xen: make direct versions of irq_enable/disable/save/restore to common code

Now that x86-64 has directly accessible percpu variables, it can also
implement the direct versions of these operations, which operate on a
vcpu_info structure directly embedded in the percpu area.

In fact, the 64-bit versions are more or less identical, and so can be
shared.  The only two differences are:
 1. xen_restore_fl_direct takes its argument in eax on 32-bit, and rdi on 64-bit.
    Unfortunately it isn't possible to directly refer to the 2nd lsb of rdi directly
    (as you can with %ah), so the code isn't quite as dense.
 2. check_events needs to variants to save different registers.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 3 insertions, 131 deletions

diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
index d6fc51f4ce85..d205a283efe0 100644
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -11,142 +11,14 @@
         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/segment.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
-/*
-        FIXME: x86_64 now can support direct access to percpu variables
-        via a segment override.  Update xen accordingly.
- */
-#define BUG                     ud2a
-#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