new_page) | L1_PROT), UVMF_INVLPG);
if (!rc)
return 1;
printk("Map zero page to %lx failed: %d.\n", addr, rc);
return 0;
}
static void do_stack_walk(unsigned long frame_base)
{
unsigned long *frame = (void*) frame_base;
printk("base is %#lx ", frame_base);
printk("caller is %#lx\n", frame[1]);
if (frame[0])
do_stack_walk(frame[0]);
}
void stack_walk(void)
{
unsigned long bp;
#ifdef __x86_64__
asm("movq %%rbp, %0":"=r"(bp));
#else
asm("movl %%ebp, %0":"=r"(bp));
#endif
do_stack_walk(bp);
}
static void dump_mem(unsigned long addr)
{
unsigned long i;
if (addr < PAGE_SIZE)
return;
for (i = ((addr)-16 ) & ~15; i < (((addr)+48 ) & ~15); i++)
{
if (!(i%16))
printk("\n%lx:", i);
printk(" %02x", *(unsigned char *)i);
}
printk("\n");
}
#define read_cr2() \
(HYPERVISOR_shared_info->vcpu_info[smp_processor_id()].arch.cr2)
static int handling_pg_fault = 0;
void do_page_fault(struct pt_regs *regs, unsigned long error_code)
{
unsigned long addr = read_cr2();
struct sched_shutdown sched_shutdown = { .reason = SHUTDOWN_crash };
if ((error_code & TRAP_PF_WRITE) && handle_cow(addr))
return;
/* If we are already handling a page fault, and got another one
that means we faulted in pagetable walk. Continuing here would cause
a recursive fault */
if(handling_pg_fault == 1)
{
printk("Page fault in pagetable walk (access to invalid memory?).\n");
HYPERVISOR_sched_op(SCHEDOP_shutdown, &sched_shutdown);
}
handling_pg_fault++;
barrier();
#if defined(__x86_64__)
printk("Page fault at linear address %p, rip %p, regs %p, sp %p, our_sp %p, code %lx\n",
addr, regs->rip, regs, regs->rsp, &addr, error_code);
#else
printk("Page fault at linear address %p, eip %p, regs %p, sp %p, our_sp %p, code %lx\n",
addr, regs->eip, regs, regs->esp, &addr, error_code);
#endif
dump_regs(regs);
#if defined(__x86_64__)
do_stack_walk(regs->rbp);
dump_mem(regs->rsp);
dump_mem(regs->rbp);
dump_mem(regs->rip);
#else
do_stack_walk(regs->ebp);
dump_mem(regs->esp);
dump_mem(regs->ebp);
dump_mem(regs->eip);
#endif
page_walk(addr);
HYPERVISOR_sched_op(SCHEDOP_shutdown, &sched_shutdown);
/* We should never get here ... but still */
handling_pg_fault--;
}
void do_general_protection(struct pt_regs *regs, long error_code)
{
struct sched_shutdown sched_shutdown = { .reason = SHUTDOWN_crash };
#ifdef __i386__
printk("GPF eip: %p, error_code=%lx\n", regs->eip, error_code);
#else
printk("GPF rip: %p, error_code=%lx\n", regs->rip, error_code);
#endif
dump_regs(regs);
#if defined(__x86_64__)
do_stack_walk(regs->rbp);
dump_mem(regs->rsp);
dump_mem(regs->rbp);
dump_mem(regs->rip);
#else
do_stack_walk(regs->ebp);
dump_mem(regs->esp);
dump_mem(regs->ebp);
dump_mem(regs->eip);
#endif
HYPERVISOR_sched_op(SCHEDOP_shutdown, &sched_shutdown);
}
void do_debug(struct pt_regs * regs)
{
printk("Debug exception\n");
#define TF_MASK 0x100
regs->eflags &= ~TF_MASK;
dump_regs(regs);
do_exit();
}
void do_coprocessor_error(struct pt_regs * regs)
{
printk("Copro error\n");
dump_regs(regs);
do_exit();
}
void simd_math_error(void *eip)
{
printk("SIMD error\n");
}
void do_simd_coprocessor_error(struct pt_regs * regs)
{
printk("SIMD copro error\n");
}
void do_spurious_interrupt_bug(struct pt_regs * regs)
{
}
/*
* Submit a virtual IDT to teh hypervisor. This consists of tuples
* (interrupt vector, privilege ring, CS:EIP of handler).
* The 'privilege ring' field specifies the least-privileged ring that
* can trap to that vector using a software-interrupt instruction (INT).
*/
static trap_info_t trap_table[] = {
{ 0, 0, __KERNEL_CS, (unsigned long)divide_error },
{ 1, 0, __KERNEL_CS, (unsigned long)debug },
{ 3, 3, __KERNEL_CS, (unsigned long)int3 },
{ 4, 3, __KERNEL_CS, (unsigned long)overflow },
{ 5, 3, __KERNEL_CS, (unsigned long)bounds },
{ 6, 0, __KERNEL_CS, (unsigned long)invalid_op },
{ 7, 0, __KERNEL_CS, (unsigned long)device_not_available },
{ 9, 0, __KERNEL_CS, (unsigned long)coprocessor_segment_overrun },
{ 10, 0, __KERNEL_CS, (unsigned long)invalid_TSS },
{ 11, 0, __KERNEL_CS, (unsigned long)segment_not_present },
{ 12, 0, __KERNEL_CS, (unsigned long)stack_segment },
{ 13, 0, __KERNEL_CS, (unsigned long)general_protection },
{ 14, 0, __KERNEL_CS, (unsigned long)page_fault },
{ 15, 0, __KERNEL_CS, (unsigned long)spurious_interrupt_bug },
{ 16, 0, __KERNEL_CS, (unsigned long)coprocessor_error },
{ 17, 0, __KERNEL_CS, (unsigned long)alignment_check },
{ 19, 0, __KERNEL_CS, (unsigned long)simd_coprocessor_error },
{ 0, 0, 0, 0 }
};
void trap_init(void)
{
HYPERVISOR_set_trap_table(trap_table);
}
void trap_fini(void)
{
HYPERVISOR_set_trap_table(NULL);
}
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