1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
|
/*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Amit Bhor, Kanika Nema: Codito Technologies 2004
*/
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/syscalls.h>
#include <linux/elf.h>
#include <linux/tick.h>
SYSCALL_DEFINE1(arc_settls, void *, user_tls_data_ptr)
{
task_thread_info(current)->thr_ptr = (unsigned int)user_tls_data_ptr;
return 0;
}
/*
* We return the user space TLS data ptr as sys-call return code
* Ideally it should be copy to user.
* However we can cheat by the fact that some sys-calls do return
* absurdly high values
* Since the tls dat aptr is not going to be in range of 0xFFFF_xxxx
* it won't be considered a sys-call error
* and it will be loads better than copy-to-user, which is a definite
* D-TLB Miss
*/
SYSCALL_DEFINE0(arc_gettls)
{
return task_thread_info(current)->thr_ptr;
}
SYSCALL_DEFINE3(arc_usr_cmpxchg, int *, uaddr, int, expected, int, new)
{
int uval;
int ret;
/*
* This is only for old cores lacking LLOCK/SCOND, which by defintion
* can't possibly be SMP. Thus doesn't need to be SMP safe.
* And this also helps reduce the overhead for serializing in
* the UP case
*/
WARN_ON_ONCE(IS_ENABLED(CONFIG_SMP));
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
return -EFAULT;
preempt_disable();
ret = __get_user(uval, uaddr);
if (ret)
goto done;
if (uval != expected)
ret = -EAGAIN;
else
ret = __put_user(new, uaddr);
done:
preempt_enable();
return ret;
}
void arch_cpu_idle(void)
{
/* sleep, but enable all interrupts before committing */
__asm__ __volatile__(
"sleep %0 \n"
:
:"I"(ISA_SLEEP_ARG)); /* can't be "r" has to be embedded const */
}
asmlinkage void ret_from_fork(void);
/*
* Copy architecture-specific thread state
*
* Layout of Child kernel mode stack as setup at the end of this function is
*
* | ... |
* | ... |
* | unused |
* | |
* ------------------
* | r25 | <==== top of Stack (thread.ksp)
* ~ ~
* | --to-- | (CALLEE Regs of kernel mode)
* | r13 |
* ------------------
* | fp |
* | blink | @ret_from_fork
* ------------------
* | |
* ~ ~
* ~ ~
* | |
* ------------------
* | r12 |
* ~ ~
* | --to-- | (scratch Regs of user mode)
* | r0 |
* ------------------
* | SP |
* | orig_r0 |
* | event/ECR |
* | user_r25 |
* ------------------ <===== END of PAGE
*/
int copy_thread(unsigned long clone_flags,
unsigned long usp, unsigned long kthread_arg,
struct task_struct *p)
{
struct pt_regs *c_regs; /* child's pt_regs */
unsigned long *childksp; /* to unwind out of __switch_to() */
struct callee_regs *c_callee; /* child's callee regs */
struct callee_regs *parent_callee; /* paren't callee */
struct pt_regs *regs = current_pt_regs();
/* Mark the specific anchors to begin with (see pic above) */
c_regs = task_pt_regs(p);
childksp = (unsigned long *)c_regs - 2; /* 2 words for FP/BLINK */
c_callee = ((struct callee_regs *)childksp) - 1;
/*
* __switch_to() uses thread.ksp to start unwinding stack
* For kernel threads we don't need to create callee regs, the
* stack layout nevertheless needs to remain the same.
* Also, since __switch_to anyways unwinds callee regs, we use
* this to populate kernel thread entry-pt/args into callee regs,
* so that ret_from_kernel_thread() becomes simpler.
*/
p->thread.ksp = (unsigned long)c_callee; /* THREAD_KSP */
/* __switch_to expects FP(0), BLINK(return addr) at top */
childksp[0] = 0; /* fp */
childksp[1] = (unsigned long)ret_from_fork; /* blink */
if (unlikely(p->flags & PF_KTHREAD)) {
memset(c_regs, 0, sizeof(struct pt_regs));
c_callee->r13 = kthread_arg;
c_callee->r14 = usp; /* function */
return 0;
}
/*--------- User Task Only --------------*/
/* __switch_to expects FP(0), BLINK(return addr) at top of stack */
childksp[0] = 0; /* for POP fp */
childksp[1] = (unsigned long)ret_from_fork; /* for POP blink */
/* Copy parents pt regs on child's kernel mode stack */
*c_regs = *regs;
if (usp)
c_regs->sp = usp;
c_regs->r0 = 0; /* fork returns 0 in child */
parent_callee = ((struct callee_regs *)regs) - 1;
*c_callee = *parent_callee;
if (unlikely(clone_flags & CLONE_SETTLS)) {
/*
* set task's userland tls data ptr from 4th arg
* clone C-lib call is difft from clone sys-call
*/
task_thread_info(p)->thr_ptr = regs->r3;
} else {
/* Normal fork case: set parent's TLS ptr in child */
task_thread_info(p)->thr_ptr =
task_thread_info(current)->thr_ptr;
}
return 0;
}
/*
* Do necessary setup to start up a new user task
*/
void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long usp)
{
regs->sp = usp;
regs->ret = pc;
/*
* [U]ser Mode bit set
* [L] ZOL loop inhibited to begin with - cleared by a LP insn
* Interrupts enabled
*/
regs->status32 = STATUS_U_MASK | STATUS_L_MASK | ISA_INIT_STATUS_BITS;
/* bogus seed values for debugging */
regs->lp_start = 0x10;
regs->lp_end = 0x80;
}
/*
* Some archs flush debug and FPU info here
*/
void flush_thread(void)
{
}
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
{
return 0;
}
int elf_check_arch(const struct elf32_hdr *x)
{
unsigned int eflags;
if (x->e_machine != EM_ARC_INUSE) {
pr_err("ELF not built for %s ISA\n",
is_isa_arcompact() ? "ARCompact":"ARCv2");
return 0;
}
eflags = x->e_flags;
if ((eflags & EF_ARC_OSABI_MSK) != EF_ARC_OSABI_CURRENT) {
pr_err("ABI mismatch - you need newer toolchain\n");
force_sigsegv(SIGSEGV, current);
return 0;
}
return 1;
}
EXPORT_SYMBOL(elf_check_arch);
|
