1 /* 2 * arch/sh/kernel/process.c 3 * 4 * This file handles the architecture-dependent parts of process handling.. 5 * 6 * Copyright (C) 1995 Linus Torvalds 7 * 8 * SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima 9 * Copyright (C) 2006 Lineo Solutions Inc. support SH4A UBC 10 * Copyright (C) 2002 - 2008 Paul Mundt 11 * 12 * This file is subject to the terms and conditions of the GNU General Public 13 * License. See the file "COPYING" in the main directory of this archive 14 * for more details. 15 */ 16 #include <linux/module.h> 17 #include <linux/mm.h> 18 #include <linux/slab.h> 19 #include <linux/elfcore.h> 20 #include <linux/kallsyms.h> 21 #include <linux/fs.h> 22 #include <linux/ftrace.h> 23 #include <linux/hw_breakpoint.h> 24 #include <linux/prefetch.h> 25 #include <linux/stackprotector.h> 26 #include <asm/uaccess.h> 27 #include <asm/mmu_context.h> 28 #include <asm/fpu.h> 29 #include <asm/syscalls.h> 30 #include <asm/switch_to.h> 31 32 void show_regs(struct pt_regs * regs) 33 { 34 printk("\n"); 35 printk("Pid : %d, Comm: \t\t%s\n", task_pid_nr(current), current->comm); 36 printk("CPU : %d \t\t%s (%s %.*s)\n\n", 37 smp_processor_id(), print_tainted(), init_utsname()->release, 38 (int)strcspn(init_utsname()->version, " "), 39 init_utsname()->version); 40 41 print_symbol("PC is at %s\n", instruction_pointer(regs)); 42 print_symbol("PR is at %s\n", regs->pr); 43 44 printk("PC : %08lx SP : %08lx SR : %08lx ", 45 regs->pc, regs->regs[15], regs->sr); 46 #ifdef CONFIG_MMU 47 printk("TEA : %08x\n", __raw_readl(MMU_TEA)); 48 #else 49 printk("\n"); 50 #endif 51 52 printk("R0 : %08lx R1 : %08lx R2 : %08lx R3 : %08lx\n", 53 regs->regs[0],regs->regs[1], 54 regs->regs[2],regs->regs[3]); 55 printk("R4 : %08lx R5 : %08lx R6 : %08lx R7 : %08lx\n", 56 regs->regs[4],regs->regs[5], 57 regs->regs[6],regs->regs[7]); 58 printk("R8 : %08lx R9 : %08lx R10 : %08lx R11 : %08lx\n", 59 regs->regs[8],regs->regs[9], 60 regs->regs[10],regs->regs[11]); 61 printk("R12 : %08lx R13 : %08lx R14 : %08lx\n", 62 regs->regs[12],regs->regs[13], 63 regs->regs[14]); 64 printk("MACH: %08lx MACL: %08lx GBR : %08lx PR : %08lx\n", 65 regs->mach, regs->macl, regs->gbr, regs->pr); 66 67 show_trace(NULL, (unsigned long *)regs->regs[15], regs); 68 show_code(regs); 69 } 70 71 /* 72 * Create a kernel thread 73 */ 74 __noreturn void kernel_thread_helper(void *arg, int (*fn)(void *)) 75 { 76 do_exit(fn(arg)); 77 } 78 79 /* Don't use this in BL=1(cli). Or else, CPU resets! */ 80 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) 81 { 82 struct pt_regs regs; 83 int pid; 84 85 memset(®s, 0, sizeof(regs)); 86 regs.regs[4] = (unsigned long)arg; 87 regs.regs[5] = (unsigned long)fn; 88 89 regs.pc = (unsigned long)kernel_thread_helper; 90 regs.sr = SR_MD; 91 #if defined(CONFIG_SH_FPU) 92 regs.sr |= SR_FD; 93 #endif 94 95 /* Ok, create the new process.. */ 96 pid = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, 97 ®s, 0, NULL, NULL); 98 99 return pid; 100 } 101 EXPORT_SYMBOL(kernel_thread); 102 103 void start_thread(struct pt_regs *regs, unsigned long new_pc, 104 unsigned long new_sp) 105 { 106 regs->pr = 0; 107 regs->sr = SR_FD; 108 regs->pc = new_pc; 109 regs->regs[15] = new_sp; 110 111 free_thread_xstate(current); 112 } 113 EXPORT_SYMBOL(start_thread); 114 115 /* 116 * Free current thread data structures etc.. 117 */ 118 void exit_thread(void) 119 { 120 } 121 122 void flush_thread(void) 123 { 124 struct task_struct *tsk = current; 125 126 flush_ptrace_hw_breakpoint(tsk); 127 128 #if defined(CONFIG_SH_FPU) 129 /* Forget lazy FPU state */ 130 clear_fpu(tsk, task_pt_regs(tsk)); 131 clear_used_math(); 132 #endif 133 } 134 135 void release_thread(struct task_struct *dead_task) 136 { 137 /* do nothing */ 138 } 139 140 /* Fill in the fpu structure for a core dump.. */ 141 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) 142 { 143 int fpvalid = 0; 144 145 #if defined(CONFIG_SH_FPU) 146 struct task_struct *tsk = current; 147 148 fpvalid = !!tsk_used_math(tsk); 149 if (fpvalid) 150 fpvalid = !fpregs_get(tsk, NULL, 0, 151 sizeof(struct user_fpu_struct), 152 fpu, NULL); 153 #endif 154 155 return fpvalid; 156 } 157 EXPORT_SYMBOL(dump_fpu); 158 159 /* 160 * This gets called before we allocate a new thread and copy 161 * the current task into it. 162 */ 163 void prepare_to_copy(struct task_struct *tsk) 164 { 165 unlazy_fpu(tsk, task_pt_regs(tsk)); 166 } 167 168 asmlinkage void ret_from_fork(void); 169 170 int copy_thread(unsigned long clone_flags, unsigned long usp, 171 unsigned long unused, 172 struct task_struct *p, struct pt_regs *regs) 173 { 174 struct thread_info *ti = task_thread_info(p); 175 struct pt_regs *childregs; 176 177 #if defined(CONFIG_SH_DSP) 178 struct task_struct *tsk = current; 179 180 if (is_dsp_enabled(tsk)) { 181 /* We can use the __save_dsp or just copy the struct: 182 * __save_dsp(p); 183 * p->thread.dsp_status.status |= SR_DSP 184 */ 185 p->thread.dsp_status = tsk->thread.dsp_status; 186 } 187 #endif 188 189 childregs = task_pt_regs(p); 190 *childregs = *regs; 191 192 if (user_mode(regs)) { 193 childregs->regs[15] = usp; 194 ti->addr_limit = USER_DS; 195 } else { 196 childregs->regs[15] = (unsigned long)childregs; 197 ti->addr_limit = KERNEL_DS; 198 ti->status &= ~TS_USEDFPU; 199 p->fpu_counter = 0; 200 } 201 202 if (clone_flags & CLONE_SETTLS) 203 childregs->gbr = childregs->regs[0]; 204 205 childregs->regs[0] = 0; /* Set return value for child */ 206 207 p->thread.sp = (unsigned long) childregs; 208 p->thread.pc = (unsigned long) ret_from_fork; 209 210 memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); 211 212 return 0; 213 } 214 215 /* 216 * switch_to(x,y) should switch tasks from x to y. 217 * 218 */ 219 __notrace_funcgraph struct task_struct * 220 __switch_to(struct task_struct *prev, struct task_struct *next) 221 { 222 struct thread_struct *next_t = &next->thread; 223 224 #if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP) 225 __stack_chk_guard = next->stack_canary; 226 #endif 227 228 unlazy_fpu(prev, task_pt_regs(prev)); 229 230 /* we're going to use this soon, after a few expensive things */ 231 if (next->fpu_counter > 5) 232 prefetch(next_t->xstate); 233 234 #ifdef CONFIG_MMU 235 /* 236 * Restore the kernel mode register 237 * k7 (r7_bank1) 238 */ 239 asm volatile("ldc %0, r7_bank" 240 : /* no output */ 241 : "r" (task_thread_info(next))); 242 #endif 243 244 /* 245 * If the task has used fpu the last 5 timeslices, just do a full 246 * restore of the math state immediately to avoid the trap; the 247 * chances of needing FPU soon are obviously high now 248 */ 249 if (next->fpu_counter > 5) 250 __fpu_state_restore(); 251 252 return prev; 253 } 254 255 asmlinkage int sys_fork(unsigned long r4, unsigned long r5, 256 unsigned long r6, unsigned long r7, 257 struct pt_regs __regs) 258 { 259 #ifdef CONFIG_MMU 260 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 261 return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL); 262 #else 263 /* fork almost works, enough to trick you into looking elsewhere :-( */ 264 return -EINVAL; 265 #endif 266 } 267 268 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp, 269 unsigned long parent_tidptr, 270 unsigned long child_tidptr, 271 struct pt_regs __regs) 272 { 273 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 274 if (!newsp) 275 newsp = regs->regs[15]; 276 return do_fork(clone_flags, newsp, regs, 0, 277 (int __user *)parent_tidptr, 278 (int __user *)child_tidptr); 279 } 280 281 /* 282 * This is trivial, and on the face of it looks like it 283 * could equally well be done in user mode. 284 * 285 * Not so, for quite unobvious reasons - register pressure. 286 * In user mode vfork() cannot have a stack frame, and if 287 * done by calling the "clone()" system call directly, you 288 * do not have enough call-clobbered registers to hold all 289 * the information you need. 290 */ 291 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5, 292 unsigned long r6, unsigned long r7, 293 struct pt_regs __regs) 294 { 295 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 296 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs, 297 0, NULL, NULL); 298 } 299 300 /* 301 * sys_execve() executes a new program. 302 */ 303 asmlinkage int sys_execve(const char __user *ufilename, 304 const char __user *const __user *uargv, 305 const char __user *const __user *uenvp, 306 unsigned long r7, struct pt_regs __regs) 307 { 308 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 309 int error; 310 char *filename; 311 312 filename = getname(ufilename); 313 error = PTR_ERR(filename); 314 if (IS_ERR(filename)) 315 goto out; 316 317 error = do_execve(filename, uargv, uenvp, regs); 318 putname(filename); 319 out: 320 return error; 321 } 322 323 unsigned long get_wchan(struct task_struct *p) 324 { 325 unsigned long pc; 326 327 if (!p || p == current || p->state == TASK_RUNNING) 328 return 0; 329 330 /* 331 * The same comment as on the Alpha applies here, too ... 332 */ 333 pc = thread_saved_pc(p); 334 335 #ifdef CONFIG_FRAME_POINTER 336 if (in_sched_functions(pc)) { 337 unsigned long schedule_frame = (unsigned long)p->thread.sp; 338 return ((unsigned long *)schedule_frame)[21]; 339 } 340 #endif 341 342 return pc; 343 } 344