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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/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 int uval = -EFAULT;
48
49 /*
50 * This is only for old cores lacking LLOCK/SCOND, which by defintion
51 * can't possibly be SMP. Thus doesn't need to be SMP safe.
52 * And this also helps reduce the overhead for serializing in
53 * the UP case
54 */
55 WARN_ON_ONCE(IS_ENABLED(CONFIG_SMP));
56
57 /* Z indicates to userspace if operation succeded */
58 regs->status32 &= ~STATUS_Z_MASK;
59
60 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
61 return -EFAULT;
62
63 preempt_disable();
64
65 if (__get_user(uval, uaddr))
66 goto done;
67
68 if (uval == expected) {
69 if (!__put_user(new, uaddr))
70 regs->status32 |= STATUS_Z_MASK;
71 }
72
73done:
74 preempt_enable();
75
76 return uval;
77}
78
79void arch_cpu_idle(void)
80{
81 /* sleep, but enable all interrupts before committing */
82 __asm__ __volatile__(
83 "sleep %0 \n"
84 :
85 :"I"(ISA_SLEEP_ARG)); /* can't be "r" has to be embedded const */
86}
87
88asmlinkage void ret_from_fork(void);
89
90/*
91 * Copy architecture-specific thread state
92 *
93 * Layout of Child kernel mode stack as setup at the end of this function is
94 *
95 * | ... |
96 * | ... |
97 * | unused |
98 * | |
99 * ------------------
100 * | r25 | <==== top of Stack (thread.ksp)
101 * ~ ~
102 * | --to-- | (CALLEE Regs of kernel mode)
103 * | r13 |
104 * ------------------
105 * | fp |
106 * | blink | @ret_from_fork
107 * ------------------
108 * | |
109 * ~ ~
110 * ~ ~
111 * | |
112 * ------------------
113 * | r12 |
114 * ~ ~
115 * | --to-- | (scratch Regs of user mode)
116 * | r0 |
117 * ------------------
118 * | SP |
119 * | orig_r0 |
120 * | event/ECR |
121 * | user_r25 |
122 * ------------------ <===== END of PAGE
123 */
124int copy_thread(unsigned long clone_flags,
125 unsigned long usp, unsigned long kthread_arg,
126 struct task_struct *p)
127{
128 struct pt_regs *c_regs; /* child's pt_regs */
129 unsigned long *childksp; /* to unwind out of __switch_to() */
130 struct callee_regs *c_callee; /* child's callee regs */
131 struct callee_regs *parent_callee; /* paren't callee */
132 struct pt_regs *regs = current_pt_regs();
133
134 /* Mark the specific anchors to begin with (see pic above) */
135 c_regs = task_pt_regs(p);
136 childksp = (unsigned long *)c_regs - 2; /* 2 words for FP/BLINK */
137 c_callee = ((struct callee_regs *)childksp) - 1;
138
139 /*
140 * __switch_to() uses thread.ksp to start unwinding stack
141 * For kernel threads we don't need to create callee regs, the
142 * stack layout nevertheless needs to remain the same.
143 * Also, since __switch_to anyways unwinds callee regs, we use
144 * this to populate kernel thread entry-pt/args into callee regs,
145 * so that ret_from_kernel_thread() becomes simpler.
146 */
147 p->thread.ksp = (unsigned long)c_callee; /* THREAD_KSP */
148
149 /* __switch_to expects FP(0), BLINK(return addr) at top */
150 childksp[0] = 0; /* fp */
151 childksp[1] = (unsigned long)ret_from_fork; /* blink */
152
153 if (unlikely(p->flags & PF_KTHREAD)) {
154 memset(c_regs, 0, sizeof(struct pt_regs));
155
156 c_callee->r13 = kthread_arg;
157 c_callee->r14 = usp; /* function */
158
159 return 0;
160 }
161
162 /*--------- User Task Only --------------*/
163
164 /* __switch_to expects FP(0), BLINK(return addr) at top of stack */
165 childksp[0] = 0; /* for POP fp */
166 childksp[1] = (unsigned long)ret_from_fork; /* for POP blink */
167
168 /* Copy parents pt regs on child's kernel mode stack */
169 *c_regs = *regs;
170
171 if (usp)
172 c_regs->sp = usp;
173
174 c_regs->r0 = 0; /* fork returns 0 in child */
175
176 parent_callee = ((struct callee_regs *)regs) - 1;
177 *c_callee = *parent_callee;
178
179 if (unlikely(clone_flags & CLONE_SETTLS)) {
180 /*
181 * set task's userland tls data ptr from 4th arg
182 * clone C-lib call is difft from clone sys-call
183 */
184 task_thread_info(p)->thr_ptr = regs->r3;
185 } else {
186 /* Normal fork case: set parent's TLS ptr in child */
187 task_thread_info(p)->thr_ptr =
188 task_thread_info(current)->thr_ptr;
189 }
190
191 return 0;
192}
193
194/*
195 * Do necessary setup to start up a new user task
196 */
197void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long usp)
198{
199 regs->sp = usp;
200 regs->ret = pc;
201
202 /*
203 * [U]ser Mode bit set
204 * [L] ZOL loop inhibited to begin with - cleared by a LP insn
205 * Interrupts enabled
206 */
207 regs->status32 = STATUS_U_MASK | STATUS_L_MASK | ISA_INIT_STATUS_BITS;
208
209 /* bogus seed values for debugging */
210 regs->lp_start = 0x10;
211 regs->lp_end = 0x80;
212}
213
214/*
215 * Some archs flush debug and FPU info here
216 */
217void flush_thread(void)
218{
219}
220
221int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
222{
223 return 0;
224}
225
226int elf_check_arch(const struct elf32_hdr *x)
227{
228 unsigned int eflags;
229
230 if (x->e_machine != EM_ARC_INUSE) {
231 pr_err("ELF not built for %s ISA\n",
232 is_isa_arcompact() ? "ARCompact":"ARCv2");
233 return 0;
234 }
235
236 eflags = x->e_flags;
237 if ((eflags & EF_ARC_OSABI_MSK) != EF_ARC_OSABI_CURRENT) {
238 pr_err("ABI mismatch - you need newer toolchain\n");
239 force_sigsegv(SIGSEGV, current);
240 return 0;
241 }
242
243 return 1;
244}
245EXPORT_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);