[RFC PATCH 20/35] subarch stack pointer update

[Chris Wright <chrisw@sous-sol.org>]

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

Signed-off-by: Ian Pratt <ian.pratt@xensource.com>
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
---
 include/asm-i386/mach-default/mach_processor.h |    7 +++++++
 include/asm-i386/mach-xen/mach_processor.h     |    8 ++++++++
 include/asm-i386/processor.h                   |    1 +
 3 files changed, 16 insertions(+)

--- linus-2.6.orig/include/asm-i386/mach-default/mach_processor.h
+++ linus-2.6/include/asm-i386/mach-default/mach_processor.h
@@ -4,4 +4,11 @@
 #define CPUID cpuid
 #define CPUID_STR "cpuid"
 
+#ifndef __ASSEMBLY__
+static inline void mach_update_kernel_stack(unsigned long esp0,
+					    unsigned short ss0)
+{
+}
+#endif
+
 #endif /* __ASM_MACH_PROCESSOR_H */
--- linus-2.6.orig/include/asm-i386/mach-xen/mach_processor.h
+++ linus-2.6/include/asm-i386/mach-xen/mach_processor.h
@@ -6,4 +6,12 @@
 #define CPUID XEN_CPUID
 #define CPUID_STR XEN_CPUID
 
+#ifndef __ASSEMBLY__
+static inline void mach_update_kernel_stack(unsigned long esp0,
+					    unsigned short ss0)
+{
+	HYPERVISOR_stack_switch(ss0, esp0);
+}
+#endif
+
 #endif /* __ASM_MACH_PROCESSOR_H */
--- linus-2.6.orig/include/asm-i386/processor.h
+++ linus-2.6/include/asm-i386/processor.h
@@ -500,6 +500,7 @@ static inline void load_esp0(struct tss_
 		tss->ss1 = thread->sysenter_cs;
 		wrmsr(MSR_IA32_SYSENTER_CS, thread->sysenter_cs, 0);
 	}
+	mach_update_kernel_stack(tss->esp0, tss->ss0);
 }
 
 #define start_thread(regs, new_eip, new_esp) do {		\

--
-
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