diff options
Diffstat (limited to 'arch/sparc/kernel/process_64.c')
-rw-r--r-- | arch/sparc/kernel/process_64.c | 779 |
1 files changed, 779 insertions, 0 deletions
diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c new file mode 100644 index 000000000..46a59643b --- /dev/null +++ b/arch/sparc/kernel/process_64.c @@ -0,0 +1,779 @@ +/* arch/sparc64/kernel/process.c + * + * Copyright (C) 1995, 1996, 2008 David S. Miller (davem@davemloft.net) + * Copyright (C) 1996 Eddie C. Dost (ecd@skynet.be) + * Copyright (C) 1997, 1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz) + */ + +/* + * This file handles the architecture-dependent parts of process handling.. + */ + +#include <stdarg.h> + +#include <linux/errno.h> +#include <linux/export.h> +#include <linux/sched.h> +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/fs.h> +#include <linux/smp.h> +#include <linux/stddef.h> +#include <linux/ptrace.h> +#include <linux/slab.h> +#include <linux/user.h> +#include <linux/delay.h> +#include <linux/compat.h> +#include <linux/tick.h> +#include <linux/init.h> +#include <linux/cpu.h> +#include <linux/perf_event.h> +#include <linux/elfcore.h> +#include <linux/sysrq.h> +#include <linux/nmi.h> +#include <linux/context_tracking.h> + +#include <asm/uaccess.h> +#include <asm/page.h> +#include <asm/pgalloc.h> +#include <asm/pgtable.h> +#include <asm/processor.h> +#include <asm/pstate.h> +#include <asm/elf.h> +#include <asm/fpumacro.h> +#include <asm/head.h> +#include <asm/cpudata.h> +#include <asm/mmu_context.h> +#include <asm/unistd.h> +#include <asm/hypervisor.h> +#include <asm/syscalls.h> +#include <asm/irq_regs.h> +#include <asm/smp.h> +#include <asm/pcr.h> + +#include "kstack.h" + +/* Idle loop support on sparc64. */ +void arch_cpu_idle(void) +{ + if (tlb_type != hypervisor) { + touch_nmi_watchdog(); + local_irq_enable(); + } else { + unsigned long pstate; + + local_irq_enable(); + + /* The sun4v sleeping code requires that we have PSTATE.IE cleared over + * the cpu sleep hypervisor call. + */ + __asm__ __volatile__( + "rdpr %%pstate, %0\n\t" + "andn %0, %1, %0\n\t" + "wrpr %0, %%g0, %%pstate" + : "=&r" (pstate) + : "i" (PSTATE_IE)); + + if (!need_resched() && !cpu_is_offline(smp_processor_id())) + sun4v_cpu_yield(); + + /* Re-enable interrupts. */ + __asm__ __volatile__( + "rdpr %%pstate, %0\n\t" + "or %0, %1, %0\n\t" + "wrpr %0, %%g0, %%pstate" + : "=&r" (pstate) + : "i" (PSTATE_IE)); + } +} + +#ifdef CONFIG_HOTPLUG_CPU +void arch_cpu_idle_dead(void) +{ + sched_preempt_enable_no_resched(); + cpu_play_dead(); +} +#endif + +#ifdef CONFIG_COMPAT +static void show_regwindow32(struct pt_regs *regs) +{ + struct reg_window32 __user *rw; + struct reg_window32 r_w; + mm_segment_t old_fs; + + __asm__ __volatile__ ("flushw"); + rw = compat_ptr((unsigned)regs->u_regs[14]); + old_fs = get_fs(); + set_fs (USER_DS); + if (copy_from_user (&r_w, rw, sizeof(r_w))) { + set_fs (old_fs); + return; + } + + set_fs (old_fs); + printk("l0: %08x l1: %08x l2: %08x l3: %08x " + "l4: %08x l5: %08x l6: %08x l7: %08x\n", + r_w.locals[0], r_w.locals[1], r_w.locals[2], r_w.locals[3], + r_w.locals[4], r_w.locals[5], r_w.locals[6], r_w.locals[7]); + printk("i0: %08x i1: %08x i2: %08x i3: %08x " + "i4: %08x i5: %08x i6: %08x i7: %08x\n", + r_w.ins[0], r_w.ins[1], r_w.ins[2], r_w.ins[3], + r_w.ins[4], r_w.ins[5], r_w.ins[6], r_w.ins[7]); +} +#else +#define show_regwindow32(regs) do { } while (0) +#endif + +static void show_regwindow(struct pt_regs *regs) +{ + struct reg_window __user *rw; + struct reg_window *rwk; + struct reg_window r_w; + mm_segment_t old_fs; + + if ((regs->tstate & TSTATE_PRIV) || !(test_thread_flag(TIF_32BIT))) { + __asm__ __volatile__ ("flushw"); + rw = (struct reg_window __user *) + (regs->u_regs[14] + STACK_BIAS); + rwk = (struct reg_window *) + (regs->u_regs[14] + STACK_BIAS); + if (!(regs->tstate & TSTATE_PRIV)) { + old_fs = get_fs(); + set_fs (USER_DS); + if (copy_from_user (&r_w, rw, sizeof(r_w))) { + set_fs (old_fs); + return; + } + rwk = &r_w; + set_fs (old_fs); + } + } else { + show_regwindow32(regs); + return; + } + printk("l0: %016lx l1: %016lx l2: %016lx l3: %016lx\n", + rwk->locals[0], rwk->locals[1], rwk->locals[2], rwk->locals[3]); + printk("l4: %016lx l5: %016lx l6: %016lx l7: %016lx\n", + rwk->locals[4], rwk->locals[5], rwk->locals[6], rwk->locals[7]); + printk("i0: %016lx i1: %016lx i2: %016lx i3: %016lx\n", + rwk->ins[0], rwk->ins[1], rwk->ins[2], rwk->ins[3]); + printk("i4: %016lx i5: %016lx i6: %016lx i7: %016lx\n", + rwk->ins[4], rwk->ins[5], rwk->ins[6], rwk->ins[7]); + if (regs->tstate & TSTATE_PRIV) + printk("I7: <%pS>\n", (void *) rwk->ins[7]); +} + +void show_regs(struct pt_regs *regs) +{ + show_regs_print_info(KERN_DEFAULT); + + printk("TSTATE: %016lx TPC: %016lx TNPC: %016lx Y: %08x %s\n", regs->tstate, + regs->tpc, regs->tnpc, regs->y, print_tainted()); + printk("TPC: <%pS>\n", (void *) regs->tpc); + printk("g0: %016lx g1: %016lx g2: %016lx g3: %016lx\n", + regs->u_regs[0], regs->u_regs[1], regs->u_regs[2], + regs->u_regs[3]); + printk("g4: %016lx g5: %016lx g6: %016lx g7: %016lx\n", + regs->u_regs[4], regs->u_regs[5], regs->u_regs[6], + regs->u_regs[7]); + printk("o0: %016lx o1: %016lx o2: %016lx o3: %016lx\n", + regs->u_regs[8], regs->u_regs[9], regs->u_regs[10], + regs->u_regs[11]); + printk("o4: %016lx o5: %016lx sp: %016lx ret_pc: %016lx\n", + regs->u_regs[12], regs->u_regs[13], regs->u_regs[14], + regs->u_regs[15]); + printk("RPC: <%pS>\n", (void *) regs->u_regs[15]); + show_regwindow(regs); + show_stack(current, (unsigned long *) regs->u_regs[UREG_FP]); +} + +union global_cpu_snapshot global_cpu_snapshot[NR_CPUS]; +static DEFINE_SPINLOCK(global_cpu_snapshot_lock); + +static void __global_reg_self(struct thread_info *tp, struct pt_regs *regs, + int this_cpu) +{ + struct global_reg_snapshot *rp; + + flushw_all(); + + rp = &global_cpu_snapshot[this_cpu].reg; + + rp->tstate = regs->tstate; + rp->tpc = regs->tpc; + rp->tnpc = regs->tnpc; + rp->o7 = regs->u_regs[UREG_I7]; + + if (regs->tstate & TSTATE_PRIV) { + struct reg_window *rw; + + rw = (struct reg_window *) + (regs->u_regs[UREG_FP] + STACK_BIAS); + if (kstack_valid(tp, (unsigned long) rw)) { + rp->i7 = rw->ins[7]; + rw = (struct reg_window *) + (rw->ins[6] + STACK_BIAS); + if (kstack_valid(tp, (unsigned long) rw)) + rp->rpc = rw->ins[7]; + } + } else { + rp->i7 = 0; + rp->rpc = 0; + } + rp->thread = tp; +} + +/* In order to avoid hangs we do not try to synchronize with the + * global register dump client cpus. The last store they make is to + * the thread pointer, so do a short poll waiting for that to become + * non-NULL. + */ +static void __global_reg_poll(struct global_reg_snapshot *gp) +{ + int limit = 0; + + while (!gp->thread && ++limit < 100) { + barrier(); + udelay(1); + } +} + +void arch_trigger_all_cpu_backtrace(bool include_self) +{ + struct thread_info *tp = current_thread_info(); + struct pt_regs *regs = get_irq_regs(); + unsigned long flags; + int this_cpu, cpu; + + if (!regs) + regs = tp->kregs; + + spin_lock_irqsave(&global_cpu_snapshot_lock, flags); + + this_cpu = raw_smp_processor_id(); + + memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot)); + + if (include_self) + __global_reg_self(tp, regs, this_cpu); + + smp_fetch_global_regs(); + + for_each_online_cpu(cpu) { + struct global_reg_snapshot *gp; + + if (!include_self && cpu == this_cpu) + continue; + + gp = &global_cpu_snapshot[cpu].reg; + + __global_reg_poll(gp); + + tp = gp->thread; + printk("%c CPU[%3d]: TSTATE[%016lx] TPC[%016lx] TNPC[%016lx] TASK[%s:%d]\n", + (cpu == this_cpu ? '*' : ' '), cpu, + gp->tstate, gp->tpc, gp->tnpc, + ((tp && tp->task) ? tp->task->comm : "NULL"), + ((tp && tp->task) ? tp->task->pid : -1)); + + if (gp->tstate & TSTATE_PRIV) { + printk(" TPC[%pS] O7[%pS] I7[%pS] RPC[%pS]\n", + (void *) gp->tpc, + (void *) gp->o7, + (void *) gp->i7, + (void *) gp->rpc); + } else { + printk(" TPC[%lx] O7[%lx] I7[%lx] RPC[%lx]\n", + gp->tpc, gp->o7, gp->i7, gp->rpc); + } + + touch_nmi_watchdog(); + } + + memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot)); + + spin_unlock_irqrestore(&global_cpu_snapshot_lock, flags); +} + +#ifdef CONFIG_MAGIC_SYSRQ + +static void sysrq_handle_globreg(int key) +{ + arch_trigger_all_cpu_backtrace(true); +} + +static struct sysrq_key_op sparc_globalreg_op = { + .handler = sysrq_handle_globreg, + .help_msg = "global-regs(y)", + .action_msg = "Show Global CPU Regs", +}; + +static void __global_pmu_self(int this_cpu) +{ + struct global_pmu_snapshot *pp; + int i, num; + + if (!pcr_ops) + return; + + pp = &global_cpu_snapshot[this_cpu].pmu; + + num = 1; + if (tlb_type == hypervisor && + sun4v_chip_type >= SUN4V_CHIP_NIAGARA4) + num = 4; + + for (i = 0; i < num; i++) { + pp->pcr[i] = pcr_ops->read_pcr(i); + pp->pic[i] = pcr_ops->read_pic(i); + } +} + +static void __global_pmu_poll(struct global_pmu_snapshot *pp) +{ + int limit = 0; + + while (!pp->pcr[0] && ++limit < 100) { + barrier(); + udelay(1); + } +} + +static void pmu_snapshot_all_cpus(void) +{ + unsigned long flags; + int this_cpu, cpu; + + spin_lock_irqsave(&global_cpu_snapshot_lock, flags); + + memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot)); + + this_cpu = raw_smp_processor_id(); + + __global_pmu_self(this_cpu); + + smp_fetch_global_pmu(); + + for_each_online_cpu(cpu) { + struct global_pmu_snapshot *pp = &global_cpu_snapshot[cpu].pmu; + + __global_pmu_poll(pp); + + printk("%c CPU[%3d]: PCR[%08lx:%08lx:%08lx:%08lx] PIC[%08lx:%08lx:%08lx:%08lx]\n", + (cpu == this_cpu ? '*' : ' '), cpu, + pp->pcr[0], pp->pcr[1], pp->pcr[2], pp->pcr[3], + pp->pic[0], pp->pic[1], pp->pic[2], pp->pic[3]); + + touch_nmi_watchdog(); + } + + memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot)); + + spin_unlock_irqrestore(&global_cpu_snapshot_lock, flags); +} + +static void sysrq_handle_globpmu(int key) +{ + pmu_snapshot_all_cpus(); +} + +static struct sysrq_key_op sparc_globalpmu_op = { + .handler = sysrq_handle_globpmu, + .help_msg = "global-pmu(x)", + .action_msg = "Show Global PMU Regs", +}; + +static int __init sparc_sysrq_init(void) +{ + int ret = register_sysrq_key('y', &sparc_globalreg_op); + + if (!ret) + ret = register_sysrq_key('x', &sparc_globalpmu_op); + return ret; +} + +core_initcall(sparc_sysrq_init); + +#endif + +unsigned long thread_saved_pc(struct task_struct *tsk) +{ + struct thread_info *ti = task_thread_info(tsk); + unsigned long ret = 0xdeadbeefUL; + + if (ti && ti->ksp) { + unsigned long *sp; + sp = (unsigned long *)(ti->ksp + STACK_BIAS); + if (((unsigned long)sp & (sizeof(long) - 1)) == 0UL && + sp[14]) { + unsigned long *fp; + fp = (unsigned long *)(sp[14] + STACK_BIAS); + if (((unsigned long)fp & (sizeof(long) - 1)) == 0UL) + ret = fp[15]; + } + } + return ret; +} + +/* Free current thread data structures etc.. */ +void exit_thread(void) +{ + struct thread_info *t = current_thread_info(); + + if (t->utraps) { + if (t->utraps[0] < 2) + kfree (t->utraps); + else + t->utraps[0]--; + } +} + +void flush_thread(void) +{ + struct thread_info *t = current_thread_info(); + struct mm_struct *mm; + + mm = t->task->mm; + if (mm) + tsb_context_switch(mm); + + set_thread_wsaved(0); + + /* Clear FPU register state. */ + t->fpsaved[0] = 0; +} + +/* It's a bit more tricky when 64-bit tasks are involved... */ +static unsigned long clone_stackframe(unsigned long csp, unsigned long psp) +{ + bool stack_64bit = test_thread_64bit_stack(psp); + unsigned long fp, distance, rval; + + if (stack_64bit) { + csp += STACK_BIAS; + psp += STACK_BIAS; + __get_user(fp, &(((struct reg_window __user *)psp)->ins[6])); + fp += STACK_BIAS; + if (test_thread_flag(TIF_32BIT)) + fp &= 0xffffffff; + } else + __get_user(fp, &(((struct reg_window32 __user *)psp)->ins[6])); + + /* Now align the stack as this is mandatory in the Sparc ABI + * due to how register windows work. This hides the + * restriction from thread libraries etc. + */ + csp &= ~15UL; + + distance = fp - psp; + rval = (csp - distance); + if (copy_in_user((void __user *) rval, (void __user *) psp, distance)) + rval = 0; + else if (!stack_64bit) { + if (put_user(((u32)csp), + &(((struct reg_window32 __user *)rval)->ins[6]))) + rval = 0; + } else { + if (put_user(((u64)csp - STACK_BIAS), + &(((struct reg_window __user *)rval)->ins[6]))) + rval = 0; + else + rval = rval - STACK_BIAS; + } + + return rval; +} + +/* Standard stuff. */ +static inline void shift_window_buffer(int first_win, int last_win, + struct thread_info *t) +{ + int i; + + for (i = first_win; i < last_win; i++) { + t->rwbuf_stkptrs[i] = t->rwbuf_stkptrs[i+1]; + memcpy(&t->reg_window[i], &t->reg_window[i+1], + sizeof(struct reg_window)); + } +} + +void synchronize_user_stack(void) +{ + struct thread_info *t = current_thread_info(); + unsigned long window; + + flush_user_windows(); + if ((window = get_thread_wsaved()) != 0) { + window -= 1; + do { + struct reg_window *rwin = &t->reg_window[window]; + int winsize = sizeof(struct reg_window); + unsigned long sp; + + sp = t->rwbuf_stkptrs[window]; + + if (test_thread_64bit_stack(sp)) + sp += STACK_BIAS; + else + winsize = sizeof(struct reg_window32); + + if (!copy_to_user((char __user *)sp, rwin, winsize)) { + shift_window_buffer(window, get_thread_wsaved() - 1, t); + set_thread_wsaved(get_thread_wsaved() - 1); + } + } while (window--); + } +} + +static void stack_unaligned(unsigned long sp) +{ + siginfo_t info; + + info.si_signo = SIGBUS; + info.si_errno = 0; + info.si_code = BUS_ADRALN; + info.si_addr = (void __user *) sp; + info.si_trapno = 0; + force_sig_info(SIGBUS, &info, current); +} + +void fault_in_user_windows(void) +{ + struct thread_info *t = current_thread_info(); + unsigned long window; + + flush_user_windows(); + window = get_thread_wsaved(); + + if (likely(window != 0)) { + window -= 1; + do { + struct reg_window *rwin = &t->reg_window[window]; + int winsize = sizeof(struct reg_window); + unsigned long sp; + + sp = t->rwbuf_stkptrs[window]; + + if (test_thread_64bit_stack(sp)) + sp += STACK_BIAS; + else + winsize = sizeof(struct reg_window32); + + if (unlikely(sp & 0x7UL)) + stack_unaligned(sp); + + if (unlikely(copy_to_user((char __user *)sp, + rwin, winsize))) + goto barf; + } while (window--); + } + set_thread_wsaved(0); + return; + +barf: + set_thread_wsaved(window + 1); + user_exit(); + do_exit(SIGILL); +} + +asmlinkage long sparc_do_fork(unsigned long clone_flags, + unsigned long stack_start, + struct pt_regs *regs, + unsigned long stack_size) +{ + int __user *parent_tid_ptr, *child_tid_ptr; + unsigned long orig_i1 = regs->u_regs[UREG_I1]; + long ret; + +#ifdef CONFIG_COMPAT + if (test_thread_flag(TIF_32BIT)) { + parent_tid_ptr = compat_ptr(regs->u_regs[UREG_I2]); + child_tid_ptr = compat_ptr(regs->u_regs[UREG_I4]); + } else +#endif + { + parent_tid_ptr = (int __user *) regs->u_regs[UREG_I2]; + child_tid_ptr = (int __user *) regs->u_regs[UREG_I4]; + } + + ret = do_fork(clone_flags, stack_start, stack_size, + parent_tid_ptr, child_tid_ptr); + + /* If we get an error and potentially restart the system + * call, we're screwed because copy_thread() clobbered + * the parent's %o1. So detect that case and restore it + * here. + */ + if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK) + regs->u_regs[UREG_I1] = orig_i1; + + return ret; +} + +/* Copy a Sparc thread. The fork() return value conventions + * under SunOS are nothing short of bletcherous: + * Parent --> %o0 == childs pid, %o1 == 0 + * Child --> %o0 == parents pid, %o1 == 1 + */ +int copy_thread(unsigned long clone_flags, unsigned long sp, + unsigned long arg, struct task_struct *p) +{ + struct thread_info *t = task_thread_info(p); + struct pt_regs *regs = current_pt_regs(); + struct sparc_stackf *parent_sf; + unsigned long child_stack_sz; + char *child_trap_frame; + + /* Calculate offset to stack_frame & pt_regs */ + child_stack_sz = (STACKFRAME_SZ + TRACEREG_SZ); + child_trap_frame = (task_stack_page(p) + + (THREAD_SIZE - child_stack_sz)); + + t->new_child = 1; + t->ksp = ((unsigned long) child_trap_frame) - STACK_BIAS; + t->kregs = (struct pt_regs *) (child_trap_frame + + sizeof(struct sparc_stackf)); + t->fpsaved[0] = 0; + + if (unlikely(p->flags & PF_KTHREAD)) { + memset(child_trap_frame, 0, child_stack_sz); + __thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP] = + (current_pt_regs()->tstate + 1) & TSTATE_CWP; + t->current_ds = ASI_P; + t->kregs->u_regs[UREG_G1] = sp; /* function */ + t->kregs->u_regs[UREG_G2] = arg; + return 0; + } + + parent_sf = ((struct sparc_stackf *) regs) - 1; + memcpy(child_trap_frame, parent_sf, child_stack_sz); + if (t->flags & _TIF_32BIT) { + sp &= 0x00000000ffffffffUL; + regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL; + } + t->kregs->u_regs[UREG_FP] = sp; + __thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP] = + (regs->tstate + 1) & TSTATE_CWP; + t->current_ds = ASI_AIUS; + if (sp != regs->u_regs[UREG_FP]) { + unsigned long csp; + + csp = clone_stackframe(sp, regs->u_regs[UREG_FP]); + if (!csp) + return -EFAULT; + t->kregs->u_regs[UREG_FP] = csp; + } + if (t->utraps) + t->utraps[0]++; + + /* Set the return value for the child. */ + t->kregs->u_regs[UREG_I0] = current->pid; + t->kregs->u_regs[UREG_I1] = 1; + + /* Set the second return value for the parent. */ + regs->u_regs[UREG_I1] = 0; + + if (clone_flags & CLONE_SETTLS) + t->kregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3]; + + return 0; +} + +typedef struct { + union { + unsigned int pr_regs[32]; + unsigned long pr_dregs[16]; + } pr_fr; + unsigned int __unused; + unsigned int pr_fsr; + unsigned char pr_qcnt; + unsigned char pr_q_entrysize; + unsigned char pr_en; + unsigned int pr_q[64]; +} elf_fpregset_t32; + +/* + * fill in the fpu structure for a core dump. + */ +int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs) +{ + unsigned long *kfpregs = current_thread_info()->fpregs; + unsigned long fprs = current_thread_info()->fpsaved[0]; + + if (test_thread_flag(TIF_32BIT)) { + elf_fpregset_t32 *fpregs32 = (elf_fpregset_t32 *)fpregs; + + if (fprs & FPRS_DL) + memcpy(&fpregs32->pr_fr.pr_regs[0], kfpregs, + sizeof(unsigned int) * 32); + else + memset(&fpregs32->pr_fr.pr_regs[0], 0, + sizeof(unsigned int) * 32); + fpregs32->pr_qcnt = 0; + fpregs32->pr_q_entrysize = 8; + memset(&fpregs32->pr_q[0], 0, + (sizeof(unsigned int) * 64)); + if (fprs & FPRS_FEF) { + fpregs32->pr_fsr = (unsigned int) current_thread_info()->xfsr[0]; + fpregs32->pr_en = 1; + } else { + fpregs32->pr_fsr = 0; + fpregs32->pr_en = 0; + } + } else { + if(fprs & FPRS_DL) + memcpy(&fpregs->pr_regs[0], kfpregs, + sizeof(unsigned int) * 32); + else + memset(&fpregs->pr_regs[0], 0, + sizeof(unsigned int) * 32); + if(fprs & FPRS_DU) + memcpy(&fpregs->pr_regs[16], kfpregs+16, + sizeof(unsigned int) * 32); + else + memset(&fpregs->pr_regs[16], 0, + sizeof(unsigned int) * 32); + if(fprs & FPRS_FEF) { + fpregs->pr_fsr = current_thread_info()->xfsr[0]; + fpregs->pr_gsr = current_thread_info()->gsr[0]; + } else { + fpregs->pr_fsr = fpregs->pr_gsr = 0; + } + fpregs->pr_fprs = fprs; + } + return 1; +} +EXPORT_SYMBOL(dump_fpu); + +unsigned long get_wchan(struct task_struct *task) +{ + unsigned long pc, fp, bias = 0; + struct thread_info *tp; + struct reg_window *rw; + unsigned long ret = 0; + int count = 0; + + if (!task || task == current || + task->state == TASK_RUNNING) + goto out; + + tp = task_thread_info(task); + bias = STACK_BIAS; + fp = task_thread_info(task)->ksp + bias; + + do { + if (!kstack_valid(tp, fp)) + break; + rw = (struct reg_window *) fp; + pc = rw->ins[7]; + if (!in_sched_functions(pc)) { + ret = pc; + goto out; + } + fp = rw->ins[6] + bias; + } while (++count < 16); + +out: + return ret; +} |