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401 lines
9.8 KiB
401 lines
9.8 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* linux/arch/alpha/kernel/process.c |
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* |
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* Copyright (C) 1995 Linus Torvalds |
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*/ |
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/* |
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* This file handles the architecture-dependent parts of process handling. |
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*/ |
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#include <linux/errno.h> |
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#include <linux/module.h> |
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#include <linux/sched.h> |
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#include <linux/sched/debug.h> |
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#include <linux/sched/task.h> |
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#include <linux/sched/task_stack.h> |
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#include <linux/kernel.h> |
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#include <linux/mm.h> |
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#include <linux/smp.h> |
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#include <linux/stddef.h> |
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#include <linux/unistd.h> |
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#include <linux/ptrace.h> |
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#include <linux/user.h> |
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#include <linux/time.h> |
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#include <linux/major.h> |
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#include <linux/stat.h> |
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#include <linux/vt.h> |
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#include <linux/mman.h> |
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#include <linux/elfcore.h> |
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#include <linux/reboot.h> |
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#include <linux/tty.h> |
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#include <linux/console.h> |
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#include <linux/slab.h> |
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#include <linux/rcupdate.h> |
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#include <asm/reg.h> |
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#include <linux/uaccess.h> |
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#include <asm/io.h> |
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#include <asm/hwrpb.h> |
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#include <asm/fpu.h> |
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#include "proto.h" |
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#include "pci_impl.h" |
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/* |
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* Power off function, if any |
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*/ |
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void (*pm_power_off)(void) = machine_power_off; |
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EXPORT_SYMBOL(pm_power_off); |
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#ifdef CONFIG_ALPHA_WTINT |
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/* |
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* Sleep the CPU. |
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* EV6, LCA45 and QEMU know how to power down, skipping N timer interrupts. |
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*/ |
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void arch_cpu_idle(void) |
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{ |
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wtint(0); |
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raw_local_irq_enable(); |
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} |
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void arch_cpu_idle_dead(void) |
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{ |
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wtint(INT_MAX); |
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} |
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#endif /* ALPHA_WTINT */ |
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struct halt_info { |
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int mode; |
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char *restart_cmd; |
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}; |
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static void |
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common_shutdown_1(void *generic_ptr) |
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{ |
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struct halt_info *how = (struct halt_info *)generic_ptr; |
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struct percpu_struct *cpup; |
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unsigned long *pflags, flags; |
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int cpuid = smp_processor_id(); |
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/* No point in taking interrupts anymore. */ |
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local_irq_disable(); |
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cpup = (struct percpu_struct *) |
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((unsigned long)hwrpb + hwrpb->processor_offset |
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+ hwrpb->processor_size * cpuid); |
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pflags = &cpup->flags; |
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flags = *pflags; |
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/* Clear reason to "default"; clear "bootstrap in progress". */ |
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flags &= ~0x00ff0001UL; |
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#ifdef CONFIG_SMP |
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/* Secondaries halt here. */ |
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if (cpuid != boot_cpuid) { |
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flags |= 0x00040000UL; /* "remain halted" */ |
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*pflags = flags; |
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set_cpu_present(cpuid, false); |
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set_cpu_possible(cpuid, false); |
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halt(); |
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} |
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#endif |
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if (how->mode == LINUX_REBOOT_CMD_RESTART) { |
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if (!how->restart_cmd) { |
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flags |= 0x00020000UL; /* "cold bootstrap" */ |
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} else { |
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/* For SRM, we could probably set environment |
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variables to get this to work. We'd have to |
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delay this until after srm_paging_stop unless |
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we ever got srm_fixup working. |
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At the moment, SRM will use the last boot device, |
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but the file and flags will be the defaults, when |
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doing a "warm" bootstrap. */ |
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flags |= 0x00030000UL; /* "warm bootstrap" */ |
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} |
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} else { |
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flags |= 0x00040000UL; /* "remain halted" */ |
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} |
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*pflags = flags; |
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#ifdef CONFIG_SMP |
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/* Wait for the secondaries to halt. */ |
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set_cpu_present(boot_cpuid, false); |
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set_cpu_possible(boot_cpuid, false); |
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while (cpumask_weight(cpu_present_mask)) |
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barrier(); |
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#endif |
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/* If booted from SRM, reset some of the original environment. */ |
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if (alpha_using_srm) { |
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#ifdef CONFIG_DUMMY_CONSOLE |
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/* If we've gotten here after SysRq-b, leave interrupt |
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context before taking over the console. */ |
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if (in_irq()) |
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irq_exit(); |
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/* This has the effect of resetting the VGA video origin. */ |
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console_lock(); |
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do_take_over_console(&dummy_con, 0, MAX_NR_CONSOLES-1, 1); |
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console_unlock(); |
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#endif |
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pci_restore_srm_config(); |
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set_hae(srm_hae); |
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} |
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if (alpha_mv.kill_arch) |
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alpha_mv.kill_arch(how->mode); |
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if (! alpha_using_srm && how->mode != LINUX_REBOOT_CMD_RESTART) { |
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/* Unfortunately, since MILO doesn't currently understand |
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the hwrpb bits above, we can't reliably halt the |
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processor and keep it halted. So just loop. */ |
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return; |
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} |
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if (alpha_using_srm) |
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srm_paging_stop(); |
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halt(); |
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} |
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static void |
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common_shutdown(int mode, char *restart_cmd) |
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{ |
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struct halt_info args; |
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args.mode = mode; |
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args.restart_cmd = restart_cmd; |
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on_each_cpu(common_shutdown_1, &args, 0); |
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} |
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void |
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machine_restart(char *restart_cmd) |
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{ |
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common_shutdown(LINUX_REBOOT_CMD_RESTART, restart_cmd); |
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} |
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void |
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machine_halt(void) |
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{ |
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common_shutdown(LINUX_REBOOT_CMD_HALT, NULL); |
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} |
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void |
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machine_power_off(void) |
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{ |
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common_shutdown(LINUX_REBOOT_CMD_POWER_OFF, NULL); |
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} |
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/* Used by sysrq-p, among others. I don't believe r9-r15 are ever |
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saved in the context it's used. */ |
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void |
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show_regs(struct pt_regs *regs) |
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{ |
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show_regs_print_info(KERN_DEFAULT); |
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dik_show_regs(regs, NULL); |
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} |
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/* |
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* Re-start a thread when doing execve() |
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*/ |
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void |
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start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp) |
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{ |
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regs->pc = pc; |
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regs->ps = 8; |
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wrusp(sp); |
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} |
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EXPORT_SYMBOL(start_thread); |
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void |
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flush_thread(void) |
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{ |
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/* Arrange for each exec'ed process to start off with a clean slate |
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with respect to the FPU. This is all exceptions disabled. */ |
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current_thread_info()->ieee_state = 0; |
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wrfpcr(FPCR_DYN_NORMAL | ieee_swcr_to_fpcr(0)); |
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/* Clean slate for TLS. */ |
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current_thread_info()->pcb.unique = 0; |
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} |
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void |
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release_thread(struct task_struct *dead_task) |
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{ |
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} |
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/* |
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* Copy architecture-specific thread state |
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*/ |
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int copy_thread(unsigned long clone_flags, unsigned long usp, |
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unsigned long kthread_arg, struct task_struct *p, |
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unsigned long tls) |
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{ |
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extern void ret_from_fork(void); |
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extern void ret_from_kernel_thread(void); |
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struct thread_info *childti = task_thread_info(p); |
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struct pt_regs *childregs = task_pt_regs(p); |
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struct pt_regs *regs = current_pt_regs(); |
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struct switch_stack *childstack, *stack; |
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childstack = ((struct switch_stack *) childregs) - 1; |
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childti->pcb.ksp = (unsigned long) childstack; |
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childti->pcb.flags = 1; /* set FEN, clear everything else */ |
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if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) { |
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/* kernel thread */ |
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memset(childstack, 0, |
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sizeof(struct switch_stack) + sizeof(struct pt_regs)); |
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childstack->r26 = (unsigned long) ret_from_kernel_thread; |
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childstack->r9 = usp; /* function */ |
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childstack->r10 = kthread_arg; |
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childregs->hae = alpha_mv.hae_cache; |
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childti->pcb.usp = 0; |
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return 0; |
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} |
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/* Note: if CLONE_SETTLS is not set, then we must inherit the |
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value from the parent, which will have been set by the block |
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copy in dup_task_struct. This is non-intuitive, but is |
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required for proper operation in the case of a threaded |
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application calling fork. */ |
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if (clone_flags & CLONE_SETTLS) |
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childti->pcb.unique = tls; |
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else |
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regs->r20 = 0; /* OSF/1 has some strange fork() semantics. */ |
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childti->pcb.usp = usp ?: rdusp(); |
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*childregs = *regs; |
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childregs->r0 = 0; |
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childregs->r19 = 0; |
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childregs->r20 = 1; /* OSF/1 has some strange fork() semantics. */ |
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stack = ((struct switch_stack *) regs) - 1; |
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*childstack = *stack; |
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childstack->r26 = (unsigned long) ret_from_fork; |
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return 0; |
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} |
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/* |
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* Fill in the user structure for a ELF core dump. |
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*/ |
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void |
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dump_elf_thread(elf_greg_t *dest, struct pt_regs *pt, struct thread_info *ti) |
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{ |
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/* switch stack follows right below pt_regs: */ |
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struct switch_stack * sw = ((struct switch_stack *) pt) - 1; |
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dest[ 0] = pt->r0; |
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dest[ 1] = pt->r1; |
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dest[ 2] = pt->r2; |
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dest[ 3] = pt->r3; |
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dest[ 4] = pt->r4; |
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dest[ 5] = pt->r5; |
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dest[ 6] = pt->r6; |
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dest[ 7] = pt->r7; |
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dest[ 8] = pt->r8; |
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dest[ 9] = sw->r9; |
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dest[10] = sw->r10; |
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dest[11] = sw->r11; |
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dest[12] = sw->r12; |
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dest[13] = sw->r13; |
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dest[14] = sw->r14; |
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dest[15] = sw->r15; |
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dest[16] = pt->r16; |
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dest[17] = pt->r17; |
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dest[18] = pt->r18; |
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dest[19] = pt->r19; |
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dest[20] = pt->r20; |
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dest[21] = pt->r21; |
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dest[22] = pt->r22; |
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dest[23] = pt->r23; |
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dest[24] = pt->r24; |
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dest[25] = pt->r25; |
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dest[26] = pt->r26; |
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dest[27] = pt->r27; |
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dest[28] = pt->r28; |
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dest[29] = pt->gp; |
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dest[30] = ti == current_thread_info() ? rdusp() : ti->pcb.usp; |
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dest[31] = pt->pc; |
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/* Once upon a time this was the PS value. Which is stupid |
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since that is always 8 for usermode. Usurped for the more |
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useful value of the thread's UNIQUE field. */ |
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dest[32] = ti->pcb.unique; |
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} |
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EXPORT_SYMBOL(dump_elf_thread); |
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int |
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dump_elf_task(elf_greg_t *dest, struct task_struct *task) |
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{ |
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dump_elf_thread(dest, task_pt_regs(task), task_thread_info(task)); |
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return 1; |
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} |
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EXPORT_SYMBOL(dump_elf_task); |
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int |
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dump_elf_task_fp(elf_fpreg_t *dest, struct task_struct *task) |
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{ |
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struct switch_stack *sw = (struct switch_stack *)task_pt_regs(task) - 1; |
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memcpy(dest, sw->fp, 32 * 8); |
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return 1; |
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} |
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EXPORT_SYMBOL(dump_elf_task_fp); |
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/* |
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* Return saved PC of a blocked thread. This assumes the frame |
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* pointer is the 6th saved long on the kernel stack and that the |
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* saved return address is the first long in the frame. This all |
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* holds provided the thread blocked through a call to schedule() ($15 |
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* is the frame pointer in schedule() and $15 is saved at offset 48 by |
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* entry.S:do_switch_stack). |
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* |
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* Under heavy swap load I've seen this lose in an ugly way. So do |
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* some extra sanity checking on the ranges we expect these pointers |
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* to be in so that we can fail gracefully. This is just for ps after |
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* all. -- r~ |
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*/ |
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static unsigned long |
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thread_saved_pc(struct task_struct *t) |
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{ |
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unsigned long base = (unsigned long)task_stack_page(t); |
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unsigned long fp, sp = task_thread_info(t)->pcb.ksp; |
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if (sp > base && sp+6*8 < base + 16*1024) { |
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fp = ((unsigned long*)sp)[6]; |
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if (fp > sp && fp < base + 16*1024) |
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return *(unsigned long *)fp; |
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} |
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return 0; |
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} |
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unsigned long |
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get_wchan(struct task_struct *p) |
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{ |
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unsigned long schedule_frame; |
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unsigned long pc; |
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if (!p || p == current || task_is_running(p)) |
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return 0; |
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/* |
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* This one depends on the frame size of schedule(). Do a |
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* "disass schedule" in gdb to find the frame size. Also, the |
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* code assumes that sleep_on() follows immediately after |
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* interruptible_sleep_on() and that add_timer() follows |
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* immediately after interruptible_sleep(). Ugly, isn't it? |
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* Maybe adding a wchan field to task_struct would be better, |
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* after all... |
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*/ |
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pc = thread_saved_pc(p); |
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if (in_sched_functions(pc)) { |
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schedule_frame = ((unsigned long *)task_thread_info(p)->pcb.ksp)[6]; |
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return ((unsigned long *)schedule_frame)[12]; |
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} |
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return pc; |
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}
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