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458 lines
11 KiB
458 lines
11 KiB
/*
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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/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/slab.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 <asm/reg.h>
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#include <asm/uaccess.h>
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#include <asm/system.h>
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#include <asm/io.h>
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#include <asm/pgtable.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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void
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cpu_idle(void)
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{
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set_thread_flag(TIF_POLLING_NRFLAG);
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while (1) {
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/* FIXME -- EV6 and LCA45 know how to power down
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the CPU. */
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while (!need_resched())
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cpu_relax();
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schedule();
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}
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}
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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 (cpus_weight(cpu_present_map))
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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_interrupt())
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irq_exit();
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/* This has the effect of resetting the VGA video origin. */
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take_over_console(&dummy_con, 0, MAX_NR_CONSOLES-1, 1);
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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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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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set_fs(USER_DS);
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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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/*
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* Free current thread data structures etc..
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*/
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void
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exit_thread(void)
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{
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}
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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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* "alpha_clone()".. By the time we get here, the
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* non-volatile registers have also been saved on the
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* stack. We do some ugly pointer stuff here.. (see
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* also copy_thread)
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*
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* Notice that "fork()" is implemented in terms of clone,
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* with parameters (SIGCHLD, 0).
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*/
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int
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alpha_clone(unsigned long clone_flags, unsigned long usp,
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int __user *parent_tid, int __user *child_tid,
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unsigned long tls_value, struct pt_regs *regs)
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{
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if (!usp)
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usp = rdusp();
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return do_fork(clone_flags, usp, regs, 0, parent_tid, child_tid);
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}
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int
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alpha_vfork(struct pt_regs *regs)
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{
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return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(),
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regs, 0, NULL, NULL);
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}
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/*
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* Copy an alpha thread..
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*
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* Note the "stack_offset" stuff: when returning to kernel mode, we need
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* to have some extra stack-space for the kernel stack that still exists
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* after the "ret_from_fork". When returning to user mode, we only want
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* the space needed by the syscall stack frame (ie "struct pt_regs").
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* Use the passed "regs" pointer to determine how much space we need
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* for a kernel fork().
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*/
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int
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copy_thread(unsigned long clone_flags, unsigned long usp,
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unsigned long unused,
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struct task_struct * p, struct pt_regs * regs)
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{
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extern void ret_from_fork(void);
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struct thread_info *childti = task_thread_info(p);
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struct pt_regs * childregs;
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struct switch_stack * childstack, *stack;
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unsigned long stack_offset, settls;
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stack_offset = PAGE_SIZE - sizeof(struct pt_regs);
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if (!(regs->ps & 8))
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stack_offset = (PAGE_SIZE-1) & (unsigned long) regs;
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childregs = (struct pt_regs *)
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(stack_offset + PAGE_SIZE + task_stack_page(p));
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*childregs = *regs;
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settls = regs->r20;
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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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regs->r20 = 0;
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stack = ((struct switch_stack *) regs) - 1;
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childstack = ((struct switch_stack *) childregs) - 1;
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*childstack = *stack;
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childstack->r26 = (unsigned long) ret_from_fork;
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childti->pcb.usp = usp;
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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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/* Set a new TLS for the child thread? Peek back into the
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syscall arguments that we saved on syscall entry. Oops,
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except we'd have clobbered it with the parent/child set
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of r20. Read the saved copy. */
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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 = settls;
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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] = rdusp();
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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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* sys_execve() executes a new program.
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*/
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asmlinkage int
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do_sys_execve(char __user *ufilename, char __user * __user *argv,
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char __user * __user *envp, struct pt_regs *regs)
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{
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int error;
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char *filename;
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filename = getname(ufilename);
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error = PTR_ERR(filename);
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if (IS_ERR(filename))
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goto out;
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error = do_execve(filename, argv, envp, regs);
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putname(filename);
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out:
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return error;
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}
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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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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 || p->state == TASK_RUNNING)
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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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