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Vineet Gupta4adeefe2013-01-18 15:12:18 +05301/*
2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * Amit Bhor, Kanika Nema: Codito Technologies 2004
9 */
10
11#include <linux/errno.h>
12#include <linux/module.h>
13#include <linux/sched.h>
Ingo Molnar29930022017-02-08 18:51:36 +010014#include <linux/sched/task.h>
Ingo Molnar68db0cf2017-02-08 18:51:37 +010015#include <linux/sched/task_stack.h>
Ingo Molnar29930022017-02-08 18:51:36 +010016
Vineet Gupta4adeefe2013-01-18 15:12:18 +053017#include <linux/mm.h>
18#include <linux/fs.h>
19#include <linux/unistd.h>
20#include <linux/ptrace.h>
21#include <linux/slab.h>
22#include <linux/syscalls.h>
23#include <linux/elf.h>
24#include <linux/tick.h>
25
26SYSCALL_DEFINE1(arc_settls, void *, user_tls_data_ptr)
27{
28 task_thread_info(current)->thr_ptr = (unsigned int)user_tls_data_ptr;
29 return 0;
30}
31
32/*
33 * We return the user space TLS data ptr as sys-call return code
34 * Ideally it should be copy to user.
35 * However we can cheat by the fact that some sys-calls do return
36 * absurdly high values
37 * Since the tls dat aptr is not going to be in range of 0xFFFF_xxxx
38 * it won't be considered a sys-call error
39 * and it will be loads better than copy-to-user, which is a definite
40 * D-TLB Miss
41 */
42SYSCALL_DEFINE0(arc_gettls)
43{
44 return task_thread_info(current)->thr_ptr;
45}
Vineet Guptabf90e1e2013-01-18 15:12:18 +053046
Vineet Gupta91e040a2016-10-20 07:39:45 -070047SYSCALL_DEFINE3(arc_usr_cmpxchg, int *, uaddr, int, expected, int, new)
48{
Vineet Guptae6e335b2016-11-07 10:36:46 -080049 struct pt_regs *regs = current_pt_regs();
Peter Zijlstra09af6c92018-06-19 17:22:05 +030050 u32 uval;
51 int ret;
Vineet Gupta91e040a2016-10-20 07:39:45 -070052
53 /*
54 * This is only for old cores lacking LLOCK/SCOND, which by defintion
55 * can't possibly be SMP. Thus doesn't need to be SMP safe.
56 * And this also helps reduce the overhead for serializing in
57 * the UP case
58 */
59 WARN_ON_ONCE(IS_ENABLED(CONFIG_SMP));
60
Vineet Guptae6e335b2016-11-07 10:36:46 -080061 /* Z indicates to userspace if operation succeded */
62 regs->status32 &= ~STATUS_Z_MASK;
63
Peter Zijlstra09af6c92018-06-19 17:22:05 +030064 ret = access_ok(VERIFY_WRITE, uaddr, sizeof(*uaddr));
65 if (!ret)
66 goto fail;
Vineet Gupta91e040a2016-10-20 07:39:45 -070067
Peter Zijlstra09af6c92018-06-19 17:22:05 +030068again:
Vineet Gupta91e040a2016-10-20 07:39:45 -070069 preempt_disable();
70
Peter Zijlstra09af6c92018-06-19 17:22:05 +030071 ret = __get_user(uval, uaddr);
72 if (ret)
73 goto fault;
Vineet Gupta91e040a2016-10-20 07:39:45 -070074
Peter Zijlstra09af6c92018-06-19 17:22:05 +030075 if (uval != expected)
76 goto out;
Vineet Gupta91e040a2016-10-20 07:39:45 -070077
Peter Zijlstra09af6c92018-06-19 17:22:05 +030078 ret = __put_user(new, uaddr);
79 if (ret)
80 goto fault;
81
82 regs->status32 |= STATUS_Z_MASK;
83
84out:
85 preempt_enable();
86 return uval;
87
88fault:
Vineet Gupta91e040a2016-10-20 07:39:45 -070089 preempt_enable();
90
Peter Zijlstra09af6c92018-06-19 17:22:05 +030091 if (unlikely(ret != -EFAULT))
92 goto fail;
93
94 down_read(&current->mm->mmap_sem);
95 ret = fixup_user_fault(current, current->mm, (unsigned long) uaddr,
96 FAULT_FLAG_WRITE, NULL);
97 up_read(&current->mm->mmap_sem);
98
99 if (likely(!ret))
100 goto again;
101
102fail:
103 force_sig(SIGSEGV, current);
104 return ret;
Vineet Gupta91e040a2016-10-20 07:39:45 -0700105}
106
Vineet Gupta64f42ce2017-06-02 11:49:10 -0700107#ifdef CONFIG_ISA_ARCV2
108
Thomas Gleixnerfa35e422013-03-21 22:49:36 +0100109void arch_cpu_idle(void)
Vineet Guptabf90e1e2013-01-18 15:12:18 +0530110{
Vineet Gupta64f42ce2017-06-02 11:49:10 -0700111 /* Re-enable interrupts <= default irq priority before commiting SLEEP */
112 const unsigned int arg = 0x10 | ARCV2_IRQ_DEF_PRIO;
113
Vineet Gupta512b5b82015-11-16 13:52:07 +0530114 __asm__ __volatile__(
115 "sleep %0 \n"
116 :
Vineet Gupta64f42ce2017-06-02 11:49:10 -0700117 :"I"(arg)); /* can't be "r" has to be embedded const */
Vineet Guptabf90e1e2013-01-18 15:12:18 +0530118}
119
Noam Camus644fa022017-05-28 09:52:06 +0300120#elif defined(CONFIG_EZNPS_MTM_EXT) /* ARC700 variant in NPS */
121
122void arch_cpu_idle(void)
123{
124 /* only the calling HW thread needs to sleep */
125 __asm__ __volatile__(
126 ".word %0 \n"
127 :
128 :"i"(CTOP_INST_HWSCHD_WFT_IE12));
129}
130
131#else /* ARC700 */
Vineet Gupta64f42ce2017-06-02 11:49:10 -0700132
133void arch_cpu_idle(void)
134{
135 /* sleep, but enable both set E1/E2 (levels of interrutps) before committing */
136 __asm__ __volatile__("sleep 0x3 \n");
137}
138
139#endif
140
Vineet Guptabf90e1e2013-01-18 15:12:18 +0530141asmlinkage void ret_from_fork(void);
142
Alex Dowad18e1d1b2015-03-13 20:04:18 +0200143/*
144 * Copy architecture-specific thread state
145 *
146 * Layout of Child kernel mode stack as setup at the end of this function is
Vineet Guptabf90e1e2013-01-18 15:12:18 +0530147 *
148 * | ... |
149 * | ... |
150 * | unused |
151 * | |
Vineet Guptabf90e1e2013-01-18 15:12:18 +0530152 * ------------------
Vineet Gupta16f9afe2013-05-27 21:43:41 +0530153 * | r25 | <==== top of Stack (thread.ksp)
Vineet Guptabf90e1e2013-01-18 15:12:18 +0530154 * ~ ~
Vineet Gupta09074952015-08-19 17:23:58 +0530155 * | --to-- | (CALLEE Regs of kernel mode)
Vineet Guptabf90e1e2013-01-18 15:12:18 +0530156 * | r13 |
157 * ------------------
158 * | fp |
159 * | blink | @ret_from_fork
160 * ------------------
161 * | |
162 * ~ ~
163 * ~ ~
164 * | |
165 * ------------------
166 * | r12 |
167 * ~ ~
168 * | --to-- | (scratch Regs of user mode)
169 * | r0 |
Vineet Gupta3ebedbb2013-05-28 13:24:43 +0530170 * ------------------
171 * | SP |
172 * | orig_r0 |
Vineet Gupta502a0c72013-06-11 18:56:54 +0530173 * | event/ECR |
Vineet Gupta359105b2013-05-28 13:50:41 +0530174 * | user_r25 |
Vineet Guptabf90e1e2013-01-18 15:12:18 +0530175 * ------------------ <===== END of PAGE
176 */
177int copy_thread(unsigned long clone_flags,
Alex Dowad18e1d1b2015-03-13 20:04:18 +0200178 unsigned long usp, unsigned long kthread_arg,
Vineet Guptabf90e1e2013-01-18 15:12:18 +0530179 struct task_struct *p)
180{
181 struct pt_regs *c_regs; /* child's pt_regs */
182 unsigned long *childksp; /* to unwind out of __switch_to() */
183 struct callee_regs *c_callee; /* child's callee regs */
184 struct callee_regs *parent_callee; /* paren't callee */
185 struct pt_regs *regs = current_pt_regs();
186
187 /* Mark the specific anchors to begin with (see pic above) */
188 c_regs = task_pt_regs(p);
189 childksp = (unsigned long *)c_regs - 2; /* 2 words for FP/BLINK */
190 c_callee = ((struct callee_regs *)childksp) - 1;
191
192 /*
193 * __switch_to() uses thread.ksp to start unwinding stack
194 * For kernel threads we don't need to create callee regs, the
195 * stack layout nevertheless needs to remain the same.
196 * Also, since __switch_to anyways unwinds callee regs, we use
197 * this to populate kernel thread entry-pt/args into callee regs,
198 * so that ret_from_kernel_thread() becomes simpler.
199 */
200 p->thread.ksp = (unsigned long)c_callee; /* THREAD_KSP */
201
202 /* __switch_to expects FP(0), BLINK(return addr) at top */
203 childksp[0] = 0; /* fp */
204 childksp[1] = (unsigned long)ret_from_fork; /* blink */
205
206 if (unlikely(p->flags & PF_KTHREAD)) {
207 memset(c_regs, 0, sizeof(struct pt_regs));
208
Alex Dowad18e1d1b2015-03-13 20:04:18 +0200209 c_callee->r13 = kthread_arg;
Vineet Guptabf90e1e2013-01-18 15:12:18 +0530210 c_callee->r14 = usp; /* function */
211
212 return 0;
213 }
214
215 /*--------- User Task Only --------------*/
216
217 /* __switch_to expects FP(0), BLINK(return addr) at top of stack */
218 childksp[0] = 0; /* for POP fp */
219 childksp[1] = (unsigned long)ret_from_fork; /* for POP blink */
220
221 /* Copy parents pt regs on child's kernel mode stack */
222 *c_regs = *regs;
223
224 if (usp)
225 c_regs->sp = usp;
226
227 c_regs->r0 = 0; /* fork returns 0 in child */
228
229 parent_callee = ((struct callee_regs *)regs) - 1;
230 *c_callee = *parent_callee;
231
232 if (unlikely(clone_flags & CLONE_SETTLS)) {
233 /*
234 * set task's userland tls data ptr from 4th arg
235 * clone C-lib call is difft from clone sys-call
236 */
237 task_thread_info(p)->thr_ptr = regs->r3;
238 } else {
239 /* Normal fork case: set parent's TLS ptr in child */
240 task_thread_info(p)->thr_ptr =
241 task_thread_info(current)->thr_ptr;
242 }
243
Vineet Guptab5dcd4a2018-10-05 12:48:48 -0700244
245 /*
246 * setup usermode thread pointer #1:
247 * when child is picked by scheduler, __switch_to() uses @c_callee to
248 * populate usermode callee regs: this works (despite being in a kernel
249 * function) since special return path for child @ret_from_fork()
250 * ensures those regs are not clobbered all the way to RTIE to usermode
251 */
252 c_callee->r25 = task_thread_info(p)->thr_ptr;
253
254#ifdef CONFIG_ARC_CURR_IN_REG
255 /*
256 * setup usermode thread pointer #2:
257 * however for this special use of r25 in kernel, __switch_to() sets
258 * r25 for kernel needs and only in the final return path is usermode
259 * r25 setup, from pt_regs->user_r25. So set that up as well
260 */
261 c_regs->user_r25 = c_callee->r25;
262#endif
263
Vineet Guptabf90e1e2013-01-18 15:12:18 +0530264 return 0;
265}
266
267/*
Vineet Gupta2ab402d2014-04-18 12:19:59 +0530268 * Do necessary setup to start up a new user task
269 */
270void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long usp)
271{
Vineet Gupta2ab402d2014-04-18 12:19:59 +0530272 regs->sp = usp;
273 regs->ret = pc;
274
275 /*
276 * [U]ser Mode bit set
277 * [L] ZOL loop inhibited to begin with - cleared by a LP insn
278 * Interrupts enabled
279 */
Vineet Gupta1f6ccff2013-05-13 18:30:41 +0530280 regs->status32 = STATUS_U_MASK | STATUS_L_MASK | ISA_INIT_STATUS_BITS;
Vineet Gupta2ab402d2014-04-18 12:19:59 +0530281
Liav Rehana28923f62017-06-15 11:44:00 +0300282#ifdef CONFIG_EZNPS_MTM_EXT
283 regs->eflags = 0;
284#endif
285
Vineet Gupta2ab402d2014-04-18 12:19:59 +0530286 /* bogus seed values for debugging */
287 regs->lp_start = 0x10;
288 regs->lp_end = 0x80;
289}
290
291/*
Vineet Guptabf90e1e2013-01-18 15:12:18 +0530292 * Some archs flush debug and FPU info here
293 */
294void flush_thread(void)
295{
296}
297
Vineet Guptabf90e1e2013-01-18 15:12:18 +0530298int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
299{
300 return 0;
301}
302
Vineet Guptabf90e1e2013-01-18 15:12:18 +0530303int elf_check_arch(const struct elf32_hdr *x)
304{
305 unsigned int eflags;
306
Vineet Gupta1f6ccff2013-05-13 18:30:41 +0530307 if (x->e_machine != EM_ARC_INUSE) {
308 pr_err("ELF not built for %s ISA\n",
309 is_isa_arcompact() ? "ARCompact":"ARCv2");
Vineet Guptabf90e1e2013-01-18 15:12:18 +0530310 return 0;
Vineet Gupta1f6ccff2013-05-13 18:30:41 +0530311 }
Vineet Guptabf90e1e2013-01-18 15:12:18 +0530312
313 eflags = x->e_flags;
Vineet Gupta840c0542016-08-10 14:10:57 -0700314 if ((eflags & EF_ARC_OSABI_MSK) != EF_ARC_OSABI_CURRENT) {
Vineet Guptabf90e1e2013-01-18 15:12:18 +0530315 pr_err("ABI mismatch - you need newer toolchain\n");
316 force_sigsegv(SIGSEGV, current);
317 return 0;
318 }
319
320 return 1;
321}
322EXPORT_SYMBOL(elf_check_arch);