2 /* By Ross Biro 1/23/92 */
4 * Pentium III FXSR, SSE support
5 * Gareth Hughes <gareth@valinux.com>, May 2000
8 #include <linux/kernel.h>
9 #include <linux/sched.h>
11 #include <linux/smp.h>
12 #include <linux/smp_lock.h>
13 #include <linux/errno.h>
14 #include <linux/ptrace.h>
15 #include <linux/user.h>
16 #include <linux/security.h>
17 #include <linux/audit.h>
19 #include <asm/uaccess.h>
20 #include <asm/pgtable.h>
21 #include <asm/system.h>
22 #include <asm/processor.h>
24 #include <asm/debugreg.h>
29 * does not yet catch signals sent when the child dies.
30 * in exit.c or in signal.c.
33 /* determines which flags the user has access to. */
34 /* 1 = access 0 = no access */
35 #define FLAG_MASK 0x00044dd5
37 /* set's the trap flag. */
38 #define TRAP_FLAG 0x100
41 * Offset of eflags on child stack..
43 #define EFL_OFFSET ((EFL-2)*4-sizeof(struct pt_regs))
45 static inline struct pt_regs *get_child_regs(struct task_struct *task)
47 void *stack_top = (void *)task->thread.esp0;
48 return stack_top - sizeof(struct pt_regs);
52 * this routine will get a word off of the processes privileged stack.
53 * the offset is how far from the base addr as stored in the TSS.
54 * this routine assumes that all the privileged stacks are in our
57 static inline int get_stack_long(struct task_struct *task, int offset)
61 stack = (unsigned char *)task->thread.esp0;
63 return (*((int *)stack));
67 * this routine will put a word on the processes privileged stack.
68 * the offset is how far from the base addr as stored in the TSS.
69 * this routine assumes that all the privileged stacks are in our
72 static inline int put_stack_long(struct task_struct *task, int offset,
75 unsigned char * stack;
77 stack = (unsigned char *) task->thread.esp0;
79 *(unsigned long *) stack = data;
83 static int putreg(struct task_struct *child,
84 unsigned long regno, unsigned long value)
88 if (value && (value & 3) != 3)
90 child->thread.fs = value;
93 if (value && (value & 3) != 3)
95 child->thread.gs = value;
99 if (value && (value & 3) != 3)
105 if ((value & 3) != 3)
111 value |= get_stack_long(child, EFL_OFFSET) & ~FLAG_MASK;
116 put_stack_long(child, regno - sizeof(struct pt_regs), value);
120 static unsigned long getreg(struct task_struct *child,
123 unsigned long retval = ~0UL;
125 switch (regno >> 2) {
127 retval = child->thread.fs;
130 retval = child->thread.gs;
141 regno = regno - sizeof(struct pt_regs);
142 retval &= get_stack_long(child, regno);
147 #define LDT_SEGMENT 4
149 static unsigned long convert_eip_to_linear(struct task_struct *child, struct pt_regs *regs)
151 unsigned long addr, seg;
154 seg = regs->xcs & 0xffff;
155 if (regs->eflags & VM_MASK) {
156 addr = (addr & 0xffff) + (seg << 4);
161 * We'll assume that the code segments in the GDT
162 * are all zero-based. That is largely true: the
163 * TLS segments are used for data, and the PNPBIOS
164 * and APM bios ones we just ignore here.
166 if (seg & LDT_SEGMENT) {
170 down(&child->mm->context.sem);
171 desc = child->mm->context.ldt + (seg & ~7);
172 base = (desc[0] >> 16) | ((desc[1] & 0xff) << 16) | (desc[1] & 0xff000000);
174 /* 16-bit code segment? */
175 if (!((desc[1] >> 22) & 1))
178 up(&child->mm->context.sem);
183 static inline int is_at_popf(struct task_struct *child, struct pt_regs *regs)
186 unsigned char opcode[16];
187 unsigned long addr = convert_eip_to_linear(child, regs);
189 copied = access_process_vm(child, addr, opcode, sizeof(opcode), 0);
190 for (i = 0; i < copied; i++) {
195 /* opcode and address size prefixes */
196 case 0x66: case 0x67:
198 /* irrelevant prefixes (segment overrides and repeats) */
199 case 0x26: case 0x2e:
200 case 0x36: case 0x3e:
201 case 0x64: case 0x65:
202 case 0xf0: case 0xf2: case 0xf3:
206 * pushf: NOTE! We should probably not let
207 * the user see the TF bit being set. But
208 * it's more pain than it's worth to avoid
209 * it, and a debugger could emulate this
210 * all in user space if it _really_ cares.
220 static void set_singlestep(struct task_struct *child)
222 struct pt_regs *regs = get_child_regs(child);
225 * Always set TIF_SINGLESTEP - this guarantees that
226 * we single-step system calls etc.. This will also
227 * cause us to set TF when returning to user mode.
229 set_tsk_thread_flag(child, TIF_SINGLESTEP);
232 * If TF was already set, don't do anything else
234 if (regs->eflags & TRAP_FLAG)
237 /* Set TF on the kernel stack.. */
238 regs->eflags |= TRAP_FLAG;
241 * ..but if TF is changed by the instruction we will trace,
242 * don't mark it as being "us" that set it, so that we
243 * won't clear it by hand later.
245 if (is_at_popf(child, regs))
248 child->ptrace |= PT_DTRACE;
251 static void clear_singlestep(struct task_struct *child)
253 /* Always clear TIF_SINGLESTEP... */
254 clear_tsk_thread_flag(child, TIF_SINGLESTEP);
256 /* But touch TF only if it was set by us.. */
257 if (child->ptrace & PT_DTRACE) {
258 struct pt_regs *regs = get_child_regs(child);
259 regs->eflags &= ~TRAP_FLAG;
260 child->ptrace &= ~PT_DTRACE;
265 * Called by kernel/ptrace.c when detaching..
267 * Make sure the single step bit is not set.
269 void ptrace_disable(struct task_struct *child)
271 clear_singlestep(child);
275 * Perform get_thread_area on behalf of the traced child.
278 ptrace_get_thread_area(struct task_struct *child,
279 int idx, struct user_desc __user *user_desc)
281 struct user_desc info;
282 struct desc_struct *desc;
285 * Get the current Thread-Local Storage area:
288 #define GET_BASE(desc) ( \
289 (((desc)->a >> 16) & 0x0000ffff) | \
290 (((desc)->b << 16) & 0x00ff0000) | \
291 ( (desc)->b & 0xff000000) )
293 #define GET_LIMIT(desc) ( \
294 ((desc)->a & 0x0ffff) | \
295 ((desc)->b & 0xf0000) )
297 #define GET_32BIT(desc) (((desc)->b >> 22) & 1)
298 #define GET_CONTENTS(desc) (((desc)->b >> 10) & 3)
299 #define GET_WRITABLE(desc) (((desc)->b >> 9) & 1)
300 #define GET_LIMIT_PAGES(desc) (((desc)->b >> 23) & 1)
301 #define GET_PRESENT(desc) (((desc)->b >> 15) & 1)
302 #define GET_USEABLE(desc) (((desc)->b >> 20) & 1)
304 if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
307 desc = child->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
309 info.entry_number = idx;
310 info.base_addr = GET_BASE(desc);
311 info.limit = GET_LIMIT(desc);
312 info.seg_32bit = GET_32BIT(desc);
313 info.contents = GET_CONTENTS(desc);
314 info.read_exec_only = !GET_WRITABLE(desc);
315 info.limit_in_pages = GET_LIMIT_PAGES(desc);
316 info.seg_not_present = !GET_PRESENT(desc);
317 info.useable = GET_USEABLE(desc);
319 if (copy_to_user(user_desc, &info, sizeof(info)))
326 * Perform set_thread_area on behalf of the traced child.
329 ptrace_set_thread_area(struct task_struct *child,
330 int idx, struct user_desc __user *user_desc)
332 struct user_desc info;
333 struct desc_struct *desc;
335 if (copy_from_user(&info, user_desc, sizeof(info)))
338 if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
341 desc = child->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
342 if (LDT_empty(&info)) {
346 desc->a = LDT_entry_a(&info);
347 desc->b = LDT_entry_b(&info);
353 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
355 struct task_struct *child;
356 struct user * dummy = NULL;
358 unsigned long __user *datap = (unsigned long __user *)data;
362 if (request == PTRACE_TRACEME) {
363 /* are we already being traced? */
364 if (current->ptrace & PT_PTRACED)
366 ret = security_ptrace(current->parent, current);
369 /* set the ptrace bit in the process flags. */
370 current->ptrace |= PT_PTRACED;
375 read_lock(&tasklist_lock);
376 child = find_task_by_pid(pid);
378 get_task_struct(child);
379 read_unlock(&tasklist_lock);
382 if (!vx_check(vx_task_xid(child), VX_WATCH|VX_IDENT))
386 if (pid == 1) /* you may not mess with init */
389 if (request == PTRACE_ATTACH) {
390 ret = ptrace_attach(child);
394 ret = ptrace_check_attach(child, request == PTRACE_KILL);
399 /* when I and D space are separate, these will need to be fixed. */
400 case PTRACE_PEEKTEXT: /* read word at location addr. */
401 case PTRACE_PEEKDATA: {
405 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
407 if (copied != sizeof(tmp))
409 ret = put_user(tmp, datap);
413 /* read the word at location addr in the USER area. */
414 case PTRACE_PEEKUSR: {
418 if ((addr & 3) || addr < 0 ||
419 addr > sizeof(struct user) - 3)
422 tmp = 0; /* Default return condition */
423 if(addr < FRAME_SIZE*sizeof(long))
424 tmp = getreg(child, addr);
425 if(addr >= (long) &dummy->u_debugreg[0] &&
426 addr <= (long) &dummy->u_debugreg[7]){
427 addr -= (long) &dummy->u_debugreg[0];
429 tmp = child->thread.debugreg[addr];
431 ret = put_user(tmp, datap);
435 /* when I and D space are separate, this will have to be fixed. */
436 case PTRACE_POKETEXT: /* write the word at location addr. */
437 case PTRACE_POKEDATA:
439 if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
444 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
446 if ((addr & 3) || addr < 0 ||
447 addr > sizeof(struct user) - 3)
450 if (addr < FRAME_SIZE*sizeof(long)) {
451 ret = putreg(child, addr, data);
454 /* We need to be very careful here. We implicitly
455 want to modify a portion of the task_struct, and we
456 have to be selective about what portions we allow someone
460 if(addr >= (long) &dummy->u_debugreg[0] &&
461 addr <= (long) &dummy->u_debugreg[7]){
463 if(addr == (long) &dummy->u_debugreg[4]) break;
464 if(addr == (long) &dummy->u_debugreg[5]) break;
465 if(addr < (long) &dummy->u_debugreg[4] &&
466 ((unsigned long) data) >= TASK_SIZE-3) break;
468 /* Sanity-check data. Take one half-byte at once with
469 * check = (val >> (16 + 4*i)) & 0xf. It contains the
470 * R/Wi and LENi bits; bits 0 and 1 are R/Wi, and bits
471 * 2 and 3 are LENi. Given a list of invalid values,
472 * we do mask |= 1 << invalid_value, so that
473 * (mask >> check) & 1 is a correct test for invalid
476 * R/Wi contains the type of the breakpoint /
477 * watchpoint, LENi contains the length of the watched
478 * data in the watchpoint case.
480 * The invalid values are:
481 * - LENi == 0x10 (undefined), so mask |= 0x0f00.
482 * - R/Wi == 0x10 (break on I/O reads or writes), so
484 * - R/Wi == 0x00 && LENi != 0x00, so we have mask |=
487 * Finally, mask = 0x0f00 | 0x4444 | 0x1110 == 0x5f54.
489 * See the Intel Manual "System Programming Guide",
492 * Note that LENi == 0x10 is defined on x86_64 in long
493 * mode (i.e. even for 32-bit userspace software, but
494 * 64-bit kernel), so the x86_64 mask value is 0x5454.
495 * See the AMD manual no. 24593 (AMD64 System
498 if(addr == (long) &dummy->u_debugreg[7]) {
499 data &= ~DR_CONTROL_RESERVED;
501 if ((0x5f54 >> ((data >> (16 + 4*i)) & 0xf)) & 1)
505 addr -= (long) &dummy->u_debugreg;
507 child->thread.debugreg[addr] = data;
512 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
513 case PTRACE_CONT: /* restart after signal. */
515 if ((unsigned long) data > _NSIG)
517 if (request == PTRACE_SYSCALL) {
518 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
521 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
523 child->exit_code = data;
524 /* make sure the single step bit is not set. */
525 clear_singlestep(child);
526 wake_up_process(child);
531 * make the child exit. Best I can do is send it a sigkill.
532 * perhaps it should be put in the status that it wants to
537 if (child->exit_state == EXIT_ZOMBIE) /* already dead */
539 child->exit_code = SIGKILL;
540 /* make sure the single step bit is not set. */
541 clear_singlestep(child);
542 wake_up_process(child);
545 case PTRACE_SINGLESTEP: /* set the trap flag. */
547 if ((unsigned long) data > _NSIG)
549 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
550 set_singlestep(child);
551 child->exit_code = data;
552 /* give it a chance to run. */
553 wake_up_process(child);
558 /* detach a process that was attached. */
559 ret = ptrace_detach(child, data);
562 case PTRACE_GETREGS: { /* Get all gp regs from the child. */
563 if (!access_ok(VERIFY_WRITE, datap, FRAME_SIZE*sizeof(long))) {
567 for ( i = 0; i < FRAME_SIZE*sizeof(long); i += sizeof(long) ) {
568 __put_user(getreg(child, i), datap);
575 case PTRACE_SETREGS: { /* Set all gp regs in the child. */
577 if (!access_ok(VERIFY_READ, datap, FRAME_SIZE*sizeof(long))) {
581 for ( i = 0; i < FRAME_SIZE*sizeof(long); i += sizeof(long) ) {
582 __get_user(tmp, datap);
583 putreg(child, i, tmp);
590 case PTRACE_GETFPREGS: { /* Get the child FPU state. */
591 if (!access_ok(VERIFY_WRITE, datap,
592 sizeof(struct user_i387_struct))) {
597 if (!tsk_used_math(child))
599 get_fpregs((struct user_i387_struct __user *)data, child);
603 case PTRACE_SETFPREGS: { /* Set the child FPU state. */
604 if (!access_ok(VERIFY_READ, datap,
605 sizeof(struct user_i387_struct))) {
609 set_stopped_child_used_math(child);
610 set_fpregs(child, (struct user_i387_struct __user *)data);
615 case PTRACE_GETFPXREGS: { /* Get the child extended FPU state. */
616 if (!access_ok(VERIFY_WRITE, datap,
617 sizeof(struct user_fxsr_struct))) {
621 if (!tsk_used_math(child))
623 ret = get_fpxregs((struct user_fxsr_struct __user *)data, child);
627 case PTRACE_SETFPXREGS: { /* Set the child extended FPU state. */
628 if (!access_ok(VERIFY_READ, datap,
629 sizeof(struct user_fxsr_struct))) {
633 set_stopped_child_used_math(child);
634 ret = set_fpxregs(child, (struct user_fxsr_struct __user *)data);
638 case PTRACE_GET_THREAD_AREA:
639 ret = ptrace_get_thread_area(child, addr,
640 (struct user_desc __user *) data);
643 case PTRACE_SET_THREAD_AREA:
644 ret = ptrace_set_thread_area(child, addr,
645 (struct user_desc __user *) data);
649 ret = ptrace_request(child, request, addr, data);
653 put_task_struct(child);
659 void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code)
663 tsk->thread.trap_no = 1;
664 tsk->thread.error_code = error_code;
666 memset(&info, 0, sizeof(info));
667 info.si_signo = SIGTRAP;
668 info.si_code = TRAP_BRKPT;
671 info.si_addr = user_mode(regs) ? (void __user *) regs->eip : NULL;
673 /* Send us the fakey SIGTRAP */
674 force_sig_info(SIGTRAP, &info, tsk);
677 /* notification of system call entry/exit
678 * - triggered by current->work.syscall_trace
680 __attribute__((regparm(3)))
681 void do_syscall_trace(struct pt_regs *regs, int entryexit)
683 if (unlikely(current->audit_context)) {
685 audit_syscall_entry(current, regs->orig_eax,
686 regs->ebx, regs->ecx,
687 regs->edx, regs->esi);
689 audit_syscall_exit(current, regs->eax);
692 if (!(current->ptrace & PT_PTRACED))
695 /* Fake a debug trap */
696 if (test_thread_flag(TIF_SINGLESTEP))
697 send_sigtrap(current, regs, 0);
699 if (!test_thread_flag(TIF_SYSCALL_TRACE))
702 /* the 0x80 provides a way for the tracing parent to distinguish
703 between a syscall stop and SIGTRAP delivery */
704 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));
707 * this isn't the same as continuing with a signal, but it will do
708 * for normal use. strace only continues with a signal if the
709 * stopping signal is not SIGTRAP. -brl
711 if (current->exit_code) {
712 send_sig(current->exit_code, current, 1);
713 current->exit_code = 0;