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 42 #include <asm/io.h> 43 #include <asm/asm-offsets.h> 44 #include <asm/assembly.h> 45 #include <asm/pdc.h> 46 #include <asm/pdc_chassis.h> 47 #include <asm/unwind.h> 48 #include <asm/sections.h> 49 50 #define COMMAND_GLOBAL F_EXTEND(0xfffe0030) 51 #define CMD_RESET 5 /* reset any module */ 52 53 /* 54 ** The Wright Brothers and Gecko systems have a H/W problem 55 ** (Lasi...'nuf said) may cause a broadcast reset to lockup 56 ** the system. An HVERSION dependent PDC call was developed 57 ** to perform a "safe", platform specific broadcast reset instead 58 ** of kludging up all the code. 59 ** 60 ** Older machines which do not implement PDC_BROADCAST_RESET will 61 ** return (with an error) and the regular broadcast reset can be 62 ** issued. Obviously, if the PDC does implement PDC_BROADCAST_RESET 63 ** the PDC call will not return (the system will be reset). 64 */ 65 void machine_restart(char *cmd) 66 { 67 #ifdef FASTBOOT_SELFTEST_SUPPORT 68 /* 69 ** If user has modified the Firmware Selftest Bitmap, 70 ** run the tests specified in the bitmap after the 71 ** system is rebooted w/PDC_DO_RESET. 72 ** 73 ** ftc_bitmap = 0x1AUL "Skip destructive memory tests" 74 ** 75 ** Using "directed resets" at each processor with the MEM_TOC 76 ** vector cleared will also avoid running destructive 77 ** memory self tests. (Not implemented yet) 78 */ 79 if (ftc_bitmap) { 80 pdc_do_firm_test_reset(ftc_bitmap); 81 } 82 #endif 83 /* set up a new led state on systems shipped with a LED State panel */ 84 pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN); 85 86 /* "Normal" system reset */ 87 pdc_do_reset(); 88 89 /* Nope...box should reset with just CMD_RESET now */ 90 gsc_writel(CMD_RESET, COMMAND_GLOBAL); 91 92 /* Wait for RESET to lay us to rest. */ 93 while (1) ; 94 95 } 96 97 void (*chassis_power_off)(void); 98 99 /* 100 * This routine is called from sys_reboot to actually turn off the 101 * machine 102 */ 103 void machine_power_off(void) 104 { 105 /* If there is a registered power off handler, call it. */ 106 if (chassis_power_off) 107 chassis_power_off(); 108 109 /* Put the soft power button back under hardware control. 110 * If the user had already pressed the power button, the 111 * following call will immediately power off. */ 112 pdc_soft_power_button(0); 113 114 pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN); 115 116 /* ipmi_poweroff may have been installed. */ 117 if (pm_power_off) 118 pm_power_off(); 119 120 /* It seems we have no way to power the system off via 121 * software. The user has to press the button himself. */ 122 123 printk(KERN_EMERG "System shut down completed.\n" 124 "Please power this system off now."); 125 126 /* prevent soft lockup/stalled CPU messages for endless loop. */ 127 rcu_sysrq_start(); 128 lockup_detector_soft_poweroff(); 129 for (;;); 130 } 131 132 void (*pm_power_off)(void); 133 EXPORT_SYMBOL(pm_power_off); 134 135 void machine_halt(void) 136 { 137 machine_power_off(); 138 } 139 140 void flush_thread(void) 141 { 142 /* Only needs to handle fpu stuff or perf monitors. 143 ** REVISIT: several arches implement a "lazy fpu state". 144 */ 145 } 146 147 void release_thread(struct task_struct *dead_task) 148 { 149 } 150 151 /* 152 * Idle thread support 153 * 154 * Detect when running on QEMU with SeaBIOS PDC Firmware and let 155 * QEMU idle the host too. 156 */ 157 158 int running_on_qemu __ro_after_init; 159 EXPORT_SYMBOL(running_on_qemu); 160 161 void __cpuidle arch_cpu_idle_dead(void) 162 { 163 /* nop on real hardware, qemu will offline CPU. */ 164 asm volatile("or %%r31,%%r31,%%r31\n":::); 165 } 166 167 void __cpuidle arch_cpu_idle(void) 168 { 169 raw_local_irq_enable(); 170 171 /* nop on real hardware, qemu will idle sleep. */ 172 asm volatile("or %%r10,%%r10,%%r10\n":::); 173 } 174 175 static int __init parisc_idle_init(void) 176 { 177 if (!running_on_qemu) 178 cpu_idle_poll_ctrl(1); 179 180 return 0; 181 } 182 arch_initcall(parisc_idle_init); 183 184 /* 185 * Copy architecture-specific thread state 186 */ 187 int 188 copy_thread(unsigned long clone_flags, unsigned long usp, 189 unsigned long kthread_arg, struct task_struct *p, unsigned long tls) 190 { 191 struct pt_regs *cregs = &(p->thread.regs); 192 void *stack = task_stack_page(p); 193 194 /* We have to use void * instead of a function pointer, because 195 * function pointers aren't a pointer to the function on 64-bit. 196 * Make them const so the compiler knows they live in .text */ 197 extern void * const ret_from_kernel_thread; 198 extern void * const child_return; 199 200 if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) { 201 /* kernel thread */ 202 memset(cregs, 0, sizeof(struct pt_regs)); 203 if (!usp) /* idle thread */ 204 return 0; 205 /* Must exit via ret_from_kernel_thread in order 206 * to call schedule_tail() 207 */ 208 cregs->ksp = (unsigned long) stack + FRAME_SIZE + PT_SZ_ALGN; 209 cregs->kpc = (unsigned long) &ret_from_kernel_thread; 210 /* 211 * Copy function and argument to be called from 212 * ret_from_kernel_thread. 213 */ 214 #ifdef CONFIG_64BIT 215 cregs->gr[27] = ((unsigned long *)usp)[3]; 216 cregs->gr[26] = ((unsigned long *)usp)[2]; 217 #else 218 cregs->gr[26] = usp; 219 #endif 220 cregs->gr[25] = kthread_arg; 221 } else { 222 /* user thread */ 223 /* usp must be word aligned. This also prevents users from 224 * passing in the value 1 (which is the signal for a special 225 * return for a kernel thread) */ 226 if (usp) { 227 usp = ALIGN(usp, 4); 228 if (likely(usp)) 229 cregs->gr[30] = usp; 230 } 231 cregs->ksp = (unsigned long) stack + FRAME_SIZE; 232 cregs->kpc = (unsigned long) &child_return; 233 234 /* Setup thread TLS area */ 235 if (clone_flags & CLONE_SETTLS) 236 cregs->cr27 = tls; 237 } 238 239 return 0; 240 } 241 242 unsigned long 243 __get_wchan(struct task_struct *p) 244 { 245 struct unwind_frame_info info; 246 unsigned long ip; 247 int count = 0; 248 249 /* 250 * These bracket the sleeping functions.. 251 */ 252 253 unwind_frame_init_from_blocked_task(&info, p); 254 do { 255 if (unwind_once(&info) < 0) 256 return 0; 257 if (task_is_running(p)) 258 return 0; 259 ip = info.ip; 260 if (!in_sched_functions(ip)) 261 return ip; 262 } while (count++ < MAX_UNWIND_ENTRIES); 263 return 0; 264 } 265 266 #ifdef CONFIG_64BIT 267 void *dereference_function_descriptor(void *ptr) 268 { 269 Elf64_Fdesc *desc = ptr; 270 void *p; 271 272 if (!get_kernel_nofault(p, (void *)&desc->addr)) 273 ptr = p; 274 return ptr; 275 } 276 277 void *dereference_kernel_function_descriptor(void *ptr) 278 { 279 if (ptr < (void *)__start_opd || 280 ptr >= (void *)__end_opd) 281 return ptr; 282 283 return dereference_function_descriptor(ptr); 284 } 285 #endif 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