mirror of https://go.googlesource.com/go
71 lines
2.4 KiB
ArmAsm
71 lines
2.4 KiB
ArmAsm
// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//go:build ppc64 || ppc64le
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#include "textflag.h"
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#include "asm_ppc64x.h"
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#include "abi_ppc64x.h"
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#ifdef GO_PPC64X_HAS_FUNCDESC
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// crosscall2 is marked with go:cgo_export_static. On AIX, this creates and exports
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// the symbol name and descriptor as the AIX linker expects, but does not work if
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// referenced from within Go. Create and use an aliased descriptor of crosscall2
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// to workaround this.
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DEFINE_PPC64X_FUNCDESC(_crosscall2<>, crosscall2)
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#define CROSSCALL2_FPTR $_crosscall2<>(SB)
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#else
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// Use a local trampoline, to avoid taking the address of a dynamically exported
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// function.
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#define CROSSCALL2_FPTR $crosscall2_trampoline<>(SB)
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#endif
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// Set the x_crosscall2_ptr C function pointer variable point to crosscall2.
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// It's such a pointer chain: _crosscall2_ptr -> x_crosscall2_ptr -> crosscall2
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TEXT ·set_crosscall2(SB),NOSPLIT,$0-0
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MOVD _crosscall2_ptr(SB), R5
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MOVD CROSSCALL2_FPTR, R6
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MOVD R6, (R5)
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RET
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TEXT crosscall2_trampoline<>(SB),NOSPLIT,$0-0
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JMP crosscall2(SB)
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// Called by C code generated by cmd/cgo.
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// func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)
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// Saves C callee-saved registers and calls cgocallback with three arguments.
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// fn is the PC of a func(a unsafe.Pointer) function.
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// The value of R2 is saved on the new stack frame, and not
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// the caller's frame due to issue #43228.
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TEXT crosscall2(SB),NOSPLIT|NOFRAME,$0
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// Start with standard C stack frame layout and linkage, allocate
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// 32 bytes of argument space, save callee-save regs, and set R0 to $0.
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STACK_AND_SAVE_HOST_TO_GO_ABI(32)
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// The above will not preserve R2 (TOC). Save it in case Go is
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// compiled without a TOC pointer (e.g -buildmode=default).
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MOVD R2, 24(R1)
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// Load the current g.
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BL runtime·load_g(SB)
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#ifdef GO_PPC64X_HAS_FUNCDESC
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// Load the real entry address from the first slot of the function descriptor.
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// The first argument fn might be null, that means dropm in pthread key destructor.
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CMP R3, $0
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BEQ nil_fn
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MOVD 8(R3), R2
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MOVD (R3), R3
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nil_fn:
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#endif
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MOVD R3, FIXED_FRAME+0(R1) // fn unsafe.Pointer
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MOVD R4, FIXED_FRAME+8(R1) // a unsafe.Pointer
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// Skip R5 = n uint32
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MOVD R6, FIXED_FRAME+16(R1) // ctxt uintptr
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BL runtime·cgocallback(SB)
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// Restore the old frame, and R2.
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MOVD 24(R1), R2
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UNSTACK_AND_RESTORE_GO_TO_HOST_ABI(32)
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RET
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