blob: 151cece4a293e51af727c0e10719cc454c947875 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/arch/arm/kernel/process.c
3 *
4 * Copyright (C) 1996-2000 Russell King - Converted to ARM.
5 * Original Copyright (C) 1995 Linus Torvalds
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11#include <stdarg.h>
12
Paul Gortmakerecea4ab2011-07-22 10:58:34 -040013#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/sched.h>
Ingo Molnarb17b0152017-02-08 18:51:35 +010015#include <linux/sched/debug.h>
Ingo Molnar29930022017-02-08 18:51:36 +010016#include <linux/sched/task.h>
Ingo Molnar68db0cf2017-02-08 18:51:37 +010017#include <linux/sched/task_stack.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/kernel.h>
19#include <linux/mm.h>
20#include <linux/stddef.h>
21#include <linux/unistd.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <linux/user.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include <linux/interrupt.h>
24#include <linux/kallsyms.h>
25#include <linux/init.h>
Ben Dooks84dff1a2006-03-15 23:17:23 +000026#include <linux/elfcore.h>
Richard Purdie74617fb2006-06-19 19:57:12 +010027#include <linux/pm.h>
Kevin Hilman9e4559d2007-03-14 17:33:24 +010028#include <linux/tick.h>
Russell King154c7722007-06-18 14:59:45 +010029#include <linux/utsname.h>
Russell King33fa9b12008-09-06 11:35:55 +010030#include <linux/uaccess.h>
Nicolas Pitre990cb8a2010-06-14 16:27:19 -040031#include <linux/random.h>
Will Deacon864232f2010-09-03 10:42:55 +010032#include <linux/hw_breakpoint.h>
Bryan Wufa8bbb12012-03-14 02:26:56 +080033#include <linux/leds.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
Linus Torvalds1da177e2005-04-16 15:20:36 -070035#include <asm/processor.h>
Russell Kingd6551e82006-06-21 13:31:52 +010036#include <asm/thread_notify.h>
Catalin Marinas2d7c11b2009-02-11 13:07:53 +010037#include <asm/stacktrace.h>
Russell King779dd952014-04-06 16:17:39 +010038#include <asm/system_misc.h>
Russell King2ea83392005-06-27 14:04:05 +010039#include <asm/mach/time.h>
André Hentschela4780ad2013-06-18 23:23:26 +010040#include <asm/tls.h>
Russell King045ab942015-04-01 17:02:45 +010041#include <asm/vdso.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
Nicolas Pitrec743f382010-05-24 23:55:42 -040043#ifdef CONFIG_CC_STACKPROTECTOR
44#include <linux/stackprotector.h>
45unsigned long __stack_chk_guard __read_mostly;
46EXPORT_SYMBOL(__stack_chk_guard);
47#endif
48
Uwe Kleine-Könige2e55fd2013-12-16 10:38:57 +010049static const char *processor_modes[] __maybe_unused = {
Russell Kingae0a8462007-01-09 12:57:37 +000050 "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
51 "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
Stephen Boydf3a04202014-12-01 19:45:19 +010052 "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "MON_32" , "ABT_32" ,
53 "UK8_32" , "UK9_32" , "HYP_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
Russell Kingae0a8462007-01-09 12:57:37 +000054};
55
Uwe Kleine-Könige2e55fd2013-12-16 10:38:57 +010056static const char *isa_modes[] __maybe_unused = {
George G. Davis909d6c62007-06-26 01:38:27 +010057 "ARM" , "Thumb" , "Jazelle", "ThumbEE"
58};
59
Linus Torvalds1da177e2005-04-16 15:20:36 -070060/*
Nicolas Pitre4fa20432011-08-01 17:25:06 -040061 * This is our default idle handler.
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 */
Nicolas Pitre4fa20432011-08-01 17:25:06 -040063
64void (*arm_pm_idle)(void);
65
Nicolas Pitread68cc72014-01-29 12:45:09 -050066/*
67 * Called from the core idle loop.
68 */
69
70void arch_cpu_idle(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -070071{
Nicolas Pitre4fa20432011-08-01 17:25:06 -040072 if (arm_pm_idle)
73 arm_pm_idle();
74 else
Nicolas Pitreae940912011-12-19 03:03:58 -050075 cpu_do_idle();
Russell King9ccdac32009-06-22 22:34:55 +010076 local_irq_enable();
Linus Torvalds1da177e2005-04-16 15:20:36 -070077}
78
Thomas Gleixnerf7b861b2013-03-21 22:49:38 +010079void arch_cpu_idle_prepare(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -070080{
81 local_fiq_enable();
Thomas Gleixnerf7b861b2013-03-21 22:49:38 +010082}
Linus Torvalds1da177e2005-04-16 15:20:36 -070083
Thomas Gleixnerf7b861b2013-03-21 22:49:38 +010084void arch_cpu_idle_enter(void)
85{
86 ledtrig_cpu(CPU_LED_IDLE_START);
Will Deacon11ed0ba2011-11-14 17:24:58 +010087#ifdef CONFIG_PL310_ERRATA_769419
Thomas Gleixnerf7b861b2013-03-21 22:49:38 +010088 wmb();
Will Deacon11ed0ba2011-11-14 17:24:58 +010089#endif
Thomas Gleixnerf7b861b2013-03-21 22:49:38 +010090}
91
92void arch_cpu_idle_exit(void)
93{
94 ledtrig_cpu(CPU_LED_IDLE_END);
95}
96
Russell King652a12e2005-04-17 15:50:36 +010097void __show_regs(struct pt_regs *regs)
Linus Torvalds1da177e2005-04-16 15:20:36 -070098{
Russell King154c7722007-06-18 14:59:45 +010099 unsigned long flags;
100 char buf[64];
Russell King77f1b9592015-12-03 14:34:45 +0000101#ifndef CONFIG_CPU_V7M
Russell Kinge6978e42016-05-13 11:40:20 +0100102 unsigned int domain, fs;
Russell King77f1b9592015-12-03 14:34:45 +0000103#ifdef CONFIG_CPU_SW_DOMAIN_PAN
104 /*
105 * Get the domain register for the parent context. In user
106 * mode, we don't save the DACR, so lets use what it should
107 * be. For other modes, we place it after the pt_regs struct.
108 */
Russell Kinge6978e42016-05-13 11:40:20 +0100109 if (user_mode(regs)) {
Russell King77f1b9592015-12-03 14:34:45 +0000110 domain = DACR_UACCESS_ENABLE;
Russell Kinge6978e42016-05-13 11:40:20 +0100111 fs = get_fs();
112 } else {
Russell King5fa9da52016-05-13 10:26:10 +0100113 domain = to_svc_pt_regs(regs)->dacr;
Russell Kinge6978e42016-05-13 11:40:20 +0100114 fs = to_svc_pt_regs(regs)->addr_limit;
115 }
Russell King77f1b9592015-12-03 14:34:45 +0000116#else
117 domain = get_domain();
Russell Kinge6978e42016-05-13 11:40:20 +0100118 fs = get_fs();
Russell King77f1b9592015-12-03 14:34:45 +0000119#endif
120#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121
Tejun Heoa43cb952013-04-30 15:27:17 -0700122 show_regs_print_info(KERN_DEFAULT);
123
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 print_symbol("PC is at %s\n", instruction_pointer(regs));
125 print_symbol("LR is at %s\n", regs->ARM_lr);
Joe Perches801f19b2017-05-04 09:17:55 +0100126 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n",
127 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr);
128 printk("sp : %08lx ip : %08lx fp : %08lx\n",
129 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 printk("r10: %08lx r9 : %08lx r8 : %08lx\n",
131 regs->ARM_r10, regs->ARM_r9,
132 regs->ARM_r8);
133 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
134 regs->ARM_r7, regs->ARM_r6,
135 regs->ARM_r5, regs->ARM_r4);
136 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
137 regs->ARM_r3, regs->ARM_r2,
138 regs->ARM_r1, regs->ARM_r0);
Russell King154c7722007-06-18 14:59:45 +0100139
140 flags = regs->ARM_cpsr;
141 buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
142 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
143 buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
144 buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
145 buf[4] = '\0';
146
Uwe Kleine-Könige2e55fd2013-12-16 10:38:57 +0100147#ifndef CONFIG_CPU_V7M
Russell Kinga5e090a2015-08-19 20:40:41 +0100148 {
Russell Kinga5e090a2015-08-19 20:40:41 +0100149 const char *segment;
150
Russell Kinga5e090a2015-08-19 20:40:41 +0100151 if ((domain & domain_mask(DOMAIN_USER)) ==
152 domain_val(DOMAIN_USER, DOMAIN_NOACCESS))
153 segment = "none";
Russell Kinge6978e42016-05-13 11:40:20 +0100154 else if (fs == get_ds())
Russell Kinga5e090a2015-08-19 20:40:41 +0100155 segment = "kernel";
156 else
157 segment = "user";
158
159 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n",
160 buf, interrupts_enabled(regs) ? "n" : "ff",
161 fast_interrupts_enabled(regs) ? "n" : "ff",
162 processor_modes[processor_mode(regs)],
163 isa_modes[isa_mode(regs)], segment);
164 }
Uwe Kleine-Könige2e55fd2013-12-16 10:38:57 +0100165#else
166 printk("xPSR: %08lx\n", regs->ARM_cpsr);
167#endif
168
Russell King154c7722007-06-18 14:59:45 +0100169#ifdef CONFIG_CPU_CP15
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 {
Hyok S. Choif12d0d72006-09-26 17:36:37 +0900171 unsigned int ctrl;
Russell King154c7722007-06-18 14:59:45 +0100172
173 buf[0] = '\0';
Hyok S. Choif12d0d72006-09-26 17:36:37 +0900174#ifdef CONFIG_CPU_CP15_MMU
Russell King154c7722007-06-18 14:59:45 +0100175 {
Russell King77f1b9592015-12-03 14:34:45 +0000176 unsigned int transbase;
Russell King154c7722007-06-18 14:59:45 +0100177 asm("mrc p15, 0, %0, c2, c0\n\t"
Russell King1eef5d22015-08-19 21:23:48 +0100178 : "=r" (transbase));
Russell King154c7722007-06-18 14:59:45 +0100179 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x",
Russell King77f1b9592015-12-03 14:34:45 +0000180 transbase, domain);
Russell King154c7722007-06-18 14:59:45 +0100181 }
Hyok S. Choif12d0d72006-09-26 17:36:37 +0900182#endif
Russell King154c7722007-06-18 14:59:45 +0100183 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
184
185 printk("Control: %08x%s\n", ctrl, buf);
186 }
Hyok S. Choif12d0d72006-09-26 17:36:37 +0900187#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188}
189
Russell King652a12e2005-04-17 15:50:36 +0100190void show_regs(struct pt_regs * regs)
191{
Russell King652a12e2005-04-17 15:50:36 +0100192 __show_regs(regs);
Laura Abbottb380ab42011-08-31 02:04:06 +0100193 dump_stack();
Russell King652a12e2005-04-17 15:50:36 +0100194}
195
Russell King797245f2009-12-18 14:34:43 +0000196ATOMIC_NOTIFIER_HEAD(thread_notify_head);
197
198EXPORT_SYMBOL_GPL(thread_notify_head);
199
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 * Free current thread data structures etc..
202 */
Jiri Slabye6464692016-05-20 17:00:20 -0700203void exit_thread(struct task_struct *tsk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204{
Jiri Slabye6464692016-05-20 17:00:20 -0700205 thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206}
207
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208void flush_thread(void)
209{
210 struct thread_info *thread = current_thread_info();
211 struct task_struct *tsk = current;
212
Will Deacon864232f2010-09-03 10:42:55 +0100213 flush_ptrace_hw_breakpoint(tsk);
214
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 memset(thread->used_cp, 0, sizeof(thread->used_cp));
216 memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
Russell Kingd6551e82006-06-21 13:31:52 +0100217 memset(&thread->fpstate, 0, sizeof(union fp_state));
218
Nathan Lynchfbfb8722014-09-11 02:49:08 +0100219 flush_tls();
220
Russell Kingd6551e82006-06-21 13:31:52 +0100221 thread_notify(THREAD_NOTIFY_FLUSH, thread);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222}
223
224void release_thread(struct task_struct *dead_task)
225{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226}
227
228asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
229
230int
Alexey Dobriyan6f2c55b2009-04-02 16:56:59 -0700231copy_thread(unsigned long clone_flags, unsigned long stack_start,
Al Viroafa86fc2012-10-22 22:51:14 -0400232 unsigned long stk_sz, struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233{
Al Viro815d5ec2006-01-12 01:05:57 -0800234 struct thread_info *thread = task_thread_info(p);
235 struct pt_regs *childregs = task_pt_regs(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
Al Viro9e14f822012-09-09 21:31:07 -0400238
Russell Kingaf4cb252015-09-09 21:19:49 +0100239#ifdef CONFIG_CPU_USE_DOMAINS
Russell King1eef5d22015-08-19 21:23:48 +0100240 /*
241 * Copy the initial value of the domain access control register
242 * from the current thread: thread->addr_limit will have been
243 * copied from the current thread via setup_thread_stack() in
244 * kernel/fork.c
245 */
246 thread->cpu_domain = get_domain();
Russell Kingaf4cb252015-09-09 21:19:49 +0100247#endif
Russell King1eef5d22015-08-19 21:23:48 +0100248
Al Viro38a61b62012-10-21 15:54:27 -0400249 if (likely(!(p->flags & PF_KTHREAD))) {
250 *childregs = *current_pt_regs();
Al Viro9e14f822012-09-09 21:31:07 -0400251 childregs->ARM_r0 = 0;
Al Viro38a61b62012-10-21 15:54:27 -0400252 if (stack_start)
253 childregs->ARM_sp = stack_start;
Al Viro9e14f822012-09-09 21:31:07 -0400254 } else {
Al Viro9fff2fa2012-10-10 22:23:29 -0400255 memset(childregs, 0, sizeof(struct pt_regs));
Al Viro9e14f822012-09-09 21:31:07 -0400256 thread->cpu_context.r4 = stk_sz;
257 thread->cpu_context.r5 = stack_start;
Al Viro9e14f822012-09-09 21:31:07 -0400258 childregs->ARM_cpsr = SVC_MODE;
259 }
Al Viro9fff2fa2012-10-10 22:23:29 -0400260 thread->cpu_context.pc = (unsigned long)ret_from_fork;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 thread->cpu_context.sp = (unsigned long)childregs;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262
Will Deacon864232f2010-09-03 10:42:55 +0100263 clear_ptrace_hw_breakpoint(p);
264
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 if (clone_flags & CLONE_SETTLS)
André Hentschela4780ad2013-06-18 23:23:26 +0100266 thread->tp_value[0] = childregs->ARM_r3;
267 thread->tp_value[1] = get_tpuser();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268
Catalin Marinas2e82669a2011-04-06 16:16:29 +0100269 thread_notify(THREAD_NOTIFY_COPY, thread);
270
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 return 0;
272}
273
274/*
Artem Bityutskiycde3f862009-10-13 08:54:30 +0100275 * Fill in the task's elfregs structure for a core dump.
276 */
277int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
278{
279 elf_core_copy_regs(elfregs, task_pt_regs(t));
280 return 1;
281}
282
283/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284 * fill in the fpe structure for a core dump...
285 */
286int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
287{
288 struct thread_info *thread = current_thread_info();
289 int used_math = thread->used_cp[1] | thread->used_cp[2];
290
291 if (used_math)
292 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
293
294 return used_math != 0;
295}
296EXPORT_SYMBOL(dump_fpu);
297
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298unsigned long get_wchan(struct task_struct *p)
299{
Catalin Marinas2d7c11b2009-02-11 13:07:53 +0100300 struct stackframe frame;
Konstantin Khlebnikov1b15ec72013-12-05 14:21:36 +0100301 unsigned long stack_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 int count = 0;
303 if (!p || p == current || p->state == TASK_RUNNING)
304 return 0;
305
Catalin Marinas2d7c11b2009-02-11 13:07:53 +0100306 frame.fp = thread_saved_fp(p);
307 frame.sp = thread_saved_sp(p);
308 frame.lr = 0; /* recovered from the stack */
309 frame.pc = thread_saved_pc(p);
Konstantin Khlebnikov1b15ec72013-12-05 14:21:36 +0100310 stack_page = (unsigned long)task_stack_page(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 do {
Konstantin Khlebnikov1b15ec72013-12-05 14:21:36 +0100312 if (frame.sp < stack_page ||
313 frame.sp >= stack_page + THREAD_SIZE ||
314 unwind_frame(&frame) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 return 0;
Catalin Marinas2d7c11b2009-02-11 13:07:53 +0100316 if (!in_sched_functions(frame.pc))
317 return frame.pc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 } while (count ++ < 16);
319 return 0;
320}
Nicolas Pitre990cb8a2010-06-14 16:27:19 -0400321
322unsigned long arch_randomize_brk(struct mm_struct *mm)
323{
Jason Cooperc984cbf2016-10-11 13:53:59 -0700324 return randomize_page(mm->brk, 0x02000000);
Nicolas Pitre990cb8a2010-06-14 16:27:19 -0400325}
Nicolas Pitreec706da2010-08-26 23:10:50 -0400326
Will Deacon6cde6d42011-01-11 14:04:36 +0100327#ifdef CONFIG_MMU
Russell Kinga5463cd2013-07-31 21:58:56 +0100328#ifdef CONFIG_KUSER_HELPERS
Nicolas Pitreec706da2010-08-26 23:10:50 -0400329/*
330 * The vectors page is always readable from user space for the
Russell King48be69a2013-07-24 00:29:18 +0100331 * atomic helpers. Insert it into the gate_vma so that it is visible
332 * through ptrace and /proc/<pid>/mem.
Nicolas Pitreec706da2010-08-26 23:10:50 -0400333 */
Russell Kingf6604ef2013-02-23 17:55:39 +0000334static struct vm_area_struct gate_vma = {
335 .vm_start = 0xffff0000,
336 .vm_end = 0xffff0000 + PAGE_SIZE,
337 .vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC,
Russell Kingf6604ef2013-02-23 17:55:39 +0000338};
Nicolas Pitreec706da2010-08-26 23:10:50 -0400339
Will Deaconf9d4861f2012-01-20 12:01:13 +0100340static int __init gate_vma_init(void)
Nicolas Pitreec706da2010-08-26 23:10:50 -0400341{
Russell Kingf6604ef2013-02-23 17:55:39 +0000342 gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
Will Deaconf9d4861f2012-01-20 12:01:13 +0100343 return 0;
344}
345arch_initcall(gate_vma_init);
346
347struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
348{
349 return &gate_vma;
350}
351
352int in_gate_area(struct mm_struct *mm, unsigned long addr)
353{
354 return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
355}
356
357int in_gate_area_no_mm(unsigned long addr)
358{
359 return in_gate_area(NULL, addr);
Nicolas Pitreec706da2010-08-26 23:10:50 -0400360}
Russell King1d0bbf42013-08-06 09:49:14 +0100361#define is_gate_vma(vma) ((vma) == &gate_vma)
Russell Kinga5463cd2013-07-31 21:58:56 +0100362#else
363#define is_gate_vma(vma) 0
364#endif
Nicolas Pitreec706da2010-08-26 23:10:50 -0400365
366const char *arch_vma_name(struct vm_area_struct *vma)
367{
Nathan Lynch02e04092014-09-22 22:08:42 +0100368 return is_gate_vma(vma) ? "[vectors]" : NULL;
Russell King48be69a2013-07-24 00:29:18 +0100369}
370
Nathan Lynch389522b2014-09-22 22:12:35 +0100371/* If possible, provide a placement hint at a random offset from the
Nathan Lynchecf99a42015-03-25 19:15:08 +0100372 * stack for the sigpage and vdso pages.
Nathan Lynch389522b2014-09-22 22:12:35 +0100373 */
374static unsigned long sigpage_addr(const struct mm_struct *mm,
375 unsigned int npages)
376{
377 unsigned long offset;
378 unsigned long first;
379 unsigned long last;
380 unsigned long addr;
381 unsigned int slots;
382
383 first = PAGE_ALIGN(mm->start_stack);
384
385 last = TASK_SIZE - (npages << PAGE_SHIFT);
386
387 /* No room after stack? */
388 if (first > last)
389 return 0;
390
391 /* Just enough room? */
392 if (first == last)
393 return first;
394
395 slots = ((last - first) >> PAGE_SHIFT) + 1;
396
397 offset = get_random_int() % slots;
398
399 addr = first + (offset << PAGE_SHIFT);
400
401 return addr;
Russell King48be69a2013-07-24 00:29:18 +0100402}
403
Russell Kinge0d40752013-08-03 10:30:05 +0100404static struct page *signal_page;
Russell King48be69a2013-07-24 00:29:18 +0100405extern struct page *get_signal_page(void);
406
Nathan Lynch02e04092014-09-22 22:08:42 +0100407static const struct vm_special_mapping sigpage_mapping = {
408 .name = "[sigpage]",
409 .pages = &signal_page,
410};
411
Russell King48be69a2013-07-24 00:29:18 +0100412int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
413{
414 struct mm_struct *mm = current->mm;
Nathan Lynch02e04092014-09-22 22:08:42 +0100415 struct vm_area_struct *vma;
Nathan Lynchecf99a42015-03-25 19:15:08 +0100416 unsigned long npages;
Russell King48be69a2013-07-24 00:29:18 +0100417 unsigned long addr;
Nathan Lynch389522b2014-09-22 22:12:35 +0100418 unsigned long hint;
Nathan Lynch02e04092014-09-22 22:08:42 +0100419 int ret = 0;
Russell King48be69a2013-07-24 00:29:18 +0100420
Russell Kinge0d40752013-08-03 10:30:05 +0100421 if (!signal_page)
422 signal_page = get_signal_page();
423 if (!signal_page)
Russell King48be69a2013-07-24 00:29:18 +0100424 return -ENOMEM;
425
Nathan Lynchecf99a42015-03-25 19:15:08 +0100426 npages = 1; /* for sigpage */
427 npages += vdso_total_pages;
428
Michal Hocko69048172016-05-23 16:25:54 -0700429 if (down_write_killable(&mm->mmap_sem))
430 return -EINTR;
Nathan Lynchecf99a42015-03-25 19:15:08 +0100431 hint = sigpage_addr(mm, npages);
432 addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0);
Russell King48be69a2013-07-24 00:29:18 +0100433 if (IS_ERR_VALUE(addr)) {
434 ret = addr;
435 goto up_fail;
436 }
437
Nathan Lynch02e04092014-09-22 22:08:42 +0100438 vma = _install_special_mapping(mm, addr, PAGE_SIZE,
Russell King48be69a2013-07-24 00:29:18 +0100439 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
Nathan Lynch02e04092014-09-22 22:08:42 +0100440 &sigpage_mapping);
Russell King48be69a2013-07-24 00:29:18 +0100441
Nathan Lynch02e04092014-09-22 22:08:42 +0100442 if (IS_ERR(vma)) {
443 ret = PTR_ERR(vma);
444 goto up_fail;
445 }
446
447 mm->context.sigpage = addr;
Russell King48be69a2013-07-24 00:29:18 +0100448
Nathan Lynchecf99a42015-03-25 19:15:08 +0100449 /* Unlike the sigpage, failure to install the vdso is unlikely
450 * to be fatal to the process, so no error check needed
451 * here.
452 */
453 arm_install_vdso(mm, addr + PAGE_SIZE);
454
Russell King48be69a2013-07-24 00:29:18 +0100455 up_fail:
456 up_write(&mm->mmap_sem);
457 return ret;
Nicolas Pitreec706da2010-08-26 23:10:50 -0400458}
Will Deacon6cde6d42011-01-11 14:04:36 +0100459#endif