[Xen-devel] [RFC PATCH 20/35] subarch stack pointer update

[Chris Wright <chrisw@xxxxxxxxxxxx>]

Register the new kernel ('ring 0') stack pointer with the hypervisor
during context switch. 

Signed-off-by: Ian Pratt <ian.pratt@xxxxxxxxxxxxx>
Signed-off-by: Christian Limpach <Christian.Limpach@xxxxxxxxxxxx>
Signed-off-by: Chris Wright <chrisw@xxxxxxxxxxxx>
---
 include/asm-i386/mach-default/mach_processor.h |    8 ++++++++
 include/asm-i386/mach-xen/mach_processor.h     |    9 +++++++++
 include/asm-i386/processor.h                   |    3 +++
 3 files changed, 20 insertions(+)

--- xen-subarch-2.6.orig/include/asm-i386/processor.h
+++ xen-subarch-2.6/include/asm-i386/processor.h
@@ -472,6 +472,8 @@ struct thread_struct {
        .io_bitmap_ptr = NULL,                                          \
 }
 
+#include <mach_processor.h>
+
 /*
  * Note that the .io_bitmap member must be extra-big. This is because
  * the CPU will access an additional byte beyond the end of the IO
@@ -494,6 +496,7 @@ static inline void load_esp0(struct tss_
                tss->ss1 = thread->sysenter_cs;
                wrmsr(MSR_IA32_SYSENTER_CS, thread->sysenter_cs, 0);
        }
+       mach_load_esp0(tss, thread);
 }
 
 #define start_thread(regs, new_eip, new_esp) do {              \
--- /dev/null
+++ xen-subarch-2.6/include/asm-i386/mach-xen/mach_processor.h
@@ -0,0 +1,9 @@
+#ifndef __ASM_MACH_PROCESSOR_H
+#define __ASM_MACH_PROCESSOR_H
+
+static inline void mach_load_esp0(struct tss_struct *tss, struct thread_struct 
*thread)
+{
+       HYPERVISOR_stack_switch(tss->ss0, tss->esp0);
+}
+
+#endif /* __ASM_MACH_PROCESSOR_H */
--- /dev/null
+++ xen-subarch-2.6/include/asm-i386/mach-default/mach_processor.h
@@ -0,0 +1,8 @@
+#ifndef __ASM_MACH_PROCESSOR_H
+#define __ASM_MACH_PROCESSOR_H
+
+static inline void mach_load_esp0(struct tss_struct *tss, struct thread_struct 
*thread)
+{
+}
+
+#endif /* __ASM_MACH_PROCESSOR_H */

--

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