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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 | ||
23 | SYSCALL_DEFINE1(arc_settls, void *, user_tls_data_ptr) | |
24 | { | |
25 | task_thread_info(current)->thr_ptr = (unsigned int)user_tls_data_ptr; | |
26 | return 0; | |
27 | } | |
28 | ||
29 | /* | |
30 | * We return the user space TLS data ptr as sys-call return code | |
31 | * Ideally it should be copy to user. | |
32 | * However we can cheat by the fact that some sys-calls do return | |
33 | * absurdly high values | |
34 | * Since the tls dat aptr is not going to be in range of 0xFFFF_xxxx | |
35 | * it won't be considered a sys-call error | |
36 | * and it will be loads better than copy-to-user, which is a definite | |
37 | * D-TLB Miss | |
38 | */ | |
39 | SYSCALL_DEFINE0(arc_gettls) | |
40 | { | |
41 | return task_thread_info(current)->thr_ptr; | |
42 | } | |
bf90e1ea | 43 | |
91e040a7 VG |
44 | SYSCALL_DEFINE3(arc_usr_cmpxchg, int *, uaddr, int, expected, int, new) |
45 | { | |
e6e335bf | 46 | struct pt_regs *regs = current_pt_regs(); |
e8708786 PZ |
47 | u32 uval; |
48 | int ret; | |
91e040a7 VG |
49 | |
50 | /* | |
51 | * This is only for old cores lacking LLOCK/SCOND, which by defintion | |
52 | * can't possibly be SMP. Thus doesn't need to be SMP safe. | |
53 | * And this also helps reduce the overhead for serializing in | |
54 | * the UP case | |
55 | */ | |
56 | WARN_ON_ONCE(IS_ENABLED(CONFIG_SMP)); | |
57 | ||
e6e335bf VG |
58 | /* Z indicates to userspace if operation succeded */ |
59 | regs->status32 &= ~STATUS_Z_MASK; | |
60 | ||
96d4f267 | 61 | ret = access_ok(uaddr, sizeof(*uaddr)); |
e8708786 PZ |
62 | if (!ret) |
63 | goto fail; | |
91e040a7 | 64 | |
e8708786 | 65 | again: |
91e040a7 VG |
66 | preempt_disable(); |
67 | ||
e8708786 PZ |
68 | ret = __get_user(uval, uaddr); |
69 | if (ret) | |
70 | goto fault; | |
91e040a7 | 71 | |
e8708786 PZ |
72 | if (uval != expected) |
73 | goto out; | |
91e040a7 | 74 | |
e8708786 PZ |
75 | ret = __put_user(new, uaddr); |
76 | if (ret) | |
77 | goto fault; | |
78 | ||
79 | regs->status32 |= STATUS_Z_MASK; | |
91e040a7 | 80 | |
e8708786 PZ |
81 | out: |
82 | preempt_enable(); | |
e6e335bf | 83 | return uval; |
e8708786 PZ |
84 | |
85 | fault: | |
86 | preempt_enable(); | |
87 | ||
88 | if (unlikely(ret != -EFAULT)) | |
89 | goto fail; | |
90 | ||
91 | down_read(¤t->mm->mmap_sem); | |
92 | ret = fixup_user_fault(current, current->mm, (unsigned long) uaddr, | |
93 | FAULT_FLAG_WRITE, NULL); | |
94 | up_read(¤t->mm->mmap_sem); | |
95 | ||
96 | if (likely(!ret)) | |
97 | goto again; | |
98 | ||
99 | fail: | |
100 | force_sig(SIGSEGV, current); | |
101 | return ret; | |
91e040a7 VG |
102 | } |
103 | ||
64f42cec VG |
104 | #ifdef CONFIG_ISA_ARCV2 |
105 | ||
fa35e42a | 106 | void arch_cpu_idle(void) |
bf90e1ea | 107 | { |
64f42cec VG |
108 | /* Re-enable interrupts <= default irq priority before commiting SLEEP */ |
109 | const unsigned int arg = 0x10 | ARCV2_IRQ_DEF_PRIO; | |
110 | ||
512b5b89 VG |
111 | __asm__ __volatile__( |
112 | "sleep %0 \n" | |
113 | : | |
64f42cec VG |
114 | :"I"(arg)); /* can't be "r" has to be embedded const */ |
115 | } | |
116 | ||
644fa02b NC |
117 | #elif defined(CONFIG_EZNPS_MTM_EXT) /* ARC700 variant in NPS */ |
118 | ||
119 | void arch_cpu_idle(void) | |
120 | { | |
121 | /* only the calling HW thread needs to sleep */ | |
122 | __asm__ __volatile__( | |
123 | ".word %0 \n" | |
124 | : | |
125 | :"i"(CTOP_INST_HWSCHD_WFT_IE12)); | |
126 | } | |
127 | ||
128 | #else /* ARC700 */ | |
64f42cec VG |
129 | |
130 | void arch_cpu_idle(void) | |
131 | { | |
132 | /* sleep, but enable both set E1/E2 (levels of interrutps) before committing */ | |
133 | __asm__ __volatile__("sleep 0x3 \n"); | |
bf90e1ea VG |
134 | } |
135 | ||
64f42cec VG |
136 | #endif |
137 | ||
bf90e1ea VG |
138 | asmlinkage void ret_from_fork(void); |
139 | ||
18e1d1b1 AD |
140 | /* |
141 | * Copy architecture-specific thread state | |
142 | * | |
143 | * Layout of Child kernel mode stack as setup at the end of this function is | |
bf90e1ea VG |
144 | * |
145 | * | ... | | |
146 | * | ... | | |
147 | * | unused | | |
148 | * | | | |
bf90e1ea | 149 | * ------------------ |
16f9afe6 | 150 | * | r25 | <==== top of Stack (thread.ksp) |
bf90e1ea | 151 | * ~ ~ |
09074950 | 152 | * | --to-- | (CALLEE Regs of kernel mode) |
bf90e1ea VG |
153 | * | r13 | |
154 | * ------------------ | |
155 | * | fp | | |
156 | * | blink | @ret_from_fork | |
157 | * ------------------ | |
158 | * | | | |
159 | * ~ ~ | |
160 | * ~ ~ | |
161 | * | | | |
162 | * ------------------ | |
163 | * | r12 | | |
164 | * ~ ~ | |
165 | * | --to-- | (scratch Regs of user mode) | |
166 | * | r0 | | |
3ebedbb2 VG |
167 | * ------------------ |
168 | * | SP | | |
169 | * | orig_r0 | | |
502a0c77 | 170 | * | event/ECR | |
359105bd | 171 | * | user_r25 | |
bf90e1ea VG |
172 | * ------------------ <===== END of PAGE |
173 | */ | |
174 | int copy_thread(unsigned long clone_flags, | |
18e1d1b1 | 175 | unsigned long usp, unsigned long kthread_arg, |
bf90e1ea VG |
176 | struct task_struct *p) |
177 | { | |
178 | struct pt_regs *c_regs; /* child's pt_regs */ | |
179 | unsigned long *childksp; /* to unwind out of __switch_to() */ | |
180 | struct callee_regs *c_callee; /* child's callee regs */ | |
181 | struct callee_regs *parent_callee; /* paren't callee */ | |
182 | struct pt_regs *regs = current_pt_regs(); | |
183 | ||
184 | /* Mark the specific anchors to begin with (see pic above) */ | |
185 | c_regs = task_pt_regs(p); | |
186 | childksp = (unsigned long *)c_regs - 2; /* 2 words for FP/BLINK */ | |
187 | c_callee = ((struct callee_regs *)childksp) - 1; | |
188 | ||
189 | /* | |
190 | * __switch_to() uses thread.ksp to start unwinding stack | |
191 | * For kernel threads we don't need to create callee regs, the | |
192 | * stack layout nevertheless needs to remain the same. | |
193 | * Also, since __switch_to anyways unwinds callee regs, we use | |
194 | * this to populate kernel thread entry-pt/args into callee regs, | |
195 | * so that ret_from_kernel_thread() becomes simpler. | |
196 | */ | |
197 | p->thread.ksp = (unsigned long)c_callee; /* THREAD_KSP */ | |
198 | ||
199 | /* __switch_to expects FP(0), BLINK(return addr) at top */ | |
200 | childksp[0] = 0; /* fp */ | |
201 | childksp[1] = (unsigned long)ret_from_fork; /* blink */ | |
202 | ||
203 | if (unlikely(p->flags & PF_KTHREAD)) { | |
204 | memset(c_regs, 0, sizeof(struct pt_regs)); | |
205 | ||
18e1d1b1 | 206 | c_callee->r13 = kthread_arg; |
bf90e1ea VG |
207 | c_callee->r14 = usp; /* function */ |
208 | ||
209 | return 0; | |
210 | } | |
211 | ||
212 | /*--------- User Task Only --------------*/ | |
213 | ||
214 | /* __switch_to expects FP(0), BLINK(return addr) at top of stack */ | |
215 | childksp[0] = 0; /* for POP fp */ | |
216 | childksp[1] = (unsigned long)ret_from_fork; /* for POP blink */ | |
217 | ||
218 | /* Copy parents pt regs on child's kernel mode stack */ | |
219 | *c_regs = *regs; | |
220 | ||
221 | if (usp) | |
222 | c_regs->sp = usp; | |
223 | ||
224 | c_regs->r0 = 0; /* fork returns 0 in child */ | |
225 | ||
226 | parent_callee = ((struct callee_regs *)regs) - 1; | |
227 | *c_callee = *parent_callee; | |
228 | ||
229 | if (unlikely(clone_flags & CLONE_SETTLS)) { | |
230 | /* | |
231 | * set task's userland tls data ptr from 4th arg | |
232 | * clone C-lib call is difft from clone sys-call | |
233 | */ | |
234 | task_thread_info(p)->thr_ptr = regs->r3; | |
235 | } else { | |
236 | /* Normal fork case: set parent's TLS ptr in child */ | |
237 | task_thread_info(p)->thr_ptr = | |
238 | task_thread_info(current)->thr_ptr; | |
239 | } | |
240 | ||
c58a584f VG |
241 | |
242 | /* | |
243 | * setup usermode thread pointer #1: | |
244 | * when child is picked by scheduler, __switch_to() uses @c_callee to | |
245 | * populate usermode callee regs: this works (despite being in a kernel | |
246 | * function) since special return path for child @ret_from_fork() | |
247 | * ensures those regs are not clobbered all the way to RTIE to usermode | |
248 | */ | |
249 | c_callee->r25 = task_thread_info(p)->thr_ptr; | |
250 | ||
251 | #ifdef CONFIG_ARC_CURR_IN_REG | |
252 | /* | |
253 | * setup usermode thread pointer #2: | |
254 | * however for this special use of r25 in kernel, __switch_to() sets | |
255 | * r25 for kernel needs and only in the final return path is usermode | |
256 | * r25 setup, from pt_regs->user_r25. So set that up as well | |
257 | */ | |
258 | c_regs->user_r25 = c_callee->r25; | |
259 | #endif | |
260 | ||
bf90e1ea VG |
261 | return 0; |
262 | } | |
263 | ||
2ab402df VG |
264 | /* |
265 | * Do necessary setup to start up a new user task | |
266 | */ | |
267 | void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long usp) | |
268 | { | |
2ab402df VG |
269 | regs->sp = usp; |
270 | regs->ret = pc; | |
271 | ||
272 | /* | |
273 | * [U]ser Mode bit set | |
274 | * [L] ZOL loop inhibited to begin with - cleared by a LP insn | |
275 | * Interrupts enabled | |
276 | */ | |
1f6ccfff | 277 | regs->status32 = STATUS_U_MASK | STATUS_L_MASK | ISA_INIT_STATUS_BITS; |
2ab402df | 278 | |
28923f6b LR |
279 | #ifdef CONFIG_EZNPS_MTM_EXT |
280 | regs->eflags = 0; | |
281 | #endif | |
282 | ||
2ab402df VG |
283 | /* bogus seed values for debugging */ |
284 | regs->lp_start = 0x10; | |
285 | regs->lp_end = 0x80; | |
286 | } | |
287 | ||
bf90e1ea VG |
288 | /* |
289 | * Some archs flush debug and FPU info here | |
290 | */ | |
291 | void flush_thread(void) | |
292 | { | |
293 | } | |
294 | ||
bf90e1ea VG |
295 | int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) |
296 | { | |
297 | return 0; | |
298 | } | |
299 | ||
bf90e1ea VG |
300 | int elf_check_arch(const struct elf32_hdr *x) |
301 | { | |
302 | unsigned int eflags; | |
303 | ||
1f6ccfff VG |
304 | if (x->e_machine != EM_ARC_INUSE) { |
305 | pr_err("ELF not built for %s ISA\n", | |
306 | is_isa_arcompact() ? "ARCompact":"ARCv2"); | |
bf90e1ea | 307 | return 0; |
1f6ccfff | 308 | } |
bf90e1ea VG |
309 | |
310 | eflags = x->e_flags; | |
840c054f | 311 | if ((eflags & EF_ARC_OSABI_MSK) != EF_ARC_OSABI_CURRENT) { |
bf90e1ea VG |
312 | pr_err("ABI mismatch - you need newer toolchain\n"); |
313 | force_sigsegv(SIGSEGV, current); | |
314 | return 0; | |
315 | } | |
316 | ||
317 | return 1; | |
318 | } | |
319 | EXPORT_SYMBOL(elf_check_arch); |