mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-23 20:53:53 +08:00
115 lines
3.3 KiB
ArmAsm
115 lines
3.3 KiB
ArmAsm
|
/*
|
||
|
|
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/thread_info.h>
|
||
|
|
#include <asm/percpu.h>
|
||
|
|
#include <asm/asm-offsets.h>
|
||
|
|
#include <asm/processor-flags.h>
|
||
|
|
|
||
|
|
#define RELOC(x, v) .globl x##_reloc; x##_reloc=v
|
||
|
|
#define ENDPATCH(x) .globl x##_end; x##_end=.
|
||
|
|
|
||
|
|
/*
|
||
|
|
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)
|
||
|
|
/* Clear mask and test pending */
|
||
|
|
andw $0x00ff, PER_CPU_VAR(xen_vcpu_info)+XEN_vcpu_info_pending
|
||
|
|
/* 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. */
|
||
|
|
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)
|
||
|
|
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)
|
||
|
|
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)
|
||
|
|
testb $X86_EFLAGS_IF>>8, %ah
|
||
|
|
setz %al
|
||
|
|
movb %al, 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 pending but unmasked */
|
||
|
|
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 %eax
|
||
|
|
push %ecx
|
||
|
|
push %edx
|
||
|
|
call force_evtchn_callback
|
||
|
|
pop %edx
|
||
|
|
pop %ecx
|
||
|
|
pop %eax
|
||
|
|
ret
|