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