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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
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 __user *, 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 definition
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 succeeded */
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 committing 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 raw_local_irq_disable();
119}
120
121#else /* ARC700 */
122
123void arch_cpu_idle(void)
124{
125 /* sleep, but enable both set E1/E2 (levels of interrupts) before committing */
126 __asm__ __volatile__("sleep 0x3 \n");
127 raw_local_irq_disable();
128}
129
130#endif
131
132asmlinkage void ret_from_fork(void);
133
134/*
135 * Copy architecture-specific thread state
136 *
137 * Layout of Child kernel mode stack as setup at the end of this function is
138 *
139 * | ... |
140 * | ... |
141 * | unused |
142 * | |
143 * ------------------
144 * | r25 | <==== top of Stack (thread_info.ksp)
145 * ~ ~
146 * | --to-- | (CALLEE Regs of kernel mode)
147 * | r13 |
148 * ------------------
149 * | fp |
150 * | blink | @ret_from_fork
151 * ------------------
152 * | |
153 * ~ ~
154 * ~ ~
155 * | |
156 * ------------------
157 * | r12 |
158 * ~ ~
159 * | --to-- | (scratch Regs of user mode)
160 * | r0 |
161 * ------------------
162 * | SP |
163 * | orig_r0 |
164 * | event/ECR |
165 * ------------------ <===== END of PAGE
166 */
167int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
168{
169 unsigned long clone_flags = args->flags;
170 unsigned long usp = args->stack;
171 unsigned long tls = args->tls;
172 struct pt_regs *c_regs; /* child's pt_regs */
173 unsigned long *childksp; /* to unwind out of __switch_to() */
174 struct callee_regs *c_callee; /* child's callee regs */
175 struct callee_regs *parent_callee; /* paren't callee */
176 struct pt_regs *regs = current_pt_regs();
177
178 /* Mark the specific anchors to begin with (see pic above) */
179 c_regs = task_pt_regs(p);
180 childksp = (unsigned long *)c_regs - 2; /* 2 words for FP/BLINK */
181 c_callee = ((struct callee_regs *)childksp) - 1;
182
183 /*
184 * __switch_to() uses thread_info.ksp to start unwinding stack
185 * For kernel threads we don't need to create callee regs, the
186 * stack layout nevertheless needs to remain the same.
187 * Also, since __switch_to anyways unwinds callee regs, we use
188 * this to populate kernel thread entry-pt/args into callee regs,
189 * so that ret_from_kernel_thread() becomes simpler.
190 */
191 task_thread_info(p)->ksp = (unsigned long)c_callee; /* THREAD_INFO_KSP */
192
193 /* __switch_to expects FP(0), BLINK(return addr) at top */
194 childksp[0] = 0; /* fp */
195 childksp[1] = (unsigned long)ret_from_fork; /* blink */
196
197 if (unlikely(args->fn)) {
198 memset(c_regs, 0, sizeof(struct pt_regs));
199
200 c_callee->r13 = (unsigned long)args->fn_arg;
201 c_callee->r14 = (unsigned long)args->fn;
202
203 return 0;
204 }
205
206 /*--------- User Task Only --------------*/
207
208 /* __switch_to expects FP(0), BLINK(return addr) at top of stack */
209 childksp[0] = 0; /* for POP fp */
210 childksp[1] = (unsigned long)ret_from_fork; /* for POP blink */
211
212 /* Copy parents pt regs on child's kernel mode stack */
213 *c_regs = *regs;
214
215 if (usp)
216 c_regs->sp = usp;
217
218 c_regs->r0 = 0; /* fork returns 0 in child */
219
220 parent_callee = ((struct callee_regs *)regs) - 1;
221 *c_callee = *parent_callee;
222
223 if (unlikely(clone_flags & CLONE_SETTLS)) {
224 /*
225 * set task's userland tls data ptr from 4th arg
226 * clone C-lib call is difft from clone sys-call
227 */
228 task_thread_info(p)->thr_ptr = tls;
229 } else {
230 /* Normal fork case: set parent's TLS ptr in child */
231 task_thread_info(p)->thr_ptr =
232 task_thread_info(current)->thr_ptr;
233 }
234
235
236 /*
237 * setup usermode thread pointer #1:
238 * when child is picked by scheduler, __switch_to() uses @c_callee to
239 * populate usermode callee regs: this works (despite being in a kernel
240 * function) since special return path for child @ret_from_fork()
241 * ensures those regs are not clobbered all the way to RTIE to usermode
242 */
243 c_callee->r25 = task_thread_info(p)->thr_ptr;
244
245 return 0;
246}
247
248/*
249 * Do necessary setup to start up a new user task
250 */
251void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp)
252{
253 regs->sp = usp;
254 regs->ret = pc;
255
256 /*
257 * [U]ser Mode bit set
258 * [L] ZOL loop inhibited to begin with - cleared by a LP insn
259 * Interrupts enabled
260 */
261 regs->status32 = STATUS_U_MASK | STATUS_L_MASK | ISA_INIT_STATUS_BITS;
262
263 fpu_init_task(regs);
264
265 /* bogus seed values for debugging */
266 regs->lp_start = 0x10;
267 regs->lp_end = 0x80;
268}
269
270/*
271 * Some archs flush debug and FPU info here
272 */
273void flush_thread(void)
274{
275}
276
277int elf_check_arch(const struct elf32_hdr *x)
278{
279 unsigned int eflags;
280
281 if (x->e_machine != EM_ARC_INUSE) {
282 pr_err("ELF not built for %s ISA\n",
283 is_isa_arcompact() ? "ARCompact":"ARCv2");
284 return 0;
285 }
286
287 eflags = x->e_flags;
288 if ((eflags & EF_ARC_OSABI_MSK) != EF_ARC_OSABI_CURRENT) {
289 pr_err("ABI mismatch - you need newer toolchain\n");
290 force_fatal_sig(SIGSEGV);
291 return 0;
292 }
293
294 return 1;
295}
296EXPORT_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);