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