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 <[email protected]> 18 * Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org> 19 */ 20 21 #include <stdarg.h> 22 23 #include <linux/elf.h> 24 #include <linux/errno.h> 25 #include <linux/kernel.h> 26 #include <linux/mm.h> 27 #include <linux/fs.h> 28 #include <linux/cpu.h> 29 #include <linux/module.h> 30 #include <linux/personality.h> 31 #include <linux/ptrace.h> 32 #include <linux/sched.h> 33 #include <linux/sched/debug.h> 34 #include <linux/sched/task.h> 35 #include <linux/sched/task_stack.h> 36 #include <linux/slab.h> 37 #include <linux/stddef.h> 38 #include <linux/unistd.h> 39 #include <linux/kallsyms.h> 40 #include <linux/uaccess.h> 41 #include <linux/rcupdate.h> 42 #include <linux/random.h> 43 #include <linux/nmi.h> 44 45 #include <asm/io.h> 46 #include <asm/asm-offsets.h> 47 #include <asm/assembly.h> 48 #include <asm/pdc.h> 49 #include <asm/pdc_chassis.h> 50 #include <asm/pgalloc.h> 51 #include <asm/unwind.h> 52 #include <asm/sections.h> 53 54 #define COMMAND_GLOBAL F_EXTEND(0xfffe0030) 55 #define CMD_RESET 5 /* reset any module */ 56 57 /* 58 ** The Wright Brothers and Gecko systems have a H/W problem 59 ** (Lasi...'nuf said) may cause a broadcast reset to lockup 60 ** the system. An HVERSION dependent PDC call was developed 61 ** to perform a "safe", platform specific broadcast reset instead 62 ** of kludging up all the code. 63 ** 64 ** Older machines which do not implement PDC_BROADCAST_RESET will 65 ** return (with an error) and the regular broadcast reset can be 66 ** issued. Obviously, if the PDC does implement PDC_BROADCAST_RESET 67 ** the PDC call will not return (the system will be reset). 68 */ 69 void machine_restart(char *cmd) 70 { 71 #ifdef FASTBOOT_SELFTEST_SUPPORT 72 /* 73 ** If user has modified the Firmware Selftest Bitmap, 74 ** run the tests specified in the bitmap after the 75 ** system is rebooted w/PDC_DO_RESET. 76 ** 77 ** ftc_bitmap = 0x1AUL "Skip destructive memory tests" 78 ** 79 ** Using "directed resets" at each processor with the MEM_TOC 80 ** vector cleared will also avoid running destructive 81 ** memory self tests. (Not implemented yet) 82 */ 83 if (ftc_bitmap) { 84 pdc_do_firm_test_reset(ftc_bitmap); 85 } 86 #endif 87 /* set up a new led state on systems shipped with a LED State panel */ 88 pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN); 89 90 /* "Normal" system reset */ 91 pdc_do_reset(); 92 93 /* Nope...box should reset with just CMD_RESET now */ 94 gsc_writel(CMD_RESET, COMMAND_GLOBAL); 95 96 /* Wait for RESET to lay us to rest. */ 97 while (1) ; 98 99 } 100 101 void (*chassis_power_off)(void); 102 103 /* 104 * This routine is called from sys_reboot to actually turn off the 105 * machine 106 */ 107 void machine_power_off(void) 108 { 109 /* If there is a registered power off handler, call it. */ 110 if (chassis_power_off) 111 chassis_power_off(); 112 113 /* Put the soft power button back under hardware control. 114 * If the user had already pressed the power button, the 115 * following call will immediately power off. */ 116 pdc_soft_power_button(0); 117 118 pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN); 119 120 /* ipmi_poweroff may have been installed. */ 121 if (pm_power_off) 122 pm_power_off(); 123 124 /* It seems we have no way to power the system off via 125 * software. The user has to press the button himself. */ 126 127 printk(KERN_EMERG "System shut down completed.\n" 128 "Please power this system off now."); 129 130 /* prevent soft lockup/stalled CPU messages for endless loop. */ 131 rcu_sysrq_start(); 132 lockup_detector_soft_poweroff(); 133 for (;;); 134 } 135 136 void (*pm_power_off)(void); 137 EXPORT_SYMBOL(pm_power_off); 138 139 void machine_halt(void) 140 { 141 machine_power_off(); 142 } 143 144 void flush_thread(void) 145 { 146 /* Only needs to handle fpu stuff or perf monitors. 147 ** REVISIT: several arches implement a "lazy fpu state". 148 */ 149 } 150 151 void release_thread(struct task_struct *dead_task) 152 { 153 } 154 155 /* 156 * Idle thread support 157 * 158 * Detect when running on QEMU with SeaBIOS PDC Firmware and let 159 * QEMU idle the host too. 160 */ 161 162 int running_on_qemu __ro_after_init; 163 EXPORT_SYMBOL(running_on_qemu); 164 165 void __cpuidle arch_cpu_idle_dead(void) 166 { 167 /* nop on real hardware, qemu will offline CPU. */ 168 asm volatile("or %%r31,%%r31,%%r31\n":::); 169 } 170 171 void __cpuidle arch_cpu_idle(void) 172 { 173 local_irq_enable(); 174 175 /* nop on real hardware, qemu will idle sleep. */ 176 asm volatile("or %%r10,%%r10,%%r10\n":::); 177 } 178 179 static int __init parisc_idle_init(void) 180 { 181 if (!running_on_qemu) 182 cpu_idle_poll_ctrl(1); 183 184 return 0; 185 } 186 arch_initcall(parisc_idle_init); 187 188 /* 189 * Copy architecture-specific thread state 190 */ 191 int 192 copy_thread_tls(unsigned long clone_flags, unsigned long usp, 193 unsigned long kthread_arg, struct task_struct *p, unsigned long tls) 194 { 195 struct pt_regs *cregs = &(p->thread.regs); 196 void *stack = task_stack_page(p); 197 198 /* We have to use void * instead of a function pointer, because 199 * function pointers aren't a pointer to the function on 64-bit. 200 * Make them const so the compiler knows they live in .text */ 201 extern void * const ret_from_kernel_thread; 202 extern void * const child_return; 203 204 if (unlikely(p->flags & PF_KTHREAD)) { 205 /* kernel thread */ 206 memset(cregs, 0, sizeof(struct pt_regs)); 207 if (!usp) /* idle thread */ 208 return 0; 209 /* Must exit via ret_from_kernel_thread in order 210 * to call schedule_tail() 211 */ 212 cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE; 213 cregs->kpc = (unsigned long) &ret_from_kernel_thread; 214 /* 215 * Copy function and argument to be called from 216 * ret_from_kernel_thread. 217 */ 218 #ifdef CONFIG_64BIT 219 cregs->gr[27] = ((unsigned long *)usp)[3]; 220 cregs->gr[26] = ((unsigned long *)usp)[2]; 221 #else 222 cregs->gr[26] = usp; 223 #endif 224 cregs->gr[25] = kthread_arg; 225 } else { 226 /* user thread */ 227 /* usp must be word aligned. This also prevents users from 228 * passing in the value 1 (which is the signal for a special 229 * return for a kernel thread) */ 230 if (usp) { 231 usp = ALIGN(usp, 4); 232 if (likely(usp)) 233 cregs->gr[30] = usp; 234 } 235 cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE; 236 cregs->kpc = (unsigned long) &child_return; 237 238 /* Setup thread TLS area */ 239 if (clone_flags & CLONE_SETTLS) 240 cregs->cr27 = tls; 241 } 242 243 return 0; 244 } 245 246 unsigned long 247 get_wchan(struct task_struct *p) 248 { 249 struct unwind_frame_info info; 250 unsigned long ip; 251 int count = 0; 252 253 if (!p || p == current || p->state == TASK_RUNNING) 254 return 0; 255 256 /* 257 * These bracket the sleeping functions.. 258 */ 259 260 unwind_frame_init_from_blocked_task(&info, p); 261 do { 262 if (unwind_once(&info) < 0) 263 return 0; 264 ip = info.ip; 265 if (!in_sched_functions(ip)) 266 return ip; 267 } while (count++ < MAX_UNWIND_ENTRIES); 268 return 0; 269 } 270 271 #ifdef CONFIG_64BIT 272 void *dereference_function_descriptor(void *ptr) 273 { 274 Elf64_Fdesc *desc = ptr; 275 void *p; 276 277 if (!probe_kernel_address(&desc->addr, p)) 278 ptr = p; 279 return ptr; 280 } 281 282 void *dereference_kernel_function_descriptor(void *ptr) 283 { 284 if (ptr < (void *)__start_opd || 285 ptr >= (void *)__end_opd) 286 return ptr; 287 288 return dereference_function_descriptor(ptr); 289 } 290 #endif 291 292 static inline unsigned long brk_rnd(void) 293 { 294 return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT; 295 } 296 297 unsigned long arch_randomize_brk(struct mm_struct *mm) 298 { 299 unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd()); 300 301 if (ret < mm->brk) 302 return mm->brk; 303 return ret; 304 } 305