x86, espfix: Make it possible to disable 16-bit support

[pandora-kernel.git] / arch / x86 / kernel / entry_32.S

diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index dd52355..0fa4f89 100644 (file)
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -527,6 +527,7 @@ syscall_exit:
 restore_all:
        TRACE_IRQS_IRET
 restore_all_notrace:
 restore_all:
        TRACE_IRQS_IRET
 restore_all_notrace:

+#ifdef CONFIG_X86_ESPFIX32

        movl PT_EFLAGS(%esp), %eax      # mix EFLAGS, SS and CS
        # Warning: PT_OLDSS(%esp) contains the wrong/random values if we
        # are returning to the kernel.
        movl PT_EFLAGS(%esp), %eax      # mix EFLAGS, SS and CS
        # Warning: PT_OLDSS(%esp) contains the wrong/random values if we
        # are returning to the kernel.


@@ -537,6 +538,7 @@ restore_all_notrace:
        cmpl $((SEGMENT_LDT << 8) | USER_RPL), %eax
        CFI_REMEMBER_STATE
        je ldt_ss                       # returning to user-space with LDT SS
        cmpl $((SEGMENT_LDT << 8) | USER_RPL), %eax
        CFI_REMEMBER_STATE
        je ldt_ss                       # returning to user-space with LDT SS

+#endif

 restore_nocheck:
        RESTORE_REGS 4                  # skip orig_eax/error_code
 irq_return:
 restore_nocheck:
        RESTORE_REGS 4                  # skip orig_eax/error_code
 irq_return:


@@ -552,6 +554,7 @@ ENTRY(iret_exc)
        .long irq_return,iret_exc
 .previous
 
        .long irq_return,iret_exc
 .previous
 

+#ifdef CONFIG_X86_ESPFIX32

        CFI_RESTORE_STATE
 ldt_ss:
 #ifdef CONFIG_PARAVIRT
        CFI_RESTORE_STATE
 ldt_ss:
 #ifdef CONFIG_PARAVIRT


@@ -595,6 +598,7 @@ ldt_ss:
        lss (%esp), %esp                /* switch to espfix segment */
        CFI_ADJUST_CFA_OFFSET -8
        jmp restore_nocheck
        lss (%esp), %esp                /* switch to espfix segment */
        CFI_ADJUST_CFA_OFFSET -8
        jmp restore_nocheck

+#endif

        CFI_ENDPROC
 ENDPROC(system_call)
 
        CFI_ENDPROC
 ENDPROC(system_call)
 


@@ -766,6 +770,7 @@ ENDPROC(ptregs_clone)
  * the high word of the segment base from the GDT and swiches to the
  * normal stack and adjusts ESP with the matching offset.
  */
  * the high word of the segment base from the GDT and swiches to the
  * normal stack and adjusts ESP with the matching offset.
  */

+#ifdef CONFIG_X86_ESPFIX32

        /* fixup the stack */
        mov GDT_ESPFIX_SS + 4, %al /* bits 16..23 */
        mov GDT_ESPFIX_SS + 7, %ah /* bits 24..31 */
        /* fixup the stack */
        mov GDT_ESPFIX_SS + 4, %al /* bits 16..23 */
        mov GDT_ESPFIX_SS + 7, %ah /* bits 24..31 */


@@ -775,8 +780,10 @@ ENDPROC(ptregs_clone)
        pushl_cfi %eax
        lss (%esp), %esp                /* switch to the normal stack segment */
        CFI_ADJUST_CFA_OFFSET -8
        pushl_cfi %eax
        lss (%esp), %esp                /* switch to the normal stack segment */
        CFI_ADJUST_CFA_OFFSET -8

+#endif

 .endm
 .macro UNWIND_ESPFIX_STACK
 .endm
 .macro UNWIND_ESPFIX_STACK

+#ifdef CONFIG_X86_ESPFIX32

        movl %ss, %eax
        /* see if on espfix stack */
        cmpw $__ESPFIX_SS, %ax
        movl %ss, %eax
        /* see if on espfix stack */
        cmpw $__ESPFIX_SS, %ax


@@ -787,6 +794,7 @@ ENDPROC(ptregs_clone)
        /* switch to normal stack */
        FIXUP_ESPFIX_STACK
 27:
        /* switch to normal stack */
        FIXUP_ESPFIX_STACK
 27:

+#endif

 .endm
 
 /*
 .endm
 
 /*


@@ -1323,11 +1331,13 @@ END(debug)
  */
 ENTRY(nmi)
        RING0_INT_FRAME
  */
 ENTRY(nmi)
        RING0_INT_FRAME

+#ifdef CONFIG_X86_ESPFIX32

        pushl_cfi %eax
        movl %ss, %eax
        cmpw $__ESPFIX_SS, %ax
        popl_cfi %eax
        je nmi_espfix_stack
        pushl_cfi %eax
        movl %ss, %eax
        cmpw $__ESPFIX_SS, %ax
        popl_cfi %eax
        je nmi_espfix_stack

+#endif

        cmpl $ia32_sysenter_target,(%esp)
        je nmi_stack_fixup
        pushl_cfi %eax
        cmpl $ia32_sysenter_target,(%esp)
        je nmi_stack_fixup
        pushl_cfi %eax


@@ -1367,6 +1377,7 @@ nmi_debug_stack_check:
        FIX_STACK 24, nmi_stack_correct, 1
        jmp nmi_stack_correct
 
        FIX_STACK 24, nmi_stack_correct, 1
        jmp nmi_stack_correct
 

+#ifdef CONFIG_X86_ESPFIX32

 nmi_espfix_stack:
        /* We have a RING0_INT_FRAME here.
         *
 nmi_espfix_stack:
        /* We have a RING0_INT_FRAME here.
         *


@@ -1388,6 +1399,7 @@ nmi_espfix_stack:
        lss 12+4(%esp), %esp            # back to espfix stack
        CFI_ADJUST_CFA_OFFSET -24
        jmp irq_return
        lss 12+4(%esp), %esp            # back to espfix stack
        CFI_ADJUST_CFA_OFFSET -24
        jmp irq_return

+#endif

        CFI_ENDPROC
 END(nmi)
 
        CFI_ENDPROC
 END(nmi)