5393744b71
Now that x86-64 has directly accessible percpu variables, it can also
implement the direct versions of these operations, which operate on a
vcpu_info structure directly embedded in the percpu area.
In fact, the 64-bit versions are more or less identical, and so can be
shared. The only two differences are:
1. xen_restore_fl_direct takes its argument in eax on 32-bit, and rdi on 64-bit.
Unfortunately it isn't possible to directly refer to the 2nd lsb of rdi directly
(as you can with %ah), so the code isn't quite as dense.
2. check_events needs to variants to save different registers.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
157 lines
3.2 KiB
ArmAsm
157 lines
3.2 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 <asm/errno.h>
|
|
#include <asm/percpu.h>
|
|
#include <asm/processor-flags.h>
|
|
#include <asm/segment.h>
|
|
|
|
#include <xen/interface/xen.h>
|
|
|
|
#include "xen-asm.h"
|
|
|
|
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, PER_CPU_VAR(old_rsp)
|
|
movq PER_CPU_VAR(kernel_stack),%rsp
|
|
|
|
pushq $__USER_DS
|
|
pushq PER_CPU_VAR(old_rsp)
|
|
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, PER_CPU_VAR(old_rsp)
|
|
movq PER_CPU_VAR(kernel_stack), %rsp
|
|
|
|
pushq $__USER32_DS
|
|
pushq PER_CPU_VAR(old_rsp)
|
|
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 */
|