process.c 10 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * linux/arch/arm/kernel/process.c
  4. *
  5. * Copyright (C) 1996-2000 Russell King - Converted to ARM.
  6. * Original Copyright (C) 1995 Linus Torvalds
  7. */
  8. #include <stdarg.h>
  9. #include <linux/export.h>
  10. #include <linux/sched.h>
  11. #include <linux/sched/debug.h>
  12. #include <linux/sched/task.h>
  13. #include <linux/sched/task_stack.h>
  14. #include <linux/kernel.h>
  15. #include <linux/mm.h>
  16. #include <linux/stddef.h>
  17. #include <linux/unistd.h>
  18. #include <linux/user.h>
  19. #include <linux/interrupt.h>
  20. #include <linux/init.h>
  21. #include <linux/elfcore.h>
  22. #include <linux/pm.h>
  23. #include <linux/tick.h>
  24. #include <linux/utsname.h>
  25. #include <linux/uaccess.h>
  26. #include <linux/random.h>
  27. #include <linux/hw_breakpoint.h>
  28. #include <linux/leds.h>
  29. #include <asm/processor.h>
  30. #include <asm/thread_notify.h>
  31. #include <asm/stacktrace.h>
  32. #include <asm/system_misc.h>
  33. #include <asm/mach/time.h>
  34. #include <asm/tls.h>
  35. #include <asm/vdso.h>
  36. #include "signal.h"
  37. #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK)
  38. #include <linux/stackprotector.h>
  39. unsigned long __stack_chk_guard __read_mostly;
  40. EXPORT_SYMBOL(__stack_chk_guard);
  41. #endif
  42. static const char *processor_modes[] __maybe_unused = {
  43. "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
  44. "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
  45. "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "MON_32" , "ABT_32" ,
  46. "UK8_32" , "UK9_32" , "HYP_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
  47. };
  48. static const char *isa_modes[] __maybe_unused = {
  49. "ARM" , "Thumb" , "Jazelle", "ThumbEE"
  50. };
  51. /*
  52. * This is our default idle handler.
  53. */
  54. void (*arm_pm_idle)(void);
  55. /*
  56. * Called from the core idle loop.
  57. */
  58. void arch_cpu_idle(void)
  59. {
  60. if (arm_pm_idle)
  61. arm_pm_idle();
  62. else
  63. cpu_do_idle();
  64. raw_local_irq_enable();
  65. }
  66. void arch_cpu_idle_prepare(void)
  67. {
  68. local_fiq_enable();
  69. }
  70. void arch_cpu_idle_enter(void)
  71. {
  72. ledtrig_cpu(CPU_LED_IDLE_START);
  73. #ifdef CONFIG_PL310_ERRATA_769419
  74. wmb();
  75. #endif
  76. }
  77. void arch_cpu_idle_exit(void)
  78. {
  79. ledtrig_cpu(CPU_LED_IDLE_END);
  80. }
  81. void __show_regs(struct pt_regs *regs)
  82. {
  83. unsigned long flags;
  84. char buf[64];
  85. #ifndef CONFIG_CPU_V7M
  86. unsigned int domain, fs;
  87. #ifdef CONFIG_CPU_SW_DOMAIN_PAN
  88. /*
  89. * Get the domain register for the parent context. In user
  90. * mode, we don't save the DACR, so lets use what it should
  91. * be. For other modes, we place it after the pt_regs struct.
  92. */
  93. if (user_mode(regs)) {
  94. domain = DACR_UACCESS_ENABLE;
  95. fs = get_fs();
  96. } else {
  97. domain = to_svc_pt_regs(regs)->dacr;
  98. fs = to_svc_pt_regs(regs)->addr_limit;
  99. }
  100. #else
  101. domain = get_domain();
  102. fs = get_fs();
  103. #endif
  104. #endif
  105. show_regs_print_info(KERN_DEFAULT);
  106. printk("PC is at %pS\n", (void *)instruction_pointer(regs));
  107. printk("LR is at %pS\n", (void *)regs->ARM_lr);
  108. printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n",
  109. regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr);
  110. printk("sp : %08lx ip : %08lx fp : %08lx\n",
  111. regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
  112. printk("r10: %08lx r9 : %08lx r8 : %08lx\n",
  113. regs->ARM_r10, regs->ARM_r9,
  114. regs->ARM_r8);
  115. printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
  116. regs->ARM_r7, regs->ARM_r6,
  117. regs->ARM_r5, regs->ARM_r4);
  118. printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
  119. regs->ARM_r3, regs->ARM_r2,
  120. regs->ARM_r1, regs->ARM_r0);
  121. flags = regs->ARM_cpsr;
  122. buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
  123. buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
  124. buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
  125. buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
  126. buf[4] = '\0';
  127. #ifndef CONFIG_CPU_V7M
  128. {
  129. const char *segment;
  130. if ((domain & domain_mask(DOMAIN_USER)) ==
  131. domain_val(DOMAIN_USER, DOMAIN_NOACCESS))
  132. segment = "none";
  133. else if (fs == KERNEL_DS)
  134. segment = "kernel";
  135. else
  136. segment = "user";
  137. printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n",
  138. buf, interrupts_enabled(regs) ? "n" : "ff",
  139. fast_interrupts_enabled(regs) ? "n" : "ff",
  140. processor_modes[processor_mode(regs)],
  141. isa_modes[isa_mode(regs)], segment);
  142. }
  143. #else
  144. printk("xPSR: %08lx\n", regs->ARM_cpsr);
  145. #endif
  146. #ifdef CONFIG_CPU_CP15
  147. {
  148. unsigned int ctrl;
  149. buf[0] = '\0';
  150. #ifdef CONFIG_CPU_CP15_MMU
  151. {
  152. unsigned int transbase;
  153. asm("mrc p15, 0, %0, c2, c0\n\t"
  154. : "=r" (transbase));
  155. snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x",
  156. transbase, domain);
  157. }
  158. #endif
  159. asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
  160. printk("Control: %08x%s\n", ctrl, buf);
  161. }
  162. #endif
  163. }
  164. void show_regs(struct pt_regs * regs)
  165. {
  166. __show_regs(regs);
  167. dump_stack();
  168. }
  169. ATOMIC_NOTIFIER_HEAD(thread_notify_head);
  170. EXPORT_SYMBOL_GPL(thread_notify_head);
  171. /*
  172. * Free current thread data structures etc..
  173. */
  174. void exit_thread(struct task_struct *tsk)
  175. {
  176. thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk));
  177. }
  178. void flush_thread(void)
  179. {
  180. struct thread_info *thread = current_thread_info();
  181. struct task_struct *tsk = current;
  182. flush_ptrace_hw_breakpoint(tsk);
  183. memset(thread->used_cp, 0, sizeof(thread->used_cp));
  184. memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
  185. memset(&thread->fpstate, 0, sizeof(union fp_state));
  186. flush_tls();
  187. thread_notify(THREAD_NOTIFY_FLUSH, thread);
  188. }
  189. void release_thread(struct task_struct *dead_task)
  190. {
  191. }
  192. asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
  193. int copy_thread(unsigned long clone_flags, unsigned long stack_start,
  194. unsigned long stk_sz, struct task_struct *p, unsigned long tls)
  195. {
  196. struct thread_info *thread = task_thread_info(p);
  197. struct pt_regs *childregs = task_pt_regs(p);
  198. memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
  199. #ifdef CONFIG_CPU_USE_DOMAINS
  200. /*
  201. * Copy the initial value of the domain access control register
  202. * from the current thread: thread->addr_limit will have been
  203. * copied from the current thread via setup_thread_stack() in
  204. * kernel/fork.c
  205. */
  206. thread->cpu_domain = get_domain();
  207. #endif
  208. if (likely(!(p->flags & PF_KTHREAD))) {
  209. *childregs = *current_pt_regs();
  210. childregs->ARM_r0 = 0;
  211. if (stack_start)
  212. childregs->ARM_sp = stack_start;
  213. } else {
  214. memset(childregs, 0, sizeof(struct pt_regs));
  215. thread->cpu_context.r4 = stk_sz;
  216. thread->cpu_context.r5 = stack_start;
  217. childregs->ARM_cpsr = SVC_MODE;
  218. }
  219. thread->cpu_context.pc = (unsigned long)ret_from_fork;
  220. thread->cpu_context.sp = (unsigned long)childregs;
  221. clear_ptrace_hw_breakpoint(p);
  222. if (clone_flags & CLONE_SETTLS)
  223. thread->tp_value[0] = tls;
  224. thread->tp_value[1] = get_tpuser();
  225. thread_notify(THREAD_NOTIFY_COPY, thread);
  226. #ifdef CONFIG_STACKPROTECTOR_PER_TASK
  227. thread->stack_canary = p->stack_canary;
  228. #endif
  229. return 0;
  230. }
  231. /*
  232. * Fill in the task's elfregs structure for a core dump.
  233. */
  234. int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
  235. {
  236. elf_core_copy_regs(elfregs, task_pt_regs(t));
  237. return 1;
  238. }
  239. unsigned long get_wchan(struct task_struct *p)
  240. {
  241. struct stackframe frame;
  242. unsigned long stack_page;
  243. int count = 0;
  244. if (!p || p == current || p->state == TASK_RUNNING)
  245. return 0;
  246. frame.fp = thread_saved_fp(p);
  247. frame.sp = thread_saved_sp(p);
  248. frame.lr = 0; /* recovered from the stack */
  249. frame.pc = thread_saved_pc(p);
  250. stack_page = (unsigned long)task_stack_page(p);
  251. do {
  252. if (frame.sp < stack_page ||
  253. frame.sp >= stack_page + THREAD_SIZE ||
  254. unwind_frame(&frame) < 0)
  255. return 0;
  256. if (!in_sched_functions(frame.pc))
  257. return frame.pc;
  258. } while (count ++ < 16);
  259. return 0;
  260. }
  261. #ifdef CONFIG_MMU
  262. #ifdef CONFIG_KUSER_HELPERS
  263. /*
  264. * The vectors page is always readable from user space for the
  265. * atomic helpers. Insert it into the gate_vma so that it is visible
  266. * through ptrace and /proc/<pid>/mem.
  267. */
  268. static struct vm_area_struct gate_vma;
  269. static int __init gate_vma_init(void)
  270. {
  271. vma_init(&gate_vma, NULL);
  272. gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
  273. gate_vma.vm_start = 0xffff0000;
  274. gate_vma.vm_end = 0xffff0000 + PAGE_SIZE;
  275. gate_vma.vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC;
  276. return 0;
  277. }
  278. arch_initcall(gate_vma_init);
  279. struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
  280. {
  281. return &gate_vma;
  282. }
  283. int in_gate_area(struct mm_struct *mm, unsigned long addr)
  284. {
  285. return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
  286. }
  287. int in_gate_area_no_mm(unsigned long addr)
  288. {
  289. return in_gate_area(NULL, addr);
  290. }
  291. #define is_gate_vma(vma) ((vma) == &gate_vma)
  292. #else
  293. #define is_gate_vma(vma) 0
  294. #endif
  295. const char *arch_vma_name(struct vm_area_struct *vma)
  296. {
  297. return is_gate_vma(vma) ? "[vectors]" : NULL;
  298. }
  299. /* If possible, provide a placement hint at a random offset from the
  300. * stack for the sigpage and vdso pages.
  301. */
  302. static unsigned long sigpage_addr(const struct mm_struct *mm,
  303. unsigned int npages)
  304. {
  305. unsigned long offset;
  306. unsigned long first;
  307. unsigned long last;
  308. unsigned long addr;
  309. unsigned int slots;
  310. first = PAGE_ALIGN(mm->start_stack);
  311. last = TASK_SIZE - (npages << PAGE_SHIFT);
  312. /* No room after stack? */
  313. if (first > last)
  314. return 0;
  315. /* Just enough room? */
  316. if (first == last)
  317. return first;
  318. slots = ((last - first) >> PAGE_SHIFT) + 1;
  319. offset = get_random_int() % slots;
  320. addr = first + (offset << PAGE_SHIFT);
  321. return addr;
  322. }
  323. static struct page *signal_page;
  324. extern struct page *get_signal_page(void);
  325. static int sigpage_mremap(const struct vm_special_mapping *sm,
  326. struct vm_area_struct *new_vma)
  327. {
  328. current->mm->context.sigpage = new_vma->vm_start;
  329. return 0;
  330. }
  331. static const struct vm_special_mapping sigpage_mapping = {
  332. .name = "[sigpage]",
  333. .pages = &signal_page,
  334. .mremap = sigpage_mremap,
  335. };
  336. int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
  337. {
  338. struct mm_struct *mm = current->mm;
  339. struct vm_area_struct *vma;
  340. unsigned long npages;
  341. unsigned long addr;
  342. unsigned long hint;
  343. int ret = 0;
  344. if (!signal_page)
  345. signal_page = get_signal_page();
  346. if (!signal_page)
  347. return -ENOMEM;
  348. npages = 1; /* for sigpage */
  349. npages += vdso_total_pages;
  350. if (mmap_write_lock_killable(mm))
  351. return -EINTR;
  352. hint = sigpage_addr(mm, npages);
  353. addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0);
  354. if (IS_ERR_VALUE(addr)) {
  355. ret = addr;
  356. goto up_fail;
  357. }
  358. vma = _install_special_mapping(mm, addr, PAGE_SIZE,
  359. VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
  360. &sigpage_mapping);
  361. if (IS_ERR(vma)) {
  362. ret = PTR_ERR(vma);
  363. goto up_fail;
  364. }
  365. mm->context.sigpage = addr;
  366. /* Unlike the sigpage, failure to install the vdso is unlikely
  367. * to be fatal to the process, so no error check needed
  368. * here.
  369. */
  370. arm_install_vdso(mm, addr + PAGE_SIZE);
  371. up_fail:
  372. mmap_write_unlock(mm);
  373. return ret;
  374. }
  375. #endif