[FIX] obtaining correct stack pointer (for x86)

Change-Id: Ic47f43766c842207c207c688ba542cc30747c327
Signed-off-by: Vyacheslav Cherkashin <v.cherkashin@samsung.com>

diff --git a/kprobe/arch/asm-x86/dbi_kprobes.c b/kprobe/arch/asm-x86/dbi_kprobes.c
index 2d67539..37f9678 100644 (file)
--- a/kprobe/arch/asm-x86/dbi_kprobes.c
+++ b/kprobe/arch/asm-x86/dbi_kprobes.c
@@ -95,6 +95,8 @@ IMP_MOD_DEP_WRAPPER(text_poke, addr, opcode, len)
 DECLARE_MOD_DEP_WRAPPER(show_registers, void, struct pt_regs * regs)
 IMP_MOD_DEP_WRAPPER(show_registers, regs)
 
+#define stack_addr(regs) ((unsigned long *)kernel_stack_pointer(regs))
+
 /*
  * Function return probe trampoline:
  *      - init_kprobes() establishes a probepoint here
@@ -519,7 +521,7 @@ int setjmp_pre_handler (struct kprobe *p, struct pt_regs *regs)
        entry = (entry_point_t) jp->entry;
 
        kcb->jprobe_saved_regs = *regs;
-       kcb->jprobe_saved_esp = &regs->EREG(sp);
+       kcb->jprobe_saved_esp = stack_addr(regs);
        addr = (unsigned long)(kcb->jprobe_saved_esp);
 
        /* TBD: As Linus pointed out, gcc assumes that the callee
@@ -588,7 +590,7 @@ static void resume_execution (struct kprobe *p, struct pt_regs *regs, struct kpr
 
        regs->EREG (flags) &= ~TF_MASK;
 
-       tos = (unsigned long *)&regs->EREG(sp);
+       tos = stack_addr(regs);
        insns[0] = p->ainsn.insn[0];
        insns[1] = p->ainsn.insn[1];
 
@@ -822,10 +824,10 @@ int longjmp_break_handler (struct kprobe *p, struct pt_regs *regs)
 
        if ((addr > (u8 *) dbi_jprobe_return) && (addr < (u8 *) dbi_jprobe_return_end))
        {
-               if ((unsigned long *)(&regs->EREG(sp)) != kcb->jprobe_saved_esp)
-               {
+               if (stack_addr(regs) != kcb->jprobe_saved_esp) {
                        struct pt_regs *saved_regs = &kcb->jprobe_saved_regs;
-                       printk ("current esp %p does not match saved esp %p\n", &regs->EREG (sp), kcb->jprobe_saved_esp);
+                       printk("current esp %p does not match saved esp %p\n",
+                              stack_addr(regs), kcb->jprobe_saved_esp);
                        printk ("Saved registers for jprobe %p\n", jp);
                        show_registers (saved_regs);
                        printk ("Current registers\n");
@@ -860,16 +862,14 @@ static __used void *trampoline_probe_handler_x86(struct pt_regs *regs)
 
 void arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs)
 {
-       unsigned long *ptr_ret_addr;
+       unsigned long *ptr_ret_addr = stack_addr(regs);
 
        /* for __switch_to probe */
        if ((unsigned long)ri->rp->kp.addr == sched_addr) {
-               ptr_ret_addr = (unsigned long *)kernel_stack_pointer(regs);
                ri->sp = NULL;
                ri->task = (struct task_struct *)regs->dx;
        } else {
-               ptr_ret_addr = (unsigned long *)&regs->sp;
-               ri->sp = &regs->sp;
+               ri->sp = ptr_ret_addr;
        }
 
        /* Save the return address */