1 // SPDX-License-Identifier: GPL-2.0
3 * Kernel support for the ptrace() and syscall tracing interfaces.
5 * Copyright (C) 2000 Hewlett-Packard Co, Linuxcare Inc.
6 * Copyright (C) 2000 Matthew Wilcox <matthew@wil.cx>
7 * Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
8 * Copyright (C) 2008-2016 Helge Deller <deller@gmx.de>
11 #include <linux/kernel.h>
12 #include <linux/sched.h>
14 #include <linux/smp.h>
15 #include <linux/elf.h>
16 #include <linux/errno.h>
17 #include <linux/ptrace.h>
18 #include <linux/tracehook.h>
19 #include <linux/user.h>
20 #include <linux/personality.h>
21 #include <linux/regset.h>
22 #include <linux/security.h>
23 #include <linux/seccomp.h>
24 #include <linux/compat.h>
25 #include <linux/signal.h>
26 #include <linux/audit.h>
28 #include <linux/uaccess.h>
29 #include <asm/processor.h>
30 #include <asm/asm-offsets.h>
32 /* PSW bits we allow the debugger to modify */
33 #define USER_PSW_BITS (PSW_N | PSW_B | PSW_V | PSW_CB)
35 #define CREATE_TRACE_POINTS
36 #include <trace/events/syscalls.h>
39 * These are our native regset flavors.
47 * Called by kernel/ptrace.c when detaching..
49 * Make sure single step bits etc are not set.
51 void ptrace_disable(struct task_struct *task)
53 clear_tsk_thread_flag(task, TIF_SINGLESTEP);
54 clear_tsk_thread_flag(task, TIF_BLOCKSTEP);
56 /* make sure the trap bits are not set */
64 * The following functions are called by ptrace_resume() when
65 * enabling or disabling single/block tracing.
67 void user_disable_single_step(struct task_struct *task)
72 void user_enable_single_step(struct task_struct *task)
74 clear_tsk_thread_flag(task, TIF_BLOCKSTEP);
75 set_tsk_thread_flag(task, TIF_SINGLESTEP);
77 if (pa_psw(task)->n) {
78 /* Nullified, just crank over the queue. */
79 task_regs(task)->iaoq[0] = task_regs(task)->iaoq[1];
80 task_regs(task)->iasq[0] = task_regs(task)->iasq[1];
81 task_regs(task)->iaoq[1] = task_regs(task)->iaoq[0] + 4;
88 /* Don't wake up the task, but let the
89 parent know something happened. */
90 force_sig_fault_to_task(SIGTRAP, TRAP_TRACE,
91 (void __user *) (task_regs(task)->iaoq[0] & ~3),
93 /* notify_parent(task, SIGCHLD); */
97 /* Enable recovery counter traps. The recovery counter
98 * itself will be set to zero on a task switch. If the
99 * task is suspended on a syscall then the syscall return
100 * path will overwrite the recovery counter with a suitable
101 * value such that it traps once back in user space. We
102 * disable interrupts in the tasks PSW here also, to avoid
103 * interrupts while the recovery counter is decrementing.
111 void user_enable_block_step(struct task_struct *task)
113 clear_tsk_thread_flag(task, TIF_SINGLESTEP);
114 set_tsk_thread_flag(task, TIF_BLOCKSTEP);
116 /* Enable taken branch trap. */
123 long arch_ptrace(struct task_struct *child, long request,
124 unsigned long addr, unsigned long data)
126 unsigned long __user *datap = (unsigned long __user *)data;
130 unsigned long user_regs_struct_size = sizeof(struct user_regs_struct);
132 if (is_compat_task())
133 user_regs_struct_size /= 2;
138 /* Read the word at location addr in the USER area. For ptraced
139 processes, the kernel saves all regs on a syscall. */
141 if ((addr & (sizeof(unsigned long)-1)) ||
142 addr >= sizeof(struct pt_regs))
144 tmp = *(unsigned long *) ((char *) task_regs(child) + addr);
145 ret = put_user(tmp, datap);
148 /* Write the word at location addr in the USER area. This will need
149 to change when the kernel no longer saves all regs on a syscall.
150 FIXME. There is a problem at the moment in that r3-r18 are only
151 saved if the process is ptraced on syscall entry, and even then
152 those values are overwritten by actual register values on syscall
155 /* Some register values written here may be ignored in
156 * entry.S:syscall_restore_rfi; e.g. iaoq is written with
157 * r31/r31+4, and not with the values in pt_regs.
159 if (addr == PT_PSW) {
160 /* Allow writing to Nullify, Divide-step-correction,
161 * and carry/borrow bits.
162 * BEWARE, if you set N, and then single step, it won't
163 * stop on the nullified instruction.
165 data &= USER_PSW_BITS;
166 task_regs(child)->gr[0] &= ~USER_PSW_BITS;
167 task_regs(child)->gr[0] |= data;
172 if ((addr & (sizeof(unsigned long)-1)) ||
173 addr >= sizeof(struct pt_regs))
175 if (addr == PT_IAOQ0 || addr == PT_IAOQ1) {
176 data |= 3; /* ensure userspace privilege */
178 if ((addr >= PT_GR1 && addr <= PT_GR31) ||
179 addr == PT_IAOQ0 || addr == PT_IAOQ1 ||
180 (addr >= PT_FR0 && addr <= PT_FR31 + 4) ||
182 *(unsigned long *) ((char *) task_regs(child) + addr) = data;
187 case PTRACE_GETREGS: /* Get all gp regs from the child. */
188 return copy_regset_to_user(child,
189 task_user_regset_view(current),
191 0, user_regs_struct_size,
194 case PTRACE_SETREGS: /* Set all gp regs in the child. */
195 return copy_regset_from_user(child,
196 task_user_regset_view(current),
198 0, user_regs_struct_size,
201 case PTRACE_GETFPREGS: /* Get the child FPU state. */
202 return copy_regset_to_user(child,
203 task_user_regset_view(current),
205 0, sizeof(struct user_fp_struct),
208 case PTRACE_SETFPREGS: /* Set the child FPU state. */
209 return copy_regset_from_user(child,
210 task_user_regset_view(current),
212 0, sizeof(struct user_fp_struct),
216 ret = ptrace_request(child, request, addr, data);
226 /* This function is needed to translate 32 bit pt_regs offsets in to
227 * 64 bit pt_regs offsets. For example, a 32 bit gdb under a 64 bit kernel
228 * will request offset 12 if it wants gr3, but the lower 32 bits of
229 * the 64 bit kernels view of gr3 will be at offset 28 (3*8 + 4).
230 * This code relies on a 32 bit pt_regs being comprised of 32 bit values
231 * except for the fp registers which (a) are 64 bits, and (b) follow
232 * the gr registers at the start of pt_regs. The 32 bit pt_regs should
233 * be half the size of the 64 bit pt_regs, plus 32*4 to allow for fr[]
234 * being 64 bit in both cases.
237 static compat_ulong_t translate_usr_offset(compat_ulong_t offset)
241 if (offset < 32*4) /* gr[0..31] */
242 pos = offset * 2 + 4;
243 else if (offset < 32*4+32*8) /* fr[0] ... fr[31] */
244 pos = (offset - 32*4) + PT_FR0;
245 else if (offset < sizeof(struct pt_regs)/2 + 32*4) /* sr[0] ... ipsw */
246 pos = (offset - 32*4 - 32*8) * 2 + PT_SR0 + 4;
248 pos = sizeof(struct pt_regs);
253 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
254 compat_ulong_t addr, compat_ulong_t data)
262 if (addr & (sizeof(compat_uint_t)-1))
264 addr = translate_usr_offset(addr);
265 if (addr >= sizeof(struct pt_regs))
268 tmp = *(compat_uint_t *) ((char *) task_regs(child) + addr);
269 ret = put_user(tmp, (compat_uint_t *) (unsigned long) data);
272 /* Write the word at location addr in the USER area. This will need
273 to change when the kernel no longer saves all regs on a syscall.
274 FIXME. There is a problem at the moment in that r3-r18 are only
275 saved if the process is ptraced on syscall entry, and even then
276 those values are overwritten by actual register values on syscall
279 /* Some register values written here may be ignored in
280 * entry.S:syscall_restore_rfi; e.g. iaoq is written with
281 * r31/r31+4, and not with the values in pt_regs.
283 if (addr == PT_PSW) {
284 /* Since PT_PSW==0, it is valid for 32 bit processes
285 * under 64 bit kernels as well.
287 ret = arch_ptrace(child, request, addr, data);
289 if (addr & (sizeof(compat_uint_t)-1))
291 addr = translate_usr_offset(addr);
292 if (addr >= sizeof(struct pt_regs))
294 if (addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4) {
295 data |= 3; /* ensure userspace privilege */
297 if (addr >= PT_FR0 && addr <= PT_FR31 + 4) {
298 /* Special case, fp regs are 64 bits anyway */
299 *(__u32 *) ((char *) task_regs(child) + addr) = data;
302 else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) ||
303 addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4 ||
305 /* Zero the top 32 bits */
306 *(__u32 *) ((char *) task_regs(child) + addr - 4) = 0;
307 *(__u32 *) ((char *) task_regs(child) + addr) = data;
314 case PTRACE_GETFPREGS:
315 case PTRACE_SETFPREGS:
316 return arch_ptrace(child, request, addr, data);
319 ret = compat_ptrace_request(child, request, addr, data);
327 long do_syscall_trace_enter(struct pt_regs *regs)
329 if (test_thread_flag(TIF_SYSCALL_TRACE)) {
330 int rc = tracehook_report_syscall_entry(regs);
333 * As tracesys_next does not set %r28 to -ENOSYS
334 * when %r20 is set to -1, initialize it here.
336 regs->gr[28] = -ENOSYS;
340 * A nonzero return code from
341 * tracehook_report_syscall_entry() tells us
342 * to prevent the syscall execution. Skip
343 * the syscall call and the syscall restart handling.
345 * Note that the tracer may also just change
346 * regs->gr[20] to an invalid syscall number,
347 * that is handled by tracesys_next.
354 /* Do the secure computing check after ptrace. */
355 if (secure_computing() == -1)
358 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
359 if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
360 trace_sys_enter(regs, regs->gr[20]);
364 if (!is_compat_task())
365 audit_syscall_entry(regs->gr[20], regs->gr[26], regs->gr[25],
366 regs->gr[24], regs->gr[23]);
369 audit_syscall_entry(regs->gr[20] & 0xffffffff,
370 regs->gr[26] & 0xffffffff,
371 regs->gr[25] & 0xffffffff,
372 regs->gr[24] & 0xffffffff,
373 regs->gr[23] & 0xffffffff);
376 * Sign extend the syscall number to 64bit since it may have been
377 * modified by a compat ptrace call
379 return (int) ((u32) regs->gr[20]);
382 void do_syscall_trace_exit(struct pt_regs *regs)
384 int stepping = test_thread_flag(TIF_SINGLESTEP) ||
385 test_thread_flag(TIF_BLOCKSTEP);
387 audit_syscall_exit(regs);
389 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
390 if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
391 trace_sys_exit(regs, regs->gr[20]);
394 if (stepping || test_thread_flag(TIF_SYSCALL_TRACE))
395 tracehook_report_syscall_exit(regs, stepping);
403 static int fpr_get(struct task_struct *target,
404 const struct user_regset *regset,
407 struct pt_regs *regs = task_regs(target);
409 return membuf_write(&to, regs->fr, ELF_NFPREG * sizeof(__u64));
412 static int fpr_set(struct task_struct *target,
413 const struct user_regset *regset,
414 unsigned int pos, unsigned int count,
415 const void *kbuf, const void __user *ubuf)
417 struct pt_regs *regs = task_regs(target);
418 const __u64 *k = kbuf;
419 const __u64 __user *u = ubuf;
423 count /= sizeof(reg);
426 for (; count > 0 && pos < ELF_NFPREG; --count)
427 regs->fr[pos++] = *k++;
429 for (; count > 0 && pos < ELF_NFPREG; --count) {
430 if (__get_user(reg, u++))
432 regs->fr[pos++] = reg;
438 count *= sizeof(reg);
439 return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
440 ELF_NFPREG * sizeof(reg), -1);
443 #define RI(reg) (offsetof(struct user_regs_struct,reg) / sizeof(long))
445 static unsigned long get_reg(struct pt_regs *regs, int num)
448 case RI(gr[0]) ... RI(gr[31]): return regs->gr[num - RI(gr[0])];
449 case RI(sr[0]) ... RI(sr[7]): return regs->sr[num - RI(sr[0])];
450 case RI(iasq[0]): return regs->iasq[0];
451 case RI(iasq[1]): return regs->iasq[1];
452 case RI(iaoq[0]): return regs->iaoq[0];
453 case RI(iaoq[1]): return regs->iaoq[1];
454 case RI(sar): return regs->sar;
455 case RI(iir): return regs->iir;
456 case RI(isr): return regs->isr;
457 case RI(ior): return regs->ior;
458 case RI(ipsw): return regs->ipsw;
459 case RI(cr27): return regs->cr27;
460 case RI(cr0): return mfctl(0);
461 case RI(cr24): return mfctl(24);
462 case RI(cr25): return mfctl(25);
463 case RI(cr26): return mfctl(26);
464 case RI(cr28): return mfctl(28);
465 case RI(cr29): return mfctl(29);
466 case RI(cr30): return mfctl(30);
467 case RI(cr31): return mfctl(31);
468 case RI(cr8): return mfctl(8);
469 case RI(cr9): return mfctl(9);
470 case RI(cr12): return mfctl(12);
471 case RI(cr13): return mfctl(13);
472 case RI(cr10): return mfctl(10);
473 case RI(cr15): return mfctl(15);
478 static void set_reg(struct pt_regs *regs, int num, unsigned long val)
483 * Allow writing to Nullify, Divide-step-correction,
484 * and carry/borrow bits.
485 * BEWARE, if you set N, and then single step, it won't
486 * stop on the nullified instruction.
488 val &= USER_PSW_BITS;
489 regs->gr[0] &= ~USER_PSW_BITS;
492 case RI(gr[1]) ... RI(gr[31]):
493 regs->gr[num - RI(gr[0])] = val;
497 /* set 2 lowest bits to ensure userspace privilege: */
498 regs->iaoq[num - RI(iaoq[0])] = val | 3;
500 case RI(sar): regs->sar = val;
504 /* do not allow to change any of the following registers (yet) */
505 case RI(sr[0]) ... RI(sr[7]): return regs->sr[num - RI(sr[0])];
506 case RI(iasq[0]): return regs->iasq[0];
507 case RI(iasq[1]): return regs->iasq[1];
508 case RI(iir): return regs->iir;
509 case RI(isr): return regs->isr;
510 case RI(ior): return regs->ior;
511 case RI(ipsw): return regs->ipsw;
512 case RI(cr27): return regs->cr27;
513 case cr0, cr24, cr25, cr26, cr27, cr28, cr29, cr30, cr31;
514 case cr8, cr9, cr12, cr13, cr10, cr15;
519 static int gpr_get(struct task_struct *target,
520 const struct user_regset *regset,
523 struct pt_regs *regs = task_regs(target);
526 for (pos = 0; pos < ELF_NGREG; pos++)
527 membuf_store(&to, get_reg(regs, pos));
531 static int gpr_set(struct task_struct *target,
532 const struct user_regset *regset,
533 unsigned int pos, unsigned int count,
534 const void *kbuf, const void __user *ubuf)
536 struct pt_regs *regs = task_regs(target);
537 const unsigned long *k = kbuf;
538 const unsigned long __user *u = ubuf;
542 count /= sizeof(reg);
545 for (; count > 0 && pos < ELF_NGREG; --count)
546 set_reg(regs, pos++, *k++);
548 for (; count > 0 && pos < ELF_NGREG; --count) {
549 if (__get_user(reg, u++))
551 set_reg(regs, pos++, reg);
557 count *= sizeof(reg);
558 return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
559 ELF_NGREG * sizeof(reg), -1);
562 static const struct user_regset native_regsets[] = {
564 .core_note_type = NT_PRSTATUS, .n = ELF_NGREG,
565 .size = sizeof(long), .align = sizeof(long),
566 .regset_get = gpr_get, .set = gpr_set
569 .core_note_type = NT_PRFPREG, .n = ELF_NFPREG,
570 .size = sizeof(__u64), .align = sizeof(__u64),
571 .regset_get = fpr_get, .set = fpr_set
575 static const struct user_regset_view user_parisc_native_view = {
576 .name = "parisc", .e_machine = ELF_ARCH, .ei_osabi = ELFOSABI_LINUX,
577 .regsets = native_regsets, .n = ARRAY_SIZE(native_regsets)
581 #include <linux/compat.h>
583 static int gpr32_get(struct task_struct *target,
584 const struct user_regset *regset,
587 struct pt_regs *regs = task_regs(target);
590 for (pos = 0; pos < ELF_NGREG; pos++)
591 membuf_store(&to, (compat_ulong_t)get_reg(regs, pos));
596 static int gpr32_set(struct task_struct *target,
597 const struct user_regset *regset,
598 unsigned int pos, unsigned int count,
599 const void *kbuf, const void __user *ubuf)
601 struct pt_regs *regs = task_regs(target);
602 const compat_ulong_t *k = kbuf;
603 const compat_ulong_t __user *u = ubuf;
607 count /= sizeof(reg);
610 for (; count > 0 && pos < ELF_NGREG; --count)
611 set_reg(regs, pos++, *k++);
613 for (; count > 0 && pos < ELF_NGREG; --count) {
614 if (__get_user(reg, u++))
616 set_reg(regs, pos++, reg);
622 count *= sizeof(reg);
623 return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
624 ELF_NGREG * sizeof(reg), -1);
628 * These are the regset flavors matching the 32bit native set.
630 static const struct user_regset compat_regsets[] = {
632 .core_note_type = NT_PRSTATUS, .n = ELF_NGREG,
633 .size = sizeof(compat_long_t), .align = sizeof(compat_long_t),
634 .regset_get = gpr32_get, .set = gpr32_set
637 .core_note_type = NT_PRFPREG, .n = ELF_NFPREG,
638 .size = sizeof(__u64), .align = sizeof(__u64),
639 .regset_get = fpr_get, .set = fpr_set
643 static const struct user_regset_view user_parisc_compat_view = {
644 .name = "parisc", .e_machine = EM_PARISC, .ei_osabi = ELFOSABI_LINUX,
645 .regsets = compat_regsets, .n = ARRAY_SIZE(compat_regsets)
647 #endif /* CONFIG_64BIT */
649 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
651 BUILD_BUG_ON(sizeof(struct user_regs_struct)/sizeof(long) != ELF_NGREG);
652 BUILD_BUG_ON(sizeof(struct user_fp_struct)/sizeof(__u64) != ELF_NFPREG);
654 if (is_compat_task())
655 return &user_parisc_compat_view;
657 return &user_parisc_native_view;
661 /* HAVE_REGS_AND_STACK_ACCESS_API feature */
663 struct pt_regs_offset {
668 #define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
669 #define REG_OFFSET_INDEX(r,i) {.name = #r#i, .offset = offsetof(struct pt_regs, r[i])}
670 #define REG_OFFSET_END {.name = NULL, .offset = 0}
672 static const struct pt_regs_offset regoffset_table[] = {
673 REG_OFFSET_INDEX(gr,0),
674 REG_OFFSET_INDEX(gr,1),
675 REG_OFFSET_INDEX(gr,2),
676 REG_OFFSET_INDEX(gr,3),
677 REG_OFFSET_INDEX(gr,4),
678 REG_OFFSET_INDEX(gr,5),
679 REG_OFFSET_INDEX(gr,6),
680 REG_OFFSET_INDEX(gr,7),
681 REG_OFFSET_INDEX(gr,8),
682 REG_OFFSET_INDEX(gr,9),
683 REG_OFFSET_INDEX(gr,10),
684 REG_OFFSET_INDEX(gr,11),
685 REG_OFFSET_INDEX(gr,12),
686 REG_OFFSET_INDEX(gr,13),
687 REG_OFFSET_INDEX(gr,14),
688 REG_OFFSET_INDEX(gr,15),
689 REG_OFFSET_INDEX(gr,16),
690 REG_OFFSET_INDEX(gr,17),
691 REG_OFFSET_INDEX(gr,18),
692 REG_OFFSET_INDEX(gr,19),
693 REG_OFFSET_INDEX(gr,20),
694 REG_OFFSET_INDEX(gr,21),
695 REG_OFFSET_INDEX(gr,22),
696 REG_OFFSET_INDEX(gr,23),
697 REG_OFFSET_INDEX(gr,24),
698 REG_OFFSET_INDEX(gr,25),
699 REG_OFFSET_INDEX(gr,26),
700 REG_OFFSET_INDEX(gr,27),
701 REG_OFFSET_INDEX(gr,28),
702 REG_OFFSET_INDEX(gr,29),
703 REG_OFFSET_INDEX(gr,30),
704 REG_OFFSET_INDEX(gr,31),
705 REG_OFFSET_INDEX(sr,0),
706 REG_OFFSET_INDEX(sr,1),
707 REG_OFFSET_INDEX(sr,2),
708 REG_OFFSET_INDEX(sr,3),
709 REG_OFFSET_INDEX(sr,4),
710 REG_OFFSET_INDEX(sr,5),
711 REG_OFFSET_INDEX(sr,6),
712 REG_OFFSET_INDEX(sr,7),
713 REG_OFFSET_INDEX(iasq,0),
714 REG_OFFSET_INDEX(iasq,1),
715 REG_OFFSET_INDEX(iaoq,0),
716 REG_OFFSET_INDEX(iaoq,1),
717 REG_OFFSET_NAME(cr27),
718 REG_OFFSET_NAME(ksp),
719 REG_OFFSET_NAME(kpc),
720 REG_OFFSET_NAME(sar),
721 REG_OFFSET_NAME(iir),
722 REG_OFFSET_NAME(isr),
723 REG_OFFSET_NAME(ior),
724 REG_OFFSET_NAME(ipsw),
729 * regs_query_register_offset() - query register offset from its name
730 * @name: the name of a register
732 * regs_query_register_offset() returns the offset of a register in struct
733 * pt_regs from its name. If the name is invalid, this returns -EINVAL;
735 int regs_query_register_offset(const char *name)
737 const struct pt_regs_offset *roff;
738 for (roff = regoffset_table; roff->name != NULL; roff++)
739 if (!strcmp(roff->name, name))
745 * regs_query_register_name() - query register name from its offset
746 * @offset: the offset of a register in struct pt_regs.
748 * regs_query_register_name() returns the name of a register from its
749 * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
751 const char *regs_query_register_name(unsigned int offset)
753 const struct pt_regs_offset *roff;
754 for (roff = regoffset_table; roff->name != NULL; roff++)
755 if (roff->offset == offset)
761 * regs_within_kernel_stack() - check the address in the stack
762 * @regs: pt_regs which contains kernel stack pointer.
763 * @addr: address which is checked.
765 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
766 * If @addr is within the kernel stack, it returns true. If not, returns false.
768 int regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
770 return ((addr & ~(THREAD_SIZE - 1)) ==
771 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
775 * regs_get_kernel_stack_nth() - get Nth entry of the stack
776 * @regs: pt_regs which contains kernel stack pointer.
777 * @n: stack entry number.
779 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
780 * is specified by @regs. If the @n th entry is NOT in the kernel stack,
783 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
785 unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
789 if (!regs_within_kernel_stack(regs, (unsigned long)addr))