1 /* By Ross Biro 1/23/92 */
3 * Pentium III FXSR, SSE support
4 * Gareth Hughes <gareth@valinux.com>, May 2000
7 #include <linux/kernel.h>
8 #include <linux/sched.h>
10 #include <linux/smp.h>
11 #include <linux/errno.h>
12 #include <linux/ptrace.h>
13 #include <linux/user.h>
14 #include <linux/security.h>
15 #include <linux/audit.h>
16 #include <linux/seccomp.h>
17 #include <linux/signal.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.
34 * Determines which flags the user has access to [1 = access, 0 = no access].
35 * Prohibits changing ID(21), VIP(20), VIF(19), VM(17), NT(14), IOPL(12-13), IF(9).
36 * Also masks reserved bits (31-22, 15, 5, 3, 1).
38 #define FLAG_MASK 0x00050dd5
40 static long *pt_regs_access(struct pt_regs *regs, unsigned long regno)
42 BUILD_BUG_ON(offsetof(struct pt_regs, bx) != 0);
45 return ®s->bx + regno;
48 static int putreg(struct task_struct *child,
49 unsigned long regno, unsigned long value)
51 struct pt_regs *regs = task_pt_regs(child);
55 if (value && (value & 3) != 3)
57 child->thread.gs = value;
60 * The user-mode %gs is not affected by
61 * kernel entry, so we must update the CPU.
63 loadsegment(gs, value);
68 if (value && (value & 3) != 3)
81 * If the user value contains TF, mark that
82 * it was not "us" (the debugger) that set it.
83 * If not, make sure it stays set if we had.
85 if (value & X86_EFLAGS_TF)
86 clear_tsk_thread_flag(child, TIF_FORCED_TF);
87 else if (test_tsk_thread_flag(child, TIF_FORCED_TF))
88 value |= X86_EFLAGS_TF;
89 value |= regs->flags & ~FLAG_MASK;
92 *pt_regs_access(regs, regno) = value;
96 static unsigned long getreg(struct task_struct *child, unsigned long regno)
98 struct pt_regs *regs = task_pt_regs(child);
99 unsigned long retval = ~0UL;
105 * If the debugger set TF, hide it from the readout.
107 retval = regs->flags;
108 if (test_tsk_thread_flag(child, TIF_FORCED_TF))
109 retval &= ~X86_EFLAGS_TF;
112 retval = child->thread.gs;
113 if (child == current)
114 savesegment(gs, retval);
124 retval &= *pt_regs_access(regs, regno);
130 * This function is trivial and will be inlined by the compiler.
131 * Having it separates the implementation details of debug
132 * registers from the interface details of ptrace.
134 static unsigned long ptrace_get_debugreg(struct task_struct *child, int n)
137 case 0: return child->thread.debugreg0;
138 case 1: return child->thread.debugreg1;
139 case 2: return child->thread.debugreg2;
140 case 3: return child->thread.debugreg3;
141 case 6: return child->thread.debugreg6;
142 case 7: return child->thread.debugreg7;
147 static int ptrace_set_debugreg(struct task_struct *child,
148 int n, unsigned long data)
152 if (unlikely(n == 4 || n == 5))
155 if (n < 4 && unlikely(data >= TASK_SIZE - 3))
159 case 0: child->thread.debugreg0 = data; break;
160 case 1: child->thread.debugreg1 = data; break;
161 case 2: child->thread.debugreg2 = data; break;
162 case 3: child->thread.debugreg3 = data; break;
165 child->thread.debugreg6 = data;
170 * Sanity-check data. Take one half-byte at once with
171 * check = (val >> (16 + 4*i)) & 0xf. It contains the
172 * R/Wi and LENi bits; bits 0 and 1 are R/Wi, and bits
173 * 2 and 3 are LENi. Given a list of invalid values,
174 * we do mask |= 1 << invalid_value, so that
175 * (mask >> check) & 1 is a correct test for invalid
178 * R/Wi contains the type of the breakpoint /
179 * watchpoint, LENi contains the length of the watched
180 * data in the watchpoint case.
182 * The invalid values are:
183 * - LENi == 0x10 (undefined), so mask |= 0x0f00.
184 * - R/Wi == 0x10 (break on I/O reads or writes), so
186 * - R/Wi == 0x00 && LENi != 0x00, so we have mask |=
189 * Finally, mask = 0x0f00 | 0x4444 | 0x1110 == 0x5f54.
191 * See the Intel Manual "System Programming Guide",
194 * Note that LENi == 0x10 is defined on x86_64 in long
195 * mode (i.e. even for 32-bit userspace software, but
196 * 64-bit kernel), so the x86_64 mask value is 0x5454.
197 * See the AMD manual no. 24593 (AMD64 System Programming)
199 data &= ~DR_CONTROL_RESERVED;
200 for (i = 0; i < 4; i++)
201 if ((0x5f54 >> ((data >> (16 + 4*i)) & 0xf)) & 1)
203 child->thread.debugreg7 = data;
205 set_tsk_thread_flag(child, TIF_DEBUG);
207 clear_tsk_thread_flag(child, TIF_DEBUG);
215 * Called by kernel/ptrace.c when detaching..
217 * Make sure the single step bit is not set.
219 void ptrace_disable(struct task_struct *child)
221 user_disable_single_step(child);
222 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
225 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
227 struct user * dummy = NULL;
229 unsigned long __user *datap = (unsigned long __user *)data;
232 /* when I and D space are separate, these will need to be fixed. */
233 case PTRACE_PEEKTEXT: /* read word at location addr. */
234 case PTRACE_PEEKDATA:
235 ret = generic_ptrace_peekdata(child, addr, data);
238 /* read the word at location addr in the USER area. */
239 case PTRACE_PEEKUSR: {
243 if ((addr & 3) || addr < 0 ||
244 addr > sizeof(struct user) - 3)
247 tmp = 0; /* Default return condition */
248 if(addr < FRAME_SIZE*sizeof(long))
249 tmp = getreg(child, addr);
250 if(addr >= (long) &dummy->u_debugreg[0] &&
251 addr <= (long) &dummy->u_debugreg[7]){
252 addr -= (long) &dummy->u_debugreg[0];
254 tmp = ptrace_get_debugreg(child, addr);
256 ret = put_user(tmp, datap);
260 /* when I and D space are separate, this will have to be fixed. */
261 case PTRACE_POKETEXT: /* write the word at location addr. */
262 case PTRACE_POKEDATA:
263 ret = generic_ptrace_pokedata(child, addr, data);
266 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
268 if ((addr & 3) || addr < 0 ||
269 addr > sizeof(struct user) - 3)
272 if (addr < FRAME_SIZE*sizeof(long)) {
273 ret = putreg(child, addr, data);
276 /* We need to be very careful here. We implicitly
277 want to modify a portion of the task_struct, and we
278 have to be selective about what portions we allow someone
282 if(addr >= (long) &dummy->u_debugreg[0] &&
283 addr <= (long) &dummy->u_debugreg[7]){
284 addr -= (long) &dummy->u_debugreg;
286 ret = ptrace_set_debugreg(child, addr, data);
290 case PTRACE_GETREGS: { /* Get all gp regs from the child. */
291 if (!access_ok(VERIFY_WRITE, datap, FRAME_SIZE*sizeof(long))) {
295 for ( i = 0; i < FRAME_SIZE*sizeof(long); i += sizeof(long) ) {
296 __put_user(getreg(child, i), datap);
303 case PTRACE_SETREGS: { /* Set all gp regs in the child. */
305 if (!access_ok(VERIFY_READ, datap, FRAME_SIZE*sizeof(long))) {
309 for ( i = 0; i < FRAME_SIZE*sizeof(long); i += sizeof(long) ) {
310 __get_user(tmp, datap);
311 putreg(child, i, tmp);
318 case PTRACE_GETFPREGS: { /* Get the child FPU state. */
319 if (!access_ok(VERIFY_WRITE, datap,
320 sizeof(struct user_i387_struct))) {
325 if (!tsk_used_math(child))
327 get_fpregs((struct user_i387_struct __user *)data, child);
331 case PTRACE_SETFPREGS: { /* Set the child FPU state. */
332 if (!access_ok(VERIFY_READ, datap,
333 sizeof(struct user_i387_struct))) {
337 set_stopped_child_used_math(child);
338 set_fpregs(child, (struct user_i387_struct __user *)data);
343 case PTRACE_GETFPXREGS: { /* Get the child extended FPU state. */
344 if (!access_ok(VERIFY_WRITE, datap,
345 sizeof(struct user_fxsr_struct))) {
349 if (!tsk_used_math(child))
351 ret = get_fpxregs((struct user_fxsr_struct __user *)data, child);
355 case PTRACE_SETFPXREGS: { /* Set the child extended FPU state. */
356 if (!access_ok(VERIFY_READ, datap,
357 sizeof(struct user_fxsr_struct))) {
361 set_stopped_child_used_math(child);
362 ret = set_fpxregs(child, (struct user_fxsr_struct __user *)data);
366 case PTRACE_GET_THREAD_AREA:
369 ret = do_get_thread_area(child, addr,
370 (struct user_desc __user *) data);
373 case PTRACE_SET_THREAD_AREA:
376 ret = do_set_thread_area(child, addr,
377 (struct user_desc __user *) data, 0);
381 ret = ptrace_request(child, request, addr, data);
388 void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code)
392 tsk->thread.trap_no = 1;
393 tsk->thread.error_code = error_code;
395 memset(&info, 0, sizeof(info));
396 info.si_signo = SIGTRAP;
397 info.si_code = TRAP_BRKPT;
400 info.si_addr = user_mode_vm(regs) ? (void __user *) regs->ip : NULL;
402 /* Send us the fake SIGTRAP */
403 force_sig_info(SIGTRAP, &info, tsk);
406 /* notification of system call entry/exit
407 * - triggered by current->work.syscall_trace
409 __attribute__((regparm(3)))
410 int do_syscall_trace(struct pt_regs *regs, int entryexit)
412 int is_sysemu = test_thread_flag(TIF_SYSCALL_EMU);
414 * With TIF_SYSCALL_EMU set we want to ignore TIF_SINGLESTEP for syscall
417 int is_singlestep = !is_sysemu && test_thread_flag(TIF_SINGLESTEP);
420 /* do the secure computing check first */
422 secure_computing(regs->orig_ax);
424 if (unlikely(current->audit_context)) {
426 audit_syscall_exit(AUDITSC_RESULT(regs->ax),
428 /* Debug traps, when using PTRACE_SINGLESTEP, must be sent only
429 * on the syscall exit path. Normally, when TIF_SYSCALL_AUDIT is
430 * not used, entry.S will call us only on syscall exit, not
431 * entry; so when TIF_SYSCALL_AUDIT is used we must avoid
432 * calling send_sigtrap() on syscall entry.
434 * Note that when PTRACE_SYSEMU_SINGLESTEP is used,
435 * is_singlestep is false, despite his name, so we will still do
438 else if (is_singlestep)
442 if (!(current->ptrace & PT_PTRACED))
445 /* If a process stops on the 1st tracepoint with SYSCALL_TRACE
446 * and then is resumed with SYSEMU_SINGLESTEP, it will come in
447 * here. We have to check this and return */
448 if (is_sysemu && entryexit)
451 /* Fake a debug trap */
453 send_sigtrap(current, regs, 0);
455 if (!test_thread_flag(TIF_SYSCALL_TRACE) && !is_sysemu)
458 /* the 0x80 provides a way for the tracing parent to distinguish
459 between a syscall stop and SIGTRAP delivery */
460 /* Note that the debugger could change the result of test_thread_flag!*/
461 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ? 0x80:0));
464 * this isn't the same as continuing with a signal, but it will do
465 * for normal use. strace only continues with a signal if the
466 * stopping signal is not SIGTRAP. -brl
468 if (current->exit_code) {
469 send_sig(current->exit_code, current, 1);
470 current->exit_code = 0;
474 if (unlikely(current->audit_context) && !entryexit)
475 audit_syscall_entry(AUDIT_ARCH_I386, regs->orig_ax,
476 regs->bx, regs->cx, regs->dx, regs->si);
480 regs->orig_ax = -1; /* force skip of syscall restarting */
481 if (unlikely(current->audit_context))
482 audit_syscall_exit(AUDITSC_RESULT(regs->ax), regs->ax);