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>
14 #include <linux/sched/task.h>
15 #include <linux/sched/task_stack.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>
26 SYSCALL_DEFINE1(arc_settls, void *, user_tls_data_ptr)
28 task_thread_info(current)->thr_ptr = (unsigned int)user_tls_data_ptr;
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
42 SYSCALL_DEFINE0(arc_gettls)
44 return task_thread_info(current)->thr_ptr;
47 SYSCALL_DEFINE3(arc_usr_cmpxchg, int *, uaddr, int, expected, int, new)
49 struct pt_regs *regs = current_pt_regs();
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
58 WARN_ON_ONCE(IS_ENABLED(CONFIG_SMP));
60 /* Z indicates to userspace if operation succeded */
61 regs->status32 &= ~STATUS_Z_MASK;
63 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
68 if (__get_user(uval, uaddr))
71 if (uval == expected) {
72 if (!__put_user(new, uaddr))
73 regs->status32 |= STATUS_Z_MASK;
82 void arch_cpu_idle(void)
84 /* sleep, but enable all interrupts before committing */
88 :"I"(ISA_SLEEP_ARG)); /* can't be "r" has to be embedded const */
91 asmlinkage void ret_from_fork(void);
94 * Copy architecture-specific thread state
96 * Layout of Child kernel mode stack as setup at the end of this function is
103 * | r25 | <==== top of Stack (thread.ksp)
105 * | --to-- | (CALLEE Regs of kernel mode)
109 * | blink | @ret_from_fork
118 * | --to-- | (scratch Regs of user mode)
125 * ------------------ <===== END of PAGE
127 int copy_thread(unsigned long clone_flags,
128 unsigned long usp, unsigned long kthread_arg,
129 struct task_struct *p)
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();
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;
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.
150 p->thread.ksp = (unsigned long)c_callee; /* THREAD_KSP */
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 */
156 if (unlikely(p->flags & PF_KTHREAD)) {
157 memset(c_regs, 0, sizeof(struct pt_regs));
159 c_callee->r13 = kthread_arg;
160 c_callee->r14 = usp; /* function */
165 /*--------- User Task Only --------------*/
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 */
171 /* Copy parents pt regs on child's kernel mode stack */
177 c_regs->r0 = 0; /* fork returns 0 in child */
179 parent_callee = ((struct callee_regs *)regs) - 1;
180 *c_callee = *parent_callee;
182 if (unlikely(clone_flags & CLONE_SETTLS)) {
184 * set task's userland tls data ptr from 4th arg
185 * clone C-lib call is difft from clone sys-call
187 task_thread_info(p)->thr_ptr = regs->r3;
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;
198 * Do necessary setup to start up a new user task
200 void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long usp)
206 * [U]ser Mode bit set
207 * [L] ZOL loop inhibited to begin with - cleared by a LP insn
210 regs->status32 = STATUS_U_MASK | STATUS_L_MASK | ISA_INIT_STATUS_BITS;
212 /* bogus seed values for debugging */
213 regs->lp_start = 0x10;
218 * Some archs flush debug and FPU info here
220 void flush_thread(void)
224 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
229 int elf_check_arch(const struct elf32_hdr *x)
233 if (x->e_machine != EM_ARC_INUSE) {
234 pr_err("ELF not built for %s ISA\n",
235 is_isa_arcompact() ? "ARCompact":"ARCv2");
240 if ((eflags & EF_ARC_OSABI_MSK) != EF_ARC_OSABI_CURRENT) {
241 pr_err("ABI mismatch - you need newer toolchain\n");
242 force_sigsegv(SIGSEGV, current);
248 EXPORT_SYMBOL(elf_check_arch);