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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/*
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>
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
44void arch_cpu_idle(void)
45{
46 /* sleep, but enable all interrupts before committing */
47 __asm__("sleep 0x3");
48}
49
50asmlinkage void ret_from_fork(void);
51
52/* Layout of Child kernel mode stack as setup at the end of this function is
53 *
54 * | ... |
55 * | ... |
56 * | unused |
57 * | |
58 * ------------------
59 * | r25 | <==== top of Stack (thread.ksp)
60 * ~ ~
61 * | --to-- | (CALLEE Regs of user mode)
62 * | r13 |
63 * ------------------
64 * | fp |
65 * | blink | @ret_from_fork
66 * ------------------
67 * | |
68 * ~ ~
69 * ~ ~
70 * | |
71 * ------------------
72 * | r12 |
73 * ~ ~
74 * | --to-- | (scratch Regs of user mode)
75 * | r0 |
76 * ------------------
77 * | SP |
78 * | orig_r0 |
79 * | event/ECR |
80 * | user_r25 |
81 * ------------------ <===== END of PAGE
82 */
83int copy_thread(unsigned long clone_flags,
84 unsigned long usp, unsigned long arg,
85 struct task_struct *p)
86{
87 struct pt_regs *c_regs; /* child's pt_regs */
88 unsigned long *childksp; /* to unwind out of __switch_to() */
89 struct callee_regs *c_callee; /* child's callee regs */
90 struct callee_regs *parent_callee; /* paren't callee */
91 struct pt_regs *regs = current_pt_regs();
92
93 /* Mark the specific anchors to begin with (see pic above) */
94 c_regs = task_pt_regs(p);
95 childksp = (unsigned long *)c_regs - 2; /* 2 words for FP/BLINK */
96 c_callee = ((struct callee_regs *)childksp) - 1;
97
98 /*
99 * __switch_to() uses thread.ksp to start unwinding stack
100 * For kernel threads we don't need to create callee regs, the
101 * stack layout nevertheless needs to remain the same.
102 * Also, since __switch_to anyways unwinds callee regs, we use
103 * this to populate kernel thread entry-pt/args into callee regs,
104 * so that ret_from_kernel_thread() becomes simpler.
105 */
106 p->thread.ksp = (unsigned long)c_callee; /* THREAD_KSP */
107
108 /* __switch_to expects FP(0), BLINK(return addr) at top */
109 childksp[0] = 0; /* fp */
110 childksp[1] = (unsigned long)ret_from_fork; /* blink */
111
112 if (unlikely(p->flags & PF_KTHREAD)) {
113 memset(c_regs, 0, sizeof(struct pt_regs));
114
115 c_callee->r13 = arg; /* argument to kernel thread */
116 c_callee->r14 = usp; /* function */
117
118 return 0;
119 }
120
121 /*--------- User Task Only --------------*/
122
123 /* __switch_to expects FP(0), BLINK(return addr) at top of stack */
124 childksp[0] = 0; /* for POP fp */
125 childksp[1] = (unsigned long)ret_from_fork; /* for POP blink */
126
127 /* Copy parents pt regs on child's kernel mode stack */
128 *c_regs = *regs;
129
130 if (usp)
131 c_regs->sp = usp;
132
133 c_regs->r0 = 0; /* fork returns 0 in child */
134
135 parent_callee = ((struct callee_regs *)regs) - 1;
136 *c_callee = *parent_callee;
137
138 if (unlikely(clone_flags & CLONE_SETTLS)) {
139 /*
140 * set task's userland tls data ptr from 4th arg
141 * clone C-lib call is difft from clone sys-call
142 */
143 task_thread_info(p)->thr_ptr = regs->r3;
144 } else {
145 /* Normal fork case: set parent's TLS ptr in child */
146 task_thread_info(p)->thr_ptr =
147 task_thread_info(current)->thr_ptr;
148 }
149
150 return 0;
151}
152
153/*
154 * Some archs flush debug and FPU info here
155 */
156void flush_thread(void)
157{
158}
159
160/*
161 * Free any architecture-specific thread data structures, etc.
162 */
163void exit_thread(void)
164{
165}
166
167int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
168{
169 return 0;
170}
171
172/*
173 * API: expected by schedular Code: If thread is sleeping where is that.
174 * What is this good for? it will be always the scheduler or ret_from_fork.
175 * So we hard code that anyways.
176 */
177unsigned long thread_saved_pc(struct task_struct *t)
178{
179 struct pt_regs *regs = task_pt_regs(t);
180 unsigned long blink = 0;
181
182 /*
183 * If the thread being queried for in not itself calling this, then it
184 * implies it is not executing, which in turn implies it is sleeping,
185 * which in turn implies it got switched OUT by the schedular.
186 * In that case, it's kernel mode blink can reliably retrieved as per
187 * the picture above (right above pt_regs).
188 */
189 if (t != current && t->state != TASK_RUNNING)
190 blink = *((unsigned int *)regs - 1);
191
192 return blink;
193}
194
195int elf_check_arch(const struct elf32_hdr *x)
196{
197 unsigned int eflags;
198
199 if (x->e_machine != EM_ARCOMPACT)
200 return 0;
201
202 eflags = x->e_flags;
203 if ((eflags & EF_ARC_OSABI_MSK) < EF_ARC_OSABI_CURRENT) {
204 pr_err("ABI mismatch - you need newer toolchain\n");
205 force_sigsegv(SIGSEGV, current);
206 return 0;
207 }
208
209 return 1;
210}
211EXPORT_SYMBOL(elf_check_arch);