-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
xen: make direct versions of irq_enable/disable/save/restore to commo…
…n 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>- Loading branch information
Jeremy Fitzhardinge
authored and
H. Peter Anvin
committed
Feb 5, 2009
1 parent
3834143
commit 5393744
Showing
5 changed files
with
169 additions
and
231 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,140 @@ | ||
| /* | ||
| 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> | ||
| #include <asm/percpu.h> | ||
| #include <asm/processor-flags.h> | ||
|
|
||
| #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. | ||
| */ | ||
| 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. */ | ||
|
|
||
| /* 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) | ||
| 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) | ||
| #ifdef CONFIG_X86_64 | ||
| testw $X86_EFLAGS_IF, %di | ||
| #else | ||
| 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. */ | ||
|
|
||
| /* 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: | ||
| #ifdef CONFIG_X86_32 | ||
| push %eax | ||
| push %ecx | ||
| push %edx | ||
| call xen_force_evtchn_callback | ||
| pop %edx | ||
| pop %ecx | ||
| pop %eax | ||
| #else | ||
| 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 | ||
| #endif | ||
| ret | ||
|
|
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,12 @@ | ||
| #ifndef _XEN_XEN_ASM_H | ||
| #define _XEN_XEN_ASM_H | ||
|
|
||
| #include <linux/linkage.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 | ||
|
|
||
| #endif |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.