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Commit | Line | Data |
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cdacc127 | 1 | /* |
130ace11 TH |
2 | * Asm versions of Xen pv-ops, suitable for either direct use or |
3 | * inlining. The inline versions are the same as the direct-use | |
4 | * versions, with the pre- and post-amble chopped off. | |
5 | * | |
6 | * This code is encoded for size rather than absolute efficiency, with | |
7 | * a view to being able to inline as much as possible. | |
8 | * | |
9 | * We only bother with direct forms (ie, vcpu in pda) of the | |
10 | * operations here; the indirect forms are better handled in C, since | |
11 | * they're generally too large to inline anyway. | |
cdacc127 JF |
12 | */ |
13 | ||
6fcac6d3 | 14 | #include <asm/errno.h> |
9af45651 | 15 | #include <asm/percpu.h> |
5393744b JF |
16 | #include <asm/processor-flags.h> |
17 | #include <asm/segment.h> | |
63332a84 | 18 | #include <asm/asm-offsets.h> |
cdacc127 JF |
19 | |
20 | #include <xen/interface/xen.h> | |
21 | ||
5393744b | 22 | #include "xen-asm.h" |
cdacc127 | 23 | |
997409d3 | 24 | ENTRY(xen_adjust_exception_frame) |
130ace11 TH |
25 | mov 8+0(%rsp), %rcx |
26 | mov 8+8(%rsp), %r11 | |
997409d3 JF |
27 | ret $16 |
28 | ||
6fcac6d3 JF |
29 | hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32 |
30 | /* | |
130ace11 TH |
31 | * Xen64 iret frame: |
32 | * | |
33 | * ss | |
34 | * rsp | |
35 | * rflags | |
36 | * cs | |
37 | * rip <-- standard iret frame | |
38 | * | |
39 | * flags | |
40 | * | |
41 | * rcx } | |
42 | * r11 }<-- pushed by hypercall page | |
43 | * rsp->rax } | |
6fcac6d3 | 44 | */ |
cdacc127 JF |
45 | ENTRY(xen_iret) |
46 | pushq $0 | |
6fcac6d3 JF |
47 | 1: jmp hypercall_iret |
48 | ENDPATCH(xen_iret) | |
49 | RELOC(xen_iret, 1b+1) | |
cdacc127 | 50 | |
6fcac6d3 | 51 | ENTRY(xen_sysret64) |
130ace11 TH |
52 | /* |
53 | * We're already on the usermode stack at this point, but | |
54 | * still with the kernel gs, so we can easily switch back | |
55 | */ | |
c38e5038 | 56 | movq %rsp, PER_CPU_VAR(rsp_scratch) |
63332a84 | 57 | movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp |
6fcac6d3 JF |
58 | |
59 | pushq $__USER_DS | |
c38e5038 | 60 | pushq PER_CPU_VAR(rsp_scratch) |
6fcac6d3 JF |
61 | pushq %r11 |
62 | pushq $__USER_CS | |
63 | pushq %rcx | |
64 | ||
65 | pushq $VGCF_in_syscall | |
66 | 1: jmp hypercall_iret | |
67 | ENDPATCH(xen_sysret64) | |
68 | RELOC(xen_sysret64, 1b+1) | |
69 | ||
70 | ENTRY(xen_sysret32) | |
130ace11 TH |
71 | /* |
72 | * We're already on the usermode stack at this point, but | |
73 | * still with the kernel gs, so we can easily switch back | |
74 | */ | |
c38e5038 | 75 | movq %rsp, PER_CPU_VAR(rsp_scratch) |
63332a84 | 76 | movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp |
6fcac6d3 JF |
77 | |
78 | pushq $__USER32_DS | |
c38e5038 | 79 | pushq PER_CPU_VAR(rsp_scratch) |
6fcac6d3 JF |
80 | pushq %r11 |
81 | pushq $__USER32_CS | |
82 | pushq %rcx | |
83 | ||
6aaf5d63 | 84 | pushq $0 |
6fcac6d3 JF |
85 | 1: jmp hypercall_iret |
86 | ENDPATCH(xen_sysret32) | |
87 | RELOC(xen_sysret32, 1b+1) | |
88 | ||
89 | /* | |
130ace11 TH |
90 | * Xen handles syscall callbacks much like ordinary exceptions, which |
91 | * means we have: | |
92 | * - kernel gs | |
93 | * - kernel rsp | |
94 | * - an iret-like stack frame on the stack (including rcx and r11): | |
95 | * ss | |
96 | * rsp | |
97 | * rflags | |
98 | * cs | |
99 | * rip | |
100 | * r11 | |
101 | * rsp->rcx | |
102 | * | |
103 | * In all the entrypoints, we undo all that to make it look like a | |
104 | * CPU-generated syscall/sysenter and jump to the normal entrypoint. | |
6fcac6d3 JF |
105 | */ |
106 | ||
107 | .macro undo_xen_syscall | |
130ace11 TH |
108 | mov 0*8(%rsp), %rcx |
109 | mov 1*8(%rsp), %r11 | |
110 | mov 5*8(%rsp), %rsp | |
6fcac6d3 JF |
111 | .endm |
112 | ||
113 | /* Normal 64-bit system call target */ | |
114 | ENTRY(xen_syscall_target) | |
115 | undo_xen_syscall | |
116 | jmp system_call_after_swapgs | |
117 | ENDPROC(xen_syscall_target) | |
118 | ||
119 | #ifdef CONFIG_IA32_EMULATION | |
120 | ||
121 | /* 32-bit compat syscall target */ | |
122 | ENTRY(xen_syscall32_target) | |
123 | undo_xen_syscall | |
124 | jmp ia32_cstar_target | |
125 | ENDPROC(xen_syscall32_target) | |
126 | ||
127 | /* 32-bit compat sysenter target */ | |
128 | ENTRY(xen_sysenter_target) | |
129 | undo_xen_syscall | |
130 | jmp ia32_sysenter_target | |
131 | ENDPROC(xen_sysenter_target) | |
132 | ||
133 | #else /* !CONFIG_IA32_EMULATION */ | |
134 | ||
135 | ENTRY(xen_syscall32_target) | |
136 | ENTRY(xen_sysenter_target) | |
130ace11 | 137 | lea 16(%rsp), %rsp /* strip %rcx, %r11 */ |
6fcac6d3 | 138 | mov $-ENOSYS, %rax |
6aaf5d63 | 139 | pushq $0 |
6fcac6d3 JF |
140 | jmp hypercall_iret |
141 | ENDPROC(xen_syscall32_target) | |
142 | ENDPROC(xen_sysenter_target) | |
143 | ||
144 | #endif /* CONFIG_IA32_EMULATION */ |