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Diffstat (limited to 'i386/xen/xen_locore.S')
| -rw-r--r-- | i386/xen/xen_locore.S | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/i386/xen/xen_locore.S b/i386/xen/xen_locore.S new file mode 100644 index 0000000..51f823f --- /dev/null +++ b/i386/xen/xen_locore.S @@ -0,0 +1,110 @@ +/* + * Copyright (C) 2006 Samuel Thibault <samuel.thibault@ens-lyon.org> + * + * 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/i386asm.h> +#include <i386/cpu_number.h> +#include <i386/xen.h> + + .data 2 +int_active: + .long 0 + + + .text + .globl hyp_callback, hyp_failsafe_callback + P2ALIGN(TEXT_ALIGN) +hyp_callback: + pushl %eax + 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) + pushl %ebp + movl %esp, %ebp +_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 + popl %ebp + 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 + popl %ebp + ret +0: + movb $0xff,hyp_shared_info+CPU_CLI +1: + pushl %eax + pushl %ecx + pushl %edx + incl int_active /* currently handling interrupts */ + + pushl $0 + pushl $0 + call EXT(hyp_c_callback) + popl %edx + popl %edx + + popl %edx + popl %ecx + popl %eax + 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: +#if 1 + /* load sane segments */ + mov %ss, %ax + mov %ax, %ds + mov %ax, %es + mov %ax, %fs + mov %ax, %gs + push %esp + call EXT(hyp_failsafe_c_callback) +#else + popl %ds + popl %es + popl %fs + popl %gs + iret +#endif |