1 /* arch/sparc64/kernel/process.c
3 * Copyright (C) 1995, 1996, 2008 David S. Miller (davem@davemloft.net)
4 * Copyright (C) 1996 Eddie C. Dost (ecd@skynet.be)
5 * Copyright (C) 1997, 1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
9 * This file handles the architecture-dependent parts of process handling..
14 #include <linux/errno.h>
15 #include <linux/export.h>
16 #include <linux/sched.h>
17 #include <linux/kernel.h>
20 #include <linux/smp.h>
21 #include <linux/stddef.h>
22 #include <linux/ptrace.h>
23 #include <linux/slab.h>
24 #include <linux/user.h>
25 #include <linux/delay.h>
26 #include <linux/compat.h>
27 #include <linux/tick.h>
28 #include <linux/init.h>
29 #include <linux/cpu.h>
30 #include <linux/perf_event.h>
31 #include <linux/elfcore.h>
32 #include <linux/sysrq.h>
33 #include <linux/nmi.h>
35 #include <asm/uaccess.h>
37 #include <asm/pgalloc.h>
38 #include <asm/pgtable.h>
39 #include <asm/processor.h>
40 #include <asm/pstate.h>
42 #include <asm/fpumacro.h>
44 #include <asm/cpudata.h>
45 #include <asm/mmu_context.h>
46 #include <asm/unistd.h>
47 #include <asm/hypervisor.h>
48 #include <asm/syscalls.h>
49 #include <asm/irq_regs.h>
55 static void sparc64_yield(int cpu)
57 if (tlb_type != hypervisor) {
62 clear_thread_flag(TIF_POLLING_NRFLAG);
63 smp_mb__after_clear_bit();
65 while (!need_resched() && !cpu_is_offline(cpu)) {
68 /* Disable interrupts. */
70 "rdpr %%pstate, %0\n\t"
72 "wrpr %0, %%g0, %%pstate"
76 if (!need_resched() && !cpu_is_offline(cpu))
79 /* Re-enable interrupts. */
81 "rdpr %%pstate, %0\n\t"
83 "wrpr %0, %%g0, %%pstate"
88 set_thread_flag(TIF_POLLING_NRFLAG);
91 /* The idle loop on sparc64. */
94 int cpu = smp_processor_id();
96 set_thread_flag(TIF_POLLING_NRFLAG);
99 tick_nohz_idle_enter();
102 while (!need_resched() && !cpu_is_offline(cpu))
106 tick_nohz_idle_exit();
108 #ifdef CONFIG_HOTPLUG_CPU
109 if (cpu_is_offline(cpu)) {
110 sched_preempt_enable_no_resched();
114 schedule_preempt_disabled();
119 static void show_regwindow32(struct pt_regs *regs)
121 struct reg_window32 __user *rw;
122 struct reg_window32 r_w;
125 __asm__ __volatile__ ("flushw");
126 rw = compat_ptr((unsigned)regs->u_regs[14]);
129 if (copy_from_user (&r_w, rw, sizeof(r_w))) {
135 printk("l0: %08x l1: %08x l2: %08x l3: %08x "
136 "l4: %08x l5: %08x l6: %08x l7: %08x\n",
137 r_w.locals[0], r_w.locals[1], r_w.locals[2], r_w.locals[3],
138 r_w.locals[4], r_w.locals[5], r_w.locals[6], r_w.locals[7]);
139 printk("i0: %08x i1: %08x i2: %08x i3: %08x "
140 "i4: %08x i5: %08x i6: %08x i7: %08x\n",
141 r_w.ins[0], r_w.ins[1], r_w.ins[2], r_w.ins[3],
142 r_w.ins[4], r_w.ins[5], r_w.ins[6], r_w.ins[7]);
145 #define show_regwindow32(regs) do { } while (0)
148 static void show_regwindow(struct pt_regs *regs)
150 struct reg_window __user *rw;
151 struct reg_window *rwk;
152 struct reg_window r_w;
155 if ((regs->tstate & TSTATE_PRIV) || !(test_thread_flag(TIF_32BIT))) {
156 __asm__ __volatile__ ("flushw");
157 rw = (struct reg_window __user *)
158 (regs->u_regs[14] + STACK_BIAS);
159 rwk = (struct reg_window *)
160 (regs->u_regs[14] + STACK_BIAS);
161 if (!(regs->tstate & TSTATE_PRIV)) {
164 if (copy_from_user (&r_w, rw, sizeof(r_w))) {
172 show_regwindow32(regs);
175 printk("l0: %016lx l1: %016lx l2: %016lx l3: %016lx\n",
176 rwk->locals[0], rwk->locals[1], rwk->locals[2], rwk->locals[3]);
177 printk("l4: %016lx l5: %016lx l6: %016lx l7: %016lx\n",
178 rwk->locals[4], rwk->locals[5], rwk->locals[6], rwk->locals[7]);
179 printk("i0: %016lx i1: %016lx i2: %016lx i3: %016lx\n",
180 rwk->ins[0], rwk->ins[1], rwk->ins[2], rwk->ins[3]);
181 printk("i4: %016lx i5: %016lx i6: %016lx i7: %016lx\n",
182 rwk->ins[4], rwk->ins[5], rwk->ins[6], rwk->ins[7]);
183 if (regs->tstate & TSTATE_PRIV)
184 printk("I7: <%pS>\n", (void *) rwk->ins[7]);
187 void show_regs(struct pt_regs *regs)
189 printk("TSTATE: %016lx TPC: %016lx TNPC: %016lx Y: %08x %s\n", regs->tstate,
190 regs->tpc, regs->tnpc, regs->y, print_tainted());
191 printk("TPC: <%pS>\n", (void *) regs->tpc);
192 printk("g0: %016lx g1: %016lx g2: %016lx g3: %016lx\n",
193 regs->u_regs[0], regs->u_regs[1], regs->u_regs[2],
195 printk("g4: %016lx g5: %016lx g6: %016lx g7: %016lx\n",
196 regs->u_regs[4], regs->u_regs[5], regs->u_regs[6],
198 printk("o0: %016lx o1: %016lx o2: %016lx o3: %016lx\n",
199 regs->u_regs[8], regs->u_regs[9], regs->u_regs[10],
201 printk("o4: %016lx o5: %016lx sp: %016lx ret_pc: %016lx\n",
202 regs->u_regs[12], regs->u_regs[13], regs->u_regs[14],
204 printk("RPC: <%pS>\n", (void *) regs->u_regs[15]);
205 show_regwindow(regs);
206 show_stack(current, (unsigned long *) regs->u_regs[UREG_FP]);
209 union global_cpu_snapshot global_cpu_snapshot[NR_CPUS];
210 static DEFINE_SPINLOCK(global_cpu_snapshot_lock);
212 static void __global_reg_self(struct thread_info *tp, struct pt_regs *regs,
215 struct global_reg_snapshot *rp;
219 rp = &global_cpu_snapshot[this_cpu].reg;
221 rp->tstate = regs->tstate;
223 rp->tnpc = regs->tnpc;
224 rp->o7 = regs->u_regs[UREG_I7];
226 if (regs->tstate & TSTATE_PRIV) {
227 struct reg_window *rw;
229 rw = (struct reg_window *)
230 (regs->u_regs[UREG_FP] + STACK_BIAS);
231 if (kstack_valid(tp, (unsigned long) rw)) {
233 rw = (struct reg_window *)
234 (rw->ins[6] + STACK_BIAS);
235 if (kstack_valid(tp, (unsigned long) rw))
236 rp->rpc = rw->ins[7];
245 /* In order to avoid hangs we do not try to synchronize with the
246 * global register dump client cpus. The last store they make is to
247 * the thread pointer, so do a short poll waiting for that to become
250 static void __global_reg_poll(struct global_reg_snapshot *gp)
254 while (!gp->thread && ++limit < 100) {
260 void arch_trigger_all_cpu_backtrace(void)
262 struct thread_info *tp = current_thread_info();
263 struct pt_regs *regs = get_irq_regs();
270 spin_lock_irqsave(&global_cpu_snapshot_lock, flags);
272 memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
274 this_cpu = raw_smp_processor_id();
276 __global_reg_self(tp, regs, this_cpu);
278 smp_fetch_global_regs();
280 for_each_online_cpu(cpu) {
281 struct global_reg_snapshot *gp = &global_cpu_snapshot[cpu].reg;
283 __global_reg_poll(gp);
286 printk("%c CPU[%3d]: TSTATE[%016lx] TPC[%016lx] TNPC[%016lx] TASK[%s:%d]\n",
287 (cpu == this_cpu ? '*' : ' '), cpu,
288 gp->tstate, gp->tpc, gp->tnpc,
289 ((tp && tp->task) ? tp->task->comm : "NULL"),
290 ((tp && tp->task) ? tp->task->pid : -1));
292 if (gp->tstate & TSTATE_PRIV) {
293 printk(" TPC[%pS] O7[%pS] I7[%pS] RPC[%pS]\n",
299 printk(" TPC[%lx] O7[%lx] I7[%lx] RPC[%lx]\n",
300 gp->tpc, gp->o7, gp->i7, gp->rpc);
304 memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
306 spin_unlock_irqrestore(&global_cpu_snapshot_lock, flags);
309 #ifdef CONFIG_MAGIC_SYSRQ
311 static void sysrq_handle_globreg(int key)
313 arch_trigger_all_cpu_backtrace();
316 static struct sysrq_key_op sparc_globalreg_op = {
317 .handler = sysrq_handle_globreg,
318 .help_msg = "global-regs(Y)",
319 .action_msg = "Show Global CPU Regs",
322 static void __global_pmu_self(int this_cpu)
324 struct global_pmu_snapshot *pp;
327 pp = &global_cpu_snapshot[this_cpu].pmu;
330 if (tlb_type == hypervisor &&
331 sun4v_chip_type >= SUN4V_CHIP_NIAGARA4)
334 for (i = 0; i < num; i++) {
335 pp->pcr[i] = pcr_ops->read_pcr(i);
336 pp->pic[i] = pcr_ops->read_pic(i);
340 static void __global_pmu_poll(struct global_pmu_snapshot *pp)
344 while (!pp->pcr[0] && ++limit < 100) {
350 static void pmu_snapshot_all_cpus(void)
355 spin_lock_irqsave(&global_cpu_snapshot_lock, flags);
357 memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
359 this_cpu = raw_smp_processor_id();
361 __global_pmu_self(this_cpu);
363 smp_fetch_global_pmu();
365 for_each_online_cpu(cpu) {
366 struct global_pmu_snapshot *pp = &global_cpu_snapshot[cpu].pmu;
368 __global_pmu_poll(pp);
370 printk("%c CPU[%3d]: PCR[%08lx:%08lx:%08lx:%08lx] PIC[%08lx:%08lx:%08lx:%08lx]\n",
371 (cpu == this_cpu ? '*' : ' '), cpu,
372 pp->pcr[0], pp->pcr[1], pp->pcr[2], pp->pcr[3],
373 pp->pic[0], pp->pic[1], pp->pic[2], pp->pic[3]);
376 memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
378 spin_unlock_irqrestore(&global_cpu_snapshot_lock, flags);
381 static void sysrq_handle_globpmu(int key)
383 pmu_snapshot_all_cpus();
386 static struct sysrq_key_op sparc_globalpmu_op = {
387 .handler = sysrq_handle_globpmu,
388 .help_msg = "global-pmu(X)",
389 .action_msg = "Show Global PMU Regs",
392 static int __init sparc_sysrq_init(void)
394 int ret = register_sysrq_key('y', &sparc_globalreg_op);
397 ret = register_sysrq_key('x', &sparc_globalpmu_op);
401 core_initcall(sparc_sysrq_init);
405 unsigned long thread_saved_pc(struct task_struct *tsk)
407 struct thread_info *ti = task_thread_info(tsk);
408 unsigned long ret = 0xdeadbeefUL;
412 sp = (unsigned long *)(ti->ksp + STACK_BIAS);
413 if (((unsigned long)sp & (sizeof(long) - 1)) == 0UL &&
416 fp = (unsigned long *)(sp[14] + STACK_BIAS);
417 if (((unsigned long)fp & (sizeof(long) - 1)) == 0UL)
424 /* Free current thread data structures etc.. */
425 void exit_thread(void)
427 struct thread_info *t = current_thread_info();
430 if (t->utraps[0] < 2)
437 void flush_thread(void)
439 struct thread_info *t = current_thread_info();
440 struct mm_struct *mm;
444 tsb_context_switch(mm);
446 set_thread_wsaved(0);
448 /* Clear FPU register state. */
452 /* It's a bit more tricky when 64-bit tasks are involved... */
453 static unsigned long clone_stackframe(unsigned long csp, unsigned long psp)
455 bool stack_64bit = test_thread_64bit_stack(psp);
456 unsigned long fp, distance, rval;
461 __get_user(fp, &(((struct reg_window __user *)psp)->ins[6]));
463 if (test_thread_flag(TIF_32BIT))
466 __get_user(fp, &(((struct reg_window32 __user *)psp)->ins[6]));
468 /* Now align the stack as this is mandatory in the Sparc ABI
469 * due to how register windows work. This hides the
470 * restriction from thread libraries etc.
475 rval = (csp - distance);
476 if (copy_in_user((void __user *) rval, (void __user *) psp, distance))
478 else if (!stack_64bit) {
479 if (put_user(((u32)csp),
480 &(((struct reg_window32 __user *)rval)->ins[6])))
483 if (put_user(((u64)csp - STACK_BIAS),
484 &(((struct reg_window __user *)rval)->ins[6])))
487 rval = rval - STACK_BIAS;
493 /* Standard stuff. */
494 static inline void shift_window_buffer(int first_win, int last_win,
495 struct thread_info *t)
499 for (i = first_win; i < last_win; i++) {
500 t->rwbuf_stkptrs[i] = t->rwbuf_stkptrs[i+1];
501 memcpy(&t->reg_window[i], &t->reg_window[i+1],
502 sizeof(struct reg_window));
506 void synchronize_user_stack(void)
508 struct thread_info *t = current_thread_info();
509 unsigned long window;
511 flush_user_windows();
512 if ((window = get_thread_wsaved()) != 0) {
515 struct reg_window *rwin = &t->reg_window[window];
516 int winsize = sizeof(struct reg_window);
519 sp = t->rwbuf_stkptrs[window];
521 if (test_thread_64bit_stack(sp))
524 winsize = sizeof(struct reg_window32);
526 if (!copy_to_user((char __user *)sp, rwin, winsize)) {
527 shift_window_buffer(window, get_thread_wsaved() - 1, t);
528 set_thread_wsaved(get_thread_wsaved() - 1);
534 static void stack_unaligned(unsigned long sp)
538 info.si_signo = SIGBUS;
540 info.si_code = BUS_ADRALN;
541 info.si_addr = (void __user *) sp;
543 force_sig_info(SIGBUS, &info, current);
546 void fault_in_user_windows(void)
548 struct thread_info *t = current_thread_info();
549 unsigned long window;
551 flush_user_windows();
552 window = get_thread_wsaved();
554 if (likely(window != 0)) {
557 struct reg_window *rwin = &t->reg_window[window];
558 int winsize = sizeof(struct reg_window);
561 sp = t->rwbuf_stkptrs[window];
563 if (test_thread_64bit_stack(sp))
566 winsize = sizeof(struct reg_window32);
568 if (unlikely(sp & 0x7UL))
571 if (unlikely(copy_to_user((char __user *)sp,
576 set_thread_wsaved(0);
580 set_thread_wsaved(window + 1);
584 asmlinkage long sparc_do_fork(unsigned long clone_flags,
585 unsigned long stack_start,
586 struct pt_regs *regs,
587 unsigned long stack_size)
589 int __user *parent_tid_ptr, *child_tid_ptr;
590 unsigned long orig_i1 = regs->u_regs[UREG_I1];
594 if (test_thread_flag(TIF_32BIT)) {
595 parent_tid_ptr = compat_ptr(regs->u_regs[UREG_I2]);
596 child_tid_ptr = compat_ptr(regs->u_regs[UREG_I4]);
600 parent_tid_ptr = (int __user *) regs->u_regs[UREG_I2];
601 child_tid_ptr = (int __user *) regs->u_regs[UREG_I4];
604 ret = do_fork(clone_flags, stack_start,
606 parent_tid_ptr, child_tid_ptr);
608 /* If we get an error and potentially restart the system
609 * call, we're screwed because copy_thread() clobbered
610 * the parent's %o1. So detect that case and restore it
613 if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
614 regs->u_regs[UREG_I1] = orig_i1;
619 /* Copy a Sparc thread. The fork() return value conventions
620 * under SunOS are nothing short of bletcherous:
621 * Parent --> %o0 == childs pid, %o1 == 0
622 * Child --> %o0 == parents pid, %o1 == 1
624 int copy_thread(unsigned long clone_flags, unsigned long sp,
625 unsigned long unused,
626 struct task_struct *p, struct pt_regs *regs)
628 struct thread_info *t = task_thread_info(p);
629 struct sparc_stackf *parent_sf;
630 unsigned long child_stack_sz;
631 char *child_trap_frame;
634 kernel_thread = (regs->tstate & TSTATE_PRIV) ? 1 : 0;
635 parent_sf = ((struct sparc_stackf *) regs) - 1;
637 /* Calculate offset to stack_frame & pt_regs */
638 child_stack_sz = ((STACKFRAME_SZ + TRACEREG_SZ) +
639 (kernel_thread ? STACKFRAME_SZ : 0));
640 child_trap_frame = (task_stack_page(p) +
641 (THREAD_SIZE - child_stack_sz));
642 memcpy(child_trap_frame, parent_sf, child_stack_sz);
644 t->flags = (t->flags & ~((0xffUL << TI_FLAG_CWP_SHIFT) |
645 (0xffUL << TI_FLAG_CURRENT_DS_SHIFT))) |
646 (((regs->tstate + 1) & TSTATE_CWP) << TI_FLAG_CWP_SHIFT);
648 t->ksp = ((unsigned long) child_trap_frame) - STACK_BIAS;
649 t->kregs = (struct pt_regs *) (child_trap_frame +
650 sizeof(struct sparc_stackf));
654 struct sparc_stackf *child_sf = (struct sparc_stackf *)
655 (child_trap_frame + (STACKFRAME_SZ + TRACEREG_SZ));
657 /* Zero terminate the stack backtrace. */
659 t->kregs->u_regs[UREG_FP] =
660 ((unsigned long) child_sf) - STACK_BIAS;
662 t->flags |= ((long)ASI_P << TI_FLAG_CURRENT_DS_SHIFT);
663 t->kregs->u_regs[UREG_G6] = (unsigned long) t;
664 t->kregs->u_regs[UREG_G4] = (unsigned long) t->task;
666 if (t->flags & _TIF_32BIT) {
667 sp &= 0x00000000ffffffffUL;
668 regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
670 t->kregs->u_regs[UREG_FP] = sp;
671 t->flags |= ((long)ASI_AIUS << TI_FLAG_CURRENT_DS_SHIFT);
672 if (sp != regs->u_regs[UREG_FP]) {
675 csp = clone_stackframe(sp, regs->u_regs[UREG_FP]);
678 t->kregs->u_regs[UREG_FP] = csp;
684 /* Set the return value for the child. */
685 t->kregs->u_regs[UREG_I0] = current->pid;
686 t->kregs->u_regs[UREG_I1] = 1;
688 /* Set the second return value for the parent. */
689 regs->u_regs[UREG_I1] = 0;
691 if (clone_flags & CLONE_SETTLS)
692 t->kregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
698 * This is the mechanism for creating a new kernel thread.
700 * NOTE! Only a kernel-only process(ie the swapper or direct descendants
701 * who haven't done an "execve()") should use this: it will work within
702 * a system call from a "real" process, but the process memory space will
703 * not be freed until both the parent and the child have exited.
705 pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
709 /* If the parent runs before fn(arg) is called by the child,
710 * the input registers of this function can be clobbered.
711 * So we stash 'fn' and 'arg' into global registers which
712 * will not be modified by the parent.
714 __asm__ __volatile__("mov %4, %%g2\n\t" /* Save FN into global */
715 "mov %5, %%g3\n\t" /* Save ARG into global */
716 "mov %1, %%g1\n\t" /* Clone syscall nr. */
717 "mov %2, %%o0\n\t" /* Clone flags. */
718 "mov 0, %%o1\n\t" /* usp arg == 0 */
719 "t 0x6d\n\t" /* Linux/Sparc clone(). */
720 "brz,a,pn %%o1, 1f\n\t" /* Parent, just return. */
722 "jmpl %%g2, %%o7\n\t" /* Call the function. */
723 " mov %%g3, %%o0\n\t" /* Set arg in delay. */
725 "t 0x6d\n\t" /* Linux/Sparc exit(). */
726 /* Notreached by child. */
729 "i" (__NR_clone), "r" (flags | CLONE_VM | CLONE_UNTRACED),
730 "i" (__NR_exit), "r" (fn), "r" (arg) :
731 "g1", "g2", "g3", "o0", "o1", "memory", "cc");
734 EXPORT_SYMBOL(kernel_thread);
738 unsigned int pr_regs[32];
739 unsigned long pr_dregs[16];
741 unsigned int __unused;
743 unsigned char pr_qcnt;
744 unsigned char pr_q_entrysize;
746 unsigned int pr_q[64];
750 * fill in the fpu structure for a core dump.
752 int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
754 unsigned long *kfpregs = current_thread_info()->fpregs;
755 unsigned long fprs = current_thread_info()->fpsaved[0];
757 if (test_thread_flag(TIF_32BIT)) {
758 elf_fpregset_t32 *fpregs32 = (elf_fpregset_t32 *)fpregs;
761 memcpy(&fpregs32->pr_fr.pr_regs[0], kfpregs,
762 sizeof(unsigned int) * 32);
764 memset(&fpregs32->pr_fr.pr_regs[0], 0,
765 sizeof(unsigned int) * 32);
766 fpregs32->pr_qcnt = 0;
767 fpregs32->pr_q_entrysize = 8;
768 memset(&fpregs32->pr_q[0], 0,
769 (sizeof(unsigned int) * 64));
770 if (fprs & FPRS_FEF) {
771 fpregs32->pr_fsr = (unsigned int) current_thread_info()->xfsr[0];
774 fpregs32->pr_fsr = 0;
779 memcpy(&fpregs->pr_regs[0], kfpregs,
780 sizeof(unsigned int) * 32);
782 memset(&fpregs->pr_regs[0], 0,
783 sizeof(unsigned int) * 32);
785 memcpy(&fpregs->pr_regs[16], kfpregs+16,
786 sizeof(unsigned int) * 32);
788 memset(&fpregs->pr_regs[16], 0,
789 sizeof(unsigned int) * 32);
790 if(fprs & FPRS_FEF) {
791 fpregs->pr_fsr = current_thread_info()->xfsr[0];
792 fpregs->pr_gsr = current_thread_info()->gsr[0];
794 fpregs->pr_fsr = fpregs->pr_gsr = 0;
796 fpregs->pr_fprs = fprs;
800 EXPORT_SYMBOL(dump_fpu);
803 * sparc_execve() executes a new program after the asm stub has set
804 * things up for us. This should basically do what I want it to.
806 asmlinkage int sparc_execve(struct pt_regs *regs)
809 struct filename *filename;
811 /* User register window flush is done by entry.S */
813 /* Check for indirect call. */
814 if (regs->u_regs[UREG_G1] == 0)
817 filename = getname((char __user *)regs->u_regs[base + UREG_I0]);
818 error = PTR_ERR(filename);
819 if (IS_ERR(filename))
821 error = do_execve(filename->name,
822 (const char __user *const __user *)
823 regs->u_regs[base + UREG_I1],
824 (const char __user *const __user *)
825 regs->u_regs[base + UREG_I2], regs);
829 current_thread_info()->xfsr[0] = 0;
830 current_thread_info()->fpsaved[0] = 0;
831 regs->tstate &= ~TSTATE_PEF;
837 unsigned long get_wchan(struct task_struct *task)
839 unsigned long pc, fp, bias = 0;
840 struct thread_info *tp;
841 struct reg_window *rw;
842 unsigned long ret = 0;
845 if (!task || task == current ||
846 task->state == TASK_RUNNING)
849 tp = task_thread_info(task);
851 fp = task_thread_info(task)->ksp + bias;
854 if (!kstack_valid(tp, fp))
856 rw = (struct reg_window *) fp;
858 if (!in_sched_functions(pc)) {
862 fp = rw->ins[6] + bias;
863 } while (++count < 16);