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authorMasami Hiramatsu <mhiramat@redhat.com>2008-01-30 07:31:21 -0500
committerIngo Molnar <mingo@elte.hu>2008-01-30 07:31:21 -0500
commitd6be29b871e285d33be0e3025929e2d6bcabb0c0 (patch)
tree5dbcd8ef953d19e3978062d337c76e4fa103150b /arch
parent8533bbe9f87b01f49ff951f665ea1988252fa3c2 (diff)
x86: kprobes code for x86 unification
This patch unifies kprobes code. - Unify kprobes_*.h to kprobes.h - Unify kprobes_*.c to kprobes.c (Differences are separated by ifdefs) - Most differences are related to REX prefix and rip relatives. - Two inline assembly code are different. - One difference in kprobe_handlre() - One fixup exception code is different, but it will be unified if mm/extable_*.c are unified. - Merge history logs into arch/x86/kernel/kprobes.c. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Jim Keniston <jkenisto@us.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/Makefile_322
-rw-r--r--arch/x86/kernel/Makefile_642
-rw-r--r--arch/x86/kernel/kprobes.c (renamed from arch/x86/kernel/kprobes_64.c)164
-rw-r--r--arch/x86/kernel/kprobes_32.c848
4 files changed, 130 insertions, 886 deletions
diff --git a/arch/x86/kernel/Makefile_32 b/arch/x86/kernel/Makefile_32
index a854e23eac0b..c7a959da363a 100644
--- a/arch/x86/kernel/Makefile_32
+++ b/arch/x86/kernel/Makefile_32
@@ -35,7 +35,7 @@ obj-$(CONFIG_KEXEC) += machine_kexec_32.o relocate_kernel_32.o crash.o
35obj-$(CONFIG_CRASH_DUMP) += crash_dump_32.o 35obj-$(CONFIG_CRASH_DUMP) += crash_dump_32.o
36obj-$(CONFIG_X86_NUMAQ) += numaq_32.o 36obj-$(CONFIG_X86_NUMAQ) += numaq_32.o
37obj-$(CONFIG_X86_SUMMIT_NUMA) += summit_32.o 37obj-$(CONFIG_X86_SUMMIT_NUMA) += summit_32.o
38obj-$(CONFIG_KPROBES) += kprobes_32.o 38obj-$(CONFIG_KPROBES) += kprobes.o
39obj-$(CONFIG_MODULES) += module_32.o 39obj-$(CONFIG_MODULES) += module_32.o
40obj-$(CONFIG_ACPI_SRAT) += srat_32.o 40obj-$(CONFIG_ACPI_SRAT) += srat_32.o
41obj-$(CONFIG_EFI) += efi.o efi_32.o efi_stub_32.o 41obj-$(CONFIG_EFI) += efi.o efi_32.o efi_stub_32.o
diff --git a/arch/x86/kernel/Makefile_64 b/arch/x86/kernel/Makefile_64
index e5093dd8cf01..fbb370071239 100644
--- a/arch/x86/kernel/Makefile_64
+++ b/arch/x86/kernel/Makefile_64
@@ -34,7 +34,7 @@ obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
34obj-$(CONFIG_GART_IOMMU) += pci-gart_64.o aperture_64.o 34obj-$(CONFIG_GART_IOMMU) += pci-gart_64.o aperture_64.o
35obj-$(CONFIG_CALGARY_IOMMU) += pci-calgary_64.o tce_64.o 35obj-$(CONFIG_CALGARY_IOMMU) += pci-calgary_64.o tce_64.o
36obj-$(CONFIG_SWIOTLB) += pci-swiotlb_64.o 36obj-$(CONFIG_SWIOTLB) += pci-swiotlb_64.o
37obj-$(CONFIG_KPROBES) += kprobes_64.o 37obj-$(CONFIG_KPROBES) += kprobes.o
38obj-$(CONFIG_X86_PM_TIMER) += pmtimer_64.o 38obj-$(CONFIG_X86_PM_TIMER) += pmtimer_64.o
39obj-$(CONFIG_X86_VSMP) += vsmp_64.o 39obj-$(CONFIG_X86_VSMP) += vsmp_64.o
40obj-$(CONFIG_K8_NB) += k8.o 40obj-$(CONFIG_K8_NB) += k8.o
diff --git a/arch/x86/kernel/kprobes_64.c b/arch/x86/kernel/kprobes.c
index 2d7763749b1b..9aadd4d4a229 100644
--- a/arch/x86/kernel/kprobes_64.c
+++ b/arch/x86/kernel/kprobes.c
@@ -22,14 +22,22 @@
22 * Rusty Russell). 22 * Rusty Russell).
23 * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes 23 * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
24 * interface to access function arguments. 24 * interface to access function arguments.
25 * 2004-Oct Jim Keniston <kenistoj@us.ibm.com> and Prasanna S Panchamukhi 25 * 2004-Oct Jim Keniston <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
26 * <prasanna@in.ibm.com> adapted for x86_64 26 * <prasanna@in.ibm.com> adapted for x86_64 from i386.
27 * 2005-Mar Roland McGrath <roland@redhat.com> 27 * 2005-Mar Roland McGrath <roland@redhat.com>
28 * Fixed to handle %rip-relative addressing mode correctly. 28 * Fixed to handle %rip-relative addressing mode correctly.
29 * 2005-May Rusty Lynch <rusty.lynch@intel.com> 29 * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston
30 * Added function return probes functionality 30 * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
31 * <prasanna@in.ibm.com> added function-return probes.
32 * 2005-May Rusty Lynch <rusty.lynch@intel.com>
33 * Added function return probes functionality
34 * 2006-Feb Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp> added
35 * kprobe-booster and kretprobe-booster for i386.
31 * 2007-Dec Masami Hiramatsu <mhiramat@redhat.com> added kprobe-booster 36 * 2007-Dec Masami Hiramatsu <mhiramat@redhat.com> added kprobe-booster
32 * and kretprobe-booster for x86-64 37 * and kretprobe-booster for x86-64
38 * 2007-Dec Masami Hiramatsu <mhiramat@redhat.com>, Arjan van de Ven
39 * <arjan@infradead.org> and Jim Keniston <jkenisto@us.ibm.com>
40 * unified x86 kprobes code.
33 */ 41 */
34 42
35#include <linux/kprobes.h> 43#include <linux/kprobes.h>
@@ -51,7 +59,19 @@ void jprobe_return_end(void);
51DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; 59DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
52DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); 60DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
53 61
62#ifdef CONFIG_X86_64
54#define stack_addr(regs) ((unsigned long *)regs->sp) 63#define stack_addr(regs) ((unsigned long *)regs->sp)
64#else
65/*
66 * "&regs->sp" looks wrong, but it's correct for x86_32. x86_32 CPUs
67 * don't save the ss and esp registers if the CPU is already in kernel
68 * mode when it traps. So for kprobes, regs->sp and regs->ss are not
69 * the [nonexistent] saved stack pointer and ss register, but rather
70 * the top 8 bytes of the pre-int3 stack. So &regs->sp happens to
71 * point to the top of the pre-int3 stack.
72 */
73#define stack_addr(regs) ((unsigned long *)&regs->sp)
74#endif
55 75
56#define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\ 76#define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\
57 (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \ 77 (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \
@@ -151,8 +171,8 @@ static __always_inline void set_jmp_op(void *from, void *to)
151} 171}
152 172
153/* 173/*
154 * returns non-zero if opcode is boostable. 174 * Returns non-zero if opcode is boostable.
155 * RIP relative instructions are adjusted at copying time 175 * RIP relative instructions are adjusted at copying time in 64 bits mode
156 */ 176 */
157static __always_inline int can_boost(kprobe_opcode_t *opcodes) 177static __always_inline int can_boost(kprobe_opcode_t *opcodes)
158{ 178{
@@ -173,8 +193,10 @@ retry:
173 } 193 }
174 194
175 switch (opcode & 0xf0) { 195 switch (opcode & 0xf0) {
196#ifdef CONFIG_X86_64
176 case 0x40: 197 case 0x40:
177 goto retry; /* REX prefix is boostable */ 198 goto retry; /* REX prefix is boostable */
199#endif
178 case 0x60: 200 case 0x60:
179 if (0x63 < opcode && opcode < 0x67) 201 if (0x63 < opcode && opcode < 0x67)
180 goto retry; /* prefixes */ 202 goto retry; /* prefixes */
@@ -206,7 +228,7 @@ retry:
206} 228}
207 229
208/* 230/*
209 * returns non-zero if opcode modifies the interrupt flag. 231 * Returns non-zero if opcode modifies the interrupt flag.
210 */ 232 */
211static int __kprobes is_IF_modifier(kprobe_opcode_t *insn) 233static int __kprobes is_IF_modifier(kprobe_opcode_t *insn)
212{ 234{
@@ -217,16 +239,18 @@ static int __kprobes is_IF_modifier(kprobe_opcode_t *insn)
217 case 0x9d: /* popf/popfd */ 239 case 0x9d: /* popf/popfd */
218 return 1; 240 return 1;
219 } 241 }
220 242#ifdef CONFIG_X86_64
221 /* 243 /*
222 * on 64 bit x86, 0x40-0x4f are prefixes so we need to look 244 * on 64 bit x86, 0x40-0x4f are prefixes so we need to look
223 * at the next byte instead.. but of course not recurse infinitely 245 * at the next byte instead.. but of course not recurse infinitely
224 */ 246 */
225 if (*insn >= 0x40 && *insn <= 0x4f) 247 if (*insn >= 0x40 && *insn <= 0x4f)
226 return is_IF_modifier(++insn); 248 return is_IF_modifier(++insn);
249#endif
227 return 0; 250 return 0;
228} 251}
229 252
253#ifdef CONFIG_X86_64
230/* 254/*
231 * Adjust the displacement if the instruction uses the %rip-relative 255 * Adjust the displacement if the instruction uses the %rip-relative
232 * addressing mode. 256 * addressing mode.
@@ -263,17 +287,20 @@ static void __kprobes fix_riprel(struct kprobe *p)
263 if ((*insn & 0xf0) == 0x40) 287 if ((*insn & 0xf0) == 0x40)
264 ++insn; 288 ++insn;
265 289
266 if (*insn == 0x0f) { /* Two-byte opcode. */ 290 if (*insn == 0x0f) {
291 /* Two-byte opcode. */
267 ++insn; 292 ++insn;
268 need_modrm = test_bit(*insn, 293 need_modrm = test_bit(*insn,
269 (unsigned long *)twobyte_has_modrm); 294 (unsigned long *)twobyte_has_modrm);
270 } else /* One-byte opcode. */ 295 } else
296 /* One-byte opcode. */
271 need_modrm = test_bit(*insn, 297 need_modrm = test_bit(*insn,
272 (unsigned long *)onebyte_has_modrm); 298 (unsigned long *)onebyte_has_modrm);
273 299
274 if (need_modrm) { 300 if (need_modrm) {
275 u8 modrm = *++insn; 301 u8 modrm = *++insn;
276 if ((modrm & 0xc7) == 0x05) { /* %rip+disp32 addressing mode */ 302 if ((modrm & 0xc7) == 0x05) {
303 /* %rip+disp32 addressing mode */
277 /* Displacement follows ModRM byte. */ 304 /* Displacement follows ModRM byte. */
278 ++insn; 305 ++insn;
279 /* 306 /*
@@ -296,11 +323,14 @@ static void __kprobes fix_riprel(struct kprobe *p)
296 } 323 }
297 } 324 }
298} 325}
326#endif
299 327
300static void __kprobes arch_copy_kprobe(struct kprobe *p) 328static void __kprobes arch_copy_kprobe(struct kprobe *p)
301{ 329{
302 memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); 330 memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
331#ifdef CONFIG_X86_64
303 fix_riprel(p); 332 fix_riprel(p);
333#endif
304 if (can_boost(p->addr)) 334 if (can_boost(p->addr))
305 p->ainsn.boostable = 0; 335 p->ainsn.boostable = 0;
306 else 336 else
@@ -365,13 +395,13 @@ static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
365static __always_inline void clear_btf(void) 395static __always_inline void clear_btf(void)
366{ 396{
367 if (test_thread_flag(TIF_DEBUGCTLMSR)) 397 if (test_thread_flag(TIF_DEBUGCTLMSR))
368 wrmsrl(MSR_IA32_DEBUGCTLMSR, 0); 398 wrmsr(MSR_IA32_DEBUGCTLMSR, 0, 0);
369} 399}
370 400
371static __always_inline void restore_btf(void) 401static __always_inline void restore_btf(void)
372{ 402{
373 if (test_thread_flag(TIF_DEBUGCTLMSR)) 403 if (test_thread_flag(TIF_DEBUGCTLMSR))
374 wrmsrl(MSR_IA32_DEBUGCTLMSR, current->thread.debugctlmsr); 404 wrmsr(MSR_IA32_DEBUGCTLMSR, current->thread.debugctlmsr, 0);
375} 405}
376 406
377static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) 407static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
@@ -427,6 +457,7 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
427 regs->flags &= ~TF_MASK; 457 regs->flags &= ~TF_MASK;
428 regs->flags |= kcb->kprobe_saved_flags; 458 regs->flags |= kcb->kprobe_saved_flags;
429 goto no_kprobe; 459 goto no_kprobe;
460#ifdef CONFIG_X86_64
430 } else if (kcb->kprobe_status == KPROBE_HIT_SSDONE) { 461 } else if (kcb->kprobe_status == KPROBE_HIT_SSDONE) {
431 /* TODO: Provide re-entrancy from 462 /* TODO: Provide re-entrancy from
432 * post_kprobes_handler() and avoid exception 463 * post_kprobes_handler() and avoid exception
@@ -437,6 +468,7 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
437 regs->ip = (unsigned long)p->addr; 468 regs->ip = (unsigned long)p->addr;
438 reset_current_kprobe(); 469 reset_current_kprobe();
439 return 1; 470 return 1;
471#endif
440 } 472 }
441 /* We have reentered the kprobe_handler(), since 473 /* We have reentered the kprobe_handler(), since
442 * another probe was hit while within the handler. 474 * another probe was hit while within the handler.
@@ -461,9 +493,8 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
461 goto no_kprobe; 493 goto no_kprobe;
462 } 494 }
463 p = __get_cpu_var(current_kprobe); 495 p = __get_cpu_var(current_kprobe);
464 if (p->break_handler && p->break_handler(p, regs)) { 496 if (p->break_handler && p->break_handler(p, regs))
465 goto ss_probe; 497 goto ss_probe;
466 }
467 } 498 }
468 goto no_kprobe; 499 goto no_kprobe;
469 } 500 }
@@ -519,8 +550,10 @@ no_kprobe:
519 */ 550 */
520 void __kprobes kretprobe_trampoline_holder(void) 551 void __kprobes kretprobe_trampoline_holder(void)
521 { 552 {
522 asm volatile ( ".global kretprobe_trampoline\n" 553 asm volatile (
554 ".global kretprobe_trampoline\n"
523 "kretprobe_trampoline: \n" 555 "kretprobe_trampoline: \n"
556#ifdef CONFIG_X86_64
524 /* We don't bother saving the ss register */ 557 /* We don't bother saving the ss register */
525 " pushq %rsp\n" 558 " pushq %rsp\n"
526 " pushfq\n" 559 " pushfq\n"
@@ -566,25 +599,64 @@ no_kprobe:
566 /* Skip orig_ax, ip, cs */ 599 /* Skip orig_ax, ip, cs */
567 " addq $24, %rsp\n" 600 " addq $24, %rsp\n"
568 " popfq\n" 601 " popfq\n"
602#else
603 " pushf\n"
604 /*
605 * Skip cs, ip, orig_ax.
606 * trampoline_handler() will plug in these values
607 */
608 " subl $12, %esp\n"
609 " pushl %fs\n"
610 " pushl %ds\n"
611 " pushl %es\n"
612 " pushl %eax\n"
613 " pushl %ebp\n"
614 " pushl %edi\n"
615 " pushl %esi\n"
616 " pushl %edx\n"
617 " pushl %ecx\n"
618 " pushl %ebx\n"
619 " movl %esp, %eax\n"
620 " call trampoline_handler\n"
621 /* Move flags to cs */
622 " movl 52(%esp), %edx\n"
623 " movl %edx, 48(%esp)\n"
624 /* Replace saved flags with true return address. */
625 " movl %eax, 52(%esp)\n"
626 " popl %ebx\n"
627 " popl %ecx\n"
628 " popl %edx\n"
629 " popl %esi\n"
630 " popl %edi\n"
631 " popl %ebp\n"
632 " popl %eax\n"
633 /* Skip ip, orig_ax, es, ds, fs */
634 " addl $20, %esp\n"
635 " popf\n"
636#endif
569 " ret\n"); 637 " ret\n");
570 } 638 }
571 639
572/* 640/*
573 * Called from kretprobe_trampoline 641 * Called from kretprobe_trampoline
574 */ 642 */
575fastcall void * __kprobes trampoline_handler(struct pt_regs *regs) 643void * __kprobes trampoline_handler(struct pt_regs *regs)
576{ 644{
577 struct kretprobe_instance *ri = NULL; 645 struct kretprobe_instance *ri = NULL;
578 struct hlist_head *head, empty_rp; 646 struct hlist_head *head, empty_rp;
579 struct hlist_node *node, *tmp; 647 struct hlist_node *node, *tmp;
580 unsigned long flags, orig_ret_address = 0; 648 unsigned long flags, orig_ret_address = 0;
581 unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline; 649 unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;
582 650
583 INIT_HLIST_HEAD(&empty_rp); 651 INIT_HLIST_HEAD(&empty_rp);
584 spin_lock_irqsave(&kretprobe_lock, flags); 652 spin_lock_irqsave(&kretprobe_lock, flags);
585 head = kretprobe_inst_table_head(current); 653 head = kretprobe_inst_table_head(current);
586 /* fixup registers */ 654 /* fixup registers */
655#ifdef CONFIG_X86_64
587 regs->cs = __KERNEL_CS; 656 regs->cs = __KERNEL_CS;
657#else
658 regs->cs = __KERNEL_CS | get_kernel_rpl();
659#endif
588 regs->ip = trampoline_address; 660 regs->ip = trampoline_address;
589 regs->orig_ax = ~0UL; 661 regs->orig_ax = ~0UL;
590 662
@@ -671,9 +743,11 @@ static void __kprobes resume_execution(struct kprobe *p,
671 unsigned long orig_ip = (unsigned long)p->addr; 743 unsigned long orig_ip = (unsigned long)p->addr;
672 kprobe_opcode_t *insn = p->ainsn.insn; 744 kprobe_opcode_t *insn = p->ainsn.insn;
673 745
746#ifdef CONFIG_X86_64
674 /*skip the REX prefix*/ 747 /*skip the REX prefix*/
675 if (*insn >= 0x40 && *insn <= 0x4f) 748 if (*insn >= 0x40 && *insn <= 0x4f)
676 insn++; 749 insn++;
750#endif
677 751
678 regs->flags &= ~TF_MASK; 752 regs->flags &= ~TF_MASK;
679 switch (*insn) { 753 switch (*insn) {
@@ -693,6 +767,11 @@ static void __kprobes resume_execution(struct kprobe *p,
693 case 0xe8: /* call relative - Fix return addr */ 767 case 0xe8: /* call relative - Fix return addr */
694 *tos = orig_ip + (*tos - copy_ip); 768 *tos = orig_ip + (*tos - copy_ip);
695 break; 769 break;
770#ifndef CONFIG_X86_64
771 case 0x9a: /* call absolute -- same as call absolute, indirect */
772 *tos = orig_ip + (*tos - copy_ip);
773 goto no_change;
774#endif
696 case 0xff: 775 case 0xff:
697 if ((insn[1] & 0x30) == 0x10) { 776 if ((insn[1] & 0x30) == 0x10) {
698 /* 777 /*
@@ -783,9 +862,8 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
783{ 862{
784 struct kprobe *cur = kprobe_running(); 863 struct kprobe *cur = kprobe_running();
785 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); 864 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
786 const struct exception_table_entry *fixup;
787 865
788 switch(kcb->kprobe_status) { 866 switch (kcb->kprobe_status) {
789 case KPROBE_HIT_SS: 867 case KPROBE_HIT_SS:
790 case KPROBE_REENTER: 868 case KPROBE_REENTER:
791 /* 869 /*
@@ -826,12 +904,19 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
826 * In case the user-specified fault handler returned 904 * In case the user-specified fault handler returned
827 * zero, try to fix up. 905 * zero, try to fix up.
828 */ 906 */
829 fixup = search_exception_tables(regs->ip); 907#ifdef CONFIG_X86_64
830 if (fixup) { 908 {
831 regs->ip = fixup->fixup; 909 const struct exception_table_entry *fixup;
832 return 1; 910 fixup = search_exception_tables(regs->ip);
911 if (fixup) {
912 regs->ip = fixup->fixup;
913 return 1;
914 }
833 } 915 }
834 916#else
917 if (fixup_exception(regs))
918 return 1;
919#endif
835 /* 920 /*
836 * fixup routine could not handle it, 921 * fixup routine could not handle it,
837 * Let do_page_fault() fix it. 922 * Let do_page_fault() fix it.
@@ -896,7 +981,7 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
896 * the argument area. 981 * the argument area.
897 */ 982 */
898 memcpy(kcb->jprobes_stack, (kprobe_opcode_t *)addr, 983 memcpy(kcb->jprobes_stack, (kprobe_opcode_t *)addr,
899 MIN_STACK_SIZE(addr)); 984 MIN_STACK_SIZE(addr));
900 regs->flags &= ~IF_MASK; 985 regs->flags &= ~IF_MASK;
901 trace_hardirqs_off(); 986 trace_hardirqs_off();
902 regs->ip = (unsigned long)(jp->entry); 987 regs->ip = (unsigned long)(jp->entry);
@@ -907,12 +992,17 @@ void __kprobes jprobe_return(void)
907{ 992{
908 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); 993 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
909 994
910 asm volatile (" xchg %%rbx,%%rsp \n" 995 asm volatile (
911 " int3 \n" 996#ifdef CONFIG_X86_64
912 " .globl jprobe_return_end \n" 997 " xchg %%rbx,%%rsp \n"
913 " jprobe_return_end: \n" 998#else
914 " nop \n"::"b" 999 " xchgl %%ebx,%%esp \n"
915 (kcb->jprobe_saved_sp):"memory"); 1000#endif
1001 " int3 \n"
1002 " .globl jprobe_return_end\n"
1003 " jprobe_return_end: \n"
1004 " nop \n"::"b"
1005 (kcb->jprobe_saved_sp):"memory");
916} 1006}
917 1007
918int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) 1008int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
@@ -921,14 +1011,16 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
921 u8 *addr = (u8 *) (regs->ip - 1); 1011 u8 *addr = (u8 *) (regs->ip - 1);
922 struct jprobe *jp = container_of(p, struct jprobe, kp); 1012 struct jprobe *jp = container_of(p, struct jprobe, kp);
923 1013
924 if ((addr > (u8 *) jprobe_return) && (addr < (u8 *) jprobe_return_end)) { 1014 if ((addr > (u8 *) jprobe_return) &&
1015 (addr < (u8 *) jprobe_return_end)) {
925 if (stack_addr(regs) != kcb->jprobe_saved_sp) { 1016 if (stack_addr(regs) != kcb->jprobe_saved_sp) {
926 struct pt_regs *saved_regs = &kcb->jprobe_saved_regs; 1017 struct pt_regs *saved_regs = &kcb->jprobe_saved_regs;
927 printk("current sp %p does not match saved sp %p\n", 1018 printk(KERN_ERR
1019 "current sp %p does not match saved sp %p\n",
928 stack_addr(regs), kcb->jprobe_saved_sp); 1020 stack_addr(regs), kcb->jprobe_saved_sp);
929 printk("Saved registers for jprobe %p\n", jp); 1021 printk(KERN_ERR "Saved registers for jprobe %p\n", jp);
930 show_registers(saved_regs); 1022 show_registers(saved_regs);
931 printk("Current registers\n"); 1023 printk(KERN_ERR "Current registers\n");
932 show_registers(regs); 1024 show_registers(regs);
933 BUG(); 1025 BUG();
934 } 1026 }
diff --git a/arch/x86/kernel/kprobes_32.c b/arch/x86/kernel/kprobes_32.c
deleted file mode 100644
index 8e06431d8b03..000000000000
--- a/arch/x86/kernel/kprobes_32.c
+++ /dev/null
@@ -1,848 +0,0 @@
1/*
2 * Kernel Probes (KProbes)
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 as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * Copyright (C) IBM Corporation, 2002, 2004
19 *
20 * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
21 * Probes initial implementation ( includes contributions from
22 * Rusty Russell).
23 * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
24 * interface to access function arguments.
25 * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston
26 * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
27 * <prasanna@in.ibm.com> added function-return probes.
28 */
29
30#include <linux/kprobes.h>
31#include <linux/ptrace.h>
32#include <linux/string.h>
33#include <linux/slab.h>
34#include <linux/preempt.h>
35#include <linux/module.h>
36#include <linux/kdebug.h>
37
38#include <asm/cacheflush.h>
39#include <asm/desc.h>
40#include <asm/pgtable.h>
41#include <asm/uaccess.h>
42#include <asm/alternative.h>
43
44void jprobe_return_end(void);
45
46DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
47DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
48
49/*
50 * "&regs->sp" looks wrong, but it's correct for x86_32. x86_32 CPUs
51 * don't save the ss and esp registers if the CPU is already in kernel
52 * mode when it traps. So for kprobes, regs->sp and regs->ss are not
53 * the [nonexistent] saved stack pointer and ss register, but rather
54 * the top 8 bytes of the pre-int3 stack. So &regs->sp happens to
55 * point to the top of the pre-int3 stack.
56 */
57#define stack_addr(regs) ((unsigned long *)&regs->sp)
58
59#define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\
60 (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \
61 (b4##UL << 0x4)|(b5##UL << 0x5)|(b6##UL << 0x6)|(b7##UL << 0x7) | \
62 (b8##UL << 0x8)|(b9##UL << 0x9)|(ba##UL << 0xa)|(bb##UL << 0xb) | \
63 (bc##UL << 0xc)|(bd##UL << 0xd)|(be##UL << 0xe)|(bf##UL << 0xf)) \
64 << (row % 32))
65 /*
66 * Undefined/reserved opcodes, conditional jump, Opcode Extension
67 * Groups, and some special opcodes can not boost.
68 */
69static const u32 twobyte_is_boostable[256 / 32] = {
70 /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
71 /* ---------------------------------------------- */
72 W(0x00, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0) | /* 00 */
73 W(0x10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 10 */
74 W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 20 */
75 W(0x30, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 30 */
76 W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 40 */
77 W(0x50, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 50 */
78 W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1) | /* 60 */
79 W(0x70, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1) , /* 70 */
80 W(0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 80 */
81 W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 90 */
82 W(0xa0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1) | /* a0 */
83 W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1) , /* b0 */
84 W(0xc0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1) | /* c0 */
85 W(0xd0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1) , /* d0 */
86 W(0xe0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1) | /* e0 */
87 W(0xf0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0) /* f0 */
88 /* ----------------------------------------------- */
89 /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
90};
91static const u32 onebyte_has_modrm[256 / 32] = {
92 /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
93 /* ----------------------------------------------- */
94 W(0x00, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 00 */
95 W(0x10, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) , /* 10 */
96 W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 20 */
97 W(0x30, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) , /* 30 */
98 W(0x40, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 40 */
99 W(0x50, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 50 */
100 W(0x60, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0) | /* 60 */
101 W(0x70, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 70 */
102 W(0x80, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 80 */
103 W(0x90, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 90 */
104 W(0xa0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* a0 */
105 W(0xb0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* b0 */
106 W(0xc0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0) | /* c0 */
107 W(0xd0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1) , /* d0 */
108 W(0xe0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* e0 */
109 W(0xf0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1) /* f0 */
110 /* ----------------------------------------------- */
111 /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
112};
113static const u32 twobyte_has_modrm[256 / 32] = {
114 /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
115 /* ----------------------------------------------- */
116 W(0x00, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1) | /* 0f */
117 W(0x10, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0) , /* 1f */
118 W(0x20, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1) | /* 2f */
119 W(0x30, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 3f */
120 W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 4f */
121 W(0x50, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 5f */
122 W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 6f */
123 W(0x70, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1) , /* 7f */
124 W(0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 8f */
125 W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 9f */
126 W(0xa0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1) | /* af */
127 W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1) , /* bf */
128 W(0xc0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0) | /* cf */
129 W(0xd0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* df */
130 W(0xe0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* ef */
131 W(0xf0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0) /* ff */
132 /* ----------------------------------------------- */
133 /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
134};
135#undef W
136
137struct kretprobe_blackpoint kretprobe_blacklist[] = {
138 {"__switch_to", }, /* This function switches only current task, but
139 doesn't switch kernel stack.*/
140 {NULL, NULL} /* Terminator */
141};
142const int kretprobe_blacklist_size = ARRAY_SIZE(kretprobe_blacklist);
143
144/* Insert a jump instruction at address 'from', which jumps to address 'to'.*/
145static __always_inline void set_jmp_op(void *from, void *to)
146{
147 struct __arch_jmp_op {
148 char op;
149 s32 raddr;
150 } __attribute__((packed)) * jop;
151 jop = (struct __arch_jmp_op *)from;
152 jop->raddr = (s32)((long)(to) - ((long)(from) + 5));
153 jop->op = RELATIVEJUMP_INSTRUCTION;
154}
155
156/*
157 * returns non-zero if opcode is boostable.
158 */
159static __always_inline int can_boost(kprobe_opcode_t *opcodes)
160{
161 kprobe_opcode_t opcode;
162 kprobe_opcode_t *orig_opcodes = opcodes;
163
164retry:
165 if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
166 return 0;
167 opcode = *(opcodes++);
168
169 /* 2nd-byte opcode */
170 if (opcode == 0x0f) {
171 if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
172 return 0;
173 return test_bit(*opcodes,
174 (unsigned long *)twobyte_is_boostable);
175 }
176
177 switch (opcode & 0xf0) {
178 case 0x60:
179 if (0x63 < opcode && opcode < 0x67)
180 goto retry; /* prefixes */
181 /* can't boost Address-size override and bound */
182 return (opcode != 0x62 && opcode != 0x67);
183 case 0x70:
184 return 0; /* can't boost conditional jump */
185 case 0xc0:
186 /* can't boost software-interruptions */
187 return (0xc1 < opcode && opcode < 0xcc) || opcode == 0xcf;
188 case 0xd0:
189 /* can boost AA* and XLAT */
190 return (opcode == 0xd4 || opcode == 0xd5 || opcode == 0xd7);
191 case 0xe0:
192 /* can boost in/out and absolute jmps */
193 return ((opcode & 0x04) || opcode == 0xea);
194 case 0xf0:
195 if ((opcode & 0x0c) == 0 && opcode != 0xf1)
196 goto retry; /* lock/rep(ne) prefix */
197 /* clear and set flags are boostable */
198 return (opcode == 0xf5 || (0xf7 < opcode && opcode < 0xfe));
199 default:
200 /* segment override prefixes are boostable */
201 if (opcode == 0x26 || opcode == 0x36 || opcode == 0x3e)
202 goto retry; /* prefixes */
203 /* CS override prefix and call are not boostable */
204 return (opcode != 0x2e && opcode != 0x9a);
205 }
206}
207
208/*
209 * returns non-zero if opcode modifies the interrupt flag.
210 */
211static int __kprobes is_IF_modifier(kprobe_opcode_t *insn)
212{
213 switch (*insn) {
214 case 0xfa: /* cli */
215 case 0xfb: /* sti */
216 case 0xcf: /* iret/iretd */
217 case 0x9d: /* popf/popfd */
218 return 1;
219 }
220 return 0;
221}
222
223static void __kprobes arch_copy_kprobe(struct kprobe *p)
224{
225 memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
226 if (can_boost(p->addr))
227 p->ainsn.boostable = 0;
228 else
229 p->ainsn.boostable = -1;
230
231 p->opcode = *p->addr;
232}
233
234int __kprobes arch_prepare_kprobe(struct kprobe *p)
235{
236 /* insn: must be on special executable page on x86. */
237 p->ainsn.insn = get_insn_slot();
238 if (!p->ainsn.insn)
239 return -ENOMEM;
240 arch_copy_kprobe(p);
241 return 0;
242}
243
244void __kprobes arch_arm_kprobe(struct kprobe *p)
245{
246 text_poke(p->addr, ((unsigned char []){BREAKPOINT_INSTRUCTION}), 1);
247}
248
249void __kprobes arch_disarm_kprobe(struct kprobe *p)
250{
251 text_poke(p->addr, &p->opcode, 1);
252}
253
254void __kprobes arch_remove_kprobe(struct kprobe *p)
255{
256 mutex_lock(&kprobe_mutex);
257 free_insn_slot(p->ainsn.insn, (p->ainsn.boostable == 1));
258 mutex_unlock(&kprobe_mutex);
259}
260
261static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
262{
263 kcb->prev_kprobe.kp = kprobe_running();
264 kcb->prev_kprobe.status = kcb->kprobe_status;
265 kcb->prev_kprobe.old_flags = kcb->kprobe_old_flags;
266 kcb->prev_kprobe.saved_flags = kcb->kprobe_saved_flags;
267}
268
269static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
270{
271 __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
272 kcb->kprobe_status = kcb->prev_kprobe.status;
273 kcb->kprobe_old_flags = kcb->prev_kprobe.old_flags;
274 kcb->kprobe_saved_flags = kcb->prev_kprobe.saved_flags;
275}
276
277static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
278 struct kprobe_ctlblk *kcb)
279{
280 __get_cpu_var(current_kprobe) = p;
281 kcb->kprobe_saved_flags = kcb->kprobe_old_flags
282 = (regs->flags & (TF_MASK | IF_MASK));
283 if (is_IF_modifier(p->ainsn.insn))
284 kcb->kprobe_saved_flags &= ~IF_MASK;
285}
286
287static __always_inline void clear_btf(void)
288{
289 if (test_thread_flag(TIF_DEBUGCTLMSR))
290 wrmsr(MSR_IA32_DEBUGCTLMSR, 0, 0);
291}
292
293static __always_inline void restore_btf(void)
294{
295 if (test_thread_flag(TIF_DEBUGCTLMSR))
296 wrmsr(MSR_IA32_DEBUGCTLMSR, current->thread.debugctlmsr, 0);
297}
298
299static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
300{
301 clear_btf();
302 regs->flags |= TF_MASK;
303 regs->flags &= ~IF_MASK;
304 /*single step inline if the instruction is an int3*/
305 if (p->opcode == BREAKPOINT_INSTRUCTION)
306 regs->ip = (unsigned long)p->addr;
307 else
308 regs->ip = (unsigned long)p->ainsn.insn;
309}
310
311/* Called with kretprobe_lock held */
312void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
313 struct pt_regs *regs)
314{
315 unsigned long *sara = stack_addr(regs);
316
317 ri->ret_addr = (kprobe_opcode_t *) *sara;
318
319 /* Replace the return addr with trampoline addr */
320 *sara = (unsigned long) &kretprobe_trampoline;
321}
322
323/*
324 * Interrupts are disabled on entry as trap3 is an interrupt gate and they
325 * remain disabled thorough out this function.
326 */
327static int __kprobes kprobe_handler(struct pt_regs *regs)
328{
329 struct kprobe *p;
330 int ret = 0;
331 kprobe_opcode_t *addr;
332 struct kprobe_ctlblk *kcb;
333
334 addr = (kprobe_opcode_t *)(regs->ip - sizeof(kprobe_opcode_t));
335
336 /*
337 * We don't want to be preempted for the entire
338 * duration of kprobe processing
339 */
340 preempt_disable();
341 kcb = get_kprobe_ctlblk();
342
343 /* Check we're not actually recursing */
344 if (kprobe_running()) {
345 p = get_kprobe(addr);
346 if (p) {
347 if (kcb->kprobe_status == KPROBE_HIT_SS &&
348 *p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
349 regs->flags &= ~TF_MASK;
350 regs->flags |= kcb->kprobe_saved_flags;
351 goto no_kprobe;
352 }
353 /* We have reentered the kprobe_handler(), since
354 * another probe was hit while within the handler.
355 * We here save the original kprobes variables and
356 * just single step on the instruction of the new probe
357 * without calling any user handlers.
358 */
359 save_previous_kprobe(kcb);
360 set_current_kprobe(p, regs, kcb);
361 kprobes_inc_nmissed_count(p);
362 prepare_singlestep(p, regs);
363 kcb->kprobe_status = KPROBE_REENTER;
364 return 1;
365 } else {
366 if (*addr != BREAKPOINT_INSTRUCTION) {
367 /* The breakpoint instruction was removed by
368 * another cpu right after we hit, no further
369 * handling of this interrupt is appropriate
370 */
371 regs->ip = (unsigned long)addr;
372 ret = 1;
373 goto no_kprobe;
374 }
375 p = __get_cpu_var(current_kprobe);
376 if (p->break_handler && p->break_handler(p, regs)) {
377 goto ss_probe;
378 }
379 }
380 goto no_kprobe;
381 }
382
383 p = get_kprobe(addr);
384 if (!p) {
385 if (*addr != BREAKPOINT_INSTRUCTION) {
386 /*
387 * The breakpoint instruction was removed right
388 * after we hit it. Another cpu has removed
389 * either a probepoint or a debugger breakpoint
390 * at this address. In either case, no further
391 * handling of this interrupt is appropriate.
392 * Back up over the (now missing) int3 and run
393 * the original instruction.
394 */
395 regs->ip = (unsigned long)addr;
396 ret = 1;
397 }
398 /* Not one of ours: let kernel handle it */
399 goto no_kprobe;
400 }
401
402 set_current_kprobe(p, regs, kcb);
403 kcb->kprobe_status = KPROBE_HIT_ACTIVE;
404
405 if (p->pre_handler && p->pre_handler(p, regs))
406 /* handler has already set things up, so skip ss setup */
407 return 1;
408
409ss_probe:
410#if !defined(CONFIG_PREEMPT) || defined(CONFIG_PM)
411 if (p->ainsn.boostable == 1 && !p->post_handler) {
412 /* Boost up -- we can execute copied instructions directly */
413 reset_current_kprobe();
414 regs->ip = (unsigned long)p->ainsn.insn;
415 preempt_enable_no_resched();
416 return 1;
417 }
418#endif
419 prepare_singlestep(p, regs);
420 kcb->kprobe_status = KPROBE_HIT_SS;
421 return 1;
422
423no_kprobe:
424 preempt_enable_no_resched();
425 return ret;
426}
427
428/*
429 * When a retprobed function returns, this code saves registers and
430 * calls trampoline_handler() runs, which calls the kretprobe's handler.
431 */
432 void __kprobes kretprobe_trampoline_holder(void)
433 {
434 asm volatile ( ".global kretprobe_trampoline\n"
435 "kretprobe_trampoline: \n"
436 " pushf\n"
437 /*
438 * Skip cs, ip, orig_ax.
439 * trampoline_handler() will plug in these values
440 */
441 " subl $12, %esp\n"
442 " pushl %fs\n"
443 " pushl %ds\n"
444 " pushl %es\n"
445 " pushl %eax\n"
446 " pushl %ebp\n"
447 " pushl %edi\n"
448 " pushl %esi\n"
449 " pushl %edx\n"
450 " pushl %ecx\n"
451 " pushl %ebx\n"
452 " movl %esp, %eax\n"
453 " call trampoline_handler\n"
454 /* Move flags to cs */
455 " movl 52(%esp), %edx\n"
456 " movl %edx, 48(%esp)\n"
457 /* Replace saved flags with true return address. */
458 " movl %eax, 52(%esp)\n"
459 " popl %ebx\n"
460 " popl %ecx\n"
461 " popl %edx\n"
462 " popl %esi\n"
463 " popl %edi\n"
464 " popl %ebp\n"
465 " popl %eax\n"
466 /* Skip ip, orig_ax, es, ds, fs */
467 " addl $20, %esp\n"
468 " popf\n"
469 " ret\n");
470 }
471
472/*
473 * Called from kretprobe_trampoline
474 */
475void * __kprobes trampoline_handler(struct pt_regs *regs)
476{
477 struct kretprobe_instance *ri = NULL;
478 struct hlist_head *head, empty_rp;
479 struct hlist_node *node, *tmp;
480 unsigned long flags, orig_ret_address = 0;
481 unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
482
483 INIT_HLIST_HEAD(&empty_rp);
484 spin_lock_irqsave(&kretprobe_lock, flags);
485 head = kretprobe_inst_table_head(current);
486 /* fixup registers */
487 regs->cs = __KERNEL_CS | get_kernel_rpl();
488 regs->ip = trampoline_address;
489 regs->orig_ax = ~0UL;
490
491 /*
492 * It is possible to have multiple instances associated with a given
493 * task either because multiple functions in the call path have
494 * return probes installed on them, and/or more then one
495 * return probe was registered for a target function.
496 *
497 * We can handle this because:
498 * - instances are always pushed into the head of the list
499 * - when multiple return probes are registered for the same
500 * function, the (chronologically) first instance's ret_addr
501 * will be the real return address, and all the rest will
502 * point to kretprobe_trampoline.
503 */
504 hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
505 if (ri->task != current)
506 /* another task is sharing our hash bucket */
507 continue;
508
509 if (ri->rp && ri->rp->handler) {
510 __get_cpu_var(current_kprobe) = &ri->rp->kp;
511 get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE;
512 ri->rp->handler(ri, regs);
513 __get_cpu_var(current_kprobe) = NULL;
514 }
515
516 orig_ret_address = (unsigned long)ri->ret_addr;
517 recycle_rp_inst(ri, &empty_rp);
518
519 if (orig_ret_address != trampoline_address)
520 /*
521 * This is the real return address. Any other
522 * instances associated with this task are for
523 * other calls deeper on the call stack
524 */
525 break;
526 }
527
528 kretprobe_assert(ri, orig_ret_address, trampoline_address);
529
530 spin_unlock_irqrestore(&kretprobe_lock, flags);
531
532 hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
533 hlist_del(&ri->hlist);
534 kfree(ri);
535 }
536 return (void *)orig_ret_address;
537}
538
539/*
540 * Called after single-stepping. p->addr is the address of the
541 * instruction whose first byte has been replaced by the "int 3"
542 * instruction. To avoid the SMP problems that can occur when we
543 * temporarily put back the original opcode to single-step, we
544 * single-stepped a copy of the instruction. The address of this
545 * copy is p->ainsn.insn.
546 *
547 * This function prepares to return from the post-single-step
548 * interrupt. We have to fix up the stack as follows:
549 *
550 * 0) Except in the case of absolute or indirect jump or call instructions,
551 * the new ip is relative to the copied instruction. We need to make
552 * it relative to the original instruction.
553 *
554 * 1) If the single-stepped instruction was pushfl, then the TF and IF
555 * flags are set in the just-pushed flags, and may need to be cleared.
556 *
557 * 2) If the single-stepped instruction was a call, the return address
558 * that is atop the stack is the address following the copied instruction.
559 * We need to make it the address following the original instruction.
560 *
561 * If this is the first time we've single-stepped the instruction at
562 * this probepoint, and the instruction is boostable, boost it: add a
563 * jump instruction after the copied instruction, that jumps to the next
564 * instruction after the probepoint.
565 */
566static void __kprobes resume_execution(struct kprobe *p,
567 struct pt_regs *regs, struct kprobe_ctlblk *kcb)
568{
569 unsigned long *tos = stack_addr(regs);
570 unsigned long copy_ip = (unsigned long)p->ainsn.insn;
571 unsigned long orig_ip = (unsigned long)p->addr;
572 kprobe_opcode_t *insn = p->ainsn.insn;
573
574 regs->flags &= ~TF_MASK;
575 switch (*insn) {
576 case 0x9c: /* pushfl */
577 *tos &= ~(TF_MASK | IF_MASK);
578 *tos |= kcb->kprobe_old_flags;
579 break;
580 case 0xc2: /* iret/ret/lret */
581 case 0xc3:
582 case 0xca:
583 case 0xcb:
584 case 0xcf:
585 case 0xea: /* jmp absolute -- ip is correct */
586 /* ip is already adjusted, no more changes required */
587 p->ainsn.boostable = 1;
588 goto no_change;
589 case 0xe8: /* call relative - Fix return addr */
590 *tos = orig_ip + (*tos - copy_ip);
591 break;
592 case 0x9a: /* call absolute -- same as call absolute, indirect */
593 *tos = orig_ip + (*tos - copy_ip);
594 goto no_change;
595 case 0xff:
596 if ((insn[1] & 0x30) == 0x10) {
597 /*
598 * call absolute, indirect
599 * Fix return addr; ip is correct.
600 * But this is not boostable
601 */
602 *tos = orig_ip + (*tos - copy_ip);
603 goto no_change;
604 } else if (((insn[1] & 0x31) == 0x20) ||
605 ((insn[1] & 0x31) == 0x21)) {
606 /*
607 * jmp near and far, absolute indirect
608 * ip is correct. And this is boostable
609 */
610 p->ainsn.boostable = 1;
611 goto no_change;
612 }
613 default:
614 break;
615 }
616
617 if (p->ainsn.boostable == 0) {
618 if ((regs->ip > copy_ip) &&
619 (regs->ip - copy_ip) + 5 < MAX_INSN_SIZE) {
620 /*
621 * These instructions can be executed directly if it
622 * jumps back to correct address.
623 */
624 set_jmp_op((void *)regs->ip,
625 (void *)orig_ip + (regs->ip - copy_ip));
626 p->ainsn.boostable = 1;
627 } else {
628 p->ainsn.boostable = -1;
629 }
630 }
631
632 regs->ip += orig_ip - copy_ip;
633
634no_change:
635 restore_btf();
636
637 return;
638}
639
640/*
641 * Interrupts are disabled on entry as trap1 is an interrupt gate and they
642 * remain disabled thoroughout this function.
643 */
644static int __kprobes post_kprobe_handler(struct pt_regs *regs)
645{
646 struct kprobe *cur = kprobe_running();
647 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
648
649 if (!cur)
650 return 0;
651
652 if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
653 kcb->kprobe_status = KPROBE_HIT_SSDONE;
654 cur->post_handler(cur, regs, 0);
655 }
656
657 resume_execution(cur, regs, kcb);
658 regs->flags |= kcb->kprobe_saved_flags;
659 trace_hardirqs_fixup_flags(regs->flags);
660
661 /* Restore back the original saved kprobes variables and continue. */
662 if (kcb->kprobe_status == KPROBE_REENTER) {
663 restore_previous_kprobe(kcb);
664 goto out;
665 }
666 reset_current_kprobe();
667out:
668 preempt_enable_no_resched();
669
670 /*
671 * if somebody else is singlestepping across a probe point, flags
672 * will have TF set, in which case, continue the remaining processing
673 * of do_debug, as if this is not a probe hit.
674 */
675 if (regs->flags & TF_MASK)
676 return 0;
677
678 return 1;
679}
680
681int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
682{
683 struct kprobe *cur = kprobe_running();
684 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
685
686 switch(kcb->kprobe_status) {
687 case KPROBE_HIT_SS:
688 case KPROBE_REENTER:
689 /*
690 * We are here because the instruction being single
691 * stepped caused a page fault. We reset the current
692 * kprobe and the ip points back to the probe address
693 * and allow the page fault handler to continue as a
694 * normal page fault.
695 */
696 regs->ip = (unsigned long)cur->addr;
697 regs->flags |= kcb->kprobe_old_flags;
698 if (kcb->kprobe_status == KPROBE_REENTER)
699 restore_previous_kprobe(kcb);
700 else
701 reset_current_kprobe();
702 preempt_enable_no_resched();
703 break;
704 case KPROBE_HIT_ACTIVE:
705 case KPROBE_HIT_SSDONE:
706 /*
707 * We increment the nmissed count for accounting,
708 * we can also use npre/npostfault count for accounting
709 * these specific fault cases.
710 */
711 kprobes_inc_nmissed_count(cur);
712
713 /*
714 * We come here because instructions in the pre/post
715 * handler caused the page_fault, this could happen
716 * if handler tries to access user space by
717 * copy_from_user(), get_user() etc. Let the
718 * user-specified handler try to fix it first.
719 */
720 if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
721 return 1;
722
723 /*
724 * In case the user-specified fault handler returned
725 * zero, try to fix up.
726 */
727 if (fixup_exception(regs))
728 return 1;
729
730 /*
731 * fixup routine could not handle it,
732 * Let do_page_fault() fix it.
733 */
734 break;
735 default:
736 break;
737 }
738 return 0;
739}
740
741/*
742 * Wrapper routine for handling exceptions.
743 */
744int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
745 unsigned long val, void *data)
746{
747 struct die_args *args = (struct die_args *)data;
748 int ret = NOTIFY_DONE;
749
750 if (args->regs && user_mode_vm(args->regs))
751 return ret;
752
753 switch (val) {
754 case DIE_INT3:
755 if (kprobe_handler(args->regs))
756 ret = NOTIFY_STOP;
757 break;
758 case DIE_DEBUG:
759 if (post_kprobe_handler(args->regs))
760 ret = NOTIFY_STOP;
761 break;
762 case DIE_GPF:
763 /* kprobe_running() needs smp_processor_id() */
764 preempt_disable();
765 if (kprobe_running() &&
766 kprobe_fault_handler(args->regs, args->trapnr))
767 ret = NOTIFY_STOP;
768 preempt_enable();
769 break;
770 default:
771 break;
772 }
773 return ret;
774}
775
776int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
777{
778 struct jprobe *jp = container_of(p, struct jprobe, kp);
779 unsigned long addr;
780 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
781
782 kcb->jprobe_saved_regs = *regs;
783 kcb->jprobe_saved_sp = stack_addr(regs);
784 addr = (unsigned long)(kcb->jprobe_saved_sp);
785
786 /*
787 * As Linus pointed out, gcc assumes that the callee
788 * owns the argument space and could overwrite it, e.g.
789 * tailcall optimization. So, to be absolutely safe
790 * we also save and restore enough stack bytes to cover
791 * the argument area.
792 */
793 memcpy(kcb->jprobes_stack, (kprobe_opcode_t *)addr,
794 MIN_STACK_SIZE(addr));
795 regs->flags &= ~IF_MASK;
796 trace_hardirqs_off();
797 regs->ip = (unsigned long)(jp->entry);
798 return 1;
799}
800
801void __kprobes jprobe_return(void)
802{
803 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
804
805 asm volatile (" xchgl %%ebx,%%esp \n"
806 " int3 \n"
807 " .globl jprobe_return_end \n"
808 " jprobe_return_end: \n"
809 " nop \n"::"b"
810 (kcb->jprobe_saved_sp):"memory");
811}
812
813int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
814{
815 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
816 u8 *addr = (u8 *) (regs->ip - 1);
817 struct jprobe *jp = container_of(p, struct jprobe, kp);
818
819 if ((addr > (u8 *) jprobe_return) && (addr < (u8 *) jprobe_return_end)) {
820 if (stack_addr(regs) != kcb->jprobe_saved_sp) {
821 struct pt_regs *saved_regs = &kcb->jprobe_saved_regs;
822 printk("current sp %p does not match saved sp %p\n",
823 stack_addr(regs), kcb->jprobe_saved_sp);
824 printk("Saved registers for jprobe %p\n", jp);
825 show_registers(saved_regs);
826 printk("Current registers\n");
827 show_registers(regs);
828 BUG();
829 }
830 *regs = kcb->jprobe_saved_regs;
831 memcpy((kprobe_opcode_t *)(kcb->jprobe_saved_sp),
832 kcb->jprobes_stack,
833 MIN_STACK_SIZE(kcb->jprobe_saved_sp));
834 preempt_enable_no_resched();
835 return 1;
836 }
837 return 0;
838}
839
840int __init arch_init_kprobes(void)
841{
842 return 0;
843}
844
845int __kprobes arch_trampoline_kprobe(struct kprobe *p)
846{
847 return 0;
848}
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-27 14:09:52 -0500