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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "go_asm.h"
#include "go_tls.h"
#include "textflag.h"
#include "time_windows.h"
#include "cgo/abi_amd64.h"
// Offsets into Thread Environment Block (pointer in GS)
#define TEB_TlsSlots 0x1480
#define TEB_ArbitraryPtr 0x28
// void runtime·asmstdcall(void *c);
TEXT runtime·asmstdcall(SB),NOSPLIT,$16
MOVQ SP, AX
ANDQ $~15, SP // alignment as per Windows requirement
MOVQ AX, 8(SP)
MOVQ CX, 0(SP) // asmcgocall will put first argument into CX.
MOVQ libcall_fn(CX), AX
MOVQ libcall_args(CX), SI
MOVQ libcall_n(CX), CX
// SetLastError(0).
MOVQ 0x30(GS), DI
MOVL $0, 0x68(DI)
SUBQ $(const_maxArgs*8), SP // room for args
// Fast version, do not store args on the stack.
CMPL CX, $4
JLE loadregs
// Check we have enough room for args.
CMPL CX, $const_maxArgs
JLE 2(PC)
INT $3 // not enough room -> crash
// Copy args to the stack.
MOVQ SP, DI
CLD
REP; MOVSQ
MOVQ SP, SI
loadregs:
// Load first 4 args into correspondent registers.
MOVQ 0(SI), CX
MOVQ 8(SI), DX
MOVQ 16(SI), R8
MOVQ 24(SI), R9
// Floating point arguments are passed in the XMM
// registers. Set them here in case any of the arguments
// are floating point values. For details see
// https://msdn.microsoft.com/en-us/library/zthk2dkh.aspx
MOVQ CX, X0
MOVQ DX, X1
MOVQ R8, X2
MOVQ R9, X3
// Call stdcall function.
CALL AX
ADDQ $(const_maxArgs*8), SP
// Return result.
MOVQ 0(SP), CX
MOVQ 8(SP), SP
MOVQ AX, libcall_r1(CX)
// Floating point return values are returned in XMM0. Setting r2 to this
// value in case this call returned a floating point value. For details,
// see https://docs.microsoft.com/en-us/cpp/build/x64-calling-convention
MOVQ X0, libcall_r2(CX)
// GetLastError().
MOVQ 0x30(GS), DI
MOVL 0x68(DI), AX
MOVQ AX, libcall_err(CX)
RET
// faster get/set last error
TEXT runtime·getlasterror(SB),NOSPLIT,$0
MOVQ 0x30(GS), AX
MOVL 0x68(AX), AX
MOVL AX, ret+0(FP)
RET
// Called by Windows as a Vectored Exception Handler (VEH).
// CX is pointer to struct containing
// exception record and context pointers.
// DX is the kind of sigtramp function.
// Return value of sigtrampgo is stored in AX.
TEXT sigtramp<>(SB),NOSPLIT|NOFRAME,$0-0
// Switch from the host ABI to the Go ABI.
PUSH_REGS_HOST_TO_ABI0()
// Set up ABIInternal environment: cleared X15 and R14.
// R14 is cleared in case there's a non-zero value in there
// if called from a non-go thread.
XORPS X15, X15
XORQ R14, R14
get_tls(AX)
CMPQ AX, $0
JE 2(PC)
// Exception from Go thread, set R14.
MOVQ g(AX), R14
// Reserve space for spill slots.
ADJSP $16
MOVQ CX, AX
MOVQ DX, BX
// Calling ABIInternal because TLS might be nil.
CALL runtime·sigtrampgo<ABIInternal>(SB)
// Return value is already stored in AX.
ADJSP $-16
POP_REGS_HOST_TO_ABI0()
RET
// Trampoline to resume execution from exception handler.
// This is part of the control flow guard workaround.
// It switches stacks and jumps to the continuation address.
// R8 and R9 are set above at the end of sigtrampgo
// in the context that starts executing at sigresume.
TEXT runtime·sigresume(SB),NOSPLIT|NOFRAME,$0
MOVQ R8, SP
JMP R9
TEXT runtime·exceptiontramp(SB),NOSPLIT|NOFRAME,$0
// PExceptionPointers already on CX
MOVQ $const_callbackVEH, DX
JMP sigtramp<>(SB)
TEXT runtime·firstcontinuetramp(SB),NOSPLIT|NOFRAME,$0-0
// PExceptionPointers already on CX
MOVQ $const_callbackFirstVCH, DX
JMP sigtramp<>(SB)
TEXT runtime·lastcontinuetramp(SB),NOSPLIT|NOFRAME,$0-0
// PExceptionPointers already on CX
MOVQ $const_callbackLastVCH, DX
JMP sigtramp<>(SB)
TEXT runtime·callbackasm1(SB),NOSPLIT|NOFRAME,$0
// Construct args vector for cgocallback().
// By windows/amd64 calling convention first 4 args are in CX, DX, R8, R9
// args from the 5th on are on the stack.
// In any case, even if function has 0,1,2,3,4 args, there is reserved
// but uninitialized "shadow space" for the first 4 args.
// The values are in registers.
MOVQ CX, (16+0)(SP)
MOVQ DX, (16+8)(SP)
MOVQ R8, (16+16)(SP)
MOVQ R9, (16+24)(SP)
// R8 = address of args vector
LEAQ (16+0)(SP), R8
// remove return address from stack, we are not returning to callbackasm, but to its caller.
MOVQ 0(SP), AX
ADDQ $8, SP
// determine index into runtime·cbs table
MOVQ $runtime·callbackasm(SB), DX
SUBQ DX, AX
MOVQ $0, DX
MOVQ $5, CX // divide by 5 because each call instruction in runtime·callbacks is 5 bytes long
DIVL CX
SUBQ $1, AX // subtract 1 because return PC is to the next slot
// Switch from the host ABI to the Go ABI.
PUSH_REGS_HOST_TO_ABI0()
// Create a struct callbackArgs on our stack to be passed as
// the "frame" to cgocallback and on to callbackWrap.
SUBQ $(24+callbackArgs__size), SP
MOVQ AX, (24+callbackArgs_index)(SP) // callback index
MOVQ R8, (24+callbackArgs_args)(SP) // address of args vector
MOVQ $0, (24+callbackArgs_result)(SP) // result
LEAQ 24(SP), AX
// Call cgocallback, which will call callbackWrap(frame).
MOVQ $0, 16(SP) // context
MOVQ AX, 8(SP) // frame (address of callbackArgs)
LEAQ ·callbackWrap<ABIInternal>(SB), BX // cgocallback takes an ABIInternal entry-point
MOVQ BX, 0(SP) // PC of function value to call (callbackWrap)
CALL ·cgocallback(SB)
// Get callback result.
MOVQ (24+callbackArgs_result)(SP), AX
ADDQ $(24+callbackArgs__size), SP
POP_REGS_HOST_TO_ABI0()
// The return value was placed in AX above.
RET
// uint32 tstart_stdcall(M *newm);
TEXT runtime·tstart_stdcall(SB),NOSPLIT|NOFRAME,$0
// Switch from the host ABI to the Go ABI.
PUSH_REGS_HOST_TO_ABI0()
// CX contains first arg newm
MOVQ m_g0(CX), DX // g
// Layout new m scheduler stack on os stack.
MOVQ SP, AX
MOVQ AX, (g_stack+stack_hi)(DX)
SUBQ $(64*1024), AX // initial stack size (adjusted later)
MOVQ AX, (g_stack+stack_lo)(DX)
ADDQ $const_stackGuard, AX
MOVQ AX, g_stackguard0(DX)
MOVQ AX, g_stackguard1(DX)
// Set up tls.
LEAQ m_tls(CX), DI
MOVQ CX, g_m(DX)
MOVQ DX, g(DI)
CALL runtime·settls(SB) // clobbers CX
CALL runtime·stackcheck(SB) // clobbers AX,CX
CALL runtime·mstart(SB)
POP_REGS_HOST_TO_ABI0()
XORL AX, AX // return 0 == success
RET
// set tls base to DI
TEXT runtime·settls(SB),NOSPLIT,$0
MOVQ runtime·tls_g(SB), CX
MOVQ DI, 0(CX)(GS)
RET
// Runs on OS stack.
// duration (in -100ns units) is in dt+0(FP).
// g may be nil.
// The function leaves room for 4 syscall parameters
// (as per windows amd64 calling convention).
TEXT runtime·usleep2(SB),NOSPLIT,$48-4
MOVLQSX dt+0(FP), BX
MOVQ SP, AX
ANDQ $~15, SP // alignment as per Windows requirement
MOVQ AX, 40(SP)
LEAQ 32(SP), R8 // ptime
MOVQ BX, (R8)
MOVQ $-1, CX // handle
MOVQ $0, DX // alertable
MOVQ runtime·_NtWaitForSingleObject(SB), AX
CALL AX
MOVQ 40(SP), SP
RET
// Runs on OS stack.
TEXT runtime·switchtothread(SB),NOSPLIT,$0
MOVQ SP, AX
ANDQ $~15, SP // alignment as per Windows requirement
SUBQ $(48), SP // room for SP and 4 args as per Windows requirement
// plus one extra word to keep stack 16 bytes aligned
MOVQ AX, 32(SP)
MOVQ runtime·_SwitchToThread(SB), AX
CALL AX
MOVQ 32(SP), SP
RET
TEXT runtime·nanotime1(SB),NOSPLIT,$0-8
CMPB runtime·useQPCTime(SB), $0
JNE useQPC
MOVQ $_INTERRUPT_TIME, DI
MOVQ time_lo(DI), AX
IMULQ $100, AX
MOVQ AX, ret+0(FP)
RET
useQPC:
JMP runtime·nanotimeQPC(SB)
RET
// func osSetupTLS(mp *m)
// Setup TLS. for use by needm on Windows.
TEXT runtime·osSetupTLS(SB),NOSPLIT,$0-8
MOVQ mp+0(FP), AX
LEAQ m_tls(AX), DI
CALL runtime·settls(SB)
RET
// This is called from rt0_go, which runs on the system stack
// using the initial stack allocated by the OS.
TEXT runtime·wintls(SB),NOSPLIT,$0
// Allocate a TLS slot to hold g across calls to external code
MOVQ SP, AX
ANDQ $~15, SP // alignment as per Windows requirement
SUBQ $48, SP // room for SP and 4 args as per Windows requirement
// plus one extra word to keep stack 16 bytes aligned
MOVQ AX, 32(SP)
MOVQ runtime·_TlsAlloc(SB), AX
CALL AX
MOVQ 32(SP), SP
MOVQ AX, CX // TLS index
// Assert that slot is less than 64 so we can use _TEB->TlsSlots
CMPQ CX, $64
JB ok
// Fallback to the TEB arbitrary pointer.
// TODO: don't use the arbitrary pointer (see go.dev/issue/59824)
MOVQ $TEB_ArbitraryPtr, CX
JMP settls
ok:
// Convert the TLS index at CX into
// an offset from TEB_TlsSlots.
SHLQ $3, CX
// Save offset from TLS into tls_g.
ADDQ $TEB_TlsSlots, CX
settls:
MOVQ CX, runtime·tls_g(SB)
RET