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Date: Mon, 02 Feb 2009 13:55:42 -0800
From: Jeremy Fitzhardinge <jeremy@...p.org>
To: Ingo Molnar <mingo@...e.hu>
CC: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
the arch/x86 maintainers <x86@...nel.org>,
Xen-devel <xen-devel@...ts.xensource.com>
Subject: [PATCH 2/3] 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@...rix.com>
---
arch/x86/xen/Makefile | 3
arch/x86/xen/xen-asm.S | 140 +++++++++++++++++++++++++++++++++++++++++++++
arch/x86/xen/xen-asm.h | 12 +++
arch/x86/xen/xen-asm_32.S | 113 ++++--------------------------------
arch/x86/xen/xen-asm_64.S | 136 +------------------------------------------
5 files changed, 171 insertions(+), 233 deletions(-)
===================================================================
--- a/arch/x86/xen/Makefile
+++ b/arch/x86/xen/Makefile
@@ -6,7 +6,8 @@
endif
obj-y := enlighten.o setup.o multicalls.o mmu.o irq.o \
- time.o xen-asm_$(BITS).o grant-table.o suspend.o
+ time.o xen-asm.o xen-asm_$(BITS).o \
+ grant-table.o suspend.o
obj-$(CONFIG_SMP) += smp.o spinlock.o
obj-$(CONFIG_XEN_DEBUG_FS) += debugfs.o
\ No newline at end of file
===================================================================
--- /dev/null
+++ b/arch/x86/xen/xen-asm.S
@@ -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
+
===================================================================
--- /dev/null
+++ b/arch/x86/xen/xen-asm.h
@@ -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
===================================================================
--- a/arch/x86/xen/xen-asm_32.S
+++ b/arch/x86/xen/xen-asm_32.S
@@ -11,101 +11,28 @@
generally too large to inline anyway.
*/
-#include <linux/linkage.h>
-
-#include <asm/asm-offsets.h>
+//#include <asm/asm-offsets.h>
#include <asm/thread_info.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
-
+#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.
+ Force an event check by making a hypercall,
+ but preserve regs before making the call.
*/
-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)
+check_events:
+ push %eax
+ push %ecx
+ push %edx
+ call xen_force_evtchn_callback
+ pop %edx
+ pop %ecx
+ pop %eax
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 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)
/*
We can't use sysexit directly, because we're not running in ring0.
@@ -289,17 +216,3 @@
lea 4(%edi),%esp /* point esp to new frame */
2: jmp xen_do_upcall
-
-/*
- Force an event check by making a hypercall,
- but preserve regs before making the call.
- */
-check_events:
- push %eax
- push %ecx
- push %edx
- call xen_force_evtchn_callback
- pop %edx
- pop %ecx
- pop %eax
- ret
===================================================================
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -11,143 +11,15 @@
generally too large to inline anyway.
*/
-#include <linux/linkage.h>
-
-#include <asm/asm-offsets.h>
+#include <asm/errno.h>
+#include <asm/percpu.h>
#include <asm/processor-flags.h>
-#include <asm/errno.h>
#include <asm/segment.h>
-#include <asm/percpu.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
mov 8+8(%rsp),%r11
--
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