X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=arch%2Fi386%2Fkernel%2Fkprobes.c;h=f74b755704c4c07a1137a94367d1d8bd8d52c78c;hb=6a77f38946aaee1cd85eeec6cf4229b204c15071;hp=4d066cc30ac16bbd7c7bc2c5c98aea2a91d419c7;hpb=87fc8d1bb10cd459024a742c6a10961fefcef18f;p=linux-2.6.git

diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c
index 4d066cc30..f74b75570 100644
--- a/arch/i386/kernel/kprobes.c
+++ b/arch/i386/kernel/kprobes.c
@@ -31,6 +31,7 @@
 #include <linux/spinlock.h>
 #include <linux/preempt.h>
 #include <asm/kdebug.h>
+#include <asm/desc.h>
 
 /* kprobe_status settings */
 #define KPROBE_HIT_ACTIVE	0x00000001
@@ -42,6 +43,7 @@ static struct pt_regs jprobe_saved_regs;
 static long *jprobe_saved_esp;
 /* copy of the kernel stack at the probe fire time */
 static kprobe_opcode_t jprobes_stack[MAX_STACK_SIZE];
+void jprobe_return_end(void);
 
 /*
  * returns non-zero if opcode modifies the interrupt flag.
@@ -58,9 +60,18 @@ static inline int is_IF_modifier(kprobe_opcode_t opcode)
 	return 0;
 }
 
-void arch_prepare_kprobe(struct kprobe *p)
+int arch_prepare_kprobe(struct kprobe *p)
+{
+	return 0;
+}
+
+void arch_copy_kprobe(struct kprobe *p)
+{
+	memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
+}
+
+void arch_remove_kprobe(struct kprobe *p)
 {
-	memcpy(p->insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
 }
 
 static inline void disarm_kprobe(struct kprobe *p, struct pt_regs *regs)
@@ -73,22 +84,33 @@ static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
 {
 	regs->eflags |= TF_MASK;
 	regs->eflags &= ~IF_MASK;
-	regs->eip = (unsigned long)&p->insn;
+	regs->eip = (unsigned long)&p->ainsn.insn;
 }
 
 /*
  * Interrupts are disabled on entry as trap3 is an interrupt gate and they
  * remain disabled thorough out this function.
  */
-static inline int kprobe_handler(struct pt_regs *regs)
+static int kprobe_handler(struct pt_regs *regs)
 {
 	struct kprobe *p;
 	int ret = 0;
-	u8 *addr = (u8 *) (regs->eip - 1);
+	kprobe_opcode_t *addr = NULL;
+	unsigned long *lp;
 
 	/* We're in an interrupt, but this is clear and BUG()-safe. */
 	preempt_disable();
-
+	/* Check if the application is using LDT entry for its code segment and
+	 * calculate the address by reading the base address from the LDT entry.
+	 */
+	if ((regs->xcs & 4) && (current->mm)) {
+		lp = (unsigned long *) ((unsigned long)((regs->xcs >> 3) * 8)
+					+ (char *) current->mm->context.ldt);
+		addr = (kprobe_opcode_t *) (get_desc_base(lp) + regs->eip -
+						sizeof(kprobe_opcode_t));
+	} else {
+		addr = (kprobe_opcode_t *)(regs->eip - sizeof(kprobe_opcode_t));
+	}
 	/* Check we're not actually recursing */
 	if (kprobe_running()) {
 		/* We *are* holding lock here, so this is safe.
@@ -111,6 +133,11 @@ static inline int kprobe_handler(struct pt_regs *regs)
 	p = get_kprobe(addr);
 	if (!p) {
 		unlock_kprobes();
+		if (regs->eflags & VM_MASK) {
+			/* We are in virtual-8086 mode. Return 0 */
+			goto no_kprobe;
+		}
+
 		if (*addr != BREAKPOINT_INSTRUCTION) {
 			/*
 			 * The breakpoint instruction was removed right
@@ -153,7 +180,7 @@ static inline int kprobe_handler(struct pt_regs *regs)
  * 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->insn.
+ * 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:
@@ -173,10 +200,10 @@ static void resume_execution(struct kprobe *p, struct pt_regs *regs)
 {
 	unsigned long *tos = (unsigned long *)&regs->esp;
 	unsigned long next_eip = 0;
-	unsigned long copy_eip = (unsigned long)&p->insn;
+	unsigned long copy_eip = (unsigned long)&p->ainsn.insn;
 	unsigned long orig_eip = (unsigned long)p->addr;
 
-	switch (p->insn[0]) {
+	switch (p->ainsn.insn[0]) {
 	case 0x9c:		/* pushfl */
 		*tos &= ~(TF_MASK | IF_MASK);
 		*tos |= kprobe_old_eflags;
@@ -185,13 +212,13 @@ static void resume_execution(struct kprobe *p, struct pt_regs *regs)
 		*tos = orig_eip + (*tos - copy_eip);
 		break;
 	case 0xff:
-		if ((p->insn[1] & 0x30) == 0x10) {
+		if ((p->ainsn.insn[1] & 0x30) == 0x10) {
 			/* call absolute, indirect */
 			/* Fix return addr; eip is correct. */
 			next_eip = regs->eip;
 			*tos = orig_eip + (*tos - copy_eip);
-		} else if (((p->insn[1] & 0x31) == 0x20) ||	/* jmp near, absolute indirect */
-			   ((p->insn[1] & 0x31) == 0x21)) {	/* jmp far, absolute indirect */
+		} else if (((p->ainsn.insn[1] & 0x31) == 0x20) ||	/* jmp near, absolute indirect */
+			   ((p->ainsn.insn[1] & 0x31) == 0x21)) {	/* jmp far, absolute indirect */
 			/* eip is correct. */
 			next_eip = regs->eip;
 		}
@@ -315,12 +342,12 @@ void jprobe_return(void)
 {
 	preempt_enable_no_resched();
 	asm volatile ("       xchgl   %%ebx,%%esp     \n"
-		      "       int3			\n"::"b"
+		      "       int3			\n"
+		      "       .globl jprobe_return_end	\n"
+		      "       jprobe_return_end:	\n"
+		      "       nop			\n"::"b"
 		      (jprobe_saved_esp):"memory");
 }
-void jprobe_return_end(void)
-{
-};
 
 int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
 {