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