From e2a81baf6604a2e08e10c7405b0349106f77c8af Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Mon, 17 Mar 2008 16:37:17 -0700 Subject: 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 Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- arch/x86/kernel/entry_32.S | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) (limited to 'arch/x86/kernel/entry_32.S') 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 -- cgit v1.2.3