Commit | Line | Data |
---|---|---|
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> | |
cdacc127 JF |
18 | |
19 | #include <xen/interface/xen.h> | |
20 | ||
5393744b | 21 | #include "xen-asm.h" |
cdacc127 | 22 | |
997409d3 | 23 | ENTRY(xen_adjust_exception_frame) |
130ace11 TH |
24 | mov 8+0(%rsp), %rcx |
25 | mov 8+8(%rsp), %r11 | |
997409d3 JF |
26 | ret $16 |
27 | ||
6fcac6d3 JF |
28 | hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32 |
29 | /* | |
130ace11 TH |
30 | * Xen64 iret frame: |
31 | * | |
32 | * ss | |
33 | * rsp | |
34 | * rflags | |
35 | * cs | |
36 | * rip <-- standard iret frame | |
37 | * | |
38 | * flags | |
39 | * | |
40 | * rcx } | |
41 | * r11 }<-- pushed by hypercall page | |
42 | * rsp->rax } | |
6fcac6d3 | 43 | */ |
cdacc127 JF |
44 | ENTRY(xen_iret) |
45 | pushq $0 | |
6fcac6d3 JF |
46 | 1: jmp hypercall_iret |
47 | ENDPATCH(xen_iret) | |
48 | RELOC(xen_iret, 1b+1) | |
cdacc127 | 49 | |
6fcac6d3 | 50 | /* |
130ace11 TH |
51 | * sysexit is not used for 64-bit processes, so it's only ever used to |
52 | * return to 32-bit compat userspace. | |
6fcac6d3 | 53 | */ |
cdacc127 | 54 | ENTRY(xen_sysexit) |
6fcac6d3 JF |
55 | pushq $__USER32_DS |
56 | pushq %rcx | |
57 | pushq $X86_EFLAGS_IF | |
58 | pushq $__USER32_CS | |
59 | pushq %rdx | |
60 | ||
2dc1697e | 61 | pushq $0 |
6fcac6d3 JF |
62 | 1: jmp hypercall_iret |
63 | ENDPATCH(xen_sysexit) | |
64 | RELOC(xen_sysexit, 1b+1) | |
65 | ||
66 | ENTRY(xen_sysret64) | |
130ace11 TH |
67 | /* |
68 | * We're already on the usermode stack at this point, but | |
69 | * still with the kernel gs, so we can easily switch back | |
70 | */ | |
3d1e42a7 | 71 | movq %rsp, PER_CPU_VAR(old_rsp) |
130ace11 | 72 | movq PER_CPU_VAR(kernel_stack), %rsp |
6fcac6d3 JF |
73 | |
74 | pushq $__USER_DS | |
3d1e42a7 | 75 | pushq PER_CPU_VAR(old_rsp) |
6fcac6d3 JF |
76 | pushq %r11 |
77 | pushq $__USER_CS | |
78 | pushq %rcx | |
79 | ||
80 | pushq $VGCF_in_syscall | |
81 | 1: jmp hypercall_iret | |
82 | ENDPATCH(xen_sysret64) | |
83 | RELOC(xen_sysret64, 1b+1) | |
84 | ||
85 | ENTRY(xen_sysret32) | |
130ace11 TH |
86 | /* |
87 | * We're already on the usermode stack at this point, but | |
88 | * still with the kernel gs, so we can easily switch back | |
89 | */ | |
3d1e42a7 | 90 | movq %rsp, PER_CPU_VAR(old_rsp) |
9af45651 | 91 | movq PER_CPU_VAR(kernel_stack), %rsp |
6fcac6d3 JF |
92 | |
93 | pushq $__USER32_DS | |
3d1e42a7 | 94 | pushq PER_CPU_VAR(old_rsp) |
6fcac6d3 JF |
95 | pushq %r11 |
96 | pushq $__USER32_CS | |
97 | pushq %rcx | |
98 | ||
6aaf5d63 | 99 | pushq $0 |
6fcac6d3 JF |
100 | 1: jmp hypercall_iret |
101 | ENDPATCH(xen_sysret32) | |
102 | RELOC(xen_sysret32, 1b+1) | |
103 | ||
104 | /* | |
130ace11 TH |
105 | * Xen handles syscall callbacks much like ordinary exceptions, which |
106 | * means we have: | |
107 | * - kernel gs | |
108 | * - kernel rsp | |
109 | * - an iret-like stack frame on the stack (including rcx and r11): | |
110 | * ss | |
111 | * rsp | |
112 | * rflags | |
113 | * cs | |
114 | * rip | |
115 | * r11 | |
116 | * rsp->rcx | |
117 | * | |
118 | * In all the entrypoints, we undo all that to make it look like a | |
119 | * CPU-generated syscall/sysenter and jump to the normal entrypoint. | |
6fcac6d3 JF |
120 | */ |
121 | ||
122 | .macro undo_xen_syscall | |
130ace11 TH |
123 | mov 0*8(%rsp), %rcx |
124 | mov 1*8(%rsp), %r11 | |
125 | mov 5*8(%rsp), %rsp | |
6fcac6d3 JF |
126 | .endm |
127 | ||
128 | /* Normal 64-bit system call target */ | |
129 | ENTRY(xen_syscall_target) | |
130 | undo_xen_syscall | |
131 | jmp system_call_after_swapgs | |
132 | ENDPROC(xen_syscall_target) | |
133 | ||
134 | #ifdef CONFIG_IA32_EMULATION | |
135 | ||
136 | /* 32-bit compat syscall target */ | |
137 | ENTRY(xen_syscall32_target) | |
138 | undo_xen_syscall | |
139 | jmp ia32_cstar_target | |
140 | ENDPROC(xen_syscall32_target) | |
141 | ||
142 | /* 32-bit compat sysenter target */ | |
143 | ENTRY(xen_sysenter_target) | |
144 | undo_xen_syscall | |
145 | jmp ia32_sysenter_target | |
146 | ENDPROC(xen_sysenter_target) | |
147 | ||
148 | #else /* !CONFIG_IA32_EMULATION */ | |
149 | ||
150 | ENTRY(xen_syscall32_target) | |
151 | ENTRY(xen_sysenter_target) | |
130ace11 | 152 | lea 16(%rsp), %rsp /* strip %rcx, %r11 */ |
6fcac6d3 | 153 | mov $-ENOSYS, %rax |
6aaf5d63 | 154 | pushq $0 |
6fcac6d3 JF |
155 | jmp hypercall_iret |
156 | ENDPROC(xen_syscall32_target) | |
157 | ENDPROC(xen_sysenter_target) | |
158 | ||
159 | #endif /* CONFIG_IA32_EMULATION */ |