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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
4adeefe1 VG |
2 | /* |
3 | * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) | |
4 | * | |
4adeefe1 VG |
5 | * Amit Bhor, Kanika Nema: Codito Technologies 2004 |
6 | */ | |
7 | ||
8 | #include <linux/errno.h> | |
9 | #include <linux/module.h> | |
10 | #include <linux/sched.h> | |
29930025 | 11 | #include <linux/sched/task.h> |
68db0cf1 | 12 | #include <linux/sched/task_stack.h> |
29930025 | 13 | |
4adeefe1 VG |
14 | #include <linux/mm.h> |
15 | #include <linux/fs.h> | |
16 | #include <linux/unistd.h> | |
17 | #include <linux/ptrace.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/syscalls.h> | |
20 | #include <linux/elf.h> | |
21 | #include <linux/tick.h> | |
22 | ||
f45ba2bd VG |
23 | #include <asm/fpu.h> |
24 | ||
4adeefe1 VG |
25 | SYSCALL_DEFINE1(arc_settls, void *, user_tls_data_ptr) |
26 | { | |
27 | task_thread_info(current)->thr_ptr = (unsigned int)user_tls_data_ptr; | |
28 | return 0; | |
29 | } | |
30 | ||
31 | /* | |
32 | * We return the user space TLS data ptr as sys-call return code | |
33 | * Ideally it should be copy to user. | |
34 | * However we can cheat by the fact that some sys-calls do return | |
35 | * absurdly high values | |
36 | * Since the tls dat aptr is not going to be in range of 0xFFFF_xxxx | |
37 | * it won't be considered a sys-call error | |
38 | * and it will be loads better than copy-to-user, which is a definite | |
39 | * D-TLB Miss | |
40 | */ | |
41 | SYSCALL_DEFINE0(arc_gettls) | |
42 | { | |
43 | return task_thread_info(current)->thr_ptr; | |
44 | } | |
bf90e1ea | 45 | |
034c4eba | 46 | SYSCALL_DEFINE3(arc_usr_cmpxchg, int __user *, uaddr, int, expected, int, new) |
91e040a7 | 47 | { |
e6e335bf | 48 | struct pt_regs *regs = current_pt_regs(); |
e8708786 PZ |
49 | u32 uval; |
50 | int ret; | |
91e040a7 VG |
51 | |
52 | /* | |
f79f7a2d | 53 | * This is only for old cores lacking LLOCK/SCOND, which by definition |
91e040a7 VG |
54 | * can't possibly be SMP. Thus doesn't need to be SMP safe. |
55 | * And this also helps reduce the overhead for serializing in | |
56 | * the UP case | |
57 | */ | |
58 | WARN_ON_ONCE(IS_ENABLED(CONFIG_SMP)); | |
59 | ||
f79f7a2d | 60 | /* Z indicates to userspace if operation succeeded */ |
e6e335bf VG |
61 | regs->status32 &= ~STATUS_Z_MASK; |
62 | ||
96d4f267 | 63 | ret = access_ok(uaddr, sizeof(*uaddr)); |
e8708786 PZ |
64 | if (!ret) |
65 | goto fail; | |
91e040a7 | 66 | |
e8708786 | 67 | again: |
91e040a7 VG |
68 | preempt_disable(); |
69 | ||
e8708786 PZ |
70 | ret = __get_user(uval, uaddr); |
71 | if (ret) | |
72 | goto fault; | |
91e040a7 | 73 | |
e8708786 PZ |
74 | if (uval != expected) |
75 | goto out; | |
91e040a7 | 76 | |
e8708786 PZ |
77 | ret = __put_user(new, uaddr); |
78 | if (ret) | |
79 | goto fault; | |
80 | ||
81 | regs->status32 |= STATUS_Z_MASK; | |
91e040a7 | 82 | |
e8708786 PZ |
83 | out: |
84 | preempt_enable(); | |
e6e335bf | 85 | return uval; |
e8708786 PZ |
86 | |
87 | fault: | |
88 | preempt_enable(); | |
89 | ||
90 | if (unlikely(ret != -EFAULT)) | |
91 | goto fail; | |
92 | ||
d8ed45c5 | 93 | mmap_read_lock(current->mm); |
64019a2e | 94 | ret = fixup_user_fault(current->mm, (unsigned long) uaddr, |
e8708786 | 95 | FAULT_FLAG_WRITE, NULL); |
d8ed45c5 | 96 | mmap_read_unlock(current->mm); |
e8708786 PZ |
97 | |
98 | if (likely(!ret)) | |
99 | goto again; | |
100 | ||
101 | fail: | |
3cf5d076 | 102 | force_sig(SIGSEGV); |
e8708786 | 103 | return ret; |
91e040a7 VG |
104 | } |
105 | ||
64f42cec VG |
106 | #ifdef CONFIG_ISA_ARCV2 |
107 | ||
fa35e42a | 108 | void arch_cpu_idle(void) |
bf90e1ea | 109 | { |
f79f7a2d | 110 | /* Re-enable interrupts <= default irq priority before committing SLEEP */ |
64f42cec VG |
111 | const unsigned int arg = 0x10 | ARCV2_IRQ_DEF_PRIO; |
112 | ||
512b5b89 VG |
113 | __asm__ __volatile__( |
114 | "sleep %0 \n" | |
115 | : | |
64f42cec VG |
116 | :"I"(arg)); /* can't be "r" has to be embedded const */ |
117 | } | |
118 | ||
644fa02b | 119 | #else /* ARC700 */ |
64f42cec VG |
120 | |
121 | void arch_cpu_idle(void) | |
122 | { | |
f79f7a2d | 123 | /* sleep, but enable both set E1/E2 (levels of interrupts) before committing */ |
64f42cec | 124 | __asm__ __volatile__("sleep 0x3 \n"); |
bf90e1ea VG |
125 | } |
126 | ||
64f42cec VG |
127 | #endif |
128 | ||
bf90e1ea VG |
129 | asmlinkage void ret_from_fork(void); |
130 | ||
18e1d1b1 AD |
131 | /* |
132 | * Copy architecture-specific thread state | |
133 | * | |
134 | * Layout of Child kernel mode stack as setup at the end of this function is | |
bf90e1ea VG |
135 | * |
136 | * | ... | | |
137 | * | ... | | |
138 | * | unused | | |
139 | * | | | |
bf90e1ea | 140 | * ------------------ |
16f9afe6 | 141 | * | r25 | <==== top of Stack (thread.ksp) |
bf90e1ea | 142 | * ~ ~ |
09074950 | 143 | * | --to-- | (CALLEE Regs of kernel mode) |
bf90e1ea VG |
144 | * | r13 | |
145 | * ------------------ | |
146 | * | fp | | |
147 | * | blink | @ret_from_fork | |
148 | * ------------------ | |
149 | * | | | |
150 | * ~ ~ | |
151 | * ~ ~ | |
152 | * | | | |
153 | * ------------------ | |
154 | * | r12 | | |
155 | * ~ ~ | |
156 | * | --to-- | (scratch Regs of user mode) | |
157 | * | r0 | | |
3ebedbb2 VG |
158 | * ------------------ |
159 | * | SP | | |
160 | * | orig_r0 | | |
502a0c77 | 161 | * | event/ECR | |
359105bd | 162 | * | user_r25 | |
bf90e1ea VG |
163 | * ------------------ <===== END of PAGE |
164 | */ | |
714acdbd CB |
165 | int copy_thread(unsigned long clone_flags, unsigned long usp, |
166 | unsigned long kthread_arg, struct task_struct *p, | |
167 | unsigned long tls) | |
bf90e1ea VG |
168 | { |
169 | struct pt_regs *c_regs; /* child's pt_regs */ | |
170 | unsigned long *childksp; /* to unwind out of __switch_to() */ | |
171 | struct callee_regs *c_callee; /* child's callee regs */ | |
172 | struct callee_regs *parent_callee; /* paren't callee */ | |
173 | struct pt_regs *regs = current_pt_regs(); | |
174 | ||
175 | /* Mark the specific anchors to begin with (see pic above) */ | |
176 | c_regs = task_pt_regs(p); | |
177 | childksp = (unsigned long *)c_regs - 2; /* 2 words for FP/BLINK */ | |
178 | c_callee = ((struct callee_regs *)childksp) - 1; | |
179 | ||
180 | /* | |
181 | * __switch_to() uses thread.ksp to start unwinding stack | |
182 | * For kernel threads we don't need to create callee regs, the | |
183 | * stack layout nevertheless needs to remain the same. | |
184 | * Also, since __switch_to anyways unwinds callee regs, we use | |
185 | * this to populate kernel thread entry-pt/args into callee regs, | |
186 | * so that ret_from_kernel_thread() becomes simpler. | |
187 | */ | |
188 | p->thread.ksp = (unsigned long)c_callee; /* THREAD_KSP */ | |
189 | ||
190 | /* __switch_to expects FP(0), BLINK(return addr) at top */ | |
191 | childksp[0] = 0; /* fp */ | |
192 | childksp[1] = (unsigned long)ret_from_fork; /* blink */ | |
193 | ||
4727dc20 | 194 | if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) { |
bf90e1ea VG |
195 | memset(c_regs, 0, sizeof(struct pt_regs)); |
196 | ||
18e1d1b1 | 197 | c_callee->r13 = kthread_arg; |
bf90e1ea VG |
198 | c_callee->r14 = usp; /* function */ |
199 | ||
200 | return 0; | |
201 | } | |
202 | ||
203 | /*--------- User Task Only --------------*/ | |
204 | ||
205 | /* __switch_to expects FP(0), BLINK(return addr) at top of stack */ | |
206 | childksp[0] = 0; /* for POP fp */ | |
207 | childksp[1] = (unsigned long)ret_from_fork; /* for POP blink */ | |
208 | ||
209 | /* Copy parents pt regs on child's kernel mode stack */ | |
210 | *c_regs = *regs; | |
211 | ||
212 | if (usp) | |
213 | c_regs->sp = usp; | |
214 | ||
215 | c_regs->r0 = 0; /* fork returns 0 in child */ | |
216 | ||
217 | parent_callee = ((struct callee_regs *)regs) - 1; | |
218 | *c_callee = *parent_callee; | |
219 | ||
220 | if (unlikely(clone_flags & CLONE_SETTLS)) { | |
221 | /* | |
222 | * set task's userland tls data ptr from 4th arg | |
223 | * clone C-lib call is difft from clone sys-call | |
224 | */ | |
bd71c453 | 225 | task_thread_info(p)->thr_ptr = tls; |
bf90e1ea VG |
226 | } else { |
227 | /* Normal fork case: set parent's TLS ptr in child */ | |
228 | task_thread_info(p)->thr_ptr = | |
229 | task_thread_info(current)->thr_ptr; | |
230 | } | |
231 | ||
c58a584f VG |
232 | |
233 | /* | |
234 | * setup usermode thread pointer #1: | |
235 | * when child is picked by scheduler, __switch_to() uses @c_callee to | |
236 | * populate usermode callee regs: this works (despite being in a kernel | |
237 | * function) since special return path for child @ret_from_fork() | |
238 | * ensures those regs are not clobbered all the way to RTIE to usermode | |
239 | */ | |
240 | c_callee->r25 = task_thread_info(p)->thr_ptr; | |
241 | ||
242 | #ifdef CONFIG_ARC_CURR_IN_REG | |
243 | /* | |
244 | * setup usermode thread pointer #2: | |
245 | * however for this special use of r25 in kernel, __switch_to() sets | |
246 | * r25 for kernel needs and only in the final return path is usermode | |
247 | * r25 setup, from pt_regs->user_r25. So set that up as well | |
248 | */ | |
249 | c_regs->user_r25 = c_callee->r25; | |
250 | #endif | |
251 | ||
bf90e1ea VG |
252 | return 0; |
253 | } | |
254 | ||
2ab402df VG |
255 | /* |
256 | * Do necessary setup to start up a new user task | |
257 | */ | |
f45ba2bd | 258 | void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp) |
2ab402df | 259 | { |
2ab402df VG |
260 | regs->sp = usp; |
261 | regs->ret = pc; | |
262 | ||
263 | /* | |
264 | * [U]ser Mode bit set | |
265 | * [L] ZOL loop inhibited to begin with - cleared by a LP insn | |
266 | * Interrupts enabled | |
267 | */ | |
1f6ccfff | 268 | regs->status32 = STATUS_U_MASK | STATUS_L_MASK | ISA_INIT_STATUS_BITS; |
2ab402df | 269 | |
f45ba2bd VG |
270 | fpu_init_task(regs); |
271 | ||
2ab402df VG |
272 | /* bogus seed values for debugging */ |
273 | regs->lp_start = 0x10; | |
274 | regs->lp_end = 0x80; | |
275 | } | |
276 | ||
bf90e1ea VG |
277 | /* |
278 | * Some archs flush debug and FPU info here | |
279 | */ | |
280 | void flush_thread(void) | |
281 | { | |
282 | } | |
283 | ||
bf90e1ea VG |
284 | int elf_check_arch(const struct elf32_hdr *x) |
285 | { | |
286 | unsigned int eflags; | |
287 | ||
1f6ccfff VG |
288 | if (x->e_machine != EM_ARC_INUSE) { |
289 | pr_err("ELF not built for %s ISA\n", | |
290 | is_isa_arcompact() ? "ARCompact":"ARCv2"); | |
bf90e1ea | 291 | return 0; |
1f6ccfff | 292 | } |
bf90e1ea VG |
293 | |
294 | eflags = x->e_flags; | |
840c054f | 295 | if ((eflags & EF_ARC_OSABI_MSK) != EF_ARC_OSABI_CURRENT) { |
bf90e1ea | 296 | pr_err("ABI mismatch - you need newer toolchain\n"); |
4e0608cc | 297 | force_fatal_sig(SIGSEGV); |
bf90e1ea VG |
298 | return 0; |
299 | } | |
300 | ||
301 | return 1; | |
302 | } | |
303 | EXPORT_SYMBOL(elf_check_arch); |