| #include <linux/linkage.h> |
| #include <linux/lguest.h> |
| #include <asm/asm-offsets.h> |
| #include <asm/thread_info.h> |
| #include <asm/processor-flags.h> |
| |
| /* |
| * This is where we begin: we have a magic signature which the launcher looks |
| * for. The plan is that the Linux boot protocol will be extended with a |
| * "platform type" field which will guide us here from the normal entry point, |
| * but for the moment this suffices. We pass the virtual address of the boot |
| * info to lguest_init(). |
| * |
| * We put it in .init.text will be discarded after boot. |
| */ |
| .section .init.text, "ax", @progbits |
| .ascii "GenuineLguest" |
| /* Set up initial stack. */ |
| movl $(init_thread_union+THREAD_SIZE),%esp |
| movl %esi, %eax |
| addl $__PAGE_OFFSET, %eax |
| jmp lguest_init |
| |
| /* The templates for inline patching. */ |
| #define LGUEST_PATCH(name, insns...) \ |
| lgstart_##name: insns; lgend_##name:; \ |
| .globl lgstart_##name; .globl lgend_##name |
| |
| LGUEST_PATCH(cli, movl $0, lguest_data+LGUEST_DATA_irq_enabled) |
| LGUEST_PATCH(sti, movl $X86_EFLAGS_IF, lguest_data+LGUEST_DATA_irq_enabled) |
| LGUEST_PATCH(popf, movl %eax, lguest_data+LGUEST_DATA_irq_enabled) |
| LGUEST_PATCH(pushf, movl lguest_data+LGUEST_DATA_irq_enabled, %eax) |
| |
| .text |
| /* These demark the EIP range where host should never deliver interrupts. */ |
| .global lguest_noirq_start |
| .global lguest_noirq_end |
| |
| /* |
| * We move eflags word to lguest_data.irq_enabled to restore interrupt state. |
| * For page faults, gpfs and virtual interrupts, the hypervisor has saved |
| * eflags manually, otherwise it was delivered directly and so eflags reflects |
| * the real machine IF state, ie. interrupts on. Since the kernel always dies |
| * if it takes such a trap with interrupts disabled anyway, turning interrupts |
| * back on unconditionally here is OK. |
| */ |
| ENTRY(lguest_iret) |
| pushl %eax |
| movl 12(%esp), %eax |
| lguest_noirq_start: |
| movl %eax,%ss:lguest_data+LGUEST_DATA_irq_enabled |
| popl %eax |
| iret |
| lguest_noirq_end: |
