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/sched.h> 30 #include <linux/sched/debug.h> 31 #include <linux/sched/task.h> 32 #include <linux/sched/task_stack.h> 33 #include <linux/slab.h> 34 #include <linux/stddef.h> 35 #include <linux/unistd.h> 36 #include <linux/kallsyms.h> 37 #include <linux/uaccess.h> 38 #include <linux/rcupdate.h> 39 #include <linux/random.h> 40 #include <linux/nmi.h> 41 #include <linux/sched/hotplug.h> 42 43 #include <asm/io.h> 44 #include <asm/asm-offsets.h> 45 #include <asm/assembly.h> 46 #include <asm/pdc.h> 47 #include <asm/pdc_chassis.h> 48 #include <asm/unwind.h> 49 #include <asm/sections.h> 50 #include <asm/cacheflush.h> 51 52 #define COMMAND_GLOBAL F_EXTEND(0xfffe0030) 53 #define CMD_RESET 5 /* reset any module */ 54 55 /* 56 ** The Wright Brothers and Gecko systems have a H/W problem 57 ** (Lasi...'nuf said) may cause a broadcast reset to lockup 58 ** the system. An HVERSION dependent PDC call was developed 59 ** to perform a "safe", platform specific broadcast reset instead 60 ** of kludging up all the code. 61 ** 62 ** Older machines which do not implement PDC_BROADCAST_RESET will 63 ** return (with an error) and the regular broadcast reset can be 64 ** issued. Obviously, if the PDC does implement PDC_BROADCAST_RESET 65 ** the PDC call will not return (the system will be reset). 66 */ 67 void machine_restart(char *cmd) 68 { 69 #ifdef FASTBOOT_SELFTEST_SUPPORT 70 /* 71 ** If user has modified the Firmware Selftest Bitmap, 72 ** run the tests specified in the bitmap after the 73 ** system is rebooted w/PDC_DO_RESET. 74 ** 75 ** ftc_bitmap = 0x1AUL "Skip destructive memory tests" 76 ** 77 ** Using "directed resets" at each processor with the MEM_TOC 78 ** vector cleared will also avoid running destructive 79 ** memory self tests. (Not implemented yet) 80 */ 81 if (ftc_bitmap) { 82 pdc_do_firm_test_reset(ftc_bitmap); 83 } 84 #endif 85 /* set up a new led state on systems shipped with a LED State panel */ 86 pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN); 87 88 /* "Normal" system reset */ 89 pdc_do_reset(); 90 91 /* Nope...box should reset with just CMD_RESET now */ 92 gsc_writel(CMD_RESET, COMMAND_GLOBAL); 93 94 /* Wait for RESET to lay us to rest. */ 95 while (1) ; 96 97 } 98 99 void (*chassis_power_off)(void); 100 101 /* 102 * This routine is called from sys_reboot to actually turn off the 103 * machine 104 */ 105 void machine_power_off(void) 106 { 107 /* If there is a registered power off handler, call it. */ 108 if (chassis_power_off) 109 chassis_power_off(); 110 111 /* Put the soft power button back under hardware control. 112 * If the user had already pressed the power button, the 113 * following call will immediately power off. */ 114 pdc_soft_power_button(0); 115 116 pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN); 117 118 /* ipmi_poweroff may have been installed. */ 119 if (pm_power_off) 120 pm_power_off(); 121 122 /* It seems we have no way to power the system off via 123 * software. The user has to press the button himself. */ 124 125 printk(KERN_EMERG "System shut down completed.\n" 126 "Please power this system off now."); 127 128 /* prevent soft lockup/stalled CPU messages for endless loop. */ 129 rcu_sysrq_start(); 130 lockup_detector_soft_poweroff(); 131 for (;;); 132 } 133 134 void (*pm_power_off)(void); 135 EXPORT_SYMBOL(pm_power_off); 136 137 void machine_halt(void) 138 { 139 machine_power_off(); 140 } 141 142 void flush_thread(void) 143 { 144 /* Only needs to handle fpu stuff or perf monitors. 145 ** REVISIT: several arches implement a "lazy fpu state". 146 */ 147 } 148 149 void release_thread(struct task_struct *dead_task) 150 { 151 } 152 153 /* 154 * Idle thread support 155 * 156 * Detect when running on QEMU with SeaBIOS PDC Firmware and let 157 * QEMU idle the host too. 158 */ 159 160 int running_on_qemu __ro_after_init; 161 EXPORT_SYMBOL(running_on_qemu); 162 163 /* 164 * Called from the idle thread for the CPU which has been shutdown. 165 */ 166 void arch_cpu_idle_dead(void) 167 { 168 #ifdef CONFIG_HOTPLUG_CPU 169 idle_task_exit(); 170 171 local_irq_disable(); 172 173 /* Tell __cpu_die() that this CPU is now safe to dispose of. */ 174 (void)cpu_report_death(); 175 176 /* Ensure that the cache lines are written out. */ 177 flush_cache_all_local(); 178 flush_tlb_all_local(NULL); 179 180 /* Let PDC firmware put CPU into firmware idle loop. */ 181 __pdc_cpu_rendezvous(); 182 183 pr_warn("PDC does not provide rendezvous function.\n"); 184 #endif 185 while (1); 186 } 187 188 void __cpuidle arch_cpu_idle(void) 189 { 190 raw_local_irq_enable(); 191 192 /* nop on real hardware, qemu will idle sleep. */ 193 asm volatile("or %%r10,%%r10,%%r10\n":::); 194 } 195 196 static int __init parisc_idle_init(void) 197 { 198 if (!running_on_qemu) 199 cpu_idle_poll_ctrl(1); 200 201 return 0; 202 } 203 arch_initcall(parisc_idle_init); 204 205 /* 206 * Copy architecture-specific thread state 207 */ 208 int 209 copy_thread(unsigned long clone_flags, unsigned long usp, 210 unsigned long kthread_arg, struct task_struct *p, unsigned long tls) 211 { 212 struct pt_regs *cregs = &(p->thread.regs); 213 void *stack = task_stack_page(p); 214 215 /* We have to use void * instead of a function pointer, because 216 * function pointers aren't a pointer to the function on 64-bit. 217 * Make them const so the compiler knows they live in .text */ 218 extern void * const ret_from_kernel_thread; 219 extern void * const child_return; 220 221 if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) { 222 /* kernel thread */ 223 memset(cregs, 0, sizeof(struct pt_regs)); 224 if (!usp) /* idle thread */ 225 return 0; 226 /* Must exit via ret_from_kernel_thread in order 227 * to call schedule_tail() 228 */ 229 cregs->ksp = (unsigned long) stack + FRAME_SIZE + PT_SZ_ALGN; 230 cregs->kpc = (unsigned long) &ret_from_kernel_thread; 231 /* 232 * Copy function and argument to be called from 233 * ret_from_kernel_thread. 234 */ 235 #ifdef CONFIG_64BIT 236 cregs->gr[27] = ((unsigned long *)usp)[3]; 237 cregs->gr[26] = ((unsigned long *)usp)[2]; 238 #else 239 cregs->gr[26] = usp; 240 #endif 241 cregs->gr[25] = kthread_arg; 242 } else { 243 /* user thread */ 244 /* usp must be word aligned. This also prevents users from 245 * passing in the value 1 (which is the signal for a special 246 * return for a kernel thread) */ 247 if (usp) { 248 usp = ALIGN(usp, 4); 249 if (likely(usp)) 250 cregs->gr[30] = usp; 251 } 252 cregs->ksp = (unsigned long) stack + FRAME_SIZE; 253 cregs->kpc = (unsigned long) &child_return; 254 255 /* Setup thread TLS area */ 256 if (clone_flags & CLONE_SETTLS) 257 cregs->cr27 = tls; 258 } 259 260 return 0; 261 } 262 263 unsigned long 264 __get_wchan(struct task_struct *p) 265 { 266 struct unwind_frame_info info; 267 unsigned long ip; 268 int count = 0; 269 270 /* 271 * These bracket the sleeping functions.. 272 */ 273 274 unwind_frame_init_from_blocked_task(&info, p); 275 do { 276 if (unwind_once(&info) < 0) 277 return 0; 278 if (task_is_running(p)) 279 return 0; 280 ip = info.ip; 281 if (!in_sched_functions(ip)) 282 return ip; 283 } while (count++ < MAX_UNWIND_ENTRIES); 284 return 0; 285 } 286 287 static inline unsigned long brk_rnd(void) 288 { 289 return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT; 290 } 291 292 unsigned long arch_randomize_brk(struct mm_struct *mm) 293 { 294 unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd()); 295 296 if (ret < mm->brk) 297 return mm->brk; 298 return ret; 299 } 300