/*
* Program thread launch. Often defined as a macro in processor.h,
* but we're shooting for a small footprint and it's not an inner-loop
* performance-critical operation.
*
* The Hexagon ABI specifies that R28 is zero'ed before program launch,
* so that gets automatically done here. If we ever stop doing that here,
* we'll probably want to define the ELF_PLAT_INIT macro.
*/
void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
{
/* We want to zero all data-containing registers. Is this overkill? */
memset(regs, 0, sizeof(*regs));
/* We might want to also zero all Processor registers here */
pt_set_usermode(regs);
pt_set_elr(regs, pc);
pt_set_rte_sp(regs, sp);
}
static void do_signal(struct pt_regs *regs)
{
struct k_sigaction sigact;
siginfo_t info;
int signo;
if (!user_mode(regs))
return;
if (try_to_freeze())
goto no_signal;
signo = get_signal_to_deliver(&info, &sigact, regs, NULL);
if (signo > 0) {
sigset_t *oldset;
if (test_thread_flag(TIF_RESTORE_SIGMASK))
oldset = ¤t->saved_sigmask;
else
oldset = ¤t->blocked;
if (handle_signal(signo, &info, &sigact, oldset, regs) == 0) {
clear_thread_flag(TIF_RESTORE_SIGMASK);
tracehook_signal_handler(signo, &info, &sigact, regs,
test_thread_flag(TIF_SINGLESTEP));
}
return;
}
no_signal:
if (regs->syscall_nr >= 0) {
switch (regs->r00) {
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
regs->r06 = regs->syscall_nr;
break;
case -ERESTART_RESTARTBLOCK:
regs->r06 = __NR_restart_syscall;
break;
default:
goto no_restart;
}
pt_set_elr(regs, pt_elr(regs) - 4);
regs->r00 = regs->restart_r0;
}
no_restart:
if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
clear_thread_flag(TIF_RESTORE_SIGMASK);
sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
}
}
/*
* Setup invocation of signal handler
*/
static int handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka,
sigset_t *oldset, struct pt_regs *regs)
{
int rc;
/*
* If we're handling a signal that aborted a system call,
* set up the error return value before adding the signal
* frame to the stack.
*/
if (regs->syscall_nr >= 0) {
switch (regs->r00) {
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
regs->r00 = -EINTR;
break;
case -ERESTARTSYS:
if (!(ka->sa.sa_flags & SA_RESTART)) {
regs->r00 = -EINTR;
break;
}
/* Fall through */
case -ERESTARTNOINTR:
regs->r06 = regs->syscall_nr;
pt_set_elr(regs, pt_elr(regs) - 4);
regs->r00 = regs->restart_r0;
break;
default:
break;
}
}
/*
* Set up the stack frame; not doing the SA_SIGINFO thing. We
* only set up the rt_frame flavor.
*/
rc = setup_rt_frame(sig, ka, info, oldset, regs);
/* If there was an error on setup, no signal was delivered. */
if (rc)
return rc;
spin_lock_irq(¤t->sighand->siglock);
sigorsets(¤t->blocked, ¤t->blocked, &ka->sa.sa_mask);
if (!(ka->sa.sa_flags & SA_NODEFER))
sigaddset(¤t->blocked, sig);
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
return 0;
}
int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
{
struct pt_regs regs;
memset(®s, 0, sizeof(regs));
/*
* Yes, we're exploting illicit knowledge of the ABI here.
*/
regs.r00 = (unsigned long) arg;
regs.r01 = (unsigned long) fn;
pt_set_elr(®s, (unsigned long)kernel_thread_helper);
pt_set_kmode(®s);
return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, ®s, 0, NULL, NULL);
}
/*
* Setup invocation of signal handler
*/
static void handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka,
struct pt_regs *regs)
{
/*
* If we're handling a signal that aborted a system call,
* set up the error return value before adding the signal
* frame to the stack.
*/
if (regs->syscall_nr >= 0) {
switch (regs->r00) {
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
regs->r00 = -EINTR;
break;
case -ERESTARTSYS:
if (!(ka->sa.sa_flags & SA_RESTART)) {
regs->r00 = -EINTR;
break;
}
/* Fall through */
case -ERESTARTNOINTR:
regs->r06 = regs->syscall_nr;
pt_set_elr(regs, pt_elr(regs) - 4);
regs->r00 = regs->restart_r0;
break;
default:
break;
}
}
/*
* Set up the stack frame; not doing the SA_SIGINFO thing. We
* only set up the rt_frame flavor.
*/
/* If there was an error on setup, no signal was delivered. */
if (setup_rt_frame(sig, ka, info, sigmask_to_save(), regs) < 0)
return;
signal_delivered(sig, info, ka, regs,
test_thread_flag(TIF_SINGLESTEP));
}
/*
* Setup signal stack frame with siginfo structure
*/
static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info,
sigset_t *set, struct pt_regs *regs)
{
int err = 0;
struct rt_sigframe __user *frame;
struct hexagon_vdso *vdso = current->mm->context.vdso;
frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe));
if (!access_ok(VERIFY_WRITE, frame, sizeof(struct rt_sigframe)))
goto sigsegv;
if (copy_siginfo_to_user(&frame->info, info))
goto sigsegv;
/* The on-stack signal trampoline is no longer executed;
* however, the libgcc signal frame unwinding code checks for
* the presence of these two numeric magic values.
*/
err |= __put_user(0x7800d166, &frame->tramp[0]);
err |= __put_user(0x5400c004, &frame->tramp[1]);
err |= setup_sigcontext(regs, &frame->uc.uc_mcontext);
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
err |= __save_altstack(&frame->uc.uc_stack, user_stack_pointer(regs));
if (err)
goto sigsegv;
/* Load r0/r1 pair with signumber/siginfo pointer... */
regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32)
| (unsigned long long)signr;
regs->r02 = (unsigned long) &frame->uc;
regs->r31 = (unsigned long) vdso->rt_signal_trampoline;
pt_psp(regs) = (unsigned long) frame;
pt_set_elr(regs, (unsigned long)ka->sa.sa_handler);
return 0;
sigsegv:
force_sigsegv(signr, current);
return -EFAULT;
}
/*
* Called from return-from-event code.
*/
static void do_signal(struct pt_regs *regs)
{
struct k_sigaction sigact;
siginfo_t info;
int signo;
if (!user_mode(regs))
return;
signo = get_signal_to_deliver(&info, &sigact, regs, NULL);
if (signo > 0) {
handle_signal(signo, &info, &sigact, regs);
return;
}
/*
* If we came from a system call, handle the restart.
*/
if (regs->syscall_nr >= 0) {
switch (regs->r00) {
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
regs->r06 = regs->syscall_nr;
break;
case -ERESTART_RESTARTBLOCK:
regs->r06 = __NR_restart_syscall;
break;
default:
goto no_restart;
}
pt_set_elr(regs, pt_elr(regs) - 4);
regs->r00 = regs->restart_r0;
}
no_restart:
/* If there's no signal to deliver, put the saved sigmask back */
restore_saved_sigmask();
}
static int handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka,
sigset_t *oldset, struct pt_regs *regs)
{
int rc;
if (regs->syscall_nr >= 0) {
switch (regs->r00) {
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
regs->r00 = -EINTR;
break;
case -ERESTARTSYS:
if (!(ka->sa.sa_flags & SA_RESTART)) {
regs->r00 = -EINTR;
break;
}
case -ERESTARTNOINTR:
regs->r06 = regs->syscall_nr;
pt_set_elr(regs, pt_elr(regs) - 4);
regs->r00 = regs->restart_r0;
break;
default:
break;
}
}
rc = setup_rt_frame(sig, ka, info, oldset, regs);
if (rc)
return rc;
block_sigmask(ka, sig);
return 0;
}
static int restore_sigcontext(struct pt_regs *regs,
struct sigcontext __user *sc)
{
unsigned long tmp;
int err = 0;
err |= copy_from_user(®s->r00, &sc->sc_regs.r0,
32 * sizeof(unsigned long));
err |= __get_user(regs->sa0, &sc->sc_regs.sa0);
err |= __get_user(regs->lc0, &sc->sc_regs.lc0);
err |= __get_user(regs->sa1, &sc->sc_regs.sa1);
err |= __get_user(regs->lc1, &sc->sc_regs.lc1);
err |= __get_user(regs->m0, &sc->sc_regs.m0);
err |= __get_user(regs->m1, &sc->sc_regs.m1);
err |= __get_user(regs->usr, &sc->sc_regs.usr);
err |= __get_user(regs->preds, &sc->sc_regs.p3_0);
err |= __get_user(regs->gp, &sc->sc_regs.gp);
err |= __get_user(regs->ugp, &sc->sc_regs.ugp);
err |= __get_user(tmp, &sc->sc_regs.pc); pt_set_elr(regs, tmp);
return err;
}
static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info,
sigset_t *set, struct pt_regs *regs)
{
int err = 0;
struct rt_sigframe __user *frame;
struct hexagon_vdso *vdso = current->mm->context.vdso;
frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe));
if (!access_ok(VERIFY_WRITE, frame, sizeof(struct rt_sigframe)))
goto sigsegv;
if (copy_siginfo_to_user(&frame->info, info))
goto sigsegv;
err |= __put_user(0x7800d166, &frame->tramp[0]);
err |= __put_user(0x5400c004, &frame->tramp[1]);
err |= setup_sigcontext(regs, &frame->uc.uc_mcontext);
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
if (err)
goto sigsegv;
regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32)
| (unsigned long long)signr;
regs->r02 = (unsigned long) &frame->uc;
regs->r31 = (unsigned long) vdso->rt_signal_trampoline;
pt_psp(regs) = (unsigned long) frame;
pt_set_elr(regs, (unsigned long)ka->sa.sa_handler);
return 0;
sigsegv:
force_sigsegv(signr, current);
return -EFAULT;
}
/*
* Canonical page fault handler
*/
void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
{
struct vm_area_struct *vma;
struct mm_struct *mm = current->mm;
siginfo_t info;
int si_code = SEGV_MAPERR;
int fault;
const struct exception_table_entry *fixup;
unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
/*
* If we're in an interrupt or have no user context,
* then must not take the fault.
*/
if (unlikely(in_interrupt() || !mm))
goto no_context;
local_irq_enable();
if (user_mode(regs))
flags |= FAULT_FLAG_USER;
retry:
down_read(&mm->mmap_sem);
vma = find_vma(mm, address);
if (!vma)
goto bad_area;
if (vma->vm_start <= address)
goto good_area;
if (!(vma->vm_flags & VM_GROWSDOWN))
goto bad_area;
if (expand_stack(vma, address))
goto bad_area;
good_area:
/* Address space is OK. Now check access rights. */
si_code = SEGV_ACCERR;
switch (cause) {
case FLT_IFETCH:
if (!(vma->vm_flags & VM_EXEC))
goto bad_area;
break;
case FLT_LOAD:
if (!(vma->vm_flags & VM_READ))
goto bad_area;
break;
case FLT_STORE:
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
flags |= FAULT_FLAG_WRITE;
break;
}
fault = handle_mm_fault(mm, vma, address, flags);
if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
return;
/* The most common case -- we are done. */
if (likely(!(fault & VM_FAULT_ERROR))) {
if (flags & FAULT_FLAG_ALLOW_RETRY) {
if (fault & VM_FAULT_MAJOR)
current->maj_flt++;
else
current->min_flt++;
if (fault & VM_FAULT_RETRY) {
flags &= ~FAULT_FLAG_ALLOW_RETRY;
flags |= FAULT_FLAG_TRIED;
goto retry;
}
}
up_read(&mm->mmap_sem);
return;
}
up_read(&mm->mmap_sem);
/* Handle copyin/out exception cases */
if (!user_mode(regs))
goto no_context;
if (fault & VM_FAULT_OOM) {
pagefault_out_of_memory();
return;
}
/* User-mode address is in the memory map, but we are
* unable to fix up the page fault.
*/
if (fault & VM_FAULT_SIGBUS) {
info.si_signo = SIGBUS;
info.si_code = BUS_ADRERR;
}
/* Address is not in the memory map */
else {
info.si_signo = SIGSEGV;
info.si_code = SEGV_ACCERR;
}
info.si_errno = 0;
info.si_addr = (void __user *)address;
force_sig_info(info.si_signo, &info, current);
return;
bad_area:
up_read(&mm->mmap_sem);
if (user_mode(regs)) {
info.si_signo = SIGSEGV;
info.si_errno = 0;
info.si_code = si_code;
info.si_addr = (void *)address;
force_sig_info(info.si_signo, &info, current);
return;
}
/* Kernel-mode fault falls through */
no_context:
fixup = search_exception_tables(pt_elr(regs));
if (fixup) {
pt_set_elr(regs, fixup->fixup);
return;
}
/* Things are looking very, very bad now */
bust_spinlocks(1);
printk(KERN_EMERG "Unable to handle kernel paging request at "
"virtual address 0x%08lx, regs %p\n", address, regs);
die("Bad Kernel VA", regs, SIGKILL);
}
/*
* Called from return-from-event code.
*/
static void do_signal(struct pt_regs *regs)
{
struct k_sigaction sigact;
siginfo_t info;
int signo;
if (!user_mode(regs))
return;
if (try_to_freeze())
goto no_signal;
signo = get_signal_to_deliver(&info, &sigact, regs, NULL);
if (signo > 0) {
sigset_t *oldset;
if (test_thread_flag(TIF_RESTORE_SIGMASK))
oldset = ¤t->saved_sigmask;
else
oldset = ¤t->blocked;
if (handle_signal(signo, &info, &sigact, oldset, regs) == 0) {
/*
* Successful delivery case. The saved sigmask is
* stored in the signal frame, and will be restored
* by sigreturn. We can clear the TIF flag.
*/
clear_thread_flag(TIF_RESTORE_SIGMASK);
tracehook_signal_handler(signo, &info, &sigact, regs,
test_thread_flag(TIF_SINGLESTEP));
}
return;
}
no_signal:
/*
* If we came from a system call, handle the restart.
*/
if (regs->syscall_nr >= 0) {
switch (regs->r00) {
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
regs->r06 = regs->syscall_nr;
break;
case -ERESTART_RESTARTBLOCK:
regs->r06 = __NR_restart_syscall;
break;
default:
goto no_restart;
}
pt_set_elr(regs, pt_elr(regs) - 4);
regs->r00 = regs->restart_r0;
}
no_restart:
/* If there's no signal to deliver, put the saved sigmask back */
if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
clear_thread_flag(TIF_RESTORE_SIGMASK);
sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
}
}
