Skip to content

Commit

Permalink
---
Browse files Browse the repository at this point in the history
yaml
---
r: 136743
b: refs/heads/master
c: 130ace1
h: refs/heads/master
i:
  136741: 21a645a
  136739: a835776
  136735: 5a45a1b
v: v3
  • Loading branch information
Tejun Heo authored and Ingo Molnar committed Feb 5, 2009
1 parent 6a2767c commit 0ba298d
Show file tree
Hide file tree
Showing 4 changed files with 220 additions and 205 deletions.
2 changes: 1 addition & 1 deletion [refs]
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 69b745ff91836dfc25b26d7be0ead02a6fc0286e
refs/heads/master: 130ace11a9dc682541336d1fe5cb3bc7771a149e
78 changes: 40 additions & 38 deletions trunk/arch/x86/xen/xen-asm.S
Original file line number Diff line number Diff line change
@@ -1,14 +1,14 @@
/*
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 percpu data) 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 percpu data) of the
* operations here; the indirect forms are better handled in C, since
* they're generally too large to inline anyway.
*/

#include <asm/asm-offsets.h>
Expand All @@ -18,17 +18,19 @@
#include "xen-asm.h"

/*
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.
* 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)
/* 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. */
/*
* 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
Expand All @@ -43,8 +45,8 @@ ENDPATCH(xen_irq_enable_direct)


/*
Disabling events is simply a matter of making the event mask
non-zero.
* Disabling events is simply a matter of making the event mask
* non-zero.
*/
ENTRY(xen_irq_disable_direct)
movb $1, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
Expand All @@ -54,31 +56,30 @@ ENDPATCH(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).
* (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)
testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
setz %ah
addb %ah,%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.
* 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)
#ifdef CONFIG_X86_64
Expand All @@ -87,9 +88,11 @@ ENTRY(xen_restore_fl_direct)
testb $X86_EFLAGS_IF>>8, %ah
#endif
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. */
/*
* 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
Expand All @@ -103,8 +106,8 @@ ENDPATCH(xen_restore_fl_direct)


/*
Force an event check by making a hypercall,
but preserve regs before making the call.
* Force an event check by making a hypercall, but preserve regs
* before making the call.
*/
check_events:
#ifdef CONFIG_X86_32
Expand Down Expand Up @@ -137,4 +140,3 @@ check_events:
pop %rax
#endif
ret

Loading

0 comments on commit 0ba298d

Please sign in to comment.