286 lines
6.4 KiB
ArmAsm
286 lines
6.4 KiB
ArmAsm
/*
|
|
Asm versions of Xen pv-ops, suitable for either direct use or inlining.
|
|
The inline versions are the same as the direct-use versions, with the
|
|
pre- and post-amble chopped off.
|
|
|
|
This code is encoded for size rather than absolute efficiency,
|
|
with a view to being able to inline as much as possible.
|
|
|
|
We only bother with direct forms (ie, vcpu in pda) of the operations
|
|
here; the indirect forms are better handled in C, since they're
|
|
generally too large to inline anyway.
|
|
*/
|
|
|
|
#include <linux/linkage.h>
|
|
|
|
#include <asm/asm-offsets.h>
|
|
#include <asm/processor-flags.h>
|
|
#include <asm/errno.h>
|
|
#include <asm/segment.h>
|
|
|
|
#include <xen/interface/xen.h>
|
|
|
|
#define RELOC(x, v) .globl x##_reloc; x##_reloc=v
|
|
#define ENDPATCH(x) .globl x##_end; x##_end=.
|
|
|
|
/* Pseudo-flag used for virtual NMI, which we don't implement yet */
|
|
#define XEN_EFLAGS_NMI 0x80000000
|
|
|
|
#if 1
|
|
/*
|
|
x86-64 does not yet support direct access to percpu variables
|
|
via a segment override, so we just need to make sure this code
|
|
never gets used
|
|
*/
|
|
#define BUG ud2a
|
|
#define PER_CPU_VAR(var, off) 0xdeadbeef
|
|
#endif
|
|
|
|
/*
|
|
Enable events. This clears the event mask and tests the pending
|
|
event status with one and operation. If there are pending
|
|
events, then enter the hypervisor to get them handled.
|
|
*/
|
|
ENTRY(xen_irq_enable_direct)
|
|
BUG
|
|
|
|
/* Unmask events */
|
|
movb $0, PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_mask)
|
|
|
|
/* Preempt here doesn't matter because that will deal with
|
|
any pending interrupts. The pending check may end up being
|
|
run on the wrong CPU, but that doesn't hurt. */
|
|
|
|
/* Test for pending */
|
|
testb $0xff, PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_pending)
|
|
jz 1f
|
|
|
|
2: call check_events
|
|
1:
|
|
ENDPATCH(xen_irq_enable_direct)
|
|
ret
|
|
ENDPROC(xen_irq_enable_direct)
|
|
RELOC(xen_irq_enable_direct, 2b+1)
|
|
|
|
/*
|
|
Disabling events is simply a matter of making the event mask
|
|
non-zero.
|
|
*/
|
|
ENTRY(xen_irq_disable_direct)
|
|
BUG
|
|
|
|
movb $1, PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_mask)
|
|
ENDPATCH(xen_irq_disable_direct)
|
|
ret
|
|
ENDPROC(xen_irq_disable_direct)
|
|
RELOC(xen_irq_disable_direct, 0)
|
|
|
|
/*
|
|
(xen_)save_fl is used to get the current interrupt enable status.
|
|
Callers expect the status to be in X86_EFLAGS_IF, and other bits
|
|
may be set in the return value. We take advantage of this by
|
|
making sure that X86_EFLAGS_IF has the right value (and other bits
|
|
in that byte are 0), but other bits in the return value are
|
|
undefined. We need to toggle the state of the bit, because
|
|
Xen and x86 use opposite senses (mask vs enable).
|
|
*/
|
|
ENTRY(xen_save_fl_direct)
|
|
BUG
|
|
|
|
testb $0xff, PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_mask)
|
|
setz %ah
|
|
addb %ah,%ah
|
|
ENDPATCH(xen_save_fl_direct)
|
|
ret
|
|
ENDPROC(xen_save_fl_direct)
|
|
RELOC(xen_save_fl_direct, 0)
|
|
|
|
/*
|
|
In principle the caller should be passing us a value return
|
|
from xen_save_fl_direct, but for robustness sake we test only
|
|
the X86_EFLAGS_IF flag rather than the whole byte. After
|
|
setting the interrupt mask state, it checks for unmasked
|
|
pending events and enters the hypervisor to get them delivered
|
|
if so.
|
|
*/
|
|
ENTRY(xen_restore_fl_direct)
|
|
BUG
|
|
|
|
testb $X86_EFLAGS_IF>>8, %ah
|
|
setz PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_mask)
|
|
/* Preempt here doesn't matter because that will deal with
|
|
any pending interrupts. The pending check may end up being
|
|
run on the wrong CPU, but that doesn't hurt. */
|
|
|
|
/* check for unmasked and pending */
|
|
cmpw $0x0001, PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_pending)
|
|
jz 1f
|
|
2: call check_events
|
|
1:
|
|
ENDPATCH(xen_restore_fl_direct)
|
|
ret
|
|
ENDPROC(xen_restore_fl_direct)
|
|
RELOC(xen_restore_fl_direct, 2b+1)
|
|
|
|
|
|
/*
|
|
Force an event check by making a hypercall,
|
|
but preserve regs before making the call.
|
|
*/
|
|
check_events:
|
|
push %rax
|
|
push %rcx
|
|
push %rdx
|
|
push %rsi
|
|
push %rdi
|
|
push %r8
|
|
push %r9
|
|
push %r10
|
|
push %r11
|
|
call xen_force_evtchn_callback
|
|
pop %r11
|
|
pop %r10
|
|
pop %r9
|
|
pop %r8
|
|
pop %rdi
|
|
pop %rsi
|
|
pop %rdx
|
|
pop %rcx
|
|
pop %rax
|
|
ret
|
|
|
|
ENTRY(xen_adjust_exception_frame)
|
|
mov 8+0(%rsp),%rcx
|
|
mov 8+8(%rsp),%r11
|
|
ret $16
|
|
|
|
hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32
|
|
/*
|
|
Xen64 iret frame:
|
|
|
|
ss
|
|
rsp
|
|
rflags
|
|
cs
|
|
rip <-- standard iret frame
|
|
|
|
flags
|
|
|
|
rcx }
|
|
r11 }<-- pushed by hypercall page
|
|
rsp -> rax }
|
|
*/
|
|
ENTRY(xen_iret)
|
|
pushq $0
|
|
1: jmp hypercall_iret
|
|
ENDPATCH(xen_iret)
|
|
RELOC(xen_iret, 1b+1)
|
|
|
|
/*
|
|
sysexit is not used for 64-bit processes, so it's
|
|
only ever used to return to 32-bit compat userspace.
|
|
*/
|
|
ENTRY(xen_sysexit)
|
|
pushq $__USER32_DS
|
|
pushq %rcx
|
|
pushq $X86_EFLAGS_IF
|
|
pushq $__USER32_CS
|
|
pushq %rdx
|
|
|
|
pushq $0
|
|
1: jmp hypercall_iret
|
|
ENDPATCH(xen_sysexit)
|
|
RELOC(xen_sysexit, 1b+1)
|
|
|
|
ENTRY(xen_sysret64)
|
|
/* We're already on the usermode stack at this point, but still
|
|
with the kernel gs, so we can easily switch back */
|
|
movq %rsp, %gs:pda_oldrsp
|
|
movq %gs:pda_kernelstack,%rsp
|
|
|
|
pushq $__USER_DS
|
|
pushq %gs:pda_oldrsp
|
|
pushq %r11
|
|
pushq $__USER_CS
|
|
pushq %rcx
|
|
|
|
pushq $VGCF_in_syscall
|
|
1: jmp hypercall_iret
|
|
ENDPATCH(xen_sysret64)
|
|
RELOC(xen_sysret64, 1b+1)
|
|
|
|
ENTRY(xen_sysret32)
|
|
/* We're already on the usermode stack at this point, but still
|
|
with the kernel gs, so we can easily switch back */
|
|
movq %rsp, %gs:pda_oldrsp
|
|
movq %gs:pda_kernelstack, %rsp
|
|
|
|
pushq $__USER32_DS
|
|
pushq %gs:pda_oldrsp
|
|
pushq %r11
|
|
pushq $__USER32_CS
|
|
pushq %rcx
|
|
|
|
pushq $VGCF_in_syscall
|
|
1: jmp hypercall_iret
|
|
ENDPATCH(xen_sysret32)
|
|
RELOC(xen_sysret32, 1b+1)
|
|
|
|
/*
|
|
Xen handles syscall callbacks much like ordinary exceptions,
|
|
which means we have:
|
|
- kernel gs
|
|
- kernel rsp
|
|
- an iret-like stack frame on the stack (including rcx and r11):
|
|
ss
|
|
rsp
|
|
rflags
|
|
cs
|
|
rip
|
|
r11
|
|
rsp-> rcx
|
|
|
|
In all the entrypoints, we undo all that to make it look
|
|
like a CPU-generated syscall/sysenter and jump to the normal
|
|
entrypoint.
|
|
*/
|
|
|
|
.macro undo_xen_syscall
|
|
mov 0*8(%rsp),%rcx
|
|
mov 1*8(%rsp),%r11
|
|
mov 5*8(%rsp),%rsp
|
|
.endm
|
|
|
|
/* Normal 64-bit system call target */
|
|
ENTRY(xen_syscall_target)
|
|
undo_xen_syscall
|
|
jmp system_call_after_swapgs
|
|
ENDPROC(xen_syscall_target)
|
|
|
|
#ifdef CONFIG_IA32_EMULATION
|
|
|
|
/* 32-bit compat syscall target */
|
|
ENTRY(xen_syscall32_target)
|
|
undo_xen_syscall
|
|
jmp ia32_cstar_target
|
|
ENDPROC(xen_syscall32_target)
|
|
|
|
/* 32-bit compat sysenter target */
|
|
ENTRY(xen_sysenter_target)
|
|
undo_xen_syscall
|
|
jmp ia32_sysenter_target
|
|
ENDPROC(xen_sysenter_target)
|
|
|
|
#else /* !CONFIG_IA32_EMULATION */
|
|
|
|
ENTRY(xen_syscall32_target)
|
|
ENTRY(xen_sysenter_target)
|
|
lea 16(%rsp), %rsp /* strip %rcx,%r11 */
|
|
mov $-ENOSYS, %rax
|
|
pushq $VGCF_in_syscall
|
|
jmp hypercall_iret
|
|
ENDPROC(xen_syscall32_target)
|
|
ENDPROC(xen_sysenter_target)
|
|
|
|
#endif /* CONFIG_IA32_EMULATION */
|