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| author | Jeremy Fitzhardinge <jeremy@goop.org> | 2008-03-17 16:37:17 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-04-24 23:57:31 +0200 |
| commit | e2a81baf6604a2e08e10c7405b0349106f77c8af (patch) | |
| tree | 3eaf386316be1f499d92fae213493ec3d6b5b576 /arch/x86/kernel | |
| parent | aa380c82b83252754a8c11bfc92359bd87cbf710 (diff) | |
| download | linux-e2a81baf6604a2e08e10c7405b0349106f77c8af.tar.bz2 | |
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')
| -rw-r--r-- | arch/x86/kernel/entry_32.S | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S index 568c6ccd7ae2..5d80d53eaff8 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 |