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