process.c 10 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444
  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 <linux/export.h>
  9. #include <linux/sched.h>
  10. #include <linux/sched/debug.h>
  11. #include <linux/sched/task.h>
  12. #include <linux/sched/task_stack.h>
  13. #include <linux/kernel.h>
  14. #include <linux/mm.h>
  15. #include <linux/stddef.h>
  16. #include <linux/unistd.h>
  17. #include <linux/user.h>
  18. #include <linux/interrupt.h>
  19. #include <linux/init.h>
  20. #include <linux/elfcore.h>
  21. #include <linux/pm.h>
  22. #include <linux/tick.h>
  23. #include <linux/utsname.h>
  24. #include <linux/uaccess.h>
  25. #include <linux/random.h>
  26. #include <linux/hw_breakpoint.h>
  27. #include <linux/leds.h>
  28. #include <asm/processor.h>
  29. #include <asm/thread_notify.h>
  30. #include <asm/stacktrace.h>
  31. #include <asm/system_misc.h>
  32. #include <asm/mach/time.h>
  33. #include <asm/tls.h>
  34. #include <asm/vdso.h>
  35. #include "signal.h"
  36. #if defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO) || defined(CONFIG_SMP)
  37. DEFINE_PER_CPU(struct task_struct *, __entry_task);
  38. #endif
  39. #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK)
  40. #include <linux/stackprotector.h>
  41. unsigned long __stack_chk_guard __read_mostly;
  42. EXPORT_SYMBOL(__stack_chk_guard);
  43. #endif
  44. #ifndef CONFIG_CURRENT_POINTER_IN_TPIDRURO
  45. asmlinkage struct task_struct *__current;
  46. EXPORT_SYMBOL(__current);
  47. #endif
  48. static const char *processor_modes[] __maybe_unused = {
  49. "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
  50. "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
  51. "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "MON_32" , "ABT_32" ,
  52. "UK8_32" , "UK9_32" , "HYP_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
  53. };
  54. static const char *isa_modes[] __maybe_unused = {
  55. "ARM" , "Thumb" , "Jazelle", "ThumbEE"
  56. };
  57. /*
  58. * This is our default idle handler.
  59. */
  60. void (*arm_pm_idle)(void);
  61. /*
  62. * Called from the core idle loop.
  63. */
  64. void arch_cpu_idle(void)
  65. {
  66. if (arm_pm_idle)
  67. arm_pm_idle();
  68. else
  69. cpu_do_idle();
  70. raw_local_irq_enable();
  71. }
  72. void arch_cpu_idle_prepare(void)
  73. {
  74. local_fiq_enable();
  75. }
  76. void arch_cpu_idle_enter(void)
  77. {
  78. ledtrig_cpu(CPU_LED_IDLE_START);
  79. #ifdef CONFIG_PL310_ERRATA_769419
  80. wmb();
  81. #endif
  82. }
  83. void arch_cpu_idle_exit(void)
  84. {
  85. ledtrig_cpu(CPU_LED_IDLE_END);
  86. }
  87. void __show_regs_alloc_free(struct pt_regs *regs)
  88. {
  89. int i;
  90. /* check for r0 - r12 only */
  91. for (i = 0; i < 13; i++) {
  92. pr_alert("Register r%d information:", i);
  93. mem_dump_obj((void *)regs->uregs[i]);
  94. }
  95. }
  96. void __show_regs(struct pt_regs *regs)
  97. {
  98. unsigned long flags;
  99. char buf[64];
  100. #ifndef CONFIG_CPU_V7M
  101. unsigned int domain;
  102. #ifdef CONFIG_CPU_SW_DOMAIN_PAN
  103. /*
  104. * Get the domain register for the parent context. In user
  105. * mode, we don't save the DACR, so lets use what it should
  106. * be. For other modes, we place it after the pt_regs struct.
  107. */
  108. if (user_mode(regs)) {
  109. domain = DACR_UACCESS_ENABLE;
  110. } else {
  111. domain = to_svc_pt_regs(regs)->dacr;
  112. }
  113. #else
  114. domain = get_domain();
  115. #endif
  116. #endif
  117. show_regs_print_info(KERN_DEFAULT);
  118. printk("PC is at %pS\n", (void *)instruction_pointer(regs));
  119. printk("LR is at %pS\n", (void *)regs->ARM_lr);
  120. printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n",
  121. regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr);
  122. printk("sp : %08lx ip : %08lx fp : %08lx\n",
  123. regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
  124. printk("r10: %08lx r9 : %08lx r8 : %08lx\n",
  125. regs->ARM_r10, regs->ARM_r9,
  126. regs->ARM_r8);
  127. printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
  128. regs->ARM_r7, regs->ARM_r6,
  129. regs->ARM_r5, regs->ARM_r4);
  130. printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
  131. regs->ARM_r3, regs->ARM_r2,
  132. regs->ARM_r1, regs->ARM_r0);
  133. flags = regs->ARM_cpsr;
  134. buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
  135. buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
  136. buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
  137. buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
  138. buf[4] = '\0';
  139. #ifndef CONFIG_CPU_V7M
  140. {
  141. const char *segment;
  142. if ((domain & domain_mask(DOMAIN_USER)) ==
  143. domain_val(DOMAIN_USER, DOMAIN_NOACCESS))
  144. segment = "none";
  145. else
  146. segment = "user";
  147. printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n",
  148. buf, interrupts_enabled(regs) ? "n" : "ff",
  149. fast_interrupts_enabled(regs) ? "n" : "ff",
  150. processor_modes[processor_mode(regs)],
  151. isa_modes[isa_mode(regs)], segment);
  152. }
  153. #else
  154. printk("xPSR: %08lx\n", regs->ARM_cpsr);
  155. #endif
  156. #ifdef CONFIG_CPU_CP15
  157. {
  158. unsigned int ctrl;
  159. buf[0] = '\0';
  160. #ifdef CONFIG_CPU_CP15_MMU
  161. {
  162. unsigned int transbase;
  163. asm("mrc p15, 0, %0, c2, c0\n\t"
  164. : "=r" (transbase));
  165. snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x",
  166. transbase, domain);
  167. }
  168. #endif
  169. asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
  170. printk("Control: %08x%s\n", ctrl, buf);
  171. }
  172. #endif
  173. }
  174. void show_regs(struct pt_regs * regs)
  175. {
  176. __show_regs(regs);
  177. dump_backtrace(regs, NULL, KERN_DEFAULT);
  178. }
  179. ATOMIC_NOTIFIER_HEAD(thread_notify_head);
  180. EXPORT_SYMBOL_GPL(thread_notify_head);
  181. /*
  182. * Free current thread data structures etc..
  183. */
  184. void exit_thread(struct task_struct *tsk)
  185. {
  186. thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk));
  187. }
  188. void flush_thread(void)
  189. {
  190. struct thread_info *thread = current_thread_info();
  191. struct task_struct *tsk = current;
  192. flush_ptrace_hw_breakpoint(tsk);
  193. memset(thread->used_cp, 0, sizeof(thread->used_cp));
  194. memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
  195. memset(&thread->fpstate, 0, sizeof(union fp_state));
  196. flush_tls();
  197. thread_notify(THREAD_NOTIFY_FLUSH, thread);
  198. }
  199. asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
  200. int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
  201. {
  202. unsigned long clone_flags = args->flags;
  203. unsigned long stack_start = args->stack;
  204. unsigned long tls = args->tls;
  205. struct thread_info *thread = task_thread_info(p);
  206. struct pt_regs *childregs = task_pt_regs(p);
  207. memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
  208. #ifdef CONFIG_CPU_USE_DOMAINS
  209. /*
  210. * Copy the initial value of the domain access control register
  211. * from the current thread: thread->addr_limit will have been
  212. * copied from the current thread via setup_thread_stack() in
  213. * kernel/fork.c
  214. */
  215. thread->cpu_domain = get_domain();
  216. #endif
  217. if (likely(!args->fn)) {
  218. *childregs = *current_pt_regs();
  219. childregs->ARM_r0 = 0;
  220. if (stack_start)
  221. childregs->ARM_sp = stack_start;
  222. } else {
  223. memset(childregs, 0, sizeof(struct pt_regs));
  224. thread->cpu_context.r4 = (unsigned long)args->fn_arg;
  225. thread->cpu_context.r5 = (unsigned long)args->fn;
  226. childregs->ARM_cpsr = SVC_MODE;
  227. }
  228. thread->cpu_context.pc = (unsigned long)ret_from_fork;
  229. thread->cpu_context.sp = (unsigned long)childregs;
  230. clear_ptrace_hw_breakpoint(p);
  231. if (clone_flags & CLONE_SETTLS)
  232. thread->tp_value[0] = tls;
  233. thread->tp_value[1] = get_tpuser();
  234. thread_notify(THREAD_NOTIFY_COPY, thread);
  235. return 0;
  236. }
  237. unsigned long __get_wchan(struct task_struct *p)
  238. {
  239. struct stackframe frame;
  240. unsigned long stack_page;
  241. int count = 0;
  242. frame.fp = thread_saved_fp(p);
  243. frame.sp = thread_saved_sp(p);
  244. frame.lr = 0; /* recovered from the stack */
  245. frame.pc = thread_saved_pc(p);
  246. stack_page = (unsigned long)task_stack_page(p);
  247. do {
  248. if (frame.sp < stack_page ||
  249. frame.sp >= stack_page + THREAD_SIZE ||
  250. unwind_frame(&frame) < 0)
  251. return 0;
  252. if (!in_sched_functions(frame.pc))
  253. return frame.pc;
  254. } while (count ++ < 16);
  255. return 0;
  256. }
  257. #ifdef CONFIG_MMU
  258. #ifdef CONFIG_KUSER_HELPERS
  259. /*
  260. * The vectors page is always readable from user space for the
  261. * atomic helpers. Insert it into the gate_vma so that it is visible
  262. * through ptrace and /proc/<pid>/mem.
  263. */
  264. static struct vm_area_struct gate_vma;
  265. static int __init gate_vma_init(void)
  266. {
  267. vma_init(&gate_vma, NULL);
  268. gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
  269. gate_vma.vm_start = 0xffff0000;
  270. gate_vma.vm_end = 0xffff0000 + PAGE_SIZE;
  271. vm_flags_init(&gate_vma, VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC);
  272. return 0;
  273. }
  274. arch_initcall(gate_vma_init);
  275. struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
  276. {
  277. return &gate_vma;
  278. }
  279. int in_gate_area(struct mm_struct *mm, unsigned long addr)
  280. {
  281. return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
  282. }
  283. int in_gate_area_no_mm(unsigned long addr)
  284. {
  285. return in_gate_area(NULL, addr);
  286. }
  287. #define is_gate_vma(vma) ((vma) == &gate_vma)
  288. #else
  289. #define is_gate_vma(vma) 0
  290. #endif
  291. const char *arch_vma_name(struct vm_area_struct *vma)
  292. {
  293. return is_gate_vma(vma) ? "[vectors]" : NULL;
  294. }
  295. /* If possible, provide a placement hint at a random offset from the
  296. * stack for the sigpage and vdso pages.
  297. */
  298. static unsigned long sigpage_addr(const struct mm_struct *mm,
  299. unsigned int npages)
  300. {
  301. unsigned long offset;
  302. unsigned long first;
  303. unsigned long last;
  304. unsigned long addr;
  305. unsigned int slots;
  306. first = PAGE_ALIGN(mm->start_stack);
  307. last = TASK_SIZE - (npages << PAGE_SHIFT);
  308. /* No room after stack? */
  309. if (first > last)
  310. return 0;
  311. /* Just enough room? */
  312. if (first == last)
  313. return first;
  314. slots = ((last - first) >> PAGE_SHIFT) + 1;
  315. offset = prandom_u32_max(slots);
  316. addr = first + (offset << PAGE_SHIFT);
  317. return addr;
  318. }
  319. static struct page *signal_page;
  320. extern struct page *get_signal_page(void);
  321. static int sigpage_mremap(const struct vm_special_mapping *sm,
  322. struct vm_area_struct *new_vma)
  323. {
  324. current->mm->context.sigpage = new_vma->vm_start;
  325. return 0;
  326. }
  327. static const struct vm_special_mapping sigpage_mapping = {
  328. .name = "[sigpage]",
  329. .pages = &signal_page,
  330. .mremap = sigpage_mremap,
  331. };
  332. int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
  333. {
  334. struct mm_struct *mm = current->mm;
  335. struct vm_area_struct *vma;
  336. unsigned long npages;
  337. unsigned long addr;
  338. unsigned long hint;
  339. int ret = 0;
  340. if (!signal_page)
  341. signal_page = get_signal_page();
  342. if (!signal_page)
  343. return -ENOMEM;
  344. npages = 1; /* for sigpage */
  345. npages += vdso_total_pages;
  346. if (mmap_write_lock_killable(mm))
  347. return -EINTR;
  348. hint = sigpage_addr(mm, npages);
  349. addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0);
  350. if (IS_ERR_VALUE(addr)) {
  351. ret = addr;
  352. goto up_fail;
  353. }
  354. vma = _install_special_mapping(mm, addr, PAGE_SIZE,
  355. VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
  356. &sigpage_mapping);
  357. if (IS_ERR(vma)) {
  358. ret = PTR_ERR(vma);
  359. goto up_fail;
  360. }
  361. mm->context.sigpage = addr;
  362. /* Unlike the sigpage, failure to install the vdso is unlikely
  363. * to be fatal to the process, so no error check needed
  364. * here.
  365. */
  366. arm_install_vdso(mm, addr + PAGE_SIZE);
  367. up_fail:
  368. mmap_write_unlock(mm);
  369. return ret;
  370. }
  371. #endif