1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 * PARISC Architecture-dependent parts of process handling 4 * based on the work for i386 5 * 6 * Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org> 7 * Copyright (C) 2000 Martin K Petersen <mkp at mkp.net> 8 * Copyright (C) 2000 John Marvin <jsm at parisc-linux.org> 9 * Copyright (C) 2000 David Huggins-Daines <dhd with pobox.org> 10 * Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org> 11 * Copyright (C) 2000 Philipp Rumpf <prumpf with tux.org> 12 * Copyright (C) 2000 David Kennedy <dkennedy with linuxcare.com> 13 * Copyright (C) 2000 Richard Hirst <rhirst with parisc-linux.org> 14 * Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org> 15 * Copyright (C) 2001 Alan Modra <amodra at parisc-linux.org> 16 * Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org> 17 * Copyright (C) 2001-2014 Helge Deller <deller@gmx.de> 18 * Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org> 19 */ 20#include <linux/elf.h> 21#include <linux/errno.h> 22#include <linux/kernel.h> 23#include <linux/mm.h> 24#include <linux/fs.h> 25#include <linux/cpu.h> 26#include <linux/module.h> 27#include <linux/personality.h> 28#include <linux/ptrace.h> 29#include <linux/reboot.h> 30#include <linux/sched.h> 31#include <linux/sched/debug.h> 32#include <linux/sched/task.h> 33#include <linux/sched/task_stack.h> 34#include <linux/slab.h> 35#include <linux/stddef.h> 36#include <linux/unistd.h> 37#include <linux/kallsyms.h> 38#include <linux/uaccess.h> 39#include <linux/rcupdate.h> 40#include <linux/random.h> 41#include <linux/nmi.h> 42#include <linux/sched/hotplug.h> 43 44#include <asm/io.h> 45#include <asm/asm-offsets.h> 46#include <asm/assembly.h> 47#include <asm/pdc.h> 48#include <asm/pdc_chassis.h> 49#include <asm/unwind.h> 50#include <asm/sections.h> 51#include <asm/cacheflush.h> 52 53#define COMMAND_GLOBAL F_EXTEND(0xfffe0030) 54#define CMD_RESET 5 /* reset any module */ 55 56/* 57** The Wright Brothers and Gecko systems have a H/W problem 58** (Lasi...'nuf said) may cause a broadcast reset to lockup 59** the system. An HVERSION dependent PDC call was developed 60** to perform a "safe", platform specific broadcast reset instead 61** of kludging up all the code. 62** 63** Older machines which do not implement PDC_BROADCAST_RESET will 64** return (with an error) and the regular broadcast reset can be 65** issued. Obviously, if the PDC does implement PDC_BROADCAST_RESET 66** the PDC call will not return (the system will be reset). 67*/ 68void machine_restart(char *cmd) 69{ 70#ifdef FASTBOOT_SELFTEST_SUPPORT 71 /* 72 ** If user has modified the Firmware Selftest Bitmap, 73 ** run the tests specified in the bitmap after the 74 ** system is rebooted w/PDC_DO_RESET. 75 ** 76 ** ftc_bitmap = 0x1AUL "Skip destructive memory tests" 77 ** 78 ** Using "directed resets" at each processor with the MEM_TOC 79 ** vector cleared will also avoid running destructive 80 ** memory self tests. (Not implemented yet) 81 */ 82 if (ftc_bitmap) { 83 pdc_do_firm_test_reset(ftc_bitmap); 84 } 85#endif 86 /* set up a new led state on systems shipped with a LED State panel */ 87 pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN); 88 89 /* "Normal" system reset */ 90 pdc_do_reset(); 91 92 /* Nope...box should reset with just CMD_RESET now */ 93 gsc_writel(CMD_RESET, COMMAND_GLOBAL); 94 95 /* Wait for RESET to lay us to rest. */ 96 while (1) ; 97 98} 99 100/* 101 * This routine is called from sys_reboot to actually turn off the 102 * machine 103 */ 104void machine_power_off(void) 105{ 106 /* Put the soft power button back under hardware control. 107 * If the user had already pressed the power button, the 108 * following call will immediately power off. */ 109 pdc_soft_power_button(0); 110 111 pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN); 112 113 /* ipmi_poweroff may have been installed. */ 114 do_kernel_power_off(); 115 116 /* It seems we have no way to power the system off via 117 * software. The user has to press the button himself. */ 118 119 printk("Power off or press RETURN to reboot.\n"); 120 121 /* prevent soft lockup/stalled CPU messages for endless loop. */ 122 rcu_sysrq_start(); 123 lockup_detector_soft_poweroff(); 124 while (1) { 125 /* reboot if user presses RETURN key */ 126 if (pdc_iodc_getc() == 13) { 127 printk("Rebooting...\n"); 128 machine_restart(NULL); 129 } 130 } 131} 132 133void (*pm_power_off)(void); 134EXPORT_SYMBOL(pm_power_off); 135 136void machine_halt(void) 137{ 138 machine_power_off(); 139} 140 141void flush_thread(void) 142{ 143 /* Only needs to handle fpu stuff or perf monitors. 144 ** REVISIT: several arches implement a "lazy fpu state". 145 */ 146} 147 148/* 149 * Idle thread support 150 * 151 * Detect when running on QEMU with SeaBIOS PDC Firmware and let 152 * QEMU idle the host too. 153 */ 154 155int running_on_qemu __ro_after_init; 156EXPORT_SYMBOL(running_on_qemu); 157 158/* 159 * Called from the idle thread for the CPU which has been shutdown. 160 */ 161void __noreturn arch_cpu_idle_dead(void) 162{ 163#ifdef CONFIG_HOTPLUG_CPU 164 idle_task_exit(); 165 166 local_irq_disable(); 167 168 /* Tell the core that this CPU is now safe to dispose of. */ 169 cpuhp_ap_report_dead(); 170 171 /* Ensure that the cache lines are written out. */ 172 flush_cache_all_local(); 173 flush_tlb_all_local(NULL); 174 175 /* Let PDC firmware put CPU into firmware idle loop. */ 176 __pdc_cpu_rendezvous(); 177 178 pr_warn("PDC does not provide rendezvous function.\n"); 179#endif 180 while (1); 181} 182 183void __cpuidle arch_cpu_idle(void) 184{ 185 /* nop on real hardware, qemu will idle sleep. */ 186 asm volatile("or %%r10,%%r10,%%r10\n":::); 187} 188 189static int __init parisc_idle_init(void) 190{ 191 if (!running_on_qemu) 192 cpu_idle_poll_ctrl(1); 193 194 return 0; 195} 196arch_initcall(parisc_idle_init); 197 198/* 199 * Copy architecture-specific thread state 200 */ 201int 202copy_thread(struct task_struct *p, const struct kernel_clone_args *args) 203{ 204 unsigned long clone_flags = args->flags; 205 unsigned long usp = args->stack; 206 unsigned long tls = args->tls; 207 struct pt_regs *cregs = &(p->thread.regs); 208 void *stack = task_stack_page(p); 209 210 /* We have to use void * instead of a function pointer, because 211 * function pointers aren't a pointer to the function on 64-bit. 212 * Make them const so the compiler knows they live in .text */ 213 extern void * const ret_from_kernel_thread; 214 extern void * const child_return; 215 216 if (unlikely(args->fn)) { 217 /* kernel thread */ 218 memset(cregs, 0, sizeof(struct pt_regs)); 219 if (args->idle) /* idle thread */ 220 return 0; 221 /* Must exit via ret_from_kernel_thread in order 222 * to call schedule_tail() 223 */ 224 cregs->ksp = (unsigned long) stack + FRAME_SIZE + PT_SZ_ALGN; 225 cregs->kpc = (unsigned long) &ret_from_kernel_thread; 226 /* 227 * Copy function and argument to be called from 228 * ret_from_kernel_thread. 229 */ 230#ifdef CONFIG_64BIT 231 cregs->gr[27] = ((unsigned long *)args->fn)[3]; 232 cregs->gr[26] = ((unsigned long *)args->fn)[2]; 233#else 234 cregs->gr[26] = (unsigned long) args->fn; 235#endif 236 cregs->gr[25] = (unsigned long) args->fn_arg; 237 } else { 238 /* user thread */ 239 /* usp must be word aligned. This also prevents users from 240 * passing in the value 1 (which is the signal for a special 241 * return for a kernel thread) */ 242 if (usp) { 243 usp = ALIGN(usp, 4); 244 if (likely(usp)) 245 cregs->gr[30] = usp; 246 } 247 cregs->ksp = (unsigned long) stack + FRAME_SIZE; 248 cregs->kpc = (unsigned long) &child_return; 249 250 /* Setup thread TLS area */ 251 if (clone_flags & CLONE_SETTLS) 252 cregs->cr27 = tls; 253 } 254 255 return 0; 256} 257 258unsigned long 259__get_wchan(struct task_struct *p) 260{ 261 struct unwind_frame_info info; 262 unsigned long ip; 263 int count = 0; 264 265 /* 266 * These bracket the sleeping functions.. 267 */ 268 269 unwind_frame_init_from_blocked_task(&info, p); 270 do { 271 if (unwind_once(&info) < 0) 272 return 0; 273 if (task_is_running(p)) 274 return 0; 275 ip = info.ip; 276 if (!in_sched_functions(ip)) 277 return ip; 278 } while (count++ < MAX_UNWIND_ENTRIES); 279 return 0; 280} 281