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/*
* Copyright (C) 2006-2009 Free Software Foundation
*
* This program is free software ; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation ; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY ; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with the program ; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <mach/machine/asm.h>
#include <i386/i386/i386asm.h>
#include <i386/i386/cpu_number.h>
#include <i386/i386/xen.h>
.data 2
int_active:
.long 0
.text
.globl hyp_callback, hyp_failsafe_callback
P2ALIGN(TEXT_ALIGN)
hyp_callback:
popq %rcx
popq %r11
pushq %rax
jmp EXT(all_intrs)
ENTRY(interrupt)
incl int_active /* currently handling interrupts */
call EXT(hyp_c_callback) /* call generic interrupt routine */
decl int_active /* stopped handling interrupts */
sti
ret
/* FIXME: if we're _very_ unlucky, we may be re-interrupted, filling stack
*
* Far from trivial, see mini-os. That said, maybe we could just, before poping
* everything (which is _not_ destructive), save sp into a known place and use
* it+jmp back?
*
* Mmm, there seems to be an iret hypcall that does exactly what we want:
* perform iret, and if IF is set, clear the interrupt mask.
*/
/* Pfff, we have to check pending interrupts ourselves. Some other DomUs just make an hypercall for retriggering the irq. Not sure it's really easier/faster */
ENTRY(hyp_sti)
pushq %rbp
movq %rsp, %rbp
_hyp_sti:
movb $0,hyp_shared_info+CPU_CLI /* Enable interrupts */
cmpl $0,int_active /* Check whether we were already checking pending interrupts */
jz 0f
popq %rbp
ret /* Already active, just return */
0:
/* Not active, check pending interrupts by hand */
/* no memory barrier needed on x86 */
cmpb $0,hyp_shared_info+CPU_PENDING
jne 0f
popq %rbp
ret
0:
movb $0xff,hyp_shared_info+CPU_CLI
1:
pushq %rax
pushq %rcx
pushq %rdx
pushq %rdi
pushq %rsi
pushq %r8
pushq %r9
pushq %r10
pushq %r11
incl int_active /* currently handling interrupts */
xorq %rdi,%rdi
xorq %rsi,%rsi
call EXT(hyp_c_callback)
popq %r11
popq %r10
popq %r9
popq %r8
popq %rsi
popq %rdi
popq %rdx
popq %rcx
popq %rax
decl int_active /* stopped handling interrupts */
cmpb $0,hyp_shared_info+CPU_PENDING
jne 1b
jmp _hyp_sti
/* Hypervisor failed to reload segments. Dump them. */
hyp_failsafe_callback:
ud2
#if 1
/* TODO: FIXME */
/* load sane segments */
mov %ss, %ax
#if 0
mov %ax, %ds
mov %ax, %es
#endif
mov %ax, %fs
mov %ax, %gs
movq %rsp, %rdi
call EXT(hyp_failsafe_c_callback)
#else
popq %rdx
movq %rdx,%ds
popq %rdx
movq %rdx,%es
popq %fs
popq %gs
movq (%rsp),%rax
ud2
iretq
#endif
#undef iretq
ENTRY(hyp_iretq)
testb $2,1*8(%rsp)
jnz slow
/* There is no ring1 on x86_64, we have to force ring 3 */
orb $3,1*8(%rsp)
orb $3,4*8(%rsp)
iretq
slow:
/* There is no ring 1/2 on x86_64, so going back to user needs to go through
* hypervisor */
pushq $0
jmp __hyp_iret
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