* Rusty Russell).
* 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
* interface to access function arguments.
- * 2004-Oct Jim Keniston <kenistoj@us.ibm.com> and Prasanna S Panchamukhi
- * <prasanna@in.ibm.com> adapted for x86_64
+ * 2004-Oct Jim Keniston <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
+ * <prasanna@in.ibm.com> adapted for x86_64 from i386.
* 2005-Mar Roland McGrath <roland@redhat.com>
* Fixed to handle %rip-relative addressing mode correctly.
- * 2005-May Rusty Lynch <rusty.lynch@intel.com>
- * Added function return probes functionality
+ * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston
+ * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
+ * <prasanna@in.ibm.com> added function-return probes.
+ * 2005-May Rusty Lynch <rusty.lynch@intel.com>
+ * Added function return probes functionality
+ * 2006-Feb Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp> added
+ * kprobe-booster and kretprobe-booster for i386.
* 2007-Dec Masami Hiramatsu <mhiramat@redhat.com> added kprobe-booster
* and kretprobe-booster for x86-64
+ * 2007-Dec Masami Hiramatsu <mhiramat@redhat.com>, Arjan van de Ven
+ * <arjan@infradead.org> and Jim Keniston <jkenisto@us.ibm.com>
+ * unified x86 kprobes code.
*/
#include <linux/kprobes.h>
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
+#ifdef CONFIG_X86_64
#define stack_addr(regs) ((unsigned long *)regs->sp)
+#else
+/*
+ * "®s->sp" looks wrong, but it's correct for x86_32. x86_32 CPUs
+ * don't save the ss and esp registers if the CPU is already in kernel
+ * mode when it traps. So for kprobes, regs->sp and regs->ss are not
+ * the [nonexistent] saved stack pointer and ss register, but rather
+ * the top 8 bytes of the pre-int3 stack. So ®s->sp happens to
+ * point to the top of the pre-int3 stack.
+ */
+#define stack_addr(regs) ((unsigned long *)®s->sp)
+#endif
#define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\
(((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \
}
/*
- * returns non-zero if opcode is boostable.
- * RIP relative instructions are adjusted at copying time
+ * Returns non-zero if opcode is boostable.
+ * RIP relative instructions are adjusted at copying time in 64 bits mode
*/
static __always_inline int can_boost(kprobe_opcode_t *opcodes)
{
}
switch (opcode & 0xf0) {
+#ifdef CONFIG_X86_64
case 0x40:
goto retry; /* REX prefix is boostable */
+#endif
case 0x60:
if (0x63 < opcode && opcode < 0x67)
goto retry; /* prefixes */
}
/*
- * returns non-zero if opcode modifies the interrupt flag.
+ * Returns non-zero if opcode modifies the interrupt flag.
*/
static int __kprobes is_IF_modifier(kprobe_opcode_t *insn)
{
case 0x9d: /* popf/popfd */
return 1;
}
-
+#ifdef CONFIG_X86_64
/*
* on 64 bit x86, 0x40-0x4f are prefixes so we need to look
* at the next byte instead.. but of course not recurse infinitely
*/
if (*insn >= 0x40 && *insn <= 0x4f)
return is_IF_modifier(++insn);
+#endif
return 0;
}
+#ifdef CONFIG_X86_64
/*
* Adjust the displacement if the instruction uses the %rip-relative
* addressing mode.
if ((*insn & 0xf0) == 0x40)
++insn;
- if (*insn == 0x0f) { /* Two-byte opcode. */
+ if (*insn == 0x0f) {
+ /* Two-byte opcode. */
++insn;
need_modrm = test_bit(*insn,
(unsigned long *)twobyte_has_modrm);
- } else /* One-byte opcode. */
+ } else
+ /* One-byte opcode. */
need_modrm = test_bit(*insn,
(unsigned long *)onebyte_has_modrm);
if (need_modrm) {
u8 modrm = *++insn;
- if ((modrm & 0xc7) == 0x05) { /* %rip+disp32 addressing mode */
+ if ((modrm & 0xc7) == 0x05) {
+ /* %rip+disp32 addressing mode */
/* Displacement follows ModRM byte. */
++insn;
/*
}
}
}
+#endif
static void __kprobes arch_copy_kprobe(struct kprobe *p)
{
memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
+#ifdef CONFIG_X86_64
fix_riprel(p);
+#endif
if (can_boost(p->addr))
p->ainsn.boostable = 0;
else
static __always_inline void clear_btf(void)
{
if (test_thread_flag(TIF_DEBUGCTLMSR))
- wrmsrl(MSR_IA32_DEBUGCTLMSR, 0);
+ wrmsr(MSR_IA32_DEBUGCTLMSR, 0, 0);
}
static __always_inline void restore_btf(void)
{
if (test_thread_flag(TIF_DEBUGCTLMSR))
- wrmsrl(MSR_IA32_DEBUGCTLMSR, current->thread.debugctlmsr);
+ wrmsr(MSR_IA32_DEBUGCTLMSR, current->thread.debugctlmsr, 0);
}
static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
regs->flags &= ~TF_MASK;
regs->flags |= kcb->kprobe_saved_flags;
goto no_kprobe;
+#ifdef CONFIG_X86_64
} else if (kcb->kprobe_status == KPROBE_HIT_SSDONE) {
/* TODO: Provide re-entrancy from
* post_kprobes_handler() and avoid exception
regs->ip = (unsigned long)p->addr;
reset_current_kprobe();
return 1;
+#endif
}
/* We have reentered the kprobe_handler(), since
* another probe was hit while within the handler.
goto no_kprobe;
}
p = __get_cpu_var(current_kprobe);
- if (p->break_handler && p->break_handler(p, regs)) {
+ if (p->break_handler && p->break_handler(p, regs))
goto ss_probe;
- }
}
goto no_kprobe;
}
*/
void __kprobes kretprobe_trampoline_holder(void)
{
- asm volatile ( ".global kretprobe_trampoline\n"
+ asm volatile (
+ ".global kretprobe_trampoline\n"
"kretprobe_trampoline: \n"
+#ifdef CONFIG_X86_64
/* We don't bother saving the ss register */
" pushq %rsp\n"
" pushfq\n"
/* Skip orig_ax, ip, cs */
" addq $24, %rsp\n"
" popfq\n"
+#else
+ " pushf\n"
+ /*
+ * Skip cs, ip, orig_ax.
+ * trampoline_handler() will plug in these values
+ */
+ " subl $12, %esp\n"
+ " pushl %fs\n"
+ " pushl %ds\n"
+ " pushl %es\n"
+ " pushl %eax\n"
+ " pushl %ebp\n"
+ " pushl %edi\n"
+ " pushl %esi\n"
+ " pushl %edx\n"
+ " pushl %ecx\n"
+ " pushl %ebx\n"
+ " movl %esp, %eax\n"
+ " call trampoline_handler\n"
+ /* Move flags to cs */
+ " movl 52(%esp), %edx\n"
+ " movl %edx, 48(%esp)\n"
+ /* Replace saved flags with true return address. */
+ " movl %eax, 52(%esp)\n"
+ " popl %ebx\n"
+ " popl %ecx\n"
+ " popl %edx\n"
+ " popl %esi\n"
+ " popl %edi\n"
+ " popl %ebp\n"
+ " popl %eax\n"
+ /* Skip ip, orig_ax, es, ds, fs */
+ " addl $20, %esp\n"
+ " popf\n"
+#endif
" ret\n");
}
/*
* Called from kretprobe_trampoline
*/
-fastcall void * __kprobes trampoline_handler(struct pt_regs *regs)
+void * __kprobes trampoline_handler(struct pt_regs *regs)
{
struct kretprobe_instance *ri = NULL;
struct hlist_head *head, empty_rp;
struct hlist_node *node, *tmp;
unsigned long flags, orig_ret_address = 0;
- unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
+ unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;
INIT_HLIST_HEAD(&empty_rp);
spin_lock_irqsave(&kretprobe_lock, flags);
head = kretprobe_inst_table_head(current);
/* fixup registers */
+#ifdef CONFIG_X86_64
regs->cs = __KERNEL_CS;
+#else
+ regs->cs = __KERNEL_CS | get_kernel_rpl();
+#endif
regs->ip = trampoline_address;
regs->orig_ax = ~0UL;
unsigned long orig_ip = (unsigned long)p->addr;
kprobe_opcode_t *insn = p->ainsn.insn;
+#ifdef CONFIG_X86_64
/*skip the REX prefix*/
if (*insn >= 0x40 && *insn <= 0x4f)
insn++;
+#endif
regs->flags &= ~TF_MASK;
switch (*insn) {
case 0xe8: /* call relative - Fix return addr */
*tos = orig_ip + (*tos - copy_ip);
break;
+#ifndef CONFIG_X86_64
+ case 0x9a: /* call absolute -- same as call absolute, indirect */
+ *tos = orig_ip + (*tos - copy_ip);
+ goto no_change;
+#endif
case 0xff:
if ((insn[1] & 0x30) == 0x10) {
/*
{
struct kprobe *cur = kprobe_running();
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- const struct exception_table_entry *fixup;
- switch(kcb->kprobe_status) {
+ switch (kcb->kprobe_status) {
case KPROBE_HIT_SS:
case KPROBE_REENTER:
/*
* In case the user-specified fault handler returned
* zero, try to fix up.
*/
- fixup = search_exception_tables(regs->ip);
- if (fixup) {
- regs->ip = fixup->fixup;
- return 1;
+#ifdef CONFIG_X86_64
+ {
+ const struct exception_table_entry *fixup;
+ fixup = search_exception_tables(regs->ip);
+ if (fixup) {
+ regs->ip = fixup->fixup;
+ return 1;
+ }
}
-
+#else
+ if (fixup_exception(regs))
+ return 1;
+#endif
/*
* fixup routine could not handle it,
* Let do_page_fault() fix it.
* the argument area.
*/
memcpy(kcb->jprobes_stack, (kprobe_opcode_t *)addr,
- MIN_STACK_SIZE(addr));
+ MIN_STACK_SIZE(addr));
regs->flags &= ~IF_MASK;
trace_hardirqs_off();
regs->ip = (unsigned long)(jp->entry);
{
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- asm volatile (" xchg %%rbx,%%rsp \n"
- " int3 \n"
- " .globl jprobe_return_end \n"
- " jprobe_return_end: \n"
- " nop \n"::"b"
- (kcb->jprobe_saved_sp):"memory");
+ asm volatile (
+#ifdef CONFIG_X86_64
+ " xchg %%rbx,%%rsp \n"
+#else
+ " xchgl %%ebx,%%esp \n"
+#endif
+ " int3 \n"
+ " .globl jprobe_return_end\n"
+ " jprobe_return_end: \n"
+ " nop \n"::"b"
+ (kcb->jprobe_saved_sp):"memory");
}
int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
u8 *addr = (u8 *) (regs->ip - 1);
struct jprobe *jp = container_of(p, struct jprobe, kp);
- if ((addr > (u8 *) jprobe_return) && (addr < (u8 *) jprobe_return_end)) {
+ if ((addr > (u8 *) jprobe_return) &&
+ (addr < (u8 *) jprobe_return_end)) {
if (stack_addr(regs) != kcb->jprobe_saved_sp) {
struct pt_regs *saved_regs = &kcb->jprobe_saved_regs;
- printk("current sp %p does not match saved sp %p\n",
+ printk(KERN_ERR
+ "current sp %p does not match saved sp %p\n",
stack_addr(regs), kcb->jprobe_saved_sp);
- printk("Saved registers for jprobe %p\n", jp);
+ printk(KERN_ERR "Saved registers for jprobe %p\n", jp);
show_registers(saved_regs);
- printk("Current registers\n");
+ printk(KERN_ERR "Current registers\n");
show_registers(regs);
BUG();
}
+++ /dev/null
-/*
- * Kernel Probes (KProbes)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- * Copyright (C) IBM Corporation, 2002, 2004
- *
- * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
- * Probes initial implementation ( includes contributions from
- * Rusty Russell).
- * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
- * interface to access function arguments.
- * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston
- * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
- * <prasanna@in.ibm.com> added function-return probes.
- */
-
-#include <linux/kprobes.h>
-#include <linux/ptrace.h>
-#include <linux/string.h>
-#include <linux/slab.h>
-#include <linux/preempt.h>
-#include <linux/module.h>
-#include <linux/kdebug.h>
-
-#include <asm/cacheflush.h>
-#include <asm/desc.h>
-#include <asm/pgtable.h>
-#include <asm/uaccess.h>
-#include <asm/alternative.h>
-
-void jprobe_return_end(void);
-
-DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
-DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
-
-/*
- * "®s->sp" looks wrong, but it's correct for x86_32. x86_32 CPUs
- * don't save the ss and esp registers if the CPU is already in kernel
- * mode when it traps. So for kprobes, regs->sp and regs->ss are not
- * the [nonexistent] saved stack pointer and ss register, but rather
- * the top 8 bytes of the pre-int3 stack. So ®s->sp happens to
- * point to the top of the pre-int3 stack.
- */
-#define stack_addr(regs) ((unsigned long *)®s->sp)
-
-#define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\
- (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \
- (b4##UL << 0x4)|(b5##UL << 0x5)|(b6##UL << 0x6)|(b7##UL << 0x7) | \
- (b8##UL << 0x8)|(b9##UL << 0x9)|(ba##UL << 0xa)|(bb##UL << 0xb) | \
- (bc##UL << 0xc)|(bd##UL << 0xd)|(be##UL << 0xe)|(bf##UL << 0xf)) \
- << (row % 32))
- /*
- * Undefined/reserved opcodes, conditional jump, Opcode Extension
- * Groups, and some special opcodes can not boost.
- */
-static const u32 twobyte_is_boostable[256 / 32] = {
- /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
- /* ---------------------------------------------- */
- W(0x00, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0) | /* 00 */
- W(0x10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 10 */
- W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 20 */
- W(0x30, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 30 */
- W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 40 */
- W(0x50, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 50 */
- W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1) | /* 60 */
- W(0x70, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1) , /* 70 */
- W(0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 80 */
- W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 90 */
- W(0xa0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1) | /* a0 */
- W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1) , /* b0 */
- W(0xc0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1) | /* c0 */
- W(0xd0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1) , /* d0 */
- W(0xe0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1) | /* e0 */
- W(0xf0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0) /* f0 */
- /* ----------------------------------------------- */
- /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
-};
-static const u32 onebyte_has_modrm[256 / 32] = {
- /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
- /* ----------------------------------------------- */
- W(0x00, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 00 */
- W(0x10, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) , /* 10 */
- W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 20 */
- W(0x30, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) , /* 30 */
- W(0x40, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 40 */
- W(0x50, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 50 */
- W(0x60, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0) | /* 60 */
- W(0x70, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 70 */
- W(0x80, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 80 */
- W(0x90, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 90 */
- W(0xa0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* a0 */
- W(0xb0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* b0 */
- W(0xc0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0) | /* c0 */
- W(0xd0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1) , /* d0 */
- W(0xe0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* e0 */
- W(0xf0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1) /* f0 */
- /* ----------------------------------------------- */
- /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
-};
-static const u32 twobyte_has_modrm[256 / 32] = {
- /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
- /* ----------------------------------------------- */
- W(0x00, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1) | /* 0f */
- W(0x10, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0) , /* 1f */
- W(0x20, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1) | /* 2f */
- W(0x30, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 3f */
- W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 4f */
- W(0x50, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 5f */
- W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 6f */
- W(0x70, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1) , /* 7f */
- W(0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 8f */
- W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 9f */
- W(0xa0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1) | /* af */
- W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1) , /* bf */
- W(0xc0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0) | /* cf */
- W(0xd0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* df */
- W(0xe0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* ef */
- W(0xf0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0) /* ff */
- /* ----------------------------------------------- */
- /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
-};
-#undef W
-
-struct kretprobe_blackpoint kretprobe_blacklist[] = {
- {"__switch_to", }, /* This function switches only current task, but
- doesn't switch kernel stack.*/
- {NULL, NULL} /* Terminator */
-};
-const int kretprobe_blacklist_size = ARRAY_SIZE(kretprobe_blacklist);
-
-/* Insert a jump instruction at address 'from', which jumps to address 'to'.*/
-static __always_inline void set_jmp_op(void *from, void *to)
-{
- struct __arch_jmp_op {
- char op;
- s32 raddr;
- } __attribute__((packed)) * jop;
- jop = (struct __arch_jmp_op *)from;
- jop->raddr = (s32)((long)(to) - ((long)(from) + 5));
- jop->op = RELATIVEJUMP_INSTRUCTION;
-}
-
-/*
- * returns non-zero if opcode is boostable.
- */
-static __always_inline int can_boost(kprobe_opcode_t *opcodes)
-{
- kprobe_opcode_t opcode;
- kprobe_opcode_t *orig_opcodes = opcodes;
-
-retry:
- if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
- return 0;
- opcode = *(opcodes++);
-
- /* 2nd-byte opcode */
- if (opcode == 0x0f) {
- if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
- return 0;
- return test_bit(*opcodes,
- (unsigned long *)twobyte_is_boostable);
- }
-
- switch (opcode & 0xf0) {
- case 0x60:
- if (0x63 < opcode && opcode < 0x67)
- goto retry; /* prefixes */
- /* can't boost Address-size override and bound */
- return (opcode != 0x62 && opcode != 0x67);
- case 0x70:
- return 0; /* can't boost conditional jump */
- case 0xc0:
- /* can't boost software-interruptions */
- return (0xc1 < opcode && opcode < 0xcc) || opcode == 0xcf;
- case 0xd0:
- /* can boost AA* and XLAT */
- return (opcode == 0xd4 || opcode == 0xd5 || opcode == 0xd7);
- case 0xe0:
- /* can boost in/out and absolute jmps */
- return ((opcode & 0x04) || opcode == 0xea);
- case 0xf0:
- if ((opcode & 0x0c) == 0 && opcode != 0xf1)
- goto retry; /* lock/rep(ne) prefix */
- /* clear and set flags are boostable */
- return (opcode == 0xf5 || (0xf7 < opcode && opcode < 0xfe));
- default:
- /* segment override prefixes are boostable */
- if (opcode == 0x26 || opcode == 0x36 || opcode == 0x3e)
- goto retry; /* prefixes */
- /* CS override prefix and call are not boostable */
- return (opcode != 0x2e && opcode != 0x9a);
- }
-}
-
-/*
- * returns non-zero if opcode modifies the interrupt flag.
- */
-static int __kprobes is_IF_modifier(kprobe_opcode_t *insn)
-{
- switch (*insn) {
- case 0xfa: /* cli */
- case 0xfb: /* sti */
- case 0xcf: /* iret/iretd */
- case 0x9d: /* popf/popfd */
- return 1;
- }
- return 0;
-}
-
-static void __kprobes arch_copy_kprobe(struct kprobe *p)
-{
- memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
- if (can_boost(p->addr))
- p->ainsn.boostable = 0;
- else
- p->ainsn.boostable = -1;
-
- p->opcode = *p->addr;
-}
-
-int __kprobes arch_prepare_kprobe(struct kprobe *p)
-{
- /* insn: must be on special executable page on x86. */
- p->ainsn.insn = get_insn_slot();
- if (!p->ainsn.insn)
- return -ENOMEM;
- arch_copy_kprobe(p);
- return 0;
-}
-
-void __kprobes arch_arm_kprobe(struct kprobe *p)
-{
- text_poke(p->addr, ((unsigned char []){BREAKPOINT_INSTRUCTION}), 1);
-}
-
-void __kprobes arch_disarm_kprobe(struct kprobe *p)
-{
- text_poke(p->addr, &p->opcode, 1);
-}
-
-void __kprobes arch_remove_kprobe(struct kprobe *p)
-{
- mutex_lock(&kprobe_mutex);
- free_insn_slot(p->ainsn.insn, (p->ainsn.boostable == 1));
- mutex_unlock(&kprobe_mutex);
-}
-
-static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
-{
- kcb->prev_kprobe.kp = kprobe_running();
- kcb->prev_kprobe.status = kcb->kprobe_status;
- kcb->prev_kprobe.old_flags = kcb->kprobe_old_flags;
- kcb->prev_kprobe.saved_flags = kcb->kprobe_saved_flags;
-}
-
-static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
-{
- __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
- kcb->kprobe_status = kcb->prev_kprobe.status;
- kcb->kprobe_old_flags = kcb->prev_kprobe.old_flags;
- kcb->kprobe_saved_flags = kcb->prev_kprobe.saved_flags;
-}
-
-static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
- struct kprobe_ctlblk *kcb)
-{
- __get_cpu_var(current_kprobe) = p;
- kcb->kprobe_saved_flags = kcb->kprobe_old_flags
- = (regs->flags & (TF_MASK | IF_MASK));
- if (is_IF_modifier(p->ainsn.insn))
- kcb->kprobe_saved_flags &= ~IF_MASK;
-}
-
-static __always_inline void clear_btf(void)
-{
- if (test_thread_flag(TIF_DEBUGCTLMSR))
- wrmsr(MSR_IA32_DEBUGCTLMSR, 0, 0);
-}
-
-static __always_inline void restore_btf(void)
-{
- if (test_thread_flag(TIF_DEBUGCTLMSR))
- wrmsr(MSR_IA32_DEBUGCTLMSR, current->thread.debugctlmsr, 0);
-}
-
-static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
-{
- clear_btf();
- regs->flags |= TF_MASK;
- regs->flags &= ~IF_MASK;
- /*single step inline if the instruction is an int3*/
- if (p->opcode == BREAKPOINT_INSTRUCTION)
- regs->ip = (unsigned long)p->addr;
- else
- regs->ip = (unsigned long)p->ainsn.insn;
-}
-
-/* Called with kretprobe_lock held */
-void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
- struct pt_regs *regs)
-{
- unsigned long *sara = stack_addr(regs);
-
- ri->ret_addr = (kprobe_opcode_t *) *sara;
-
- /* Replace the return addr with trampoline addr */
- *sara = (unsigned long) &kretprobe_trampoline;
-}
-
-/*
- * Interrupts are disabled on entry as trap3 is an interrupt gate and they
- * remain disabled thorough out this function.
- */
-static int __kprobes kprobe_handler(struct pt_regs *regs)
-{
- struct kprobe *p;
- int ret = 0;
- kprobe_opcode_t *addr;
- struct kprobe_ctlblk *kcb;
-
- addr = (kprobe_opcode_t *)(regs->ip - sizeof(kprobe_opcode_t));
-
- /*
- * We don't want to be preempted for the entire
- * duration of kprobe processing
- */
- preempt_disable();
- kcb = get_kprobe_ctlblk();
-
- /* Check we're not actually recursing */
- if (kprobe_running()) {
- p = get_kprobe(addr);
- if (p) {
- if (kcb->kprobe_status == KPROBE_HIT_SS &&
- *p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
- regs->flags &= ~TF_MASK;
- regs->flags |= kcb->kprobe_saved_flags;
- goto no_kprobe;
- }
- /* We have reentered the kprobe_handler(), since
- * another probe was hit while within the handler.
- * We here save the original kprobes variables and
- * just single step on the instruction of the new probe
- * without calling any user handlers.
- */
- save_previous_kprobe(kcb);
- set_current_kprobe(p, regs, kcb);
- kprobes_inc_nmissed_count(p);
- prepare_singlestep(p, regs);
- kcb->kprobe_status = KPROBE_REENTER;
- return 1;
- } else {
- if (*addr != BREAKPOINT_INSTRUCTION) {
- /* The breakpoint instruction was removed by
- * another cpu right after we hit, no further
- * handling of this interrupt is appropriate
- */
- regs->ip = (unsigned long)addr;
- ret = 1;
- goto no_kprobe;
- }
- p = __get_cpu_var(current_kprobe);
- if (p->break_handler && p->break_handler(p, regs)) {
- goto ss_probe;
- }
- }
- goto no_kprobe;
- }
-
- p = get_kprobe(addr);
- if (!p) {
- if (*addr != BREAKPOINT_INSTRUCTION) {
- /*
- * The breakpoint instruction was removed right
- * after we hit it. Another cpu has removed
- * either a probepoint or a debugger breakpoint
- * at this address. In either case, no further
- * handling of this interrupt is appropriate.
- * Back up over the (now missing) int3 and run
- * the original instruction.
- */
- regs->ip = (unsigned long)addr;
- ret = 1;
- }
- /* Not one of ours: let kernel handle it */
- goto no_kprobe;
- }
-
- set_current_kprobe(p, regs, kcb);
- kcb->kprobe_status = KPROBE_HIT_ACTIVE;
-
- if (p->pre_handler && p->pre_handler(p, regs))
- /* handler has already set things up, so skip ss setup */
- return 1;
-
-ss_probe:
-#if !defined(CONFIG_PREEMPT) || defined(CONFIG_PM)
- if (p->ainsn.boostable == 1 && !p->post_handler) {
- /* Boost up -- we can execute copied instructions directly */
- reset_current_kprobe();
- regs->ip = (unsigned long)p->ainsn.insn;
- preempt_enable_no_resched();
- return 1;
- }
-#endif
- prepare_singlestep(p, regs);
- kcb->kprobe_status = KPROBE_HIT_SS;
- return 1;
-
-no_kprobe:
- preempt_enable_no_resched();
- return ret;
-}
-
-/*
- * When a retprobed function returns, this code saves registers and
- * calls trampoline_handler() runs, which calls the kretprobe's handler.
- */
- void __kprobes kretprobe_trampoline_holder(void)
- {
- asm volatile ( ".global kretprobe_trampoline\n"
- "kretprobe_trampoline: \n"
- " pushf\n"
- /*
- * Skip cs, ip, orig_ax.
- * trampoline_handler() will plug in these values
- */
- " subl $12, %esp\n"
- " pushl %fs\n"
- " pushl %ds\n"
- " pushl %es\n"
- " pushl %eax\n"
- " pushl %ebp\n"
- " pushl %edi\n"
- " pushl %esi\n"
- " pushl %edx\n"
- " pushl %ecx\n"
- " pushl %ebx\n"
- " movl %esp, %eax\n"
- " call trampoline_handler\n"
- /* Move flags to cs */
- " movl 52(%esp), %edx\n"
- " movl %edx, 48(%esp)\n"
- /* Replace saved flags with true return address. */
- " movl %eax, 52(%esp)\n"
- " popl %ebx\n"
- " popl %ecx\n"
- " popl %edx\n"
- " popl %esi\n"
- " popl %edi\n"
- " popl %ebp\n"
- " popl %eax\n"
- /* Skip ip, orig_ax, es, ds, fs */
- " addl $20, %esp\n"
- " popf\n"
- " ret\n");
- }
-
-/*
- * Called from kretprobe_trampoline
- */
-void * __kprobes trampoline_handler(struct pt_regs *regs)
-{
- struct kretprobe_instance *ri = NULL;
- struct hlist_head *head, empty_rp;
- struct hlist_node *node, *tmp;
- unsigned long flags, orig_ret_address = 0;
- unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
-
- INIT_HLIST_HEAD(&empty_rp);
- spin_lock_irqsave(&kretprobe_lock, flags);
- head = kretprobe_inst_table_head(current);
- /* fixup registers */
- regs->cs = __KERNEL_CS | get_kernel_rpl();
- regs->ip = trampoline_address;
- regs->orig_ax = ~0UL;
-
- /*
- * It is possible to have multiple instances associated with a given
- * task either because multiple functions in the call path have
- * return probes installed on them, and/or more then one
- * return probe was registered for a target function.
- *
- * We can handle this because:
- * - instances are always pushed into the head of the list
- * - when multiple return probes are registered for the same
- * function, the (chronologically) first instance's ret_addr
- * will be the real return address, and all the rest will
- * point to kretprobe_trampoline.
- */
- hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
- if (ri->task != current)
- /* another task is sharing our hash bucket */
- continue;
-
- if (ri->rp && ri->rp->handler) {
- __get_cpu_var(current_kprobe) = &ri->rp->kp;
- get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE;
- ri->rp->handler(ri, regs);
- __get_cpu_var(current_kprobe) = NULL;
- }
-
- orig_ret_address = (unsigned long)ri->ret_addr;
- recycle_rp_inst(ri, &empty_rp);
-
- if (orig_ret_address != trampoline_address)
- /*
- * This is the real return address. Any other
- * instances associated with this task are for
- * other calls deeper on the call stack
- */
- break;
- }
-
- kretprobe_assert(ri, orig_ret_address, trampoline_address);
-
- spin_unlock_irqrestore(&kretprobe_lock, flags);
-
- hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
- hlist_del(&ri->hlist);
- kfree(ri);
- }
- return (void *)orig_ret_address;
-}
-
-/*
- * Called after single-stepping. p->addr is the address of the
- * instruction whose first byte has been replaced by the "int 3"
- * instruction. To avoid the SMP problems that can occur when we
- * temporarily put back the original opcode to single-step, we
- * single-stepped a copy of the instruction. The address of this
- * copy is p->ainsn.insn.
- *
- * This function prepares to return from the post-single-step
- * interrupt. We have to fix up the stack as follows:
- *
- * 0) Except in the case of absolute or indirect jump or call instructions,
- * the new ip is relative to the copied instruction. We need to make
- * it relative to the original instruction.
- *
- * 1) If the single-stepped instruction was pushfl, then the TF and IF
- * flags are set in the just-pushed flags, and may need to be cleared.
- *
- * 2) If the single-stepped instruction was a call, the return address
- * that is atop the stack is the address following the copied instruction.
- * We need to make it the address following the original instruction.
- *
- * If this is the first time we've single-stepped the instruction at
- * this probepoint, and the instruction is boostable, boost it: add a
- * jump instruction after the copied instruction, that jumps to the next
- * instruction after the probepoint.
- */
-static void __kprobes resume_execution(struct kprobe *p,
- struct pt_regs *regs, struct kprobe_ctlblk *kcb)
-{
- unsigned long *tos = stack_addr(regs);
- unsigned long copy_ip = (unsigned long)p->ainsn.insn;
- unsigned long orig_ip = (unsigned long)p->addr;
- kprobe_opcode_t *insn = p->ainsn.insn;
-
- regs->flags &= ~TF_MASK;
- switch (*insn) {
- case 0x9c: /* pushfl */
- *tos &= ~(TF_MASK | IF_MASK);
- *tos |= kcb->kprobe_old_flags;
- break;
- case 0xc2: /* iret/ret/lret */
- case 0xc3:
- case 0xca:
- case 0xcb:
- case 0xcf:
- case 0xea: /* jmp absolute -- ip is correct */
- /* ip is already adjusted, no more changes required */
- p->ainsn.boostable = 1;
- goto no_change;
- case 0xe8: /* call relative - Fix return addr */
- *tos = orig_ip + (*tos - copy_ip);
- break;
- case 0x9a: /* call absolute -- same as call absolute, indirect */
- *tos = orig_ip + (*tos - copy_ip);
- goto no_change;
- case 0xff:
- if ((insn[1] & 0x30) == 0x10) {
- /*
- * call absolute, indirect
- * Fix return addr; ip is correct.
- * But this is not boostable
- */
- *tos = orig_ip + (*tos - copy_ip);
- goto no_change;
- } else if (((insn[1] & 0x31) == 0x20) ||
- ((insn[1] & 0x31) == 0x21)) {
- /*
- * jmp near and far, absolute indirect
- * ip is correct. And this is boostable
- */
- p->ainsn.boostable = 1;
- goto no_change;
- }
- default:
- break;
- }
-
- if (p->ainsn.boostable == 0) {
- if ((regs->ip > copy_ip) &&
- (regs->ip - copy_ip) + 5 < MAX_INSN_SIZE) {
- /*
- * These instructions can be executed directly if it
- * jumps back to correct address.
- */
- set_jmp_op((void *)regs->ip,
- (void *)orig_ip + (regs->ip - copy_ip));
- p->ainsn.boostable = 1;
- } else {
- p->ainsn.boostable = -1;
- }
- }
-
- regs->ip += orig_ip - copy_ip;
-
-no_change:
- restore_btf();
-
- return;
-}
-
-/*
- * Interrupts are disabled on entry as trap1 is an interrupt gate and they
- * remain disabled thoroughout this function.
- */
-static int __kprobes post_kprobe_handler(struct pt_regs *regs)
-{
- struct kprobe *cur = kprobe_running();
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- if (!cur)
- return 0;
-
- if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
- kcb->kprobe_status = KPROBE_HIT_SSDONE;
- cur->post_handler(cur, regs, 0);
- }
-
- resume_execution(cur, regs, kcb);
- regs->flags |= kcb->kprobe_saved_flags;
- trace_hardirqs_fixup_flags(regs->flags);
-
- /* Restore back the original saved kprobes variables and continue. */
- if (kcb->kprobe_status == KPROBE_REENTER) {
- restore_previous_kprobe(kcb);
- goto out;
- }
- reset_current_kprobe();
-out:
- preempt_enable_no_resched();
-
- /*
- * if somebody else is singlestepping across a probe point, flags
- * will have TF set, in which case, continue the remaining processing
- * of do_debug, as if this is not a probe hit.
- */
- if (regs->flags & TF_MASK)
- return 0;
-
- return 1;
-}
-
-int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
-{
- struct kprobe *cur = kprobe_running();
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- switch(kcb->kprobe_status) {
- case KPROBE_HIT_SS:
- case KPROBE_REENTER:
- /*
- * We are here because the instruction being single
- * stepped caused a page fault. We reset the current
- * kprobe and the ip points back to the probe address
- * and allow the page fault handler to continue as a
- * normal page fault.
- */
- regs->ip = (unsigned long)cur->addr;
- regs->flags |= kcb->kprobe_old_flags;
- if (kcb->kprobe_status == KPROBE_REENTER)
- restore_previous_kprobe(kcb);
- else
- reset_current_kprobe();
- preempt_enable_no_resched();
- break;
- case KPROBE_HIT_ACTIVE:
- case KPROBE_HIT_SSDONE:
- /*
- * We increment the nmissed count for accounting,
- * we can also use npre/npostfault count for accounting
- * these specific fault cases.
- */
- kprobes_inc_nmissed_count(cur);
-
- /*
- * We come here because instructions in the pre/post
- * handler caused the page_fault, this could happen
- * if handler tries to access user space by
- * copy_from_user(), get_user() etc. Let the
- * user-specified handler try to fix it first.
- */
- if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
- return 1;
-
- /*
- * In case the user-specified fault handler returned
- * zero, try to fix up.
- */
- if (fixup_exception(regs))
- return 1;
-
- /*
- * fixup routine could not handle it,
- * Let do_page_fault() fix it.
- */
- break;
- default:
- break;
- }
- return 0;
-}
-
-/*
- * Wrapper routine for handling exceptions.
- */
-int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
- unsigned long val, void *data)
-{
- struct die_args *args = (struct die_args *)data;
- int ret = NOTIFY_DONE;
-
- if (args->regs && user_mode_vm(args->regs))
- return ret;
-
- switch (val) {
- case DIE_INT3:
- if (kprobe_handler(args->regs))
- ret = NOTIFY_STOP;
- break;
- case DIE_DEBUG:
- if (post_kprobe_handler(args->regs))
- ret = NOTIFY_STOP;
- break;
- case DIE_GPF:
- /* kprobe_running() needs smp_processor_id() */
- preempt_disable();
- if (kprobe_running() &&
- kprobe_fault_handler(args->regs, args->trapnr))
- ret = NOTIFY_STOP;
- preempt_enable();
- break;
- default:
- break;
- }
- return ret;
-}
-
-int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct jprobe *jp = container_of(p, struct jprobe, kp);
- unsigned long addr;
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- kcb->jprobe_saved_regs = *regs;
- kcb->jprobe_saved_sp = stack_addr(regs);
- addr = (unsigned long)(kcb->jprobe_saved_sp);
-
- /*
- * As Linus pointed out, gcc assumes that the callee
- * owns the argument space and could overwrite it, e.g.
- * tailcall optimization. So, to be absolutely safe
- * we also save and restore enough stack bytes to cover
- * the argument area.
- */
- memcpy(kcb->jprobes_stack, (kprobe_opcode_t *)addr,
- MIN_STACK_SIZE(addr));
- regs->flags &= ~IF_MASK;
- trace_hardirqs_off();
- regs->ip = (unsigned long)(jp->entry);
- return 1;
-}
-
-void __kprobes jprobe_return(void)
-{
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- asm volatile (" xchgl %%ebx,%%esp \n"
- " int3 \n"
- " .globl jprobe_return_end \n"
- " jprobe_return_end: \n"
- " nop \n"::"b"
- (kcb->jprobe_saved_sp):"memory");
-}
-
-int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- u8 *addr = (u8 *) (regs->ip - 1);
- struct jprobe *jp = container_of(p, struct jprobe, kp);
-
- if ((addr > (u8 *) jprobe_return) && (addr < (u8 *) jprobe_return_end)) {
- if (stack_addr(regs) != kcb->jprobe_saved_sp) {
- struct pt_regs *saved_regs = &kcb->jprobe_saved_regs;
- printk("current sp %p does not match saved sp %p\n",
- stack_addr(regs), kcb->jprobe_saved_sp);
- printk("Saved registers for jprobe %p\n", jp);
- show_registers(saved_regs);
- printk("Current registers\n");
- show_registers(regs);
- BUG();
- }
- *regs = kcb->jprobe_saved_regs;
- memcpy((kprobe_opcode_t *)(kcb->jprobe_saved_sp),
- kcb->jprobes_stack,
- MIN_STACK_SIZE(kcb->jprobe_saved_sp));
- preempt_enable_no_resched();
- return 1;
- }
- return 0;
-}
-
-int __init arch_init_kprobes(void)
-{
- return 0;
-}
-
-int __kprobes arch_trampoline_kprobe(struct kprobe *p)
-{
- return 0;
-}
projects / linux-2.6 / commitdiff