+
+/*
+ * Some functions should be protected against kprobes
+ */
+ .pushsection .kprobes.text, "ax"
+
+ENTRY(page_fault)
+ RING0_EC_FRAME
+ pushl $do_page_fault
+ CFI_ADJUST_CFA_OFFSET 4
+ ALIGN
+error_code:
+ /* the function address is in %gs's slot on the stack */
+ pushl %fs
+ CFI_ADJUST_CFA_OFFSET 4
+ /*CFI_REL_OFFSET fs, 0*/
+ pushl %es
+ CFI_ADJUST_CFA_OFFSET 4
+ /*CFI_REL_OFFSET es, 0*/
+ pushl %ds
+ CFI_ADJUST_CFA_OFFSET 4
+ /*CFI_REL_OFFSET ds, 0*/
+ pushl %eax
+ CFI_ADJUST_CFA_OFFSET 4
+ CFI_REL_OFFSET eax, 0
+ pushl %ebp
+ CFI_ADJUST_CFA_OFFSET 4
+ CFI_REL_OFFSET ebp, 0
+ pushl %edi
+ CFI_ADJUST_CFA_OFFSET 4
+ CFI_REL_OFFSET edi, 0
+ pushl %esi
+ CFI_ADJUST_CFA_OFFSET 4
+ CFI_REL_OFFSET esi, 0
+ pushl %edx
+ CFI_ADJUST_CFA_OFFSET 4
+ CFI_REL_OFFSET edx, 0
+ pushl %ecx
+ CFI_ADJUST_CFA_OFFSET 4
+ CFI_REL_OFFSET ecx, 0
+ pushl %ebx
+ CFI_ADJUST_CFA_OFFSET 4
+ CFI_REL_OFFSET ebx, 0
+ cld
+ movl $(__KERNEL_PERCPU), %ecx
+ movl %ecx, %fs
+ UNWIND_ESPFIX_STACK
+ GS_TO_REG %ecx
+ movl PT_GS(%esp), %edi # get the function address
+ movl PT_ORIG_EAX(%esp), %edx # get the error code
+ movl $-1, PT_ORIG_EAX(%esp) # no syscall to restart
+ REG_TO_PTGS %ecx
+ SET_KERNEL_GS %ecx
+ movl $(__USER_DS), %ecx
+ movl %ecx, %ds
+ movl %ecx, %es
+ TRACE_IRQS_OFF
+ movl %esp,%eax # pt_regs pointer
+ call *%edi
+ jmp ret_from_exception
+ CFI_ENDPROC
+END(page_fault)
+
+/*
+ * Debug traps and NMI can happen at the one SYSENTER instruction
+ * that sets up the real kernel stack. Check here, since we can't
+ * allow the wrong stack to be used.
+ *
+ * "TSS_sysenter_sp0+12" is because the NMI/debug handler will have
+ * already pushed 3 words if it hits on the sysenter instruction:
+ * eflags, cs and eip.
+ *
+ * We just load the right stack, and push the three (known) values
+ * by hand onto the new stack - while updating the return eip past
+ * the instruction that would have done it for sysenter.
+ */
+.macro FIX_STACK offset ok label
+ cmpw $__KERNEL_CS, 4(%esp)
+ jne \ok
+\label:
+ movl TSS_sysenter_sp0 + \offset(%esp), %esp
+ CFI_DEF_CFA esp, 0
+ CFI_UNDEFINED eip
+ pushfl
+ CFI_ADJUST_CFA_OFFSET 4
+ pushl $__KERNEL_CS
+ CFI_ADJUST_CFA_OFFSET 4
+ pushl $sysenter_past_esp
+ CFI_ADJUST_CFA_OFFSET 4
+ CFI_REL_OFFSET eip, 0
+.endm
+
+ENTRY(debug)
+ RING0_INT_FRAME
+ cmpl $ia32_sysenter_target,(%esp)
+ jne debug_stack_correct
+ FIX_STACK 12, debug_stack_correct, debug_esp_fix_insn
+debug_stack_correct:
+ pushl $-1 # mark this as an int
+ CFI_ADJUST_CFA_OFFSET 4
+ SAVE_ALL
+ TRACE_IRQS_OFF
+ xorl %edx,%edx # error code 0
+ movl %esp,%eax # pt_regs pointer
+ call do_debug
+ jmp ret_from_exception
+ CFI_ENDPROC
+END(debug)
+
+/*
+ * NMI is doubly nasty. It can happen _while_ we're handling
+ * a debug fault, and the debug fault hasn't yet been able to
+ * clear up the stack. So we first check whether we got an
+ * NMI on the sysenter entry path, but after that we need to
+ * check whether we got an NMI on the debug path where the debug
+ * fault happened on the sysenter path.
+ */
+ENTRY(nmi)
+ RING0_INT_FRAME
+ pushl %eax
+ CFI_ADJUST_CFA_OFFSET 4
+ movl %ss, %eax
+ cmpw $__ESPFIX_SS, %ax
+ popl %eax
+ CFI_ADJUST_CFA_OFFSET -4
+ je nmi_espfix_stack
+ cmpl $ia32_sysenter_target,(%esp)
+ je nmi_stack_fixup
+ pushl %eax
+ CFI_ADJUST_CFA_OFFSET 4
+ movl %esp,%eax
+ /* Do not access memory above the end of our stack page,
+ * it might not exist.
+ */
+ andl $(THREAD_SIZE-1),%eax
+ cmpl $(THREAD_SIZE-20),%eax
+ popl %eax
+ CFI_ADJUST_CFA_OFFSET -4
+ jae nmi_stack_correct
+ cmpl $ia32_sysenter_target,12(%esp)
+ je nmi_debug_stack_check
+nmi_stack_correct:
+ /* We have a RING0_INT_FRAME here */
+ pushl %eax
+ CFI_ADJUST_CFA_OFFSET 4
+ SAVE_ALL
+ xorl %edx,%edx # zero error code
+ movl %esp,%eax # pt_regs pointer
+ call do_nmi
+ jmp restore_nocheck_notrace
+ CFI_ENDPROC
+
+nmi_stack_fixup:
+ RING0_INT_FRAME
+ FIX_STACK 12, nmi_stack_correct, 1
+ jmp nmi_stack_correct
+
+nmi_debug_stack_check:
+ /* We have a RING0_INT_FRAME here */
+ cmpw $__KERNEL_CS,16(%esp)
+ jne nmi_stack_correct
+ cmpl $debug,(%esp)
+ jb nmi_stack_correct
+ cmpl $debug_esp_fix_insn,(%esp)
+ ja nmi_stack_correct
+ FIX_STACK 24, nmi_stack_correct, 1
+ jmp nmi_stack_correct
+
+nmi_espfix_stack:
+ /* We have a RING0_INT_FRAME here.
+ *
+ * create the pointer to lss back
+ */
+ pushl %ss
+ CFI_ADJUST_CFA_OFFSET 4
+ pushl %esp
+ CFI_ADJUST_CFA_OFFSET 4
+ addw $4, (%esp)
+ /* copy the iret frame of 12 bytes */
+ .rept 3
+ pushl 16(%esp)
+ CFI_ADJUST_CFA_OFFSET 4
+ .endr
+ pushl %eax
+ CFI_ADJUST_CFA_OFFSET 4
+ SAVE_ALL
+ FIXUP_ESPFIX_STACK # %eax == %esp
+ xorl %edx,%edx # zero error code
+ call do_nmi
+ RESTORE_REGS
+ lss 12+4(%esp), %esp # back to espfix stack
+ CFI_ADJUST_CFA_OFFSET -24
+ jmp irq_return
+ CFI_ENDPROC
+END(nmi)
+
+ENTRY(int3)
+ RING0_INT_FRAME
+ pushl $-1 # mark this as an int
+ CFI_ADJUST_CFA_OFFSET 4
+ SAVE_ALL
+ TRACE_IRQS_OFF
+ xorl %edx,%edx # zero error code
+ movl %esp,%eax # pt_regs pointer
+ call do_int3
+ jmp ret_from_exception
+ CFI_ENDPROC
+END(int3)
+
+ENTRY(general_protection)
+ RING0_EC_FRAME
+ pushl $do_general_protection
+ CFI_ADJUST_CFA_OFFSET 4
+ jmp error_code
+ CFI_ENDPROC
+END(general_protection)
+
+/*
+ * End of kprobes section
+ */
+ .popsection