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4adeefe1 VG |
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> | |
29930025 | 14 | #include <linux/sched/task.h> |
68db0cf1 | 15 | #include <linux/sched/task_stack.h> |
29930025 | 16 | |
4adeefe1 VG |
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 | ||
26 | SYSCALL_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 | */ | |
42 | SYSCALL_DEFINE0(arc_gettls) | |
43 | { | |
44 | return task_thread_info(current)->thr_ptr; | |
45 | } | |
bf90e1ea | 46 | |
91e040a7 VG |
47 | SYSCALL_DEFINE3(arc_usr_cmpxchg, int *, uaddr, int, expected, int, new) |
48 | { | |
e6e335bf VG |
49 | struct pt_regs *regs = current_pt_regs(); |
50 | int uval = -EFAULT; | |
91e040a7 VG |
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 | ||
e6e335bf VG |
60 | /* Z indicates to userspace if operation succeded */ |
61 | regs->status32 &= ~STATUS_Z_MASK; | |
62 | ||
91e040a7 VG |
63 | if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int))) |
64 | return -EFAULT; | |
65 | ||
66 | preempt_disable(); | |
67 | ||
e6e335bf | 68 | if (__get_user(uval, uaddr)) |
91e040a7 VG |
69 | goto done; |
70 | ||
e6e335bf VG |
71 | if (uval == expected) { |
72 | if (!__put_user(new, uaddr)) | |
73 | regs->status32 |= STATUS_Z_MASK; | |
74 | } | |
91e040a7 VG |
75 | |
76 | done: | |
77 | preempt_enable(); | |
78 | ||
e6e335bf | 79 | return uval; |
91e040a7 VG |
80 | } |
81 | ||
fa35e42a | 82 | void arch_cpu_idle(void) |
bf90e1ea VG |
83 | { |
84 | /* sleep, but enable all interrupts before committing */ | |
512b5b89 VG |
85 | __asm__ __volatile__( |
86 | "sleep %0 \n" | |
87 | : | |
88 | :"I"(ISA_SLEEP_ARG)); /* can't be "r" has to be embedded const */ | |
bf90e1ea VG |
89 | } |
90 | ||
bf90e1ea VG |
91 | asmlinkage void ret_from_fork(void); |
92 | ||
18e1d1b1 AD |
93 | /* |
94 | * Copy architecture-specific thread state | |
95 | * | |
96 | * Layout of Child kernel mode stack as setup at the end of this function is | |
bf90e1ea VG |
97 | * |
98 | * | ... | | |
99 | * | ... | | |
100 | * | unused | | |
101 | * | | | |
bf90e1ea | 102 | * ------------------ |
16f9afe6 | 103 | * | r25 | <==== top of Stack (thread.ksp) |
bf90e1ea | 104 | * ~ ~ |
09074950 | 105 | * | --to-- | (CALLEE Regs of kernel mode) |
bf90e1ea VG |
106 | * | r13 | |
107 | * ------------------ | |
108 | * | fp | | |
109 | * | blink | @ret_from_fork | |
110 | * ------------------ | |
111 | * | | | |
112 | * ~ ~ | |
113 | * ~ ~ | |
114 | * | | | |
115 | * ------------------ | |
116 | * | r12 | | |
117 | * ~ ~ | |
118 | * | --to-- | (scratch Regs of user mode) | |
119 | * | r0 | | |
3ebedbb2 VG |
120 | * ------------------ |
121 | * | SP | | |
122 | * | orig_r0 | | |
502a0c77 | 123 | * | event/ECR | |
359105bd | 124 | * | user_r25 | |
bf90e1ea VG |
125 | * ------------------ <===== END of PAGE |
126 | */ | |
127 | int copy_thread(unsigned long clone_flags, | |
18e1d1b1 | 128 | unsigned long usp, unsigned long kthread_arg, |
bf90e1ea VG |
129 | struct task_struct *p) |
130 | { | |
131 | struct pt_regs *c_regs; /* child's pt_regs */ | |
132 | unsigned long *childksp; /* to unwind out of __switch_to() */ | |
133 | struct callee_regs *c_callee; /* child's callee regs */ | |
134 | struct callee_regs *parent_callee; /* paren't callee */ | |
135 | struct pt_regs *regs = current_pt_regs(); | |
136 | ||
137 | /* Mark the specific anchors to begin with (see pic above) */ | |
138 | c_regs = task_pt_regs(p); | |
139 | childksp = (unsigned long *)c_regs - 2; /* 2 words for FP/BLINK */ | |
140 | c_callee = ((struct callee_regs *)childksp) - 1; | |
141 | ||
142 | /* | |
143 | * __switch_to() uses thread.ksp to start unwinding stack | |
144 | * For kernel threads we don't need to create callee regs, the | |
145 | * stack layout nevertheless needs to remain the same. | |
146 | * Also, since __switch_to anyways unwinds callee regs, we use | |
147 | * this to populate kernel thread entry-pt/args into callee regs, | |
148 | * so that ret_from_kernel_thread() becomes simpler. | |
149 | */ | |
150 | p->thread.ksp = (unsigned long)c_callee; /* THREAD_KSP */ | |
151 | ||
152 | /* __switch_to expects FP(0), BLINK(return addr) at top */ | |
153 | childksp[0] = 0; /* fp */ | |
154 | childksp[1] = (unsigned long)ret_from_fork; /* blink */ | |
155 | ||
156 | if (unlikely(p->flags & PF_KTHREAD)) { | |
157 | memset(c_regs, 0, sizeof(struct pt_regs)); | |
158 | ||
18e1d1b1 | 159 | c_callee->r13 = kthread_arg; |
bf90e1ea VG |
160 | c_callee->r14 = usp; /* function */ |
161 | ||
162 | return 0; | |
163 | } | |
164 | ||
165 | /*--------- User Task Only --------------*/ | |
166 | ||
167 | /* __switch_to expects FP(0), BLINK(return addr) at top of stack */ | |
168 | childksp[0] = 0; /* for POP fp */ | |
169 | childksp[1] = (unsigned long)ret_from_fork; /* for POP blink */ | |
170 | ||
171 | /* Copy parents pt regs on child's kernel mode stack */ | |
172 | *c_regs = *regs; | |
173 | ||
174 | if (usp) | |
175 | c_regs->sp = usp; | |
176 | ||
177 | c_regs->r0 = 0; /* fork returns 0 in child */ | |
178 | ||
179 | parent_callee = ((struct callee_regs *)regs) - 1; | |
180 | *c_callee = *parent_callee; | |
181 | ||
182 | if (unlikely(clone_flags & CLONE_SETTLS)) { | |
183 | /* | |
184 | * set task's userland tls data ptr from 4th arg | |
185 | * clone C-lib call is difft from clone sys-call | |
186 | */ | |
187 | task_thread_info(p)->thr_ptr = regs->r3; | |
188 | } else { | |
189 | /* Normal fork case: set parent's TLS ptr in child */ | |
190 | task_thread_info(p)->thr_ptr = | |
191 | task_thread_info(current)->thr_ptr; | |
192 | } | |
193 | ||
194 | return 0; | |
195 | } | |
196 | ||
2ab402df VG |
197 | /* |
198 | * Do necessary setup to start up a new user task | |
199 | */ | |
200 | void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long usp) | |
201 | { | |
2ab402df VG |
202 | regs->sp = usp; |
203 | regs->ret = pc; | |
204 | ||
205 | /* | |
206 | * [U]ser Mode bit set | |
207 | * [L] ZOL loop inhibited to begin with - cleared by a LP insn | |
208 | * Interrupts enabled | |
209 | */ | |
1f6ccfff | 210 | regs->status32 = STATUS_U_MASK | STATUS_L_MASK | ISA_INIT_STATUS_BITS; |
2ab402df VG |
211 | |
212 | /* bogus seed values for debugging */ | |
213 | regs->lp_start = 0x10; | |
214 | regs->lp_end = 0x80; | |
215 | } | |
216 | ||
bf90e1ea VG |
217 | /* |
218 | * Some archs flush debug and FPU info here | |
219 | */ | |
220 | void flush_thread(void) | |
221 | { | |
222 | } | |
223 | ||
bf90e1ea VG |
224 | int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) |
225 | { | |
226 | return 0; | |
227 | } | |
228 | ||
bf90e1ea VG |
229 | int elf_check_arch(const struct elf32_hdr *x) |
230 | { | |
231 | unsigned int eflags; | |
232 | ||
1f6ccfff VG |
233 | if (x->e_machine != EM_ARC_INUSE) { |
234 | pr_err("ELF not built for %s ISA\n", | |
235 | is_isa_arcompact() ? "ARCompact":"ARCv2"); | |
bf90e1ea | 236 | return 0; |
1f6ccfff | 237 | } |
bf90e1ea VG |
238 | |
239 | eflags = x->e_flags; | |
840c054f | 240 | if ((eflags & EF_ARC_OSABI_MSK) != EF_ARC_OSABI_CURRENT) { |
bf90e1ea VG |
241 | pr_err("ABI mismatch - you need newer toolchain\n"); |
242 | force_sigsegv(SIGSEGV, current); | |
243 | return 0; | |
244 | } | |
245 | ||
246 | return 1; | |
247 | } | |
248 | EXPORT_SYMBOL(elf_check_arch); |