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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397// SPDX-License-Identifier: GPL-2.0/* * linux/arch/alpha/kernel/process.c * * Copyright (C) 1995 Linus Torvalds */
/* * This file handles the architecture-dependent parts of process handling. */
#include <linux/cpu.h>#include <linux/errno.h>#include <linux/module.h>#include <linux/sched.h>#include <linux/sched/debug.h>#include <linux/sched/task.h>#include <linux/sched/task_stack.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 <linux/uaccess.h>#include <asm/io.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);
#ifdef CONFIG_ALPHA_WTINT/* * Sleep the CPU. * EV6, LCA45 and QEMU know how to power down, skipping N timer interrupts. */void arch_cpu_idle(void){ wtint(0);}
void __noreturn arch_cpu_idle_dead(void){ wtint(INT_MAX); BUG();}#endif /* ALPHA_WTINT */
struct halt_info { int mode; char *restart_cmd;};
static voidcommon_shutdown_1(void *generic_ptr){ struct halt_info *how = 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_empty(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_hardirq()) irq_exit(); /* This has the effect of resetting the VGA video origin. */ console_lock(); do_take_over_console(&dummy_con, 0, MAX_NR_CONSOLES-1, 1); console_unlock();#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 voidcommon_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);}
voidmachine_restart(char *restart_cmd){ common_shutdown(LINUX_REBOOT_CMD_RESTART, restart_cmd);}
voidmachine_halt(void){ common_shutdown(LINUX_REBOOT_CMD_HALT, NULL);}
voidmachine_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. */
voidshow_regs(struct pt_regs *regs){ show_regs_print_info(KERN_DEFAULT); dik_show_regs(regs, NULL);}
/* * Re-start a thread when doing execve() */voidstart_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp){ regs->pc = pc; regs->ps = 8; wrusp(sp);}EXPORT_SYMBOL(start_thread);
voidflush_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;}
/* * Copy architecture-specific thread state */int copy_thread(struct task_struct *p, const struct kernel_clone_args *args){ u64 clone_flags = args->flags; unsigned long usp = args->stack; unsigned long tls = args->tls; 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 */ childti->status |= TS_SAVED_FP | TS_RESTORE_FP;
if (unlikely(args->fn)) { /* kernel thread */ memset(childstack, 0, sizeof(struct switch_stack) + sizeof(struct pt_regs)); childstack->r26 = (unsigned long) ret_from_kernel_thread; childstack->r9 = (unsigned long) args->fn; childstack->r10 = (unsigned long) args->fn_arg; childregs->hae = alpha_mv.hae_cache; memset(childti->fp, '\0', sizeof(childti->fp)); 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 = tls; else regs->r20 = 0; /* OSF/1 has some strange fork() semantics. */ childti->pcb.usp = usp ?: rdusp(); *childregs = *regs; childregs->r0 = 0; childregs->r19 = 0; childregs->r20 = 1; /* OSF/1 has some strange fork() semantics. */ 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. */voiddump_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);
intdump_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 elf_core_copy_task_fpregs(struct task_struct *t, elf_fpregset_t *fpu){ memcpy(fpu, task_thread_info(t)->fp, 32 * 8); return 1;}
/* * 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~ */
static unsigned longthread_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;
/* * 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;}