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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> |
3a23208e | 19 | #include <asm/thread_info.h> |
cdacc127 JF |
20 | |
21 | #include <xen/interface/xen.h> | |
22 | ||
5393744b | 23 | #include "xen-asm.h" |
cdacc127 | 24 | |
997409d3 | 25 | ENTRY(xen_adjust_exception_frame) |
130ace11 TH |
26 | mov 8+0(%rsp), %rcx |
27 | mov 8+8(%rsp), %r11 | |
997409d3 | 28 | ret $16 |
9fd21606 | 29 | ENDPROC(xen_adjust_exception_frame) |
997409d3 | 30 | |
6fcac6d3 JF |
31 | hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32 |
32 | /* | |
130ace11 TH |
33 | * Xen64 iret frame: |
34 | * | |
35 | * ss | |
36 | * rsp | |
37 | * rflags | |
38 | * cs | |
39 | * rip <-- standard iret frame | |
40 | * | |
41 | * flags | |
42 | * | |
43 | * rcx } | |
44 | * r11 }<-- pushed by hypercall page | |
45 | * rsp->rax } | |
6fcac6d3 | 46 | */ |
cdacc127 JF |
47 | ENTRY(xen_iret) |
48 | pushq $0 | |
6fcac6d3 JF |
49 | 1: jmp hypercall_iret |
50 | ENDPATCH(xen_iret) | |
51 | RELOC(xen_iret, 1b+1) | |
cdacc127 | 52 | |
6fcac6d3 | 53 | ENTRY(xen_sysret64) |
130ace11 TH |
54 | /* |
55 | * We're already on the usermode stack at this point, but | |
56 | * still with the kernel gs, so we can easily switch back | |
57 | */ | |
c38e5038 | 58 | movq %rsp, PER_CPU_VAR(rsp_scratch) |
3a23208e | 59 | movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp |
6fcac6d3 JF |
60 | |
61 | pushq $__USER_DS | |
c38e5038 | 62 | pushq PER_CPU_VAR(rsp_scratch) |
6fcac6d3 JF |
63 | pushq %r11 |
64 | pushq $__USER_CS | |
65 | pushq %rcx | |
66 | ||
67 | pushq $VGCF_in_syscall | |
68 | 1: jmp hypercall_iret | |
69 | ENDPATCH(xen_sysret64) | |
70 | RELOC(xen_sysret64, 1b+1) | |
71 | ||
6fcac6d3 | 72 | /* |
130ace11 TH |
73 | * Xen handles syscall callbacks much like ordinary exceptions, which |
74 | * means we have: | |
75 | * - kernel gs | |
76 | * - kernel rsp | |
77 | * - an iret-like stack frame on the stack (including rcx and r11): | |
78 | * ss | |
79 | * rsp | |
80 | * rflags | |
81 | * cs | |
82 | * rip | |
83 | * r11 | |
84 | * rsp->rcx | |
85 | * | |
86 | * In all the entrypoints, we undo all that to make it look like a | |
87 | * CPU-generated syscall/sysenter and jump to the normal entrypoint. | |
6fcac6d3 JF |
88 | */ |
89 | ||
90 | .macro undo_xen_syscall | |
130ace11 TH |
91 | mov 0*8(%rsp), %rcx |
92 | mov 1*8(%rsp), %r11 | |
93 | mov 5*8(%rsp), %rsp | |
6fcac6d3 JF |
94 | .endm |
95 | ||
96 | /* Normal 64-bit system call target */ | |
97 | ENTRY(xen_syscall_target) | |
98 | undo_xen_syscall | |
b2502b41 | 99 | jmp entry_SYSCALL_64_after_swapgs |
6fcac6d3 JF |
100 | ENDPROC(xen_syscall_target) |
101 | ||
102 | #ifdef CONFIG_IA32_EMULATION | |
103 | ||
104 | /* 32-bit compat syscall target */ | |
105 | ENTRY(xen_syscall32_target) | |
106 | undo_xen_syscall | |
2cd23553 | 107 | jmp entry_SYSCALL_compat |
6fcac6d3 JF |
108 | ENDPROC(xen_syscall32_target) |
109 | ||
110 | /* 32-bit compat sysenter target */ | |
111 | ENTRY(xen_sysenter_target) | |
112 | undo_xen_syscall | |
4c8cd0c5 | 113 | jmp entry_SYSENTER_compat |
6fcac6d3 JF |
114 | ENDPROC(xen_sysenter_target) |
115 | ||
116 | #else /* !CONFIG_IA32_EMULATION */ | |
117 | ||
118 | ENTRY(xen_syscall32_target) | |
119 | ENTRY(xen_sysenter_target) | |
130ace11 | 120 | lea 16(%rsp), %rsp /* strip %rcx, %r11 */ |
6fcac6d3 | 121 | mov $-ENOSYS, %rax |
6aaf5d63 | 122 | pushq $0 |
6fcac6d3 JF |
123 | jmp hypercall_iret |
124 | ENDPROC(xen_syscall32_target) | |
125 | ENDPROC(xen_sysenter_target) | |
126 | ||
127 | #endif /* CONFIG_IA32_EMULATION */ |