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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
4 *
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>
11#include <linux/sched/task.h>
12#include <linux/sched/task_stack.h>
13
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
23SYSCALL_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 */
39SYSCALL_DEFINE0(arc_gettls)
40{
41 return task_thread_info(current)->thr_ptr;
42}
43
44SYSCALL_DEFINE3(arc_usr_cmpxchg, int *, uaddr, int, expected, int, new)
45{
46 struct pt_regs *regs = current_pt_regs();
47 u32 uval;
48 int ret;
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
58 /* Z indicates to userspace if operation succeded */
59 regs->status32 &= ~STATUS_Z_MASK;
60
61 ret = access_ok(uaddr, sizeof(*uaddr));
62 if (!ret)
63 goto fail;
64
65again:
66 preempt_disable();
67
68 ret = __get_user(uval, uaddr);
69 if (ret)
70 goto fault;
71
72 if (uval != expected)
73 goto out;
74
75 ret = __put_user(new, uaddr);
76 if (ret)
77 goto fault;
78
79 regs->status32 |= STATUS_Z_MASK;
80
81out:
82 preempt_enable();
83 return uval;
84
85fault:
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
99fail:
100 force_sig(SIGSEGV);
101 return ret;
102}
103
104#ifdef CONFIG_ISA_ARCV2
105
106void arch_cpu_idle(void)
107{
108 /* Re-enable interrupts <= default irq priority before commiting SLEEP */
109 const unsigned int arg = 0x10 | ARCV2_IRQ_DEF_PRIO;
110
111 __asm__ __volatile__(
112 "sleep %0 \n"
113 :
114 :"I"(arg)); /* can't be "r" has to be embedded const */
115}
116
117#elif defined(CONFIG_EZNPS_MTM_EXT) /* ARC700 variant in NPS */
118
119void 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 */
129
130void arch_cpu_idle(void)
131{
132 /* sleep, but enable both set E1/E2 (levels of interrutps) before committing */
133 __asm__ __volatile__("sleep 0x3 \n");
134}
135
136#endif
137
138asmlinkage void ret_from_fork(void);
139
140/*
141 * Copy architecture-specific thread state
142 *
143 * Layout of Child kernel mode stack as setup at the end of this function is
144 *
145 * | ... |
146 * | ... |
147 * | unused |
148 * | |
149 * ------------------
150 * | r25 | <==== top of Stack (thread.ksp)
151 * ~ ~
152 * | --to-- | (CALLEE Regs of kernel mode)
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 |
167 * ------------------
168 * | SP |
169 * | orig_r0 |
170 * | event/ECR |
171 * | user_r25 |
172 * ------------------ <===== END of PAGE
173 */
174int copy_thread(unsigned long clone_flags,
175 unsigned long usp, unsigned long kthread_arg,
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
206 c_callee->r13 = kthread_arg;
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
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
261 return 0;
262}
263
264/*
265 * Do necessary setup to start up a new user task
266 */
267void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long usp)
268{
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 */
277 regs->status32 = STATUS_U_MASK | STATUS_L_MASK | ISA_INIT_STATUS_BITS;
278
279#ifdef CONFIG_EZNPS_MTM_EXT
280 regs->eflags = 0;
281#endif
282
283 /* bogus seed values for debugging */
284 regs->lp_start = 0x10;
285 regs->lp_end = 0x80;
286}
287
288/*
289 * Some archs flush debug and FPU info here
290 */
291void flush_thread(void)
292{
293}
294
295int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
296{
297 return 0;
298}
299
300int elf_check_arch(const struct elf32_hdr *x)
301{
302 unsigned int eflags;
303
304 if (x->e_machine != EM_ARC_INUSE) {
305 pr_err("ELF not built for %s ISA\n",
306 is_isa_arcompact() ? "ARCompact":"ARCv2");
307 return 0;
308 }
309
310 eflags = x->e_flags;
311 if ((eflags & EF_ARC_OSABI_MSK) != EF_ARC_OSABI_CURRENT) {
312 pr_err("ABI mismatch - you need newer toolchain\n");
313 force_sigsegv(SIGSEGV);
314 return 0;
315 }
316
317 return 1;
318}
319EXPORT_SYMBOL(elf_check_arch);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
4 *
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>
11#include <linux/sched/task.h>
12#include <linux/sched/task_stack.h>
13
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#include <asm/fpu.h>
24
25SYSCALL_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 */
41SYSCALL_DEFINE0(arc_gettls)
42{
43 return task_thread_info(current)->thr_ptr;
44}
45
46SYSCALL_DEFINE3(arc_usr_cmpxchg, int *, uaddr, int, expected, int, new)
47{
48 struct pt_regs *regs = current_pt_regs();
49 u32 uval;
50 int ret;
51
52 /*
53 * This is only for old cores lacking LLOCK/SCOND, which by defintion
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
60 /* Z indicates to userspace if operation succeded */
61 regs->status32 &= ~STATUS_Z_MASK;
62
63 ret = access_ok(uaddr, sizeof(*uaddr));
64 if (!ret)
65 goto fail;
66
67again:
68 preempt_disable();
69
70 ret = __get_user(uval, uaddr);
71 if (ret)
72 goto fault;
73
74 if (uval != expected)
75 goto out;
76
77 ret = __put_user(new, uaddr);
78 if (ret)
79 goto fault;
80
81 regs->status32 |= STATUS_Z_MASK;
82
83out:
84 preempt_enable();
85 return uval;
86
87fault:
88 preempt_enable();
89
90 if (unlikely(ret != -EFAULT))
91 goto fail;
92
93 mmap_read_lock(current->mm);
94 ret = fixup_user_fault(current->mm, (unsigned long) uaddr,
95 FAULT_FLAG_WRITE, NULL);
96 mmap_read_unlock(current->mm);
97
98 if (likely(!ret))
99 goto again;
100
101fail:
102 force_sig(SIGSEGV);
103 return ret;
104}
105
106#ifdef CONFIG_ISA_ARCV2
107
108void arch_cpu_idle(void)
109{
110 /* Re-enable interrupts <= default irq priority before commiting SLEEP */
111 const unsigned int arg = 0x10 | ARCV2_IRQ_DEF_PRIO;
112
113 __asm__ __volatile__(
114 "sleep %0 \n"
115 :
116 :"I"(arg)); /* can't be "r" has to be embedded const */
117}
118
119#elif defined(CONFIG_EZNPS_MTM_EXT) /* ARC700 variant in NPS */
120
121void arch_cpu_idle(void)
122{
123 /* only the calling HW thread needs to sleep */
124 __asm__ __volatile__(
125 ".word %0 \n"
126 :
127 :"i"(CTOP_INST_HWSCHD_WFT_IE12));
128}
129
130#else /* ARC700 */
131
132void arch_cpu_idle(void)
133{
134 /* sleep, but enable both set E1/E2 (levels of interrutps) before committing */
135 __asm__ __volatile__("sleep 0x3 \n");
136}
137
138#endif
139
140asmlinkage void ret_from_fork(void);
141
142/*
143 * Copy architecture-specific thread state
144 *
145 * Layout of Child kernel mode stack as setup at the end of this function is
146 *
147 * | ... |
148 * | ... |
149 * | unused |
150 * | |
151 * ------------------
152 * | r25 | <==== top of Stack (thread.ksp)
153 * ~ ~
154 * | --to-- | (CALLEE Regs of kernel mode)
155 * | r13 |
156 * ------------------
157 * | fp |
158 * | blink | @ret_from_fork
159 * ------------------
160 * | |
161 * ~ ~
162 * ~ ~
163 * | |
164 * ------------------
165 * | r12 |
166 * ~ ~
167 * | --to-- | (scratch Regs of user mode)
168 * | r0 |
169 * ------------------
170 * | SP |
171 * | orig_r0 |
172 * | event/ECR |
173 * | user_r25 |
174 * ------------------ <===== END of PAGE
175 */
176int copy_thread(unsigned long clone_flags, unsigned long usp,
177 unsigned long kthread_arg, struct task_struct *p,
178 unsigned long tls)
179{
180 struct pt_regs *c_regs; /* child's pt_regs */
181 unsigned long *childksp; /* to unwind out of __switch_to() */
182 struct callee_regs *c_callee; /* child's callee regs */
183 struct callee_regs *parent_callee; /* paren't callee */
184 struct pt_regs *regs = current_pt_regs();
185
186 /* Mark the specific anchors to begin with (see pic above) */
187 c_regs = task_pt_regs(p);
188 childksp = (unsigned long *)c_regs - 2; /* 2 words for FP/BLINK */
189 c_callee = ((struct callee_regs *)childksp) - 1;
190
191 /*
192 * __switch_to() uses thread.ksp to start unwinding stack
193 * For kernel threads we don't need to create callee regs, the
194 * stack layout nevertheless needs to remain the same.
195 * Also, since __switch_to anyways unwinds callee regs, we use
196 * this to populate kernel thread entry-pt/args into callee regs,
197 * so that ret_from_kernel_thread() becomes simpler.
198 */
199 p->thread.ksp = (unsigned long)c_callee; /* THREAD_KSP */
200
201 /* __switch_to expects FP(0), BLINK(return addr) at top */
202 childksp[0] = 0; /* fp */
203 childksp[1] = (unsigned long)ret_from_fork; /* blink */
204
205 if (unlikely(p->flags & PF_KTHREAD)) {
206 memset(c_regs, 0, sizeof(struct pt_regs));
207
208 c_callee->r13 = kthread_arg;
209 c_callee->r14 = usp; /* function */
210
211 return 0;
212 }
213
214 /*--------- User Task Only --------------*/
215
216 /* __switch_to expects FP(0), BLINK(return addr) at top of stack */
217 childksp[0] = 0; /* for POP fp */
218 childksp[1] = (unsigned long)ret_from_fork; /* for POP blink */
219
220 /* Copy parents pt regs on child's kernel mode stack */
221 *c_regs = *regs;
222
223 if (usp)
224 c_regs->sp = usp;
225
226 c_regs->r0 = 0; /* fork returns 0 in child */
227
228 parent_callee = ((struct callee_regs *)regs) - 1;
229 *c_callee = *parent_callee;
230
231 if (unlikely(clone_flags & CLONE_SETTLS)) {
232 /*
233 * set task's userland tls data ptr from 4th arg
234 * clone C-lib call is difft from clone sys-call
235 */
236 task_thread_info(p)->thr_ptr = tls;
237 } else {
238 /* Normal fork case: set parent's TLS ptr in child */
239 task_thread_info(p)->thr_ptr =
240 task_thread_info(current)->thr_ptr;
241 }
242
243
244 /*
245 * setup usermode thread pointer #1:
246 * when child is picked by scheduler, __switch_to() uses @c_callee to
247 * populate usermode callee regs: this works (despite being in a kernel
248 * function) since special return path for child @ret_from_fork()
249 * ensures those regs are not clobbered all the way to RTIE to usermode
250 */
251 c_callee->r25 = task_thread_info(p)->thr_ptr;
252
253#ifdef CONFIG_ARC_CURR_IN_REG
254 /*
255 * setup usermode thread pointer #2:
256 * however for this special use of r25 in kernel, __switch_to() sets
257 * r25 for kernel needs and only in the final return path is usermode
258 * r25 setup, from pt_regs->user_r25. So set that up as well
259 */
260 c_regs->user_r25 = c_callee->r25;
261#endif
262
263 return 0;
264}
265
266/*
267 * Do necessary setup to start up a new user task
268 */
269void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp)
270{
271 regs->sp = usp;
272 regs->ret = pc;
273
274 /*
275 * [U]ser Mode bit set
276 * [L] ZOL loop inhibited to begin with - cleared by a LP insn
277 * Interrupts enabled
278 */
279 regs->status32 = STATUS_U_MASK | STATUS_L_MASK | ISA_INIT_STATUS_BITS;
280
281#ifdef CONFIG_EZNPS_MTM_EXT
282 regs->eflags = 0;
283#endif
284
285 fpu_init_task(regs);
286
287 /* bogus seed values for debugging */
288 regs->lp_start = 0x10;
289 regs->lp_end = 0x80;
290}
291
292/*
293 * Some archs flush debug and FPU info here
294 */
295void flush_thread(void)
296{
297}
298
299int elf_check_arch(const struct elf32_hdr *x)
300{
301 unsigned int eflags;
302
303 if (x->e_machine != EM_ARC_INUSE) {
304 pr_err("ELF not built for %s ISA\n",
305 is_isa_arcompact() ? "ARCompact":"ARCv2");
306 return 0;
307 }
308
309 eflags = x->e_flags;
310 if ((eflags & EF_ARC_OSABI_MSK) != EF_ARC_OSABI_CURRENT) {
311 pr_err("ABI mismatch - you need newer toolchain\n");
312 force_sigsegv(SIGSEGV);
313 return 0;
314 }
315
316 return 1;
317}
318EXPORT_SYMBOL(elf_check_arch);