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 if (is_isa_arcompact()) { 48 __asm__("sleep 0x3"); 49 } else { 50 /* default irq priority (<=) which can interrupt the doze */ 51 const int arg = 0x10 | ARCV2_IRQ_DEF_PRIO; 52 53 __asm__ __volatile__( 54 "sleep %0 \n" 55 : 56 :"r"(arg)); 57 } 58 } 59 60 asmlinkage void ret_from_fork(void); 61 62 /* 63 * Copy architecture-specific thread state 64 * 65 * Layout of Child kernel mode stack as setup at the end of this function is 66 * 67 * | ... | 68 * | ... | 69 * | unused | 70 * | | 71 * ------------------ 72 * | r25 | <==== top of Stack (thread.ksp) 73 * ~ ~ 74 * | --to-- | (CALLEE Regs of user mode) 75 * | r13 | 76 * ------------------ 77 * | fp | 78 * | blink | @ret_from_fork 79 * ------------------ 80 * | | 81 * ~ ~ 82 * ~ ~ 83 * | | 84 * ------------------ 85 * | r12 | 86 * ~ ~ 87 * | --to-- | (scratch Regs of user mode) 88 * | r0 | 89 * ------------------ 90 * | SP | 91 * | orig_r0 | 92 * | event/ECR | 93 * | user_r25 | 94 * ------------------ <===== END of PAGE 95 */ 96 int copy_thread(unsigned long clone_flags, 97 unsigned long usp, unsigned long kthread_arg, 98 struct task_struct *p) 99 { 100 struct pt_regs *c_regs; /* child's pt_regs */ 101 unsigned long *childksp; /* to unwind out of __switch_to() */ 102 struct callee_regs *c_callee; /* child's callee regs */ 103 struct callee_regs *parent_callee; /* paren't callee */ 104 struct pt_regs *regs = current_pt_regs(); 105 106 /* Mark the specific anchors to begin with (see pic above) */ 107 c_regs = task_pt_regs(p); 108 childksp = (unsigned long *)c_regs - 2; /* 2 words for FP/BLINK */ 109 c_callee = ((struct callee_regs *)childksp) - 1; 110 111 /* 112 * __switch_to() uses thread.ksp to start unwinding stack 113 * For kernel threads we don't need to create callee regs, the 114 * stack layout nevertheless needs to remain the same. 115 * Also, since __switch_to anyways unwinds callee regs, we use 116 * this to populate kernel thread entry-pt/args into callee regs, 117 * so that ret_from_kernel_thread() becomes simpler. 118 */ 119 p->thread.ksp = (unsigned long)c_callee; /* THREAD_KSP */ 120 121 /* __switch_to expects FP(0), BLINK(return addr) at top */ 122 childksp[0] = 0; /* fp */ 123 childksp[1] = (unsigned long)ret_from_fork; /* blink */ 124 125 if (unlikely(p->flags & PF_KTHREAD)) { 126 memset(c_regs, 0, sizeof(struct pt_regs)); 127 128 c_callee->r13 = kthread_arg; 129 c_callee->r14 = usp; /* function */ 130 131 return 0; 132 } 133 134 /*--------- User Task Only --------------*/ 135 136 /* __switch_to expects FP(0), BLINK(return addr) at top of stack */ 137 childksp[0] = 0; /* for POP fp */ 138 childksp[1] = (unsigned long)ret_from_fork; /* for POP blink */ 139 140 /* Copy parents pt regs on child's kernel mode stack */ 141 *c_regs = *regs; 142 143 if (usp) 144 c_regs->sp = usp; 145 146 c_regs->r0 = 0; /* fork returns 0 in child */ 147 148 parent_callee = ((struct callee_regs *)regs) - 1; 149 *c_callee = *parent_callee; 150 151 if (unlikely(clone_flags & CLONE_SETTLS)) { 152 /* 153 * set task's userland tls data ptr from 4th arg 154 * clone C-lib call is difft from clone sys-call 155 */ 156 task_thread_info(p)->thr_ptr = regs->r3; 157 } else { 158 /* Normal fork case: set parent's TLS ptr in child */ 159 task_thread_info(p)->thr_ptr = 160 task_thread_info(current)->thr_ptr; 161 } 162 163 return 0; 164 } 165 166 /* 167 * Do necessary setup to start up a new user task 168 */ 169 void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long usp) 170 { 171 regs->sp = usp; 172 regs->ret = pc; 173 174 /* 175 * [U]ser Mode bit set 176 * [L] ZOL loop inhibited to begin with - cleared by a LP insn 177 * Interrupts enabled 178 */ 179 regs->status32 = STATUS_U_MASK | STATUS_L_MASK | ISA_INIT_STATUS_BITS; 180 181 /* bogus seed values for debugging */ 182 regs->lp_start = 0x10; 183 regs->lp_end = 0x80; 184 } 185 186 /* 187 * Some archs flush debug and FPU info here 188 */ 189 void flush_thread(void) 190 { 191 } 192 193 /* 194 * Free any architecture-specific thread data structures, etc. 195 */ 196 void exit_thread(void) 197 { 198 } 199 200 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) 201 { 202 return 0; 203 } 204 205 int elf_check_arch(const struct elf32_hdr *x) 206 { 207 unsigned int eflags; 208 209 if (x->e_machine != EM_ARC_INUSE) { 210 pr_err("ELF not built for %s ISA\n", 211 is_isa_arcompact() ? "ARCompact":"ARCv2"); 212 return 0; 213 } 214 215 eflags = x->e_flags; 216 if ((eflags & EF_ARC_OSABI_MSK) < EF_ARC_OSABI_CURRENT) { 217 pr_err("ABI mismatch - you need newer toolchain\n"); 218 force_sigsegv(SIGSEGV, current); 219 return 0; 220 } 221 222 return 1; 223 } 224 EXPORT_SYMBOL(elf_check_arch); 225