blob: 72cc0862a30e9a96722716e561cd9633d752cdc6 [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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024#include <linux/init.h>
Ben Dooks84dff1a2006-03-15 23:17:23 +000025#include <linux/elfcore.h>
Richard Purdie74617fb2006-06-19 19:57:12 +010026#include <linux/pm.h>
Kevin Hilman9e4559d2007-03-14 17:33:24 +010027#include <linux/tick.h>
Russell King154c7722007-06-18 14:59:45 +010028#include <linux/utsname.h>
Russell King33fa9b12008-09-06 11:35:55 +010029#include <linux/uaccess.h>
Nicolas Pitre990cb8a2010-06-14 16:27:19 -040030#include <linux/random.h>
Will Deacon864232f2010-09-03 10:42:55 +010031#include <linux/hw_breakpoint.h>
Bryan Wufa8bbb12012-03-14 02:26:56 +080032#include <linux/leds.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
Linus Torvalds1da177e2005-04-16 15:20:36 -070034#include <asm/processor.h>
Russell Kingd6551e82006-06-21 13:31:52 +010035#include <asm/thread_notify.h>
Catalin Marinas2d7c11b2009-02-11 13:07:53 +010036#include <asm/stacktrace.h>
Russell King779dd952014-04-06 16:17:39 +010037#include <asm/system_misc.h>
Russell King2ea83392005-06-27 14:04:05 +010038#include <asm/mach/time.h>
André Hentschela4780ad2013-06-18 23:23:26 +010039#include <asm/tls.h>
Russell King045ab942015-04-01 17:02:45 +010040#include <asm/vdso.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070041
Ard Biesheuvel189af462018-12-06 09:32:57 +010042#if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK)
Nicolas Pitrec743f382010-05-24 23:55:42 -040043#include <linux/stackprotector.h>
44unsigned long __stack_chk_guard __read_mostly;
45EXPORT_SYMBOL(__stack_chk_guard);
46#endif
47
Uwe Kleine-Könige2e55fd2013-12-16 10:38:57 +010048static const char *processor_modes[] __maybe_unused = {
Russell Kingae0a8462007-01-09 12:57:37 +000049 "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",
Stephen Boydf3a04202014-12-01 19:45:19 +010051 "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"
Russell Kingae0a8462007-01-09 12:57:37 +000053};
54
Uwe Kleine-Könige2e55fd2013-12-16 10:38:57 +010055static const char *isa_modes[] __maybe_unused = {
George G. Davis909d6c62007-06-26 01:38:27 +010056 "ARM" , "Thumb" , "Jazelle", "ThumbEE"
57};
58
Linus Torvalds1da177e2005-04-16 15:20:36 -070059/*
Nicolas Pitre4fa20432011-08-01 17:25:06 -040060 * This is our default idle handler.
Linus Torvalds1da177e2005-04-16 15:20:36 -070061 */
Nicolas Pitre4fa20432011-08-01 17:25:06 -040062
63void (*arm_pm_idle)(void);
64
Nicolas Pitread68cc72014-01-29 12:45:09 -050065/*
66 * Called from the core idle loop.
67 */
68
69void arch_cpu_idle(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -070070{
Nicolas Pitre4fa20432011-08-01 17:25:06 -040071 if (arm_pm_idle)
72 arm_pm_idle();
73 else
Nicolas Pitreae940912011-12-19 03:03:58 -050074 cpu_do_idle();
Russell King9ccdac32009-06-22 22:34:55 +010075 local_irq_enable();
Linus Torvalds1da177e2005-04-16 15:20:36 -070076}
77
Thomas Gleixnerf7b861b2013-03-21 22:49:38 +010078void arch_cpu_idle_prepare(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -070079{
80 local_fiq_enable();
Thomas Gleixnerf7b861b2013-03-21 22:49:38 +010081}
Linus Torvalds1da177e2005-04-16 15:20:36 -070082
Thomas Gleixnerf7b861b2013-03-21 22:49:38 +010083void arch_cpu_idle_enter(void)
84{
85 ledtrig_cpu(CPU_LED_IDLE_START);
Will Deacon11ed0ba2011-11-14 17:24:58 +010086#ifdef CONFIG_PL310_ERRATA_769419
Thomas Gleixnerf7b861b2013-03-21 22:49:38 +010087 wmb();
Will Deacon11ed0ba2011-11-14 17:24:58 +010088#endif
Thomas Gleixnerf7b861b2013-03-21 22:49:38 +010089}
90
91void arch_cpu_idle_exit(void)
92{
93 ledtrig_cpu(CPU_LED_IDLE_END);
94}
95
Russell King652a12e2005-04-17 15:50:36 +010096void __show_regs(struct pt_regs *regs)
Linus Torvalds1da177e2005-04-16 15:20:36 -070097{
Russell King154c7722007-06-18 14:59:45 +010098 unsigned long flags;
99 char buf[64];
Russell King77f1b9592015-12-03 14:34:45 +0000100#ifndef CONFIG_CPU_V7M
Russell Kinge6978e42016-05-13 11:40:20 +0100101 unsigned int domain, fs;
Russell King77f1b9592015-12-03 14:34:45 +0000102#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 */
Russell Kinge6978e42016-05-13 11:40:20 +0100108 if (user_mode(regs)) {
Russell King77f1b9592015-12-03 14:34:45 +0000109 domain = DACR_UACCESS_ENABLE;
Russell Kinge6978e42016-05-13 11:40:20 +0100110 fs = get_fs();
111 } else {
Russell King5fa9da52016-05-13 10:26:10 +0100112 domain = to_svc_pt_regs(regs)->dacr;
Russell Kinge6978e42016-05-13 11:40:20 +0100113 fs = to_svc_pt_regs(regs)->addr_limit;
114 }
Russell King77f1b9592015-12-03 14:34:45 +0000115#else
116 domain = get_domain();
Russell Kinge6978e42016-05-13 11:40:20 +0100117 fs = get_fs();
Russell King77f1b9592015-12-03 14:34:45 +0000118#endif
119#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120
Tejun Heoa43cb952013-04-30 15:27:17 -0700121 show_regs_print_info(KERN_DEFAULT);
122
Sergey Senozhatsky3ea70d72017-12-11 21:50:13 +0900123 printk("PC is at %pS\n", (void *)instruction_pointer(regs));
124 printk("LR is at %pS\n", (void *)regs->ARM_lr);
Joe Perches801f19b2017-05-04 09:17:55 +0100125 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n",
126 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr);
127 printk("sp : %08lx ip : %08lx fp : %08lx\n",
128 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 printk("r10: %08lx r9 : %08lx r8 : %08lx\n",
130 regs->ARM_r10, regs->ARM_r9,
131 regs->ARM_r8);
132 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
133 regs->ARM_r7, regs->ARM_r6,
134 regs->ARM_r5, regs->ARM_r4);
135 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
136 regs->ARM_r3, regs->ARM_r2,
137 regs->ARM_r1, regs->ARM_r0);
Russell King154c7722007-06-18 14:59:45 +0100138
139 flags = regs->ARM_cpsr;
140 buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
141 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
142 buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
143 buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
144 buf[4] = '\0';
145
Uwe Kleine-Könige2e55fd2013-12-16 10:38:57 +0100146#ifndef CONFIG_CPU_V7M
Russell Kinga5e090a2015-08-19 20:40:41 +0100147 {
Russell Kinga5e090a2015-08-19 20:40:41 +0100148 const char *segment;
149
Russell Kinga5e090a2015-08-19 20:40:41 +0100150 if ((domain & domain_mask(DOMAIN_USER)) ==
151 domain_val(DOMAIN_USER, DOMAIN_NOACCESS))
152 segment = "none";
Linus Torvalds736706b2019-03-04 10:39:05 -0800153 else if (fs == KERNEL_DS)
Russell Kinga5e090a2015-08-19 20:40:41 +0100154 segment = "kernel";
155 else
156 segment = "user";
157
158 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n",
159 buf, interrupts_enabled(regs) ? "n" : "ff",
160 fast_interrupts_enabled(regs) ? "n" : "ff",
161 processor_modes[processor_mode(regs)],
162 isa_modes[isa_mode(regs)], segment);
163 }
Uwe Kleine-Könige2e55fd2013-12-16 10:38:57 +0100164#else
165 printk("xPSR: %08lx\n", regs->ARM_cpsr);
166#endif
167
Russell King154c7722007-06-18 14:59:45 +0100168#ifdef CONFIG_CPU_CP15
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 {
Hyok S. Choif12d0d72006-09-26 17:36:37 +0900170 unsigned int ctrl;
Russell King154c7722007-06-18 14:59:45 +0100171
172 buf[0] = '\0';
Hyok S. Choif12d0d72006-09-26 17:36:37 +0900173#ifdef CONFIG_CPU_CP15_MMU
Russell King154c7722007-06-18 14:59:45 +0100174 {
Russell King77f1b9592015-12-03 14:34:45 +0000175 unsigned int transbase;
Russell King154c7722007-06-18 14:59:45 +0100176 asm("mrc p15, 0, %0, c2, c0\n\t"
Russell King1eef5d22015-08-19 21:23:48 +0100177 : "=r" (transbase));
Russell King154c7722007-06-18 14:59:45 +0100178 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x",
Russell King77f1b9592015-12-03 14:34:45 +0000179 transbase, domain);
Russell King154c7722007-06-18 14:59:45 +0100180 }
Hyok S. Choif12d0d72006-09-26 17:36:37 +0900181#endif
Russell King154c7722007-06-18 14:59:45 +0100182 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
183
184 printk("Control: %08x%s\n", ctrl, buf);
185 }
Hyok S. Choif12d0d72006-09-26 17:36:37 +0900186#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187}
188
Russell King652a12e2005-04-17 15:50:36 +0100189void show_regs(struct pt_regs * regs)
190{
Russell King652a12e2005-04-17 15:50:36 +0100191 __show_regs(regs);
Laura Abbottb380ab42011-08-31 02:04:06 +0100192 dump_stack();
Russell King652a12e2005-04-17 15:50:36 +0100193}
194
Russell King797245f2009-12-18 14:34:43 +0000195ATOMIC_NOTIFIER_HEAD(thread_notify_head);
196
197EXPORT_SYMBOL_GPL(thread_notify_head);
198
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 * Free current thread data structures etc..
201 */
Jiri Slabye6464692016-05-20 17:00:20 -0700202void exit_thread(struct task_struct *tsk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203{
Jiri Slabye6464692016-05-20 17:00:20 -0700204 thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205}
206
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207void flush_thread(void)
208{
209 struct thread_info *thread = current_thread_info();
210 struct task_struct *tsk = current;
211
Will Deacon864232f2010-09-03 10:42:55 +0100212 flush_ptrace_hw_breakpoint(tsk);
213
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 memset(thread->used_cp, 0, sizeof(thread->used_cp));
215 memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
Russell Kingd6551e82006-06-21 13:31:52 +0100216 memset(&thread->fpstate, 0, sizeof(union fp_state));
217
Nathan Lynchfbfb8722014-09-11 02:49:08 +0100218 flush_tls();
219
Russell Kingd6551e82006-06-21 13:31:52 +0100220 thread_notify(THREAD_NOTIFY_FLUSH, thread);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221}
222
223void release_thread(struct task_struct *dead_task)
224{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225}
226
227asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
228
229int
Alexey Dobriyan6f2c55b2009-04-02 16:56:59 -0700230copy_thread(unsigned long clone_flags, unsigned long stack_start,
Al Viroafa86fc2012-10-22 22:51:14 -0400231 unsigned long stk_sz, struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232{
Al Viro815d5ec2006-01-12 01:05:57 -0800233 struct thread_info *thread = task_thread_info(p);
234 struct pt_regs *childregs = task_pt_regs(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
Al Viro9e14f822012-09-09 21:31:07 -0400237
Russell Kingaf4cb252015-09-09 21:19:49 +0100238#ifdef CONFIG_CPU_USE_DOMAINS
Russell King1eef5d22015-08-19 21:23:48 +0100239 /*
240 * Copy the initial value of the domain access control register
241 * from the current thread: thread->addr_limit will have been
242 * copied from the current thread via setup_thread_stack() in
243 * kernel/fork.c
244 */
245 thread->cpu_domain = get_domain();
Russell Kingaf4cb252015-09-09 21:19:49 +0100246#endif
Russell King1eef5d22015-08-19 21:23:48 +0100247
Al Viro38a61b62012-10-21 15:54:27 -0400248 if (likely(!(p->flags & PF_KTHREAD))) {
249 *childregs = *current_pt_regs();
Al Viro9e14f822012-09-09 21:31:07 -0400250 childregs->ARM_r0 = 0;
Al Viro38a61b62012-10-21 15:54:27 -0400251 if (stack_start)
252 childregs->ARM_sp = stack_start;
Al Viro9e14f822012-09-09 21:31:07 -0400253 } else {
Al Viro9fff2fa2012-10-10 22:23:29 -0400254 memset(childregs, 0, sizeof(struct pt_regs));
Al Viro9e14f822012-09-09 21:31:07 -0400255 thread->cpu_context.r4 = stk_sz;
256 thread->cpu_context.r5 = stack_start;
Al Viro9e14f822012-09-09 21:31:07 -0400257 childregs->ARM_cpsr = SVC_MODE;
258 }
Al Viro9fff2fa2012-10-10 22:23:29 -0400259 thread->cpu_context.pc = (unsigned long)ret_from_fork;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260 thread->cpu_context.sp = (unsigned long)childregs;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261
Will Deacon864232f2010-09-03 10:42:55 +0100262 clear_ptrace_hw_breakpoint(p);
263
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264 if (clone_flags & CLONE_SETTLS)
André Hentschela4780ad2013-06-18 23:23:26 +0100265 thread->tp_value[0] = childregs->ARM_r3;
266 thread->tp_value[1] = get_tpuser();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267
Catalin Marinas2e82669a2011-04-06 16:16:29 +0100268 thread_notify(THREAD_NOTIFY_COPY, thread);
269
Ard Biesheuvel189af462018-12-06 09:32:57 +0100270#ifdef CONFIG_STACKPROTECTOR_PER_TASK
271 thread->stack_canary = p->stack_canary;
272#endif
273
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 return 0;
275}
276
277/*
Artem Bityutskiycde3f862009-10-13 08:54:30 +0100278 * Fill in the task's elfregs structure for a core dump.
279 */
280int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
281{
282 elf_core_copy_regs(elfregs, task_pt_regs(t));
283 return 1;
284}
285
286/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 * fill in the fpe structure for a core dump...
288 */
289int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
290{
291 struct thread_info *thread = current_thread_info();
292 int used_math = thread->used_cp[1] | thread->used_cp[2];
293
294 if (used_math)
295 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
296
297 return used_math != 0;
298}
299EXPORT_SYMBOL(dump_fpu);
300
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301unsigned long get_wchan(struct task_struct *p)
302{
Catalin Marinas2d7c11b2009-02-11 13:07:53 +0100303 struct stackframe frame;
Konstantin Khlebnikov1b15ec72013-12-05 14:21:36 +0100304 unsigned long stack_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 int count = 0;
306 if (!p || p == current || p->state == TASK_RUNNING)
307 return 0;
308
Catalin Marinas2d7c11b2009-02-11 13:07:53 +0100309 frame.fp = thread_saved_fp(p);
310 frame.sp = thread_saved_sp(p);
311 frame.lr = 0; /* recovered from the stack */
312 frame.pc = thread_saved_pc(p);
Konstantin Khlebnikov1b15ec72013-12-05 14:21:36 +0100313 stack_page = (unsigned long)task_stack_page(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 do {
Konstantin Khlebnikov1b15ec72013-12-05 14:21:36 +0100315 if (frame.sp < stack_page ||
316 frame.sp >= stack_page + THREAD_SIZE ||
317 unwind_frame(&frame) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 return 0;
Catalin Marinas2d7c11b2009-02-11 13:07:53 +0100319 if (!in_sched_functions(frame.pc))
320 return frame.pc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 } while (count ++ < 16);
322 return 0;
323}
Nicolas Pitre990cb8a2010-06-14 16:27:19 -0400324
325unsigned long arch_randomize_brk(struct mm_struct *mm)
326{
Jason Cooperc984cbf2016-10-11 13:53:59 -0700327 return randomize_page(mm->brk, 0x02000000);
Nicolas Pitre990cb8a2010-06-14 16:27:19 -0400328}
Nicolas Pitreec706da2010-08-26 23:10:50 -0400329
Will Deacon6cde6d42011-01-11 14:04:36 +0100330#ifdef CONFIG_MMU
Russell Kinga5463cd2013-07-31 21:58:56 +0100331#ifdef CONFIG_KUSER_HELPERS
Nicolas Pitreec706da2010-08-26 23:10:50 -0400332/*
333 * The vectors page is always readable from user space for the
Russell King48be69a2013-07-24 00:29:18 +0100334 * atomic helpers. Insert it into the gate_vma so that it is visible
335 * through ptrace and /proc/<pid>/mem.
Nicolas Pitreec706da2010-08-26 23:10:50 -0400336 */
Andrew Mortona6704682018-08-21 21:53:06 -0700337static struct vm_area_struct gate_vma;
Nicolas Pitreec706da2010-08-26 23:10:50 -0400338
Will Deaconf9d4861f2012-01-20 12:01:13 +0100339static int __init gate_vma_init(void)
Nicolas Pitreec706da2010-08-26 23:10:50 -0400340{
Kirill A. Shutemov2c4541e2018-07-26 16:37:30 -0700341 vma_init(&gate_vma, NULL);
Russell Kingf6604ef2013-02-23 17:55:39 +0000342 gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
Andrew Mortona6704682018-08-21 21:53:06 -0700343 gate_vma.vm_start = 0xffff0000;
344 gate_vma.vm_end = 0xffff0000 + PAGE_SIZE;
345 gate_vma.vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC;
Will Deaconf9d4861f2012-01-20 12:01:13 +0100346 return 0;
347}
348arch_initcall(gate_vma_init);
349
350struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
351{
352 return &gate_vma;
353}
354
355int in_gate_area(struct mm_struct *mm, unsigned long addr)
356{
357 return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
358}
359
360int in_gate_area_no_mm(unsigned long addr)
361{
362 return in_gate_area(NULL, addr);
Nicolas Pitreec706da2010-08-26 23:10:50 -0400363}
Russell King1d0bbf42013-08-06 09:49:14 +0100364#define is_gate_vma(vma) ((vma) == &gate_vma)
Russell Kinga5463cd2013-07-31 21:58:56 +0100365#else
366#define is_gate_vma(vma) 0
367#endif
Nicolas Pitreec706da2010-08-26 23:10:50 -0400368
369const char *arch_vma_name(struct vm_area_struct *vma)
370{
Nathan Lynch02e04092014-09-22 22:08:42 +0100371 return is_gate_vma(vma) ? "[vectors]" : NULL;
Russell King48be69a2013-07-24 00:29:18 +0100372}
373
Nathan Lynch389522b2014-09-22 22:12:35 +0100374/* If possible, provide a placement hint at a random offset from the
Nathan Lynchecf99a42015-03-25 19:15:08 +0100375 * stack for the sigpage and vdso pages.
Nathan Lynch389522b2014-09-22 22:12:35 +0100376 */
377static unsigned long sigpage_addr(const struct mm_struct *mm,
378 unsigned int npages)
379{
380 unsigned long offset;
381 unsigned long first;
382 unsigned long last;
383 unsigned long addr;
384 unsigned int slots;
385
386 first = PAGE_ALIGN(mm->start_stack);
387
388 last = TASK_SIZE - (npages << PAGE_SHIFT);
389
390 /* No room after stack? */
391 if (first > last)
392 return 0;
393
394 /* Just enough room? */
395 if (first == last)
396 return first;
397
398 slots = ((last - first) >> PAGE_SHIFT) + 1;
399
400 offset = get_random_int() % slots;
401
402 addr = first + (offset << PAGE_SHIFT);
403
404 return addr;
Russell King48be69a2013-07-24 00:29:18 +0100405}
406
Russell Kinge0d40752013-08-03 10:30:05 +0100407static struct page *signal_page;
Russell King48be69a2013-07-24 00:29:18 +0100408extern struct page *get_signal_page(void);
409
Dmitry Safonov280e87e2017-06-19 17:32:42 +0100410static int sigpage_mremap(const struct vm_special_mapping *sm,
411 struct vm_area_struct *new_vma)
412{
413 current->mm->context.sigpage = new_vma->vm_start;
414 return 0;
415}
416
Nathan Lynch02e04092014-09-22 22:08:42 +0100417static const struct vm_special_mapping sigpage_mapping = {
418 .name = "[sigpage]",
419 .pages = &signal_page,
Dmitry Safonov280e87e2017-06-19 17:32:42 +0100420 .mremap = sigpage_mremap,
Nathan Lynch02e04092014-09-22 22:08:42 +0100421};
422
Russell King48be69a2013-07-24 00:29:18 +0100423int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
424{
425 struct mm_struct *mm = current->mm;
Nathan Lynch02e04092014-09-22 22:08:42 +0100426 struct vm_area_struct *vma;
Nathan Lynchecf99a42015-03-25 19:15:08 +0100427 unsigned long npages;
Russell King48be69a2013-07-24 00:29:18 +0100428 unsigned long addr;
Nathan Lynch389522b2014-09-22 22:12:35 +0100429 unsigned long hint;
Nathan Lynch02e04092014-09-22 22:08:42 +0100430 int ret = 0;
Russell King48be69a2013-07-24 00:29:18 +0100431
Russell Kinge0d40752013-08-03 10:30:05 +0100432 if (!signal_page)
433 signal_page = get_signal_page();
434 if (!signal_page)
Russell King48be69a2013-07-24 00:29:18 +0100435 return -ENOMEM;
436
Nathan Lynchecf99a42015-03-25 19:15:08 +0100437 npages = 1; /* for sigpage */
438 npages += vdso_total_pages;
439
Michal Hocko69048172016-05-23 16:25:54 -0700440 if (down_write_killable(&mm->mmap_sem))
441 return -EINTR;
Nathan Lynchecf99a42015-03-25 19:15:08 +0100442 hint = sigpage_addr(mm, npages);
443 addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0);
Russell King48be69a2013-07-24 00:29:18 +0100444 if (IS_ERR_VALUE(addr)) {
445 ret = addr;
446 goto up_fail;
447 }
448
Nathan Lynch02e04092014-09-22 22:08:42 +0100449 vma = _install_special_mapping(mm, addr, PAGE_SIZE,
Russell King48be69a2013-07-24 00:29:18 +0100450 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
Nathan Lynch02e04092014-09-22 22:08:42 +0100451 &sigpage_mapping);
Russell King48be69a2013-07-24 00:29:18 +0100452
Nathan Lynch02e04092014-09-22 22:08:42 +0100453 if (IS_ERR(vma)) {
454 ret = PTR_ERR(vma);
455 goto up_fail;
456 }
457
458 mm->context.sigpage = addr;
Russell King48be69a2013-07-24 00:29:18 +0100459
Nathan Lynchecf99a42015-03-25 19:15:08 +0100460 /* Unlike the sigpage, failure to install the vdso is unlikely
461 * to be fatal to the process, so no error check needed
462 * here.
463 */
464 arm_install_vdso(mm, addr + PAGE_SIZE);
465
Russell King48be69a2013-07-24 00:29:18 +0100466 up_fail:
467 up_write(&mm->mmap_sem);
468 return ret;
Nicolas Pitreec706da2010-08-26 23:10:50 -0400469}
Will Deacon6cde6d42011-01-11 14:04:36 +0100470#endif