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git.proxmox.com Git - mirror_ubuntu-kernels.git/blob - arch/arc/kernel/process.c
2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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.
8 * Amit Bhor, Kanika Nema: Codito Technologies 2004
11 #include <linux/errno.h>
12 #include <linux/module.h>
13 #include <linux/sched.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>
23 SYSCALL_DEFINE1(arc_settls
, void *, user_tls_data_ptr
)
25 task_thread_info(current
)->thr_ptr
= (unsigned int)user_tls_data_ptr
;
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
39 SYSCALL_DEFINE0(arc_gettls
)
41 return task_thread_info(current
)->thr_ptr
;
44 SYSCALL_DEFINE3(arc_usr_cmpxchg
, int *, uaddr
, int, expected
, int, new)
46 struct pt_regs
*regs
= current_pt_regs();
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
55 WARN_ON_ONCE(IS_ENABLED(CONFIG_SMP
));
57 /* Z indicates to userspace if operation succeded */
58 regs
->status32
&= ~STATUS_Z_MASK
;
60 if (!access_ok(VERIFY_WRITE
, uaddr
, sizeof(int)))
65 if (__get_user(uval
, uaddr
))
68 if (uval
== expected
) {
69 if (!__put_user(new, uaddr
))
70 regs
->status32
|= STATUS_Z_MASK
;
79 void arch_cpu_idle(void)
81 /* sleep, but enable all interrupts before committing */
85 :"I"(ISA_SLEEP_ARG
)); /* can't be "r" has to be embedded const */
88 asmlinkage
void ret_from_fork(void);
91 * Copy architecture-specific thread state
93 * Layout of Child kernel mode stack as setup at the end of this function is
100 * | r25 | <==== top of Stack (thread.ksp)
102 * | --to-- | (CALLEE Regs of kernel mode)
106 * | blink | @ret_from_fork
115 * | --to-- | (scratch Regs of user mode)
122 * ------------------ <===== END of PAGE
124 int copy_thread(unsigned long clone_flags
,
125 unsigned long usp
, unsigned long kthread_arg
,
126 struct task_struct
*p
)
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();
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;
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.
147 p
->thread
.ksp
= (unsigned long)c_callee
; /* THREAD_KSP */
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 */
153 if (unlikely(p
->flags
& PF_KTHREAD
)) {
154 memset(c_regs
, 0, sizeof(struct pt_regs
));
156 c_callee
->r13
= kthread_arg
;
157 c_callee
->r14
= usp
; /* function */
162 /*--------- User Task Only --------------*/
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 */
168 /* Copy parents pt regs on child's kernel mode stack */
174 c_regs
->r0
= 0; /* fork returns 0 in child */
176 parent_callee
= ((struct callee_regs
*)regs
) - 1;
177 *c_callee
= *parent_callee
;
179 if (unlikely(clone_flags
& CLONE_SETTLS
)) {
181 * set task's userland tls data ptr from 4th arg
182 * clone C-lib call is difft from clone sys-call
184 task_thread_info(p
)->thr_ptr
= regs
->r3
;
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
;
195 * Do necessary setup to start up a new user task
197 void start_thread(struct pt_regs
* regs
, unsigned long pc
, unsigned long usp
)
203 * [U]ser Mode bit set
204 * [L] ZOL loop inhibited to begin with - cleared by a LP insn
207 regs
->status32
= STATUS_U_MASK
| STATUS_L_MASK
| ISA_INIT_STATUS_BITS
;
209 /* bogus seed values for debugging */
210 regs
->lp_start
= 0x10;
215 * Some archs flush debug and FPU info here
217 void flush_thread(void)
221 int dump_fpu(struct pt_regs
*regs
, elf_fpregset_t
*fpu
)
226 int elf_check_arch(const struct elf32_hdr
*x
)
230 if (x
->e_machine
!= EM_ARC_INUSE
) {
231 pr_err("ELF not built for %s ISA\n",
232 is_isa_arcompact() ? "ARCompact":"ARCv2");
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
);
245 EXPORT_SYMBOL(elf_check_arch
);