diff options
Diffstat (limited to 'arch/alpha/kernel/process.c')
| -rw-r--r-- | arch/alpha/kernel/process.c | 528 |
1 files changed, 528 insertions, 0 deletions
diff --git a/arch/alpha/kernel/process.c b/arch/alpha/kernel/process.c new file mode 100644 index 0000000..4933f3c --- /dev/null +++ b/arch/alpha/kernel/process.c @@ -0,0 +1,528 @@ +/* + * linux/arch/alpha/kernel/process.c + * + * Copyright (C) 1995 Linus Torvalds + */ + +/* + * This file handles the architecture-dependent parts of process handling. + */ + +#include <linux/config.h> +#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/smp_lock.h> +#include <linux/stddef.h> +#include <linux/unistd.h> +#include <linux/ptrace.h> +#include <linux/slab.h> +#include <linux/user.h> +#include <linux/a.out.h> +#include <linux/utsname.h> +#include <linux/time.h> +#include <linux/major.h> +#include <linux/stat.h> +#include <linux/mman.h> +#include <linux/elfcore.h> +#include <linux/reboot.h> +#include <linux/tty.h> +#include <linux/console.h> + +#include <asm/reg.h> +#include <asm/uaccess.h> +#include <asm/system.h> +#include <asm/io.h> +#include <asm/pgtable.h> +#include <asm/hwrpb.h> +#include <asm/fpu.h> + +#include "proto.h" +#include "pci_impl.h" + +void default_idle(void) +{ + barrier(); +} + +void +cpu_idle(void) +{ + while (1) { + void (*idle)(void) = default_idle; + /* FIXME -- EV6 and LCA45 know how to power down + the CPU. */ + + while (!need_resched()) + idle(); + schedule(); + } +} + + +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; + clear_bit(cpuid, &cpu_present_mask); + 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. */ + cpu_clear(boot_cpuid, cpu_possible_map); + while (cpus_weight(cpu_possible_map)) + barrier(); +#endif + + /* If booted from SRM, reset some of the original environment. */ + if (alpha_using_srm) { +#ifdef CONFIG_DUMMY_CONSOLE + /* 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, 1, 0); +} + +void +machine_restart(char *restart_cmd) +{ + common_shutdown(LINUX_REBOOT_CMD_RESTART, restart_cmd); +} + +EXPORT_SYMBOL(machine_restart); + +void +machine_halt(void) +{ + common_shutdown(LINUX_REBOOT_CMD_HALT, NULL); +} + +EXPORT_SYMBOL(machine_halt); + +void +machine_power_off(void) +{ + common_shutdown(LINUX_REBOOT_CMD_POWER_OFF, NULL); +} + +EXPORT_SYMBOL(machine_power_off); + +/* 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) +{ + 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) +{ + set_fs(USER_DS); + regs->pc = pc; + regs->ps = 8; + wrusp(sp); +} + +/* + * 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) +{ +} + +/* + * "alpha_clone()".. By the time we get here, the + * non-volatile registers have also been saved on the + * stack. We do some ugly pointer stuff here.. (see + * also copy_thread) + * + * Notice that "fork()" is implemented in terms of clone, + * with parameters (SIGCHLD, 0). + */ +int +alpha_clone(unsigned long clone_flags, unsigned long usp, + int __user *parent_tid, int __user *child_tid, + unsigned long tls_value, struct pt_regs *regs) +{ + if (!usp) + usp = rdusp(); + + return do_fork(clone_flags, usp, regs, 0, parent_tid, child_tid); +} + +int +alpha_vfork(struct pt_regs *regs) +{ + return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), + regs, 0, NULL, NULL); +} + +/* + * Copy an alpha thread.. + * + * Note the "stack_offset" stuff: when returning to kernel mode, we need + * to have some extra stack-space for the kernel stack that still exists + * after the "ret_from_fork". When returning to user mode, we only want + * the space needed by the syscall stack frame (ie "struct pt_regs"). + * Use the passed "regs" pointer to determine how much space we need + * for a kernel fork(). + */ + +int +copy_thread(int nr, unsigned long clone_flags, unsigned long usp, + unsigned long unused, + struct task_struct * p, struct pt_regs * regs) +{ + extern void ret_from_fork(void); + + struct thread_info *childti = p->thread_info; + struct pt_regs * childregs; + struct switch_stack * childstack, *stack; + unsigned long stack_offset, settls; + + stack_offset = PAGE_SIZE - sizeof(struct pt_regs); + if (!(regs->ps & 8)) + stack_offset = (PAGE_SIZE-1) & (unsigned long) regs; + childregs = (struct pt_regs *) + (stack_offset + PAGE_SIZE + (long) childti); + + *childregs = *regs; + settls = regs->r20; + 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 = ((struct switch_stack *) childregs) - 1; + *childstack = *stack; + childstack->r26 = (unsigned long) ret_from_fork; + childti->pcb.usp = usp; + childti->pcb.ksp = (unsigned long) childstack; + childti->pcb.flags = 1; /* set FEN, clear everything else */ + + /* Set a new TLS for the child thread? Peek back into the + syscall arguments that we saved on syscall entry. Oops, + except we'd have clobbered it with the parent/child set + of r20. Read the saved copy. */ + /* 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 = settls; + + return 0; +} + +/* + * Fill in the user structure for an ECOFF core dump. + */ +void +dump_thread(struct pt_regs * pt, struct user * dump) +{ + /* switch stack follows right below pt_regs: */ + struct switch_stack * sw = ((struct switch_stack *) pt) - 1; + + dump->magic = CMAGIC; + dump->start_code = current->mm->start_code; + dump->start_data = current->mm->start_data; + dump->start_stack = rdusp() & ~(PAGE_SIZE - 1); + dump->u_tsize = ((current->mm->end_code - dump->start_code) + >> PAGE_SHIFT); + dump->u_dsize = ((current->mm->brk + PAGE_SIZE-1 - dump->start_data) + >> PAGE_SHIFT); + dump->u_ssize = (current->mm->start_stack - dump->start_stack + + PAGE_SIZE-1) >> PAGE_SHIFT; + + /* + * We store the registers in an order/format that is + * compatible with DEC Unix/OSF/1 as this makes life easier + * for gdb. + */ + dump->regs[EF_V0] = pt->r0; + dump->regs[EF_T0] = pt->r1; + dump->regs[EF_T1] = pt->r2; + dump->regs[EF_T2] = pt->r3; + dump->regs[EF_T3] = pt->r4; + dump->regs[EF_T4] = pt->r5; + dump->regs[EF_T5] = pt->r6; + dump->regs[EF_T6] = pt->r7; + dump->regs[EF_T7] = pt->r8; + dump->regs[EF_S0] = sw->r9; + dump->regs[EF_S1] = sw->r10; + dump->regs[EF_S2] = sw->r11; + dump->regs[EF_S3] = sw->r12; + dump->regs[EF_S4] = sw->r13; + dump->regs[EF_S5] = sw->r14; + dump->regs[EF_S6] = sw->r15; + dump->regs[EF_A3] = pt->r19; + dump->regs[EF_A4] = pt->r20; + dump->regs[EF_A5] = pt->r21; + dump->regs[EF_T8] = pt->r22; + dump->regs[EF_T9] = pt->r23; + dump->regs[EF_T10] = pt->r24; + dump->regs[EF_T11] = pt->r25; + dump->regs[EF_RA] = pt->r26; + dump->regs[EF_T12] = pt->r27; + dump->regs[EF_AT] = pt->r28; + dump->regs[EF_SP] = rdusp(); + dump->regs[EF_PS] = pt->ps; + dump->regs[EF_PC] = pt->pc; + dump->regs[EF_GP] = pt->gp; + dump->regs[EF_A0] = pt->r16; + dump->regs[EF_A1] = pt->r17; + dump->regs[EF_A2] = pt->r18; + memcpy((char *)dump->regs + EF_SIZE, sw->fp, 32 * 8); +} + +/* + * 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] = rdusp(); + 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; +} + +int +dump_elf_task(elf_greg_t *dest, struct task_struct *task) +{ + struct thread_info *ti; + struct pt_regs *pt; + + ti = task->thread_info; + pt = (struct pt_regs *)((unsigned long)ti + 2*PAGE_SIZE) - 1; + + dump_elf_thread(dest, pt, ti); + + return 1; +} + +int +dump_elf_task_fp(elf_fpreg_t *dest, struct task_struct *task) +{ + struct thread_info *ti; + struct pt_regs *pt; + struct switch_stack *sw; + + ti = task->thread_info; + pt = (struct pt_regs *)((unsigned long)ti + 2*PAGE_SIZE) - 1; + sw = (struct switch_stack *)pt - 1; + + memcpy(dest, sw->fp, 32 * 8); + + return 1; +} + +/* + * sys_execve() executes a new program. + */ +asmlinkage int +do_sys_execve(char __user *ufilename, char __user * __user *argv, + char __user * __user *envp, struct pt_regs *regs) +{ + int error; + char *filename; + + filename = getname(ufilename); + error = PTR_ERR(filename); + if (IS_ERR(filename)) + goto out; + error = do_execve(filename, argv, envp, regs); + putname(filename); +out: + return error; +} + +/* + * 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(task_t *t) +{ + unsigned long base = (unsigned long)t->thread_info; + unsigned long fp, sp = t->thread_info->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 *)p->thread_info->pcb.ksp)[6]; + return ((unsigned long *)schedule_frame)[12]; + } + return pc; +} |