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 23 SYSCALL_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 */ 39 SYSCALL_DEFINE0(arc_gettls) 40 { 41 return task_thread_info(current)->thr_ptr; 42 } 43 44 void arch_cpu_idle(void) 45 { 46 /* sleep, but enable all interrupts before committing */ 47 __asm__("sleep 0x3"); 48 } 49 50 asmlinkage void ret_from_fork(void); 51 52 /* 53 * Copy architecture-specific thread state 54 * 55 * Layout of Child kernel mode stack as setup at the end of this function is 56 * 57 * | ... | 58 * | ... | 59 * | unused | 60 * | | 61 * ------------------ 62 * | r25 | <==== top of Stack (thread.ksp) 63 * ~ ~ 64 * | --to-- | (CALLEE Regs of user mode) 65 * | r13 | 66 * ------------------ 67 * | fp | 68 * | blink | @ret_from_fork 69 * ------------------ 70 * | | 71 * ~ ~ 72 * ~ ~ 73 * | | 74 * ------------------ 75 * | r12 | 76 * ~ ~ 77 * | --to-- | (scratch Regs of user mode) 78 * | r0 | 79 * ------------------ 80 * | SP | 81 * | orig_r0 | 82 * | event/ECR | 83 * | user_r25 | 84 * ------------------ <===== END of PAGE 85 */ 86 int copy_thread(unsigned long clone_flags, 87 unsigned long usp, unsigned long kthread_arg, 88 struct task_struct *p) 89 { 90 struct pt_regs *c_regs; /* child's pt_regs */ 91 unsigned long *childksp; /* to unwind out of __switch_to() */ 92 struct callee_regs *c_callee; /* child's callee regs */ 93 struct callee_regs *parent_callee; /* paren't callee */ 94 struct pt_regs *regs = current_pt_regs(); 95 96 /* Mark the specific anchors to begin with (see pic above) */ 97 c_regs = task_pt_regs(p); 98 childksp = (unsigned long *)c_regs - 2; /* 2 words for FP/BLINK */ 99 c_callee = ((struct callee_regs *)childksp) - 1; 100 101 /* 102 * __switch_to() uses thread.ksp to start unwinding stack 103 * For kernel threads we don't need to create callee regs, the 104 * stack layout nevertheless needs to remain the same. 105 * Also, since __switch_to anyways unwinds callee regs, we use 106 * this to populate kernel thread entry-pt/args into callee regs, 107 * so that ret_from_kernel_thread() becomes simpler. 108 */ 109 p->thread.ksp = (unsigned long)c_callee; /* THREAD_KSP */ 110 111 /* __switch_to expects FP(0), BLINK(return addr) at top */ 112 childksp[0] = 0; /* fp */ 113 childksp[1] = (unsigned long)ret_from_fork; /* blink */ 114 115 if (unlikely(p->flags & PF_KTHREAD)) { 116 memset(c_regs, 0, sizeof(struct pt_regs)); 117 118 c_callee->r13 = kthread_arg; 119 c_callee->r14 = usp; /* function */ 120 121 return 0; 122 } 123 124 /*--------- User Task Only --------------*/ 125 126 /* __switch_to expects FP(0), BLINK(return addr) at top of stack */ 127 childksp[0] = 0; /* for POP fp */ 128 childksp[1] = (unsigned long)ret_from_fork; /* for POP blink */ 129 130 /* Copy parents pt regs on child's kernel mode stack */ 131 *c_regs = *regs; 132 133 if (usp) 134 c_regs->sp = usp; 135 136 c_regs->r0 = 0; /* fork returns 0 in child */ 137 138 parent_callee = ((struct callee_regs *)regs) - 1; 139 *c_callee = *parent_callee; 140 141 if (unlikely(clone_flags & CLONE_SETTLS)) { 142 /* 143 * set task's userland tls data ptr from 4th arg 144 * clone C-lib call is difft from clone sys-call 145 */ 146 task_thread_info(p)->thr_ptr = regs->r3; 147 } else { 148 /* Normal fork case: set parent's TLS ptr in child */ 149 task_thread_info(p)->thr_ptr = 150 task_thread_info(current)->thr_ptr; 151 } 152 153 return 0; 154 } 155 156 /* 157 * Do necessary setup to start up a new user task 158 */ 159 void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long usp) 160 { 161 regs->sp = usp; 162 regs->ret = pc; 163 164 /* 165 * [U]ser Mode bit set 166 * [L] ZOL loop inhibited to begin with - cleared by a LP insn 167 * Interrupts enabled 168 */ 169 regs->status32 = STATUS_U_MASK | STATUS_L_MASK | 170 STATUS_E1_MASK | STATUS_E2_MASK; 171 172 /* bogus seed values for debugging */ 173 regs->lp_start = 0x10; 174 regs->lp_end = 0x80; 175 } 176 177 /* 178 * Some archs flush debug and FPU info here 179 */ 180 void flush_thread(void) 181 { 182 } 183 184 /* 185 * Free any architecture-specific thread data structures, etc. 186 */ 187 void exit_thread(void) 188 { 189 } 190 191 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) 192 { 193 return 0; 194 } 195 196 int elf_check_arch(const struct elf32_hdr *x) 197 { 198 unsigned int eflags; 199 200 if (x->e_machine != EM_ARCOMPACT) 201 return 0; 202 203 eflags = x->e_flags; 204 if ((eflags & EF_ARC_OSABI_MSK) < EF_ARC_OSABI_CURRENT) { 205 pr_err("ABI mismatch - you need newer toolchain\n"); 206 force_sigsegv(SIGSEGV, current); 207 return 0; 208 } 209 210 return 1; 211 } 212 EXPORT_SYMBOL(elf_check_arch); 213