/*
* Process an internal exception (non maskable)
*/
static int process_iexcept(struct pt_regs *regs)
{
unsigned int iexcept_report = get_iexcept();
unsigned int iexcept_num;
ack_exception(EXCEPT_TYPE_IXF);
pr_err("IEXCEPT: PC[0x%lx]\n", regs->pc);
while (iexcept_report) {
iexcept_num = __ffs(iexcept_report);
iexcept_report &= ~(1 << iexcept_num);
set_iexcept(iexcept_report);
if (*(unsigned int *)regs->pc == BKPT_OPCODE) {
/* This is a breakpoint */
struct exception_info bkpt_exception = {
"Oops - undefined instruction",
SIGTRAP, TRAP_BRKPT
};
do_trap(&bkpt_exception, regs);
iexcept_report &= ~(0xFF);
set_iexcept(iexcept_report);
continue;
}
do_trap(&iexcept_table[iexcept_num], regs);
}
return 0;
}
void vector_exception(struct pt_regs *regs)
{
int si_code, vic;
if (!MACHINE_HAS_VX) {
do_trap(regs, SIGILL, ILL_ILLOPN, "illegal operation");
return;
}
/* get vector interrupt code from fpc */
save_fpu_regs();
vic = (current->thread.fpu.fpc & 0xf00) >> 8;
switch (vic) {
case 1: /* invalid vector operation */
si_code = FPE_FLTINV;
break;
case 2: /* division by zero */
si_code = FPE_FLTDIV;
break;
case 3: /* overflow */
si_code = FPE_FLTOVF;
break;
case 4: /* underflow */
si_code = FPE_FLTUND;
break;
case 5: /* inexact */
si_code = FPE_FLTRES;
break;
default: /* unknown cause */
si_code = 0;
}
do_trap(regs, SIGFPE, si_code, "vector exception");
}
asmlinkage void __kprobes do_int3(struct pt_regs * regs, long error_code)
{
if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP) == NOTIFY_STOP) {
return;
}
do_trap(3, SIGTRAP, "int3", regs, error_code, NULL);
return;
}
int main() {
do_rect();
do_square();
do_tri();
do_circle();
do_trap();
return 0;
}
/* Runs on IST stack */
dotraplinkage void do_stack_segment(struct pt_regs *regs, long error_code)
{
if (notify_die(DIE_TRAP, "stack segment", regs, error_code,
12, SIGBUS) == NOTIFY_STOP)
return;
preempt_conditional_sti(regs);
do_trap(12, SIGBUS, "stack segment", regs, error_code, NULL);
preempt_conditional_cli(regs);
}
/*
* Process an external exception (maskable)
*/
static void process_eexcept(struct pt_regs *regs)
{
int evt;
pr_err("EEXCEPT: PC[0x%lx]\n", regs->pc);
while ((evt = soc_get_exception()) >= 0)
do_trap(&eexcept_table[evt], regs);
ack_exception(EXCEPT_TYPE_EXC);
}
dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
{
siginfo_t info;
local_irq_enable();
info.si_signo = SIGILL;
info.si_errno = 0;
info.si_code = ILL_BADSTK;
info.si_addr = 0;
if (notify_die(DIE_TRAP, "iret exception",
regs, error_code, 32, SIGILL) == NOTIFY_STOP)
return;
do_trap(32, SIGILL, "iret exception", regs, error_code, &info);
}
/* May run on IST stack. */
dotraplinkage void __kprobes do_int3(struct pt_regs *regs, long error_code)
{
#ifdef CONFIG_KPROBES
if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
== NOTIFY_STOP)
return;
#else
if (notify_die(DIE_TRAP, "int3", regs, error_code, 3, SIGTRAP)
== NOTIFY_STOP)
return;
#endif
preempt_conditional_sti(regs);
do_trap(3, SIGTRAP, "int3", regs, error_code, NULL);
preempt_conditional_cli(regs);
}
void float_down()
{
trap_t *trap;
message("You float gently to the ground.");
trap = trap_at(you.ux, you.uy);
if (trap)
switch(get_trap_type(trap->trap_info)) {
case PIERC:
break;
case TRAPDOOR:
if (!xdnstair || you.ustuck) break;
/* fall into next case */
default:
do_trap(trap);
}
pickup(true);
}
static inline void do_fp_trap(struct pt_regs *regs, __u32 fpc)
{
int si_code = 0;
/* FPC[2] is Data Exception Code */
if ((fpc & 0x00000300) == 0) {
/* bits 6 and 7 of DXC are 0 iff IEEE exception */
if (fpc & 0x8000) /* invalid fp operation */
si_code = FPE_FLTINV;
else if (fpc & 0x4000) /* div by 0 */
si_code = FPE_FLTDIV;
else if (fpc & 0x2000) /* overflow */
si_code = FPE_FLTOVF;
else if (fpc & 0x1000) /* underflow */
si_code = FPE_FLTUND;
else if (fpc & 0x0800) /* inexact */
si_code = FPE_FLTRES;
}
do_trap(regs, SIGFPE, si_code, "floating point exception");
}
void illegal_op(struct pt_regs *regs)
{
siginfo_t info;
__u8 opcode[6];
__u16 __user *location;
int is_uprobe_insn = 0;
int signal = 0;
location = get_trap_ip(regs);
if (user_mode(regs)) {
if (get_user(*((__u16 *) opcode), (__u16 __user *) location))
return;
if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) {
if (current->ptrace) {
info.si_signo = SIGTRAP;
info.si_errno = 0;
info.si_code = TRAP_BRKPT;
info.si_addr = location;
force_sig_info(SIGTRAP, &info, current);
} else
signal = SIGILL;
#ifdef CONFIG_UPROBES
} else if (*((__u16 *) opcode) == UPROBE_SWBP_INSN) {
is_uprobe_insn = 1;
#endif
} else
signal = SIGILL;
}
/*
* We got either an illegal op in kernel mode, or user space trapped
* on a uprobes illegal instruction. See if kprobes or uprobes picks
* it up. If not, SIGILL.
*/
if (is_uprobe_insn || !user_mode(regs)) {
if (notify_die(DIE_BPT, "bpt", regs, 0,
3, SIGTRAP) != NOTIFY_STOP)
signal = SIGILL;
}
if (signal)
do_trap(regs, signal, ILL_ILLOPC, "illegal operation");
}
/*
* The fixup code for errors in iret jumps to here (iret_exc). It loses
* the original trap number and erorr code. The bogus trap 32 and error
* code 0 are what the vanilla kernel delivers via:
* DO_ERROR_INFO(32, SIGSEGV, "iret exception", iret_error, ILL_BADSTK, 0, 1)
*
* NOTE: Because of the final "1" in the macro we need to enable interrupts.
*
* In case of a general protection fault in the iret instruction, we
* need to check for a lazy CS update for exec-shield.
*/
dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
{
int ok;
int cpu;
local_irq_enable();
cpu = get_cpu();
ok = check_lazy_exec_limit(cpu, regs, error_code);
put_cpu();
if (!ok && notify_die(DIE_TRAP, "iret exception", regs,
error_code, 32, SIGSEGV) != NOTIFY_STOP) {
siginfo_t info;
info.si_signo = SIGSEGV;
info.si_errno = 0;
info.si_code = ILL_BADSTK;
info.si_addr = 0;
do_trap(32, SIGSEGV, "iret exception", regs, error_code, &info);
}
}
/*
* Main exception processing
*/
asmlinkage int process_exception(struct pt_regs *regs)
{
unsigned int type;
unsigned int type_num;
unsigned int ie_num = 9; /* default is unknown exception */
while ((type = get_except_type()) != 0) {
type_num = fls(type) - 1;
switch (type_num) {
case EXCEPT_TYPE_NXF:
ack_exception(EXCEPT_TYPE_NXF);
if (c6x_nmi_handler)
(c6x_nmi_handler)(regs);
else
pr_alert("NMI interrupt!\n");
break;
case EXCEPT_TYPE_IXF:
if (process_iexcept(regs))
return 1;
break;
case EXCEPT_TYPE_EXC:
process_eexcept(regs);
break;
case EXCEPT_TYPE_SXF:
ie_num = 8;
default:
ack_exception(type_num);
do_trap(&iexcept_table[ie_num], regs);
break;
}
}
return 0;
}
/*
* This routine handles page faults. It determines the address and the
* problem, and then passes it off to one of the appropriate routines.
*/
asmlinkage void do_page_fault(struct pt_regs *regs)
{
struct task_struct *tsk;
struct vm_area_struct *vma;
struct mm_struct *mm;
unsigned long addr, cause;
unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
int fault, code = SEGV_MAPERR;
cause = regs->scause;
addr = regs->sbadaddr;
tsk = current;
mm = tsk->mm;
/*
* Fault-in kernel-space virtual memory on-demand.
* The 'reference' page table is init_mm.pgd.
*
* NOTE! We MUST NOT take any locks for this case. We may
* be in an interrupt or a critical region, and should
* only copy the information from the master page table,
* nothing more.
*/
if (unlikely((addr >= VMALLOC_START) && (addr <= VMALLOC_END)))
goto vmalloc_fault;
/* Enable interrupts if they were enabled in the parent context. */
if (likely(regs->sstatus & SR_PIE))
local_irq_enable();
/*
* If we're in an interrupt, have no user context, or are running
* in an atomic region, then we must not take the fault.
*/
if (unlikely(in_atomic() || !mm))
goto no_context;
if (user_mode(regs))
flags |= FAULT_FLAG_USER;
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
retry:
down_read(&mm->mmap_sem);
vma = find_vma(mm, addr);
if (unlikely(!vma))
goto bad_area;
if (likely(vma->vm_start <= addr))
goto good_area;
if (unlikely(!(vma->vm_flags & VM_GROWSDOWN)))
goto bad_area;
if (unlikely(expand_stack(vma, addr)))
goto bad_area;
/*
* Ok, we have a good vm_area for this memory access, so
* we can handle it.
*/
good_area:
code = SEGV_ACCERR;
switch (cause) {
case EXC_INST_ACCESS:
if (!(vma->vm_flags & VM_EXEC))
goto bad_area;
break;
case EXC_LOAD_ACCESS:
if (!(vma->vm_flags & VM_READ))
goto bad_area;
break;
case EXC_STORE_ACCESS:
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
flags |= FAULT_FLAG_WRITE;
break;
default:
panic("%s: unhandled cause %lu", __func__, cause);
}
/*
* If for any reason at all we could not handle the fault,
* make sure we exit gracefully rather than endlessly redo
* the fault.
*/
fault = handle_mm_fault(mm, vma, addr, flags);
/*
* If we need to retry but a fatal signal is pending, handle the
* signal first. We do not need to release the mmap_sem because it
* would already be released in __lock_page_or_retry in mm/filemap.c.
*/
if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(tsk))
return;
if (unlikely(fault & VM_FAULT_ERROR)) {
if (fault & VM_FAULT_OOM)
goto out_of_memory;
else if (fault & VM_FAULT_SIGBUS)
goto do_sigbus;
BUG();
}
/*
* Major/minor page fault accounting is only done on the
* initial attempt. If we go through a retry, it is extremely
* likely that the page will be found in page cache at that point.
*/
if (flags & FAULT_FLAG_ALLOW_RETRY) {
if (fault & VM_FAULT_MAJOR) {
tsk->maj_flt++;
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, addr);
} else {
tsk->min_flt++;
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, addr);
}
if (fault & VM_FAULT_RETRY) {
/*
* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk
* of starvation.
*/
flags &= ~(FAULT_FLAG_ALLOW_RETRY);
flags |= FAULT_FLAG_TRIED;
/*
* No need to up_read(&mm->mmap_sem) as we would
* have already released it in __lock_page_or_retry
* in mm/filemap.c.
*/
goto retry;
}
}
up_read(&mm->mmap_sem);
return;
/*
* Something tried to access memory that isn't in our memory map.
* Fix it, but check if it's kernel or user first.
*/
bad_area:
up_read(&mm->mmap_sem);
/* User mode accesses just cause a SIGSEGV */
if (user_mode(regs)) {
do_trap(regs, SIGSEGV, code, addr, tsk);
return;
}
no_context:
/* Are we prepared to handle this kernel fault? */
if (fixup_exception(regs)) {
return;
}
/*
* Oops. The kernel tried to access some bad page. We'll have to
* terminate things with extreme prejudice.
*/
bust_spinlocks(1);
pr_alert("Unable to handle kernel %s at virtual address " REG_FMT "\n",
(addr < PAGE_SIZE) ? "NULL pointer dereference" :
"paging request", addr);
die(regs, "Oops");
do_exit(SIGKILL);
/*
* We ran out of memory, call the OOM killer, and return the userspace
* (which will retry the fault, or kill us if we got oom-killed).
*/
out_of_memory:
up_read(&mm->mmap_sem);
if (!user_mode(regs))
goto no_context;
pagefault_out_of_memory();
return;
do_sigbus:
up_read(&mm->mmap_sem);
/* Kernel mode? Handle exceptions or die */
if (!user_mode(regs))
goto no_context;
do_trap(regs, SIGBUS, BUS_ADRERR, addr, tsk);
return;
vmalloc_fault:
{
pgd_t *pgd, *pgd_k;
pud_t *pud, *pud_k;
pmd_t *pmd, *pmd_k;
pte_t *pte_k;
int index;
if (user_mode(regs))
goto bad_area;
/*
* Synchronize this task's top level page-table
* with the 'reference' page table.
*
* Do _not_ use "tsk->active_mm->pgd" here.
* We might be inside an interrupt in the middle
* of a task switch.
*/
index = pgd_index(addr);
pgd = (pgd_t *)pfn_to_virt(csr_read(sptbr)) + index;
pgd_k = init_mm.pgd + index;
if (!pgd_present(*pgd_k))
goto no_context;
set_pgd(pgd, *pgd_k);
pud = pud_offset(pgd, addr);
pud_k = pud_offset(pgd_k, addr);
if (!pud_present(*pud_k))
goto no_context;
/* Since the vmalloc area is global, it is unnecessary
to copy individual PTEs */
pmd = pmd_offset(pud, addr);
pmd_k = pmd_offset(pud_k, addr);
if (!pmd_present(*pmd_k))
goto no_context;
set_pmd(pmd, *pmd_k);
/* Make sure the actual PTE exists as well to
* catch kernel vmalloc-area accesses to non-mapped
* addresses. If we don't do this, this will just
* silently loop forever.
*/
pte_k = pte_offset_kernel(pmd_k, addr);
if (!pte_present(*pte_k))
goto no_context;
return;
}
}
