forked from Minki/linux
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
/*
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Asm versions of Xen pv-ops, suitable for either direct use or inlining.
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The inline versions are the same as the direct-use versions, with the
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pre- and post-amble chopped off.
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This code is encoded for size rather than absolute efficiency,
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with a view to being able to inline as much as possible.
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We only bother with direct forms (ie, vcpu in pda) of the operations
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here; the indirect forms are better handled in C, since they're
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generally too large to inline anyway.
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*/
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#include <asm/errno.h>
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#include <asm/percpu.h>
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#include <asm/processor-flags.h>
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#include <asm/segment.h>
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#include <xen/interface/xen.h>
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#include "xen-asm.h"
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ENTRY(xen_adjust_exception_frame)
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mov 8+0(%rsp),%rcx
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mov 8+8(%rsp),%r11
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ret $16
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hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32
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/*
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Xen64 iret frame:
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ss
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rsp
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rflags
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cs
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rip <-- standard iret frame
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flags
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rcx }
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r11 }<-- pushed by hypercall page
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rsp -> rax }
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*/
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ENTRY(xen_iret)
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pushq $0
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1: jmp hypercall_iret
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ENDPATCH(xen_iret)
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RELOC(xen_iret, 1b+1)
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/*
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sysexit is not used for 64-bit processes, so it's
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only ever used to return to 32-bit compat userspace.
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*/
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ENTRY(xen_sysexit)
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pushq $__USER32_DS
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pushq %rcx
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pushq $X86_EFLAGS_IF
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pushq $__USER32_CS
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pushq %rdx
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pushq $0
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1: jmp hypercall_iret
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ENDPATCH(xen_sysexit)
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RELOC(xen_sysexit, 1b+1)
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ENTRY(xen_sysret64)
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/* We're already on the usermode stack at this point, but still
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with the kernel gs, so we can easily switch back */
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movq %rsp, PER_CPU_VAR(old_rsp)
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movq PER_CPU_VAR(kernel_stack),%rsp
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pushq $__USER_DS
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pushq PER_CPU_VAR(old_rsp)
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pushq %r11
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pushq $__USER_CS
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pushq %rcx
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pushq $VGCF_in_syscall
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1: jmp hypercall_iret
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ENDPATCH(xen_sysret64)
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RELOC(xen_sysret64, 1b+1)
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ENTRY(xen_sysret32)
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/* We're already on the usermode stack at this point, but still
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with the kernel gs, so we can easily switch back */
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movq %rsp, PER_CPU_VAR(old_rsp)
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movq PER_CPU_VAR(kernel_stack), %rsp
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pushq $__USER32_DS
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pushq PER_CPU_VAR(old_rsp)
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pushq %r11
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pushq $__USER32_CS
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pushq %rcx
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pushq $VGCF_in_syscall
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1: jmp hypercall_iret
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ENDPATCH(xen_sysret32)
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RELOC(xen_sysret32, 1b+1)
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/*
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Xen handles syscall callbacks much like ordinary exceptions,
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which means we have:
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- kernel gs
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- kernel rsp
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- an iret-like stack frame on the stack (including rcx and r11):
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ss
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rsp
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rflags
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cs
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rip
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r11
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rsp-> rcx
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In all the entrypoints, we undo all that to make it look
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like a CPU-generated syscall/sysenter and jump to the normal
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entrypoint.
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*/
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.macro undo_xen_syscall
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mov 0*8(%rsp),%rcx
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mov 1*8(%rsp),%r11
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mov 5*8(%rsp),%rsp
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.endm
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/* Normal 64-bit system call target */
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ENTRY(xen_syscall_target)
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undo_xen_syscall
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jmp system_call_after_swapgs
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ENDPROC(xen_syscall_target)
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#ifdef CONFIG_IA32_EMULATION
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/* 32-bit compat syscall target */
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ENTRY(xen_syscall32_target)
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undo_xen_syscall
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jmp ia32_cstar_target
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ENDPROC(xen_syscall32_target)
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/* 32-bit compat sysenter target */
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ENTRY(xen_sysenter_target)
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undo_xen_syscall
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jmp ia32_sysenter_target
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ENDPROC(xen_sysenter_target)
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#else /* !CONFIG_IA32_EMULATION */
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ENTRY(xen_syscall32_target)
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ENTRY(xen_sysenter_target)
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lea 16(%rsp), %rsp /* strip %rcx,%r11 */
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mov $-ENOSYS, %rax
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pushq $VGCF_in_syscall
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jmp hypercall_iret
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ENDPROC(xen_syscall32_target)
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ENDPROC(xen_sysenter_target)
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#endif /* CONFIG_IA32_EMULATION */
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