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authorJeremy Fitzhardinge <jeremy@goop.org>2008-03-17 16:37:17 -0700
committerIngo Molnar <mingo@elte.hu>2008-04-24 23:57:31 +0200
commite2a81baf6604a2e08e10c7405b0349106f77c8af (patch)
tree3eaf386316be1f499d92fae213493ec3d6b5b576 /arch/x86/kernel/entry_32.S
parentaa380c82b83252754a8c11bfc92359bd87cbf710 (diff)
xen: support sysenter/sysexit if hypervisor does
64-bit Xen supports sysenter for 32-bit guests, so support its use. (sysenter is faster than int $0x80 in 32-on-64.) sysexit is still not supported, so we fake it up using iret. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/kernel/entry_32.S')
-rw-r--r--arch/x86/kernel/entry_32.S18
1 files changed, 17 insertions, 1 deletions
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index 568c6ccd7ae..5d80d53eaff 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -1017,6 +1017,13 @@ ENTRY(kernel_thread_helper)
ENDPROC(kernel_thread_helper)
#ifdef CONFIG_XEN
+/* Xen doesn't set %esp to be precisely what the normal sysenter
+ entrypoint expects, so fix it up before using the normal path. */
+ENTRY(xen_sysenter_target)
+ RING0_INT_FRAME
+ addl $5*4, %esp /* remove xen-provided frame */
+ jmp sysenter_past_esp
+
ENTRY(xen_hypervisor_callback)
CFI_STARTPROC
pushl $0
@@ -1036,8 +1043,17 @@ ENTRY(xen_hypervisor_callback)
jae 1f
call xen_iret_crit_fixup
+ jmp 2f
+
+1: cmpl $xen_sysexit_start_crit,%eax
+ jb 2f
+ cmpl $xen_sysexit_end_crit,%eax
+ jae 2f
+
+ jmp xen_sysexit_crit_fixup
-1: mov %esp, %eax
+ENTRY(xen_do_upcall)
+2: mov %esp, %eax
call xen_evtchn_do_upcall
jmp ret_from_intr
CFI_ENDPROC