summaryrefslogtreecommitdiff
path: root/arch/x86/xen/xen-asm_64.S
blob: c98a48c861fd33ec4958dccc462ecbccf6856f3b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Asm versions of Xen pv-ops, suitable for direct use.
 *
 * We only bother with direct forms (ie, vcpu in pda) of the
 * operations here; the indirect forms are better handled in C.
 */

#include <asm/errno.h>
#include <asm/percpu.h>
#include <asm/processor-flags.h>
#include <asm/segment.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>

#include <xen/interface/xen.h>

#include <linux/linkage.h>

.macro xen_pv_trap name
ENTRY(xen_\name)
	pop %rcx
	pop %r11
	jmp  \name
END(xen_\name)
.endm

xen_pv_trap divide_error
xen_pv_trap debug
xen_pv_trap xendebug
xen_pv_trap int3
xen_pv_trap xenint3
xen_pv_trap nmi
xen_pv_trap overflow
xen_pv_trap bounds
xen_pv_trap invalid_op
xen_pv_trap device_not_available
xen_pv_trap double_fault
xen_pv_trap coprocessor_segment_overrun
xen_pv_trap invalid_TSS
xen_pv_trap segment_not_present
xen_pv_trap stack_segment
xen_pv_trap general_protection
xen_pv_trap page_fault
xen_pv_trap spurious_interrupt_bug
xen_pv_trap coprocessor_error
xen_pv_trap alignment_check
#ifdef CONFIG_X86_MCE
xen_pv_trap machine_check
#endif /* CONFIG_X86_MCE */
xen_pv_trap simd_coprocessor_error
#ifdef CONFIG_IA32_EMULATION
xen_pv_trap entry_INT80_compat
#endif
xen_pv_trap hypervisor_callback

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
	jmp hypercall_iret

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(rsp_scratch)
	movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp

	pushq $__USER_DS
	pushq PER_CPU_VAR(rsp_scratch)
	pushq %r11
	pushq $__USER_CS
	pushq %rcx

	pushq $VGCF_in_syscall
	jmp hypercall_iret

/*
 * 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
 */

/* Normal 64-bit system call target */
ENTRY(xen_syscall_target)
	popq %rcx
	popq %r11

	/*
	 * Neither Xen nor the kernel really knows what the old SS and
	 * CS were.  The kernel expects __USER_DS and __USER_CS, so
	 * report those values even though Xen will guess its own values.
	 */
	movq $__USER_DS, 4*8(%rsp)
	movq $__USER_CS, 1*8(%rsp)

	jmp entry_SYSCALL_64_after_hwframe
ENDPROC(xen_syscall_target)

#ifdef CONFIG_IA32_EMULATION

/* 32-bit compat syscall target */
ENTRY(xen_syscall32_target)
	popq %rcx
	popq %r11

	/*
	 * Neither Xen nor the kernel really knows what the old SS and
	 * CS were.  The kernel expects __USER32_DS and __USER32_CS, so
	 * report those values even though Xen will guess its own values.
	 */
	movq $__USER32_DS, 4*8(%rsp)
	movq $__USER32_CS, 1*8(%rsp)

	jmp entry_SYSCALL_compat_after_hwframe
ENDPROC(xen_syscall32_target)

/* 32-bit compat sysenter target */
ENTRY(xen_sysenter_target)
	mov 0*8(%rsp), %rcx
	mov 1*8(%rsp), %r11
	mov 5*8(%rsp), %rsp
	jmp entry_SYSENTER_compat
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 $0
	jmp hypercall_iret
ENDPROC(xen_syscall32_target)
ENDPROC(xen_sysenter_target)

#endif	/* CONFIG_IA32_EMULATION */