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 */ 68 void 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 void (*chassis_power_off)(void); 101 102 /* 103 * This routine is called from sys_reboot to actually turn off the 104 * machine 105 */ 106 void machine_power_off(void) 107 { 108 /* If there is a registered power off handler, call it. */ 109 if (chassis_power_off) 110 chassis_power_off(); 111 112 /* Put the soft power button back under hardware control. 113 * If the user had already pressed the power button, the 114 * following call will immediately power off. */ 115 pdc_soft_power_button(0); 116 117 pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN); 118 119 /* ipmi_poweroff may have been installed. */ 120 do_kernel_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 /* 150 * Idle thread support 151 * 152 * Detect when running on QEMU with SeaBIOS PDC Firmware and let 153 * QEMU idle the host too. 154 */ 155 156 int running_on_qemu __ro_after_init; 157 EXPORT_SYMBOL(running_on_qemu); 158 159 /* 160 * Called from the idle thread for the CPU which has been shutdown. 161 */ 162 void __noreturn arch_cpu_idle_dead(void) 163 { 164 #ifdef CONFIG_HOTPLUG_CPU 165 idle_task_exit(); 166 167 local_irq_disable(); 168 169 /* Tell __cpu_die() that this CPU is now safe to dispose of. */ 170 (void)cpu_report_death(); 171 172 /* Ensure that the cache lines are written out. */ 173 flush_cache_all_local(); 174 flush_tlb_all_local(NULL); 175 176 /* Let PDC firmware put CPU into firmware idle loop. */ 177 __pdc_cpu_rendezvous(); 178 179 pr_warn("PDC does not provide rendezvous function.\n"); 180 #endif 181 while (1); 182 } 183 184 void __cpuidle arch_cpu_idle(void) 185 { 186 /* nop on real hardware, qemu will idle sleep. */ 187 asm volatile("or %%r10,%%r10,%%r10\n":::); 188 } 189 190 static int __init parisc_idle_init(void) 191 { 192 if (!running_on_qemu) 193 cpu_idle_poll_ctrl(1); 194 195 return 0; 196 } 197 arch_initcall(parisc_idle_init); 198 199 /* 200 * Copy architecture-specific thread state 201 */ 202 int 203 copy_thread(struct task_struct *p, const struct kernel_clone_args *args) 204 { 205 unsigned long clone_flags = args->flags; 206 unsigned long usp = args->stack; 207 unsigned long tls = args->tls; 208 struct pt_regs *cregs = &(p->thread.regs); 209 void *stack = task_stack_page(p); 210 211 /* We have to use void * instead of a function pointer, because 212 * function pointers aren't a pointer to the function on 64-bit. 213 * Make them const so the compiler knows they live in .text */ 214 extern void * const ret_from_kernel_thread; 215 extern void * const child_return; 216 217 if (unlikely(args->fn)) { 218 /* kernel thread */ 219 memset(cregs, 0, sizeof(struct pt_regs)); 220 if (args->idle) /* idle thread */ 221 return 0; 222 /* Must exit via ret_from_kernel_thread in order 223 * to call schedule_tail() 224 */ 225 cregs->ksp = (unsigned long) stack + FRAME_SIZE + PT_SZ_ALGN; 226 cregs->kpc = (unsigned long) &ret_from_kernel_thread; 227 /* 228 * Copy function and argument to be called from 229 * ret_from_kernel_thread. 230 */ 231 #ifdef CONFIG_64BIT 232 cregs->gr[27] = ((unsigned long *)args->fn)[3]; 233 cregs->gr[26] = ((unsigned long *)args->fn)[2]; 234 #else 235 cregs->gr[26] = (unsigned long) args->fn; 236 #endif 237 cregs->gr[25] = (unsigned long) args->fn_arg; 238 } else { 239 /* user thread */ 240 /* usp must be word aligned. This also prevents users from 241 * passing in the value 1 (which is the signal for a special 242 * return for a kernel thread) */ 243 if (usp) { 244 usp = ALIGN(usp, 4); 245 if (likely(usp)) 246 cregs->gr[30] = usp; 247 } 248 cregs->ksp = (unsigned long) stack + FRAME_SIZE; 249 cregs->kpc = (unsigned long) &child_return; 250 251 /* Setup thread TLS area */ 252 if (clone_flags & CLONE_SETTLS) 253 cregs->cr27 = tls; 254 } 255 256 return 0; 257 } 258 259 unsigned long 260 __get_wchan(struct task_struct *p) 261 { 262 struct unwind_frame_info info; 263 unsigned long ip; 264 int count = 0; 265 266 /* 267 * These bracket the sleeping functions.. 268 */ 269 270 unwind_frame_init_from_blocked_task(&info, p); 271 do { 272 if (unwind_once(&info) < 0) 273 return 0; 274 if (task_is_running(p)) 275 return 0; 276 ip = info.ip; 277 if (!in_sched_functions(ip)) 278 return ip; 279 } while (count++ < MAX_UNWIND_ENTRIES); 280 return 0; 281 } 282 283 static inline unsigned long brk_rnd(void) 284 { 285 return (get_random_u32() & BRK_RND_MASK) << PAGE_SHIFT; 286 } 287 288 unsigned long arch_randomize_brk(struct mm_struct *mm) 289 { 290 unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd()); 291 292 if (ret < mm->brk) 293 return mm->brk; 294 return ret; 295 } 296