1 files changed, 63 insertions, 189 deletions

diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
index 05794c566e87..02f496a8dbaa 100644
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -1,174 +1,45 @@
 /*
-        Asm versions of Xen pv-ops, suitable for either direct use or inlining.
-        The inline versions are the same as the direct-use versions, with the
-        pre- and post-amble chopped off.
-
-        This code is encoded for size rather than absolute efficiency,
-        with a view to being able to inline as much as possible.
-
-        We only bother with direct forms (ie, vcpu in pda) of the operations
-        here; the indirect forms are better handled in C, since they're
-        generally too large to inline anyway.
+ * Asm versions of Xen pv-ops, suitable for either direct use or
+ * inlining.  The inline versions are the same as the direct-use
+ * versions, with the pre- and post-amble chopped off.
+ *
+ * This code is encoded for size rather than absolute efficiency, with
+ * a view to being able to inline as much as possible.
+ *
+ * We only bother with direct forms (ie, vcpu in pda) of the
+ * operations here; the indirect forms are better handled in C, since
+ * they're generally too large to inline anyway.
  */
 
-#include <linux/linkage.h>
-
-#include <asm/asm-offsets.h>
-#include <asm/processor-flags.h>
 #include <asm/errno.h>
+#include <asm/percpu.h>
+#include <asm/processor-flags.h>
 #include <asm/segment.h>
 
 #include <xen/interface/xen.h>
 
-#define RELOC(x, v)     .globl x##_reloc; x##_reloc=v
-#define ENDPATCH(x)     .globl x##_end; x##_end=.
-
-/* Pseudo-flag used for virtual NMI, which we don't implement yet */
-#define XEN_EFLAGS_NMI  0x80000000
-
-#if 1
-/*
-        x86-64 does not yet support direct access to percpu variables
-        via a segment override, so we just need to make sure this code
-        never gets used
- */
-#define BUG                     ud2a
-#define PER_CPU_VAR(var, off)   0xdeadbeef
-#endif
-
-/*
-        Enable events.  This clears the event mask and tests the pending
-        event status with one and operation.  If there are pending
-        events, then enter the hypervisor to get them handled.
- */
-ENTRY(xen_irq_enable_direct)
-        BUG
-
-        /* Unmask events */
-        movb $0, PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_mask)
-
-        /* Preempt here doesn't matter because that will deal with
-           any pending interrupts.  The pending check may end up being
-           run on the wrong CPU, but that doesn't hurt. */
-
-        /* Test for pending */
-        testb $0xff, PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_pending)
-        jz 1f
-
-2:      call check_events
-1:
-ENDPATCH(xen_irq_enable_direct)
-        ret
-        ENDPROC(xen_irq_enable_direct)
-        RELOC(xen_irq_enable_direct, 2b+1)
-
-/*
-        Disabling events is simply a matter of making the event mask
-        non-zero.
- */
-ENTRY(xen_irq_disable_direct)
-        BUG
-
-        movb $1, PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_mask)
-ENDPATCH(xen_irq_disable_direct)
-        ret
-        ENDPROC(xen_irq_disable_direct)
-        RELOC(xen_irq_disable_direct, 0)
-
-/*
-        (xen_)save_fl is used to get the current interrupt enable status.
-        Callers expect the status to be in X86_EFLAGS_IF, and other bits
-        may be set in the return value.  We take advantage of this by
-        making sure that X86_EFLAGS_IF has the right value (and other bits
-        in that byte are 0), but other bits in the return value are
-        undefined.  We need to toggle the state of the bit, because
-        Xen and x86 use opposite senses (mask vs enable).
- */
-ENTRY(xen_save_fl_direct)
-        BUG
-
-        testb $0xff, PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_mask)
-        setz %ah
-        addb %ah,%ah
-ENDPATCH(xen_save_fl_direct)
-        ret
-        ENDPROC(xen_save_fl_direct)
-        RELOC(xen_save_fl_direct, 0)
-
-/*
-        In principle the caller should be passing us a value return
-        from xen_save_fl_direct, but for robustness sake we test only
-        the X86_EFLAGS_IF flag rather than the whole byte. After
-        setting the interrupt mask state, it checks for unmasked
-        pending events and enters the hypervisor to get them delivered
-        if so.
- */
-ENTRY(xen_restore_fl_direct)
-        BUG
-
-        testb $X86_EFLAGS_IF>>8, %ah
-        setz PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_mask)
-        /* Preempt here doesn't matter because that will deal with
-           any pending interrupts.  The pending check may end up being
-           run on the wrong CPU, but that doesn't hurt. */
-
-        /* check for unmasked and pending */
-        cmpw $0x0001, PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_pending)
-        jz 1f
-2:      call check_events
-1:
-ENDPATCH(xen_restore_fl_direct)
-        ret
-        ENDPROC(xen_restore_fl_direct)
-        RELOC(xen_restore_fl_direct, 2b+1)
-
-
-/*
-        Force an event check by making a hypercall,
-        but preserve regs before making the call.
- */
-check_events:
-        push %rax
-        push %rcx
-        push %rdx
-        push %rsi
-        push %rdi
-        push %r8
-        push %r9
-        push %r10
-        push %r11
-        call xen_force_evtchn_callback
-        pop %r11
-        pop %r10
-        pop %r9
-        pop %r8
-        pop %rdi
-        pop %rsi
-        pop %rdx
-        pop %rcx
-        pop %rax
-        ret
+#include "xen-asm.h"
 
 ENTRY(xen_adjust_exception_frame)
-        mov 8+0(%rsp),%rcx
-        mov 8+8(%rsp),%r11
+        mov 8+0(%rsp), %rcx
+        mov 8+8(%rsp), %r11
         ret $16
 
 hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32
 /*
-        Xen64 iret frame:
-
-        ss
-        rsp
-        rflags
-        cs
-        rip             <-- standard iret frame
-
-        flags
-
-        rcx             }
-        r11             }<-- pushed by hypercall page
-rsp ->  rax             }
+ * Xen64 iret frame:
+ *
+ *      ss
+ *      rsp
+ *      rflags
+ *      cs
+ *      rip             <-- standard iret frame
+ *
+ *      flags
+ *
+ *      rcx             }
+ *      r11             }<-- pushed by hypercall page
+ * rsp->rax             }
  */
 ENTRY(xen_iret)
         pushq $0
@@ -177,8 +48,8 @@ ENDPATCH(xen_iret)
 RELOC(xen_iret, 1b+1)
 
 /*
-        sysexit is not used for 64-bit processes, so it's
-        only ever used to return to 32-bit compat userspace.
+ * sysexit is not used for 64-bit processes, so it's only ever used to
+ * return to 32-bit compat userspace.
  */
 ENTRY(xen_sysexit)
         pushq $__USER32_DS
@@ -193,13 +64,15 @@ ENDPATCH(xen_sysexit)
 RELOC(xen_sysexit, 1b+1)
 
 ENTRY(xen_sysret64)
-        /* We're already on the usermode stack at this point, but still
-           with the kernel gs, so we can easily switch back */
-        movq %rsp, %gs:pda_oldrsp
-        movq %gs:pda_kernelstack,%rsp
+        /*
+         * We're already on the usermode stack at this point, but
+         * still with the kernel gs, so we can easily switch back
+         */
+        movq %rsp, PER_CPU_VAR(old_rsp)
+        movq PER_CPU_VAR(kernel_stack), %rsp
 
         pushq $__USER_DS
-        pushq %gs:pda_oldrsp
+        pushq PER_CPU_VAR(old_rsp)
         pushq %r11
         pushq $__USER_CS
         pushq %rcx
@@ -210,13 +83,15 @@ ENDPATCH(xen_sysret64)
 RELOC(xen_sysret64, 1b+1)
 
 ENTRY(xen_sysret32)
-        /* We're already on the usermode stack at this point, but still
-           with the kernel gs, so we can easily switch back */
-        movq %rsp, %gs:pda_oldrsp
-        movq %gs:pda_kernelstack, %rsp
+        /*
+         * We're already on the usermode stack at this point, but
+         * still with the kernel gs, so we can easily switch back
+         */
+        movq %rsp, PER_CPU_VAR(old_rsp)
+        movq PER_CPU_VAR(kernel_stack), %rsp
 
         pushq $__USER32_DS
-        pushq %gs:pda_oldrsp
+        pushq PER_CPU_VAR(old_rsp)
         pushq %r11
         pushq $__USER32_CS
         pushq %rcx
@@ -227,28 +102,27 @@ ENDPATCH(xen_sysret32)
 RELOC(xen_sysret32, 1b+1)
 
 /*
-        Xen handles syscall callbacks much like ordinary exceptions,
-        which means we have:
-         - kernel gs
-         - kernel rsp
-         - an iret-like stack frame on the stack (including rcx and r11):
-                ss
-                rsp
-                rflags
-                cs
-                rip
-                r11
-        rsp->   rcx
-
-        In all the entrypoints, we undo all that to make it look
-        like a CPU-generated syscall/sysenter and jump to the normal
-        entrypoint.
+ * Xen handles syscall callbacks much like ordinary exceptions, which
+ * means we have:
+ * - kernel gs
+ * - kernel rsp
+ * - an iret-like stack frame on the stack (including rcx and r11):
+ *      ss
+ *      rsp
+ *      rflags
+ *      cs
+ *      rip
+ *      r11
+ * rsp->rcx
+ *
+ * In all the entrypoints, we undo all that to make it look like a
+ * CPU-generated syscall/sysenter and jump to the normal entrypoint.
  */
 
 .macro undo_xen_syscall
-        mov 0*8(%rsp),%rcx
-        mov 1*8(%rsp),%r11
-        mov 5*8(%rsp),%rsp
+        mov 0*8(%rsp), %rcx
+        mov 1*8(%rsp), %r11
+        mov 5*8(%rsp), %rsp
 .endm
 
 /* Normal 64-bit system call target */
@@ -275,7 +149,7 @@ ENDPROC(xen_sysenter_target)
 
 ENTRY(xen_syscall32_target)
 ENTRY(xen_sysenter_target)
-        lea 16(%rsp), %rsp      /* strip %rcx,%r11 */
+        lea 16(%rsp), %rsp      /* strip %rcx, %r11 */
         mov $-ENOSYS, %rax
         pushq $VGCF_in_syscall
         jmp hypercall_iret