1// Copyright 2022 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5#include "textflag.h"
6#include "abi_loong64.h"
7
8// Set the x_crosscall2_ptr C function pointer variable point to crosscall2.
9// It's such a pointer chain: _crosscall2_ptr -> x_crosscall2_ptr -> crosscall2
10// Use a local trampoline, to avoid taking the address of a dynamically exported
11// function.
12TEXT ·set_crosscall2(SB),NOSPLIT,$0-0
13 MOVV _crosscall2_ptr(SB), R5
14 MOVV $crosscall2_trampoline<>(SB), R6
15 MOVV R6, (R5)
16 RET
17
18TEXT crosscall2_trampoline<>(SB),NOSPLIT,$0-0
19 JMP crosscall2(SB)
20
21// Called by C code generated by cmd/cgo.
22// func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)
23// Saves C callee-saved registers and calls cgocallback with three arguments.
24// fn is the PC of a func(a unsafe.Pointer) function.
25TEXT crosscall2(SB),NOSPLIT|NOFRAME,$0
26 /*
27 * We still need to save all callee save register as before, and then
28 * push 3 args for fn (R4, R5, R7), skipping R6.
29 * Also note that at procedure entry in gc world, 8(R29) will be the
30 * first arg.
31 */
32
33 ADDV $(-23*8), R3
34 MOVV R4, (1*8)(R3) // fn unsafe.Pointer
35 MOVV R5, (2*8)(R3) // a unsafe.Pointer
36 MOVV R7, (3*8)(R3) // ctxt uintptr
37
38 SAVE_R22_TO_R31((4*8))
39 SAVE_F24_TO_F31((14*8))
40 MOVV R1, (22*8)(R3)
41
42 // Initialize Go ABI environment
43 JAL runtime·load_g(SB)
44
45 JAL runtime·cgocallback(SB)
46
47 RESTORE_R22_TO_R31((4*8))
48 RESTORE_F24_TO_F31((14*8))
49 MOVV (22*8)(R3), R1
50
51 ADDV $(23*8), R3
52
53 RET
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