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linux/arch/parisc/kernel/process.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* PARISC Architecture-dependent parts of process handling
* based on the work for i386
*
* Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org>
* Copyright (C) 2000 Martin K Petersen <mkp at mkp.net>
* Copyright (C) 2000 John Marvin <jsm at parisc-linux.org>
* Copyright (C) 2000 David Huggins-Daines <dhd with pobox.org>
* Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org>
* Copyright (C) 2000 Philipp Rumpf <prumpf with tux.org>
* Copyright (C) 2000 David Kennedy <dkennedy with linuxcare.com>
* Copyright (C) 2000 Richard Hirst <rhirst with parisc-linux.org>
* Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org>
* Copyright (C) 2001 Alan Modra <amodra at parisc-linux.org>
* Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org>
* Copyright (C) 2001-2014 Helge Deller <deller@gmx.de>
* Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
*/
#include <stdarg.h>
#include <linux/elf.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/cpu.h>
#include <linux/module.h>
#include <linux/personality.h>
#include <linux/ptrace.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/sched/task.h>
#include <linux/sched/task_stack.h>
#include <linux/slab.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/kallsyms.h>
#include <linux/uaccess.h>
#include <linux/rcupdate.h>
#include <linux/random.h>
#include <linux/nmi.h>
#include <asm/io.h>
#include <asm/asm-offsets.h>
#include <asm/assembly.h>
#include <asm/pdc.h>
#include <asm/pdc_chassis.h>
#include <asm/pgalloc.h>
#include <asm/unwind.h>
#include <asm/sections.h>
#define COMMAND_GLOBAL F_EXTEND(0xfffe0030)
#define CMD_RESET 5 /* reset any module */
/*
** The Wright Brothers and Gecko systems have a H/W problem
** (Lasi...'nuf said) may cause a broadcast reset to lockup
** the system. An HVERSION dependent PDC call was developed
** to perform a "safe", platform specific broadcast reset instead
** of kludging up all the code.
**
** Older machines which do not implement PDC_BROADCAST_RESET will
** return (with an error) and the regular broadcast reset can be
** issued. Obviously, if the PDC does implement PDC_BROADCAST_RESET
** the PDC call will not return (the system will be reset).
*/
void machine_restart(char *cmd)
{
#ifdef FASTBOOT_SELFTEST_SUPPORT
/*
** If user has modified the Firmware Selftest Bitmap,
** run the tests specified in the bitmap after the
** system is rebooted w/PDC_DO_RESET.
**
** ftc_bitmap = 0x1AUL "Skip destructive memory tests"
**
** Using "directed resets" at each processor with the MEM_TOC
** vector cleared will also avoid running destructive
** memory self tests. (Not implemented yet)
*/
if (ftc_bitmap) {
pdc_do_firm_test_reset(ftc_bitmap);
}
#endif
/* set up a new led state on systems shipped with a LED State panel */
pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
/* "Normal" system reset */
pdc_do_reset();
/* Nope...box should reset with just CMD_RESET now */
gsc_writel(CMD_RESET, COMMAND_GLOBAL);
/* Wait for RESET to lay us to rest. */
while (1) ;
}
void (*chassis_power_off)(void);
/*
* This routine is called from sys_reboot to actually turn off the
* machine
*/
void machine_power_off(void)
{
/* If there is a registered power off handler, call it. */
if (chassis_power_off)
chassis_power_off();
/* Put the soft power button back under hardware control.
* If the user had already pressed the power button, the
* following call will immediately power off. */
pdc_soft_power_button(0);
pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
/* ipmi_poweroff may have been installed. */
if (pm_power_off)
pm_power_off();
/* It seems we have no way to power the system off via
* software. The user has to press the button himself. */
printk(KERN_EMERG "System shut down completed.\n"
"Please power this system off now.");
/* prevent soft lockup/stalled CPU messages for endless loop. */
rcu_sysrq_start();
lockup_detector_soft_poweroff();
for (;;);
}
void (*pm_power_off)(void);
EXPORT_SYMBOL(pm_power_off);
void machine_halt(void)
{
machine_power_off();
}
void flush_thread(void)
{
/* Only needs to handle fpu stuff or perf monitors.
** REVISIT: several arches implement a "lazy fpu state".
*/
}
void release_thread(struct task_struct *dead_task)
{
}
/*
* Fill in the FPU structure for a core dump.
*/
int dump_fpu (struct pt_regs * regs, elf_fpregset_t *r)
{
if (regs == NULL)
return 0;
memcpy(r, regs->fr, sizeof *r);
return 1;
}
int dump_task_fpu (struct task_struct *tsk, elf_fpregset_t *r)
{
memcpy(r, tsk->thread.regs.fr, sizeof(*r));
return 1;
}
/*
* Idle thread support
*
* Detect when running on QEMU with SeaBIOS PDC Firmware and let
* QEMU idle the host too.
*/
int running_on_qemu __ro_after_init;
EXPORT_SYMBOL(running_on_qemu);
void __cpuidle arch_cpu_idle_dead(void)
{
/* nop on real hardware, qemu will offline CPU. */
asm volatile("or %%r31,%%r31,%%r31\n":::);
}
void __cpuidle arch_cpu_idle(void)
{
local_irq_enable();
/* nop on real hardware, qemu will idle sleep. */
asm volatile("or %%r10,%%r10,%%r10\n":::);
}
static int __init parisc_idle_init(void)
{
if (!running_on_qemu)
cpu_idle_poll_ctrl(1);
return 0;
}
arch_initcall(parisc_idle_init);
/*
* Copy architecture-specific thread state
*/
int
copy_thread(unsigned long clone_flags, unsigned long usp,
unsigned long kthread_arg, struct task_struct *p)
{
struct pt_regs *cregs = &(p->thread.regs);
void *stack = task_stack_page(p);
/* We have to use void * instead of a function pointer, because
* function pointers aren't a pointer to the function on 64-bit.
* Make them const so the compiler knows they live in .text */
extern void * const ret_from_kernel_thread;
extern void * const child_return;
if (unlikely(p->flags & PF_KTHREAD)) {
/* kernel thread */
memset(cregs, 0, sizeof(struct pt_regs));
if (!usp) /* idle thread */
return 0;
/* Must exit via ret_from_kernel_thread in order
* to call schedule_tail()
*/
cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
cregs->kpc = (unsigned long) &ret_from_kernel_thread;
/*
* Copy function and argument to be called from
* ret_from_kernel_thread.
*/
#ifdef CONFIG_64BIT
cregs->gr[27] = ((unsigned long *)usp)[3];
cregs->gr[26] = ((unsigned long *)usp)[2];
#else
cregs->gr[26] = usp;
#endif
cregs->gr[25] = kthread_arg;
} else {
/* user thread */
/* usp must be word aligned. This also prevents users from
* passing in the value 1 (which is the signal for a special
* return for a kernel thread) */
if (usp) {
usp = ALIGN(usp, 4);
if (likely(usp))
cregs->gr[30] = usp;
}
cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
cregs->kpc = (unsigned long) &child_return;
/* Setup thread TLS area from the 4th parameter in clone */
if (clone_flags & CLONE_SETTLS)
cregs->cr27 = cregs->gr[23];
}
return 0;
}
unsigned long
get_wchan(struct task_struct *p)
{
struct unwind_frame_info info;
unsigned long ip;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
/*
* These bracket the sleeping functions..
*/
unwind_frame_init_from_blocked_task(&info, p);
do {
if (unwind_once(&info) < 0)
return 0;
ip = info.ip;
if (!in_sched_functions(ip))
return ip;
} while (count++ < MAX_UNWIND_ENTRIES);
return 0;
}
#ifdef CONFIG_64BIT
void *dereference_function_descriptor(void *ptr)
{
Elf64_Fdesc *desc = ptr;
void *p;
if (!probe_kernel_address(&desc->addr, p))
ptr = p;
return ptr;
}
void *dereference_kernel_function_descriptor(void *ptr)
{
if (ptr < (void *)__start_opd ||
ptr >= (void *)__end_opd)
return ptr;
return dereference_function_descriptor(ptr);
}
#endif
static inline unsigned long brk_rnd(void)
{
return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
}
unsigned long arch_randomize_brk(struct mm_struct *mm)
{
unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
if (ret < mm->brk)
return mm->brk;
return ret;
}
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