// Copyright 2009 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 "funcdata.h"
#include "textflag.h"
// _rt0_amd64 is common startup code for most amd64 systems when using
// internal linking. This is the entry point for the program from the
// kernel for an ordinary -buildmode=exe program. The stack holds the
// number of arguments and the C-style argv.
TEXT _rt0_amd64(SB),NOSPLIT,$-8
MOVQ 0(SP), DI // argc
LEAQ 8(SP), SI // argv
JMP runtime·rt0_go(SB)
// main is common startup code for most amd64 systems when using
// external linking. The C startup code will call the symbol "main"
// passing argc and argv in the usual C ABI registers DI and SI.
TEXT main(SB),NOSPLIT,$-8
JMP runtime·rt0_go(SB)
// _rt0_amd64_lib is common startup code for most amd64 systems when
// using -buildmode=c-archive or -buildmode=c-shared. The linker will
// arrange to invoke this function as a global constructor (for
// c-archive) or when the shared library is loaded (for c-shared).
// We expect argc and argv to be passed in the usual C ABI registers
// DI and SI.
TEXT _rt0_amd64_lib(SB),NOSPLIT,$0x50
// Align stack per ELF ABI requirements.
MOVQ SP, AX
ANDQ $~15, SP
// Save C ABI callee-saved registers, as caller may need them.
MOVQ BX, 0x10(SP)
MOVQ BP, 0x18(SP)
MOVQ R12, 0x20(SP)
MOVQ R13, 0x28(SP)
MOVQ R14, 0x30(SP)
MOVQ R15, 0x38(SP)
MOVQ AX, 0x40(SP)
MOVQ DI, _rt0_amd64_lib_argc<>(SB)
MOVQ SI, _rt0_amd64_lib_argv<>(SB)
// Synchronous initialization.
CALL runtime·libpreinit(SB)
// Create a new thread to finish Go runtime initialization.
MOVQ _cgo_sys_thread_create(SB), AX
TESTQ AX, AX
JZ nocgo
MOVQ $_rt0_amd64_lib_go(SB), DI
MOVQ $0, SI
CALL AX
JMP restore
nocgo:
MOVQ $0x800000, 0(SP) // stacksize
MOVQ $_rt0_amd64_lib_go(SB), AX
MOVQ AX, 8(SP) // fn
CALL runtime·newosproc0(SB)
restore:
MOVQ 0x10(SP), BX
MOVQ 0x18(SP), BP
MOVQ 0x20(SP), R12
MOVQ 0x28(SP), R13
MOVQ 0x30(SP), R14
MOVQ 0x38(SP), R15
MOVQ 0x40(SP), SP
RET
// _rt0_amd64_lib_go initializes the Go runtime.
// This is started in a separate thread by _rt0_amd64_lib.
TEXT _rt0_amd64_lib_go(SB),NOSPLIT,$0
MOVQ _rt0_amd64_lib_argc<>(SB), DI
MOVQ _rt0_amd64_lib_argv<>(SB), SI
JMP runtime·rt0_go(SB)
DATA _rt0_amd64_lib_argc<>(SB)/8, $0
GLOBL _rt0_amd64_lib_argc<>(SB),NOPTR, $8
DATA _rt0_amd64_lib_argv<>(SB)/8, $0
GLOBL _rt0_amd64_lib_argv<>(SB),NOPTR, $8
// Defined as ABIInternal since it does not use the stack-based Go ABI (and
// in addition there are no calls to this entry point from Go code).
TEXT runtime·rt0_go<ABIInternal>(SB),NOSPLIT,$0
// copy arguments forward on an even stack
MOVQ DI, AX // argc
MOVQ SI, BX // argv
SUBQ $(4*8+7), SP // 2args 2auto
ANDQ $~15, SP
MOVQ AX, 16(SP)
MOVQ BX, 24(SP)
// create istack out of the given (operating system) stack.
// _cgo_init may update stackguard.
MOVQ $runtime·g0(SB), DI
LEAQ (-64*1024+104)(SP), BX
MOVQ BX, g_stackguard0(DI)
MOVQ BX, g_stackguard1(DI)
MOVQ BX, (g_stack+stack_lo)(DI)
MOVQ SP, (g_stack+stack_hi)(DI)
// find out information about the processor we're on
MOVL $0, AX
CPUID
MOVL AX, SI
CMPL AX, $0
JE nocpuinfo
// Figure out how to serialize RDTSC.
// On Intel processors LFENCE is enough. AMD requires MFENCE.
// Don't know about the rest, so let's do MFENCE.
CMPL BX, $0x756E6547 // "Genu"
JNE notintel
CMPL DX, $0x49656E69 // "ineI"
JNE notintel
CMPL CX, $0x6C65746E // "ntel"
JNE notintel
MOVB $1, runtime·isIntel(SB)
MOVB $1, runtime·lfenceBeforeRdtsc(SB)
notintel:
// Load EAX=1 cpuid flags
MOVL $1, AX
CPUID
MOVL AX, runtime·processorVersionInfo(SB)
nocpuinfo:
// if there is an _cgo_init, call it.
MOVQ _cgo_init(SB), AX
TESTQ AX, AX
JZ needtls
// arg 1: g0, already in DI
MOVQ $setg_gcc<>(SB), SI // arg 2: setg_gcc
#ifdef GOOS_android
MOVQ $runtime·tls_g(SB), DX // arg 3: &tls_g
// arg 4: TLS base, stored in slot 0 (Android's TLS_SLOT_SELF).
// Compensate for tls_g (+16).
MOVQ -16(TLS), CX
#else
MOVQ $0, DX // arg 3, 4: not used when using platform's TLS
MOVQ $0, CX
#endif
#ifdef GOOS_windows
// Adjust for the Win64 calling convention.
MOVQ CX, R9 // arg 4
MOVQ DX, R8 // arg 3
MOVQ SI, DX // arg 2
MOVQ DI, CX // arg 1
#endif
CALL AX
// update stackguard after _cgo_init
MOVQ $runtime·g0(SB), CX
MOVQ (g_stack+stack_lo)(CX), AX
ADDQ $const__StackGuard, AX
MOVQ AX, g_stackguard0(CX)
MOVQ AX, g_stackguard1(CX)
#ifndef GOOS_windows
JMP ok
#endif
needtls:
#ifdef GOOS_plan9
// skip TLS setup on Plan 9
JMP ok
#endif
#ifdef GOOS_solaris
// skip TLS setup on Solaris
JMP ok
#endif
#ifdef GOOS_illumos
// skip TLS setup on illumos
JMP ok
#endif
#ifdef GOOS_darwin
// skip TLS setup on Darwin
JMP ok
#endif
#ifdef GOOS_openbsd
// skip TLS setup on OpenBSD
JMP ok
#endif
LEAQ runtime·m0+m_tls(SB), DI
CALL runtime·settls(SB)
// store through it, to make sure it works
get_tls(BX)
MOVQ $0x123, g(BX)
MOVQ runtime·m0+m_tls(SB), AX
CMPQ AX, $0x123
JEQ 2(PC)
CALL runtime·abort(SB)
ok:
// set the per-goroutine and per-mach "registers"
get_tls(BX)
LEAQ runtime·g0(SB), CX
MOVQ CX, g(BX)
LEAQ runtime·m0(SB), AX
// save m->g0 = g0
MOVQ CX, m_g0(AX)
// save m0 to g0->m
MOVQ AX, g_m(CX)
CLD // convention is D is always left cleared
CALL runtime·check(SB)
MOVL 16(SP), AX // copy argc
MOVL AX, 0(SP)
MOVQ 24(SP), AX // copy argv
MOVQ AX, 8(SP)
CALL runtime·args(SB)
CALL runtime·osinit(SB)
CALL runtime·schedinit(SB)
// create a new goroutine to start program
MOVQ $runtime·mainPC(SB), AX // entry
PUSHQ AX
PUSHQ $0 // arg size
CALL runtime·newproc(SB)
POPQ AX
POPQ AX
// start this M
CALL runtime·mstart(SB)
CALL runtime·abort(SB) // mstart should never return
RET
// Prevent dead-code elimination of debugCallV1, which is
// intended to be called by debuggers.
MOVQ $runtime·debugCallV1<ABIInternal>(SB), AX
RET
// mainPC is a function value for runtime.main, to be passed to newproc.
// The reference to runtime.main is made via ABIInternal, since the
// actual function (not the ABI0 wrapper) is needed by newproc.
DATA runtime·mainPC+0(SB)/8,$runtime·main<ABIInternal>(SB)
GLOBL runtime·mainPC(SB),RODATA,$8
TEXT runtime·breakpoint(SB),NOSPLIT,$0-0
BYTE $0xcc
RET
TEXT runtime·asminit(SB),NOSPLIT,$0-0
// No per-thread init.
RET
/*
* go-routine
*/
// func gosave(buf *gobuf)
// save state in Gobuf; setjmp
TEXT runtime·gosave(SB), NOSPLIT, $0-8
MOVQ buf+0(FP), AX // gobuf
LEAQ buf+0(FP), BX // caller's SP
MOVQ BX, gobuf_sp(AX)
MOVQ 0(SP), BX // caller's PC
MOVQ BX, gobuf_pc(AX)
MOVQ $0, gobuf_ret(AX)
MOVQ BP, gobuf_bp(AX)
// Assert ctxt is zero. See func save.
MOVQ gobuf_ctxt(AX), BX
TESTQ BX, BX
JZ 2(PC)
CALL runtime·badctxt(SB)
get_tls(CX)
MOVQ g(CX), BX
MOVQ BX, gobuf_g(AX)
RET
// func gogo(buf *gobuf)
// restore state from Gobuf; longjmp
TEXT runtime·gogo(SB), NOSPLIT, $16-8
MOVQ buf+0(FP), BX // gobuf
MOVQ gobuf_g(BX), DX
MOVQ 0(DX), CX // make sure g != nil
get_tls(CX)
MOVQ DX, g(CX)
MOVQ gobuf_sp(BX), SP // restore SP
MOVQ gobuf_ret(BX), AX
MOVQ gobuf_ctxt(BX), DX
MOVQ gobuf_bp(BX), BP
MOVQ $0, gobuf_sp(BX) // clear to help garbage collector
MOVQ $0, gobuf_ret(BX)
MOVQ $0, gobuf_ctxt(BX)
MOVQ $0, gobuf_bp(BX)
MOVQ gobuf_pc(BX), BX
JMP BX
// func mcall(fn func(*g))
// Switch to m->g0's stack, call fn(g).
// Fn must never return. It should gogo(&g->sched)
// to keep running g.
TEXT runtime·mcall(SB), NOSPLIT, $0-8
MOVQ fn+0(FP), DI
get_tls(CX)
MOVQ g(CX), AX // save state in g->sched
MOVQ 0(SP), BX // caller's PC
MOVQ BX, (g_sched+gobuf_pc)(AX)
LEAQ fn+0(FP), BX // caller's SP
MOVQ BX, (g_sched+gobuf_sp)(AX)
MOVQ AX, (g_sched+gobuf_g)(AX)
MOVQ BP, (g_sched+gobuf_bp)(AX)
// switch to m->g0 & its stack, call fn
MOVQ g(CX), BX
MOVQ g_m(BX), BX
MOVQ m_g0(BX), SI
CMPQ SI, AX // if g == m->g0 call badmcall
JNE 3(PC)
MOVQ $runtime·badmcall(SB), AX
JMP AX
MOVQ SI, g(CX) // g = m->g0
MOVQ (g_sched+gobuf_sp)(SI), SP // sp = m->g0->sched.sp
PUSHQ AX
MOVQ DI, DX
MOVQ 0(DI), DI
CALL DI
POPQ AX
MOVQ $runtime·badmcall2(SB), AX
JMP AX
RET
// systemstack_switch is a dummy routine that systemstack leaves at the bottom
// of the G stack. We need to distinguish the routine that
// lives at the bottom of the G stack from the one that lives
// at the top of the system stack because the one at the top of
// the system stack terminates the stack walk (see topofstack()).
TEXT runtime·systemstack_switch(SB), NOSPLIT, $0-0
RET
// func systemstack(fn func())
TEXT runtime·systemstack(SB), NOSPLIT, $0-8
MOVQ fn+0(FP), DI // DI = fn
get_tls(CX)
MOVQ g(CX), AX // AX = g
MOVQ g_m(AX), BX // BX = m
CMPQ AX, m_gsignal(BX)
JEQ noswitch
MOVQ m_g0(BX), DX // DX = g0
CMPQ AX, DX
JEQ noswitch
CMPQ AX, m_curg(BX)
JNE bad
// switch stacks
// save our state in g->sched. Pretend to
// be systemstack_switch if the G stack is scanned.
MOVQ $runtime·systemstack_switch(SB), SI
MOVQ SI, (g_sched+gobuf_pc)(AX)
MOVQ SP, (g_sched+gobuf_sp)(AX)
MOVQ AX, (g_sched+gobuf_g)(AX)
MOVQ BP, (g_sched+gobuf_bp)(AX)
// switch to g0
MOVQ DX, g(CX)
MOVQ (g_sched+gobuf_sp)(DX), BX
// make it look like mstart called systemstack on g0, to stop traceback
SUBQ $8, BX
MOVQ $runtime·mstart(SB), DX
MOVQ DX, 0(BX)
MOVQ BX, SP
// call target function
MOVQ DI, DX
MOVQ 0(DI), DI
CALL DI
// switch back to g
get_tls(CX)
MOVQ g(CX), AX
MOVQ g_m(AX), BX
MOVQ m_curg(BX), AX
MOVQ AX, g(CX)
MOVQ (g_sched+gobuf_sp)(AX), SP
MOVQ $0, (g_sched+gobuf_sp)(AX)
RET
noswitch:
// already on m stack; tail call the function
// Using a tail call here cleans up tracebacks since we won't stop
// at an intermediate systemstack.
MOVQ DI, DX
MOVQ 0(DI), DI
JMP DI
bad:
// Bad: g is not gsignal, not g0, not curg. What is it?
MOVQ $runtime·badsystemstack(SB), AX
CALL AX
INT $3
/*
* support for morestack
*/
// Called during function prolog when more stack is needed.
//
// The traceback routines see morestack on a g0 as being
// the top of a stack (for example, morestack calling newstack
// calling the scheduler calling newm calling gc), so we must
// record an argument size. For that purpose, it has no arguments.
TEXT runtime·morestack(SB),NOSPLIT,$0-0
// Cannot grow scheduler stack (m->g0).
get_tls(CX)
MOVQ g(CX), BX
MOVQ g_m(BX), BX
MOVQ m_g0(BX), SI
CMPQ g(CX), SI
JNE 3(PC)
CALL runtime·badmorestackg0(SB)
CALL runtime·abort(SB)
// Cannot grow signal stack (m->gsignal).
MOVQ m_gsignal(BX), SI
CMPQ g(CX), SI
JNE 3(PC)
CALL runtime·badmorestackgsignal(SB)
CALL runtime·abort(SB)
// Called from f.
// Set m->morebuf to f's caller.
NOP SP // tell vet SP changed - stop checking offsets
MOVQ 8(SP), AX // f's caller's PC
MOVQ AX, (m_morebuf+gobuf_pc)(BX)
LEAQ 16(SP), AX // f's caller's SP
MOVQ AX, (m_morebuf+gobuf_sp)(BX)
get_tls(CX)
MOVQ g(CX), SI
MOVQ SI, (m_morebuf+gobuf_g)(BX)
// Set g->sched to context in f.
MOVQ 0(SP), AX // f's PC
MOVQ AX, (g_sched+gobuf_pc)(SI)
MOVQ SI, (g_sched+gobuf_g)(SI)
LEAQ 8(SP), AX // f's SP
MOVQ AX, (g_sched+gobuf_sp)(SI)
MOVQ BP, (g_sched+gobuf_bp)(SI)
MOVQ DX, (g_sched+gobuf_ctxt)(SI)
// Call newstack on m->g0's stack.
MOVQ m_g0(BX), BX
MOVQ BX, g(CX)
MOVQ (g_sched+gobuf_sp)(BX), SP
CALL runtime·newstack(SB)
CALL runtime·abort(SB) // crash if newstack returns
RET
// morestack but not preserving ctxt.
TEXT runtime·morestack_noctxt(SB),NOSPLIT,$0
MOVL $0, DX
JMP runtime·morestack(SB)
// reflectcall: call a function with the given argument list
// func call(argtype *_type, f *FuncVal, arg *byte, argsize, retoffset uint32).
// we don't have variable-sized frames, so we use a small number
// of constant-sized-frame functions to encode a few bits of size in the pc.
// Caution: ugly multiline assembly macros in your future!
#define DISPATCH(NAME,MAXSIZE) \
CMPQ CX, $MAXSIZE; \
JA 3(PC); \
MOVQ $NAME(SB), AX; \
JMP AX
// Note: can't just "JMP NAME(SB)" - bad inlining results.
TEXT ·reflectcall<ABIInternal>(SB), NOSPLIT, $0-32
MOVLQZX argsize+24(FP), CX
DISPATCH(runtime·call16, 16)
DISPATCH(runtime·call32, 32)
DISPATCH(runtime·call64, 64)
DISPATCH(runtime·call128, 128)
DISPATCH(runtime·call256, 256)
DISPATCH(runtime·call512, 512)
DISPATCH(runtime·call1024, 1024)
DISPATCH(runtime·call2048, 2048)
DISPATCH(runtime·call4096, 4096)
DISPATCH(runtime·call8192, 8192)
DISPATCH(runtime·call16384, 16384)
DISPATCH(runtime·call32768, 32768)
DISPATCH(runtime·call65536, 65536)
DISPATCH(runtime·call131072, 131072)
DISPATCH(runtime·call262144, 262144)
DISPATCH(runtime·call524288, 524288)
DISPATCH(runtime·call1048576, 1048576)
DISPATCH(runtime·call2097152, 2097152)
DISPATCH(runtime·call4194304, 4194304)
DISPATCH(runtime·call8388608, 8388608)
DISPATCH(runtime·call16777216, 16777216)
DISPATCH(runtime·call33554432, 33554432)
DISPATCH(runtime·call67108864, 67108864)
DISPATCH(runtime·call134217728, 134217728)
DISPATCH(runtime·call268435456, 268435456)
DISPATCH(runtime·call536870912, 536870912)
DISPATCH(runtime·call1073741824, 1073741824)
MOVQ $runtime·badreflectcall(SB), AX
JMP AX
#define CALLFN(NAME,MAXSIZE) \
TEXT NAME(SB), WRAPPER, $MAXSIZE-32; \
NO_LOCAL_POINTERS; \
/* copy arguments to stack */ \
MOVQ argptr+16(FP), SI; \
MOVLQZX argsize+24(FP), CX; \
MOVQ SP, DI; \
REP;MOVSB; \
/* call function */ \
MOVQ f+8(FP), DX; \
PCDATA $PCDATA_StackMapIndex, $0; \
MOVQ (DX), AX; \
CALL AX; \
/* copy return values back */ \
MOVQ argtype+0(FP), DX; \
MOVQ argptr+16(FP), DI; \
MOVLQZX argsize+24(FP), CX; \
MOVLQZX retoffset+28(FP), BX; \
MOVQ SP, SI; \
ADDQ BX, DI; \
ADDQ BX, SI; \
SUBQ BX, CX; \
CALL callRet<>(SB); \
RET
// callRet copies return values back at the end of call*. This is a
// separate function so it can allocate stack space for the arguments
// to reflectcallmove. It does not follow the Go ABI; it expects its
// arguments in registers.
TEXT callRet<>(SB), NOSPLIT, $32-0
NO_LOCAL_POINTERS
MOVQ DX, 0(SP)
MOVQ DI, 8(SP)
MOVQ SI, 16(SP)
MOVQ CX, 24(SP)
CALL runtime·reflectcallmove(SB)
RET
CALLFN(·call16, 16)
CALLFN(·call32, 32)
CALLFN(·call64, 64)
CALLFN(·call128, 128)
CALLFN(·call256, 256)
CALLFN(·call512, 512)
CALLFN(·call1024, 1024)
CALLFN(·call2048, 2048)
CALLFN(·call4096, 4096)
CALLFN(·call8192, 8192)
CALLFN(·call16384, 16384)
CALLFN(·call32768, 32768)
CALLFN(·call65536, 65536)
CALLFN(·call131072, 131072)
CALLFN(·call262144, 262144)
CALLFN(·call524288, 524288)
CALLFN(·call1048576, 1048576)
CALLFN(·call2097152, 2097152)
CALLFN(·call4194304, 4194304)
CALLFN(·call8388608, 8388608)
CALLFN(·call16777216, 16777216)
CALLFN(·call33554432, 33554432)
CALLFN(·call67108864, 67108864)
CALLFN(·call134217728, 134217728)
CALLFN(·call268435456, 268435456)
CALLFN(·call536870912, 536870912)
CALLFN(·call1073741824, 1073741824)
TEXT runtime·procyield(SB),NOSPLIT,$0-0
MOVL cycles+0(FP), AX
again:
PAUSE
SUBL $1, AX
JNZ again
RET
TEXT ·publicationBarrier(SB),NOSPLIT,$0-0
// Stores are already ordered on x86, so this is just a
// compile barrier.
RET
// func jmpdefer(fv *funcval, argp uintptr)
// argp is a caller SP.
// called from deferreturn.
// 1. pop the caller
// 2. sub 5 bytes from the callers return
// 3. jmp to the argument
TEXT runtime·jmpdefer(SB), NOSPLIT, $0-16
MOVQ fv+0(FP), DX // fn
MOVQ argp+8(FP), BX // caller sp
LEAQ -8(BX), SP // caller sp after CALL
MOVQ -8(SP), BP // restore BP as if deferreturn returned (harmless if framepointers not in use)
SUBQ $5, (SP) // return to CALL again
MOVQ 0(DX), BX
JMP BX // but first run the deferred function
// Save state of caller into g->sched. Smashes R8, R9.
TEXT gosave<>(SB),NOSPLIT,$0
get_tls(R8)
MOVQ g(R8), R8
MOVQ 0(SP), R9
MOVQ R9, (g_sched+gobuf_pc)(R8)
LEAQ 8(SP), R9
MOVQ R9, (g_sched+gobuf_sp)(R8)
MOVQ $0, (g_sched+gobuf_ret)(R8)
MOVQ BP, (g_sched+gobuf_bp)(R8)
// Assert ctxt is zero. See func save.
MOVQ (g_sched+gobuf_ctxt)(R8), R9
TESTQ R9, R9
JZ 2(PC)
CALL runtime·badctxt(SB)
RET
// func asmcgocall(fn, arg unsafe.Pointer) int32
// Call fn(arg) on the scheduler stack,
// aligned appropriately for the gcc ABI.
// See cgocall.go for more details.
TEXT ·asmcgocall(SB),NOSPLIT,$0-20
MOVQ fn+0(FP), AX
MOVQ arg+8(FP), BX
MOVQ SP, DX
// Figure out if we need to switch to m->g0 stack.
// We get called to create new OS threads too, and those
// come in on the m->g0 stack already.
get_tls(CX)
MOVQ g(CX), R8
CMPQ R8, $0
JEQ nosave
MOVQ g_m(R8), R8
MOVQ m_g0(R8), SI
MOVQ g(CX), DI
CMPQ SI, DI
JEQ nosave
MOVQ m_gsignal(R8), SI
CMPQ SI, DI
JEQ nosave
// Switch to system stack.
MOVQ m_g0(R8), SI
CALL gosave<>(SB)
MOVQ SI, g(CX)
MOVQ (g_sched+gobuf_sp)(SI), SP
// Now on a scheduling stack (a pthread-created stack).
// Make sure we have enough room for 4 stack-backed fast-call
// registers as per windows amd64 calling convention.
SUBQ $64, SP
ANDQ $~15, SP // alignment for gcc ABI
MOVQ DI, 48(SP) // save g
MOVQ (g_stack+stack_hi)(DI), DI
SUBQ DX, DI
MOVQ DI, 40(SP) // save depth in stack (can't just save SP, as stack might be copied during a callback)
MOVQ BX, DI // DI = first argument in AMD64 ABI
MOVQ BX, CX // CX = first argument in Win64
CALL AX
// Restore registers, g, stack pointer.
get_tls(CX)
MOVQ 48(SP), DI
MOVQ (g_stack+stack_hi)(DI), SI
SUBQ 40(SP), SI
MOVQ DI, g(CX)
MOVQ SI, SP
MOVL AX, ret+16(FP)
RET
nosave:
// Running on a system stack, perhaps even without a g.
// Having no g can happen during thread creation or thread teardown
// (see needm/dropm on Solaris, for example).
// This code is like the above sequence but without saving/restoring g
// and without worrying about the stack moving out from under us
// (because we're on a system stack, not a goroutine stack).
// The above code could be used directly if already on a system stack,
// but then the only path through this code would be a rare case on Solaris.
// Using this code for all "already on system stack" calls exercises it more,
// which should help keep it correct.
SUBQ $64, SP
ANDQ $~15, SP
MOVQ $0, 48(SP) // where above code stores g, in case someone looks during debugging
MOVQ DX, 40(SP) // save original stack pointer
MOVQ BX, DI // DI = first argument in AMD64 ABI
MOVQ BX, CX // CX = first argument in Win64
CALL AX
MOVQ 40(SP), SI // restore original stack pointer
MOVQ SI, SP
MOVL AX, ret+16(FP)
RET
// func cgocallback(fn, frame unsafe.Pointer, ctxt uintptr)
// See cgocall.go for more details.
TEXT ·cgocallback(SB),NOSPLIT,$24-24
NO_LOCAL_POINTERS
// If g is nil, Go did not create the current thread.
// Call needm to obtain one m for temporary use.
// In this case, we're running on the thread stack, so there's
// lots of space, but the linker doesn't know. Hide the call from
// the linker analysis by using an indirect call through AX.
get_tls(CX)
#ifdef GOOS_windows
MOVL $0, BX
CMPQ CX, $0
JEQ 2(PC)
#endif
MOVQ g(CX), BX
CMPQ BX, $0
JEQ needm
MOVQ g_m(BX), BX
MOVQ BX, savedm-8(SP) // saved copy of oldm
JMP havem
needm:
MOVQ $runtime·needm(SB), AX
CALL AX
MOVQ $0, savedm-8(SP) // dropm on return
get_tls(CX)
MOVQ g(CX), BX
MOVQ g_m(BX), BX
// Set m->sched.sp = SP, so that if a panic happens
// during the function we are about to execute, it will
// have a valid SP to run on the g0 stack.
// The next few lines (after the havem label)
// will save this SP onto the stack and then write
// the same SP back to m->sched.sp. That seems redundant,
// but if an unrecovered panic happens, unwindm will
// restore the g->sched.sp from the stack location
// and then systemstack will try to use it. If we don't set it here,
// that restored SP will be uninitialized (typically 0) and
// will not be usable.
MOVQ m_g0(BX), SI
MOVQ SP, (g_sched+gobuf_sp)(SI)
havem:
// Now there's a valid m, and we're running on its m->g0.
// Save current m->g0->sched.sp on stack and then set it to SP.
// Save current sp in m->g0->sched.sp in preparation for
// switch back to m->curg stack.
// NOTE: unwindm knows that the saved g->sched.sp is at 0(SP).
MOVQ m_g0(BX), SI
MOVQ (g_sched+gobuf_sp)(SI), AX
MOVQ AX, 0(SP)
MOVQ SP, (g_sched+gobuf_sp)(SI)
// Switch to m->curg stack and call runtime.cgocallbackg.
// Because we are taking over the execution of m->curg
// but *not* resuming what had been running, we need to
// save that information (m->curg->sched) so we can restore it.
// We can restore m->curg->sched.sp easily, because calling
// runtime.cgocallbackg leaves SP unchanged upon return.
// To save m->curg->sched.pc, we push it onto the curg stack and
// open a frame the same size as cgocallback's g0 frame.
// Once we switch to the curg stack, the pushed PC will appear
// to be the return PC of cgocallback, so that the traceback
// will seamlessly trace back into the earlier calls.
MOVQ m_curg(BX), SI
MOVQ SI, g(CX)
MOVQ (g_sched+gobuf_sp)(SI), DI // prepare stack as DI
MOVQ (g_sched+gobuf_pc)(SI), BX
MOVQ BX, -8(DI) // "push" return PC on the g stack
// Gather our arguments into registers.
MOVQ fn+0(FP), BX
MOVQ frame+8(FP), CX
MOVQ ctxt+16(FP), DX
// Compute the size of the frame, including return PC and, if
// GOEXPERIMENT=framepointer, the saved base pointer
LEAQ fn+0(FP), AX
SUBQ SP, AX // AX is our actual frame size
SUBQ AX, DI // Allocate the same frame size on the g stack
MOVQ DI, SP
MOVQ BX, 0(SP)
MOVQ CX, 8(SP)
MOVQ DX, 16(SP)
CALL runtime·cgocallbackg(SB)
// Compute the size of the frame again. FP and SP have
// completely different values here than they did above,
// but only their difference matters.
LEAQ fn+0(FP), AX
SUBQ SP, AX
// Restore g->sched (== m->curg->sched) from saved values.
get_tls(CX)
MOVQ g(CX), SI
MOVQ SP, DI
ADDQ AX, DI
MOVQ -8(DI), BX
MOVQ BX, (g_sched+gobuf_pc)(SI)
MOVQ DI, (g_sched+gobuf_sp)(SI)
// Switch back to m->g0's stack and restore m->g0->sched.sp.
// (Unlike m->curg, the g0 goroutine never uses sched.pc,
// so we do not have to restore it.)
MOVQ g(CX), BX
MOVQ g_m(BX), BX
MOVQ m_g0(BX), SI
MOVQ SI, g(CX)
MOVQ (g_sched+gobuf_sp)(SI), SP
MOVQ 0(SP), AX
MOVQ AX, (g_sched+gobuf_sp)(SI)
// If the m on entry was nil, we called needm above to borrow an m
// for the duration of the call. Since the call is over, return it with dropm.
MOVQ savedm-8(SP), BX
CMPQ BX, $0
JNE 3(PC)
MOVQ $runtime·dropm(SB), AX
CALL AX
// Done!
RET
// func setg(gg *g)
// set g. for use by needm.
TEXT runtime·setg(SB), NOSPLIT, $0-8
MOVQ gg+0(FP), BX
#ifdef GOOS_windows
CMPQ BX, $0
JNE settls
MOVQ $0, 0x28(GS)
RET
settls:
MOVQ g_m(BX), AX
LEAQ m_tls(AX), AX
MOVQ AX, 0x28(GS)
#endif
get_tls(CX)
MOVQ BX, g(CX)
RET
// void setg_gcc(G*); set g called from gcc.
TEXT setg_gcc<>(SB),NOSPLIT,$0
get_tls(AX)
MOVQ DI, g(AX)
RET
TEXT runtime·abort(SB),NOSPLIT,$0-0
INT $3
loop:
JMP loop
// check that SP is in range [g->stack.lo, g->stack.hi)
TEXT runtime·stackcheck(SB), NOSPLIT, $0-0
get_tls(CX)
MOVQ g(CX), AX
CMPQ (g_stack+stack_hi)(AX), SP
JHI 2(PC)
CALL runtime·abort(SB)
CMPQ SP, (g_stack+stack_lo)(AX)
JHI 2(PC)
CALL runtime·abort(SB)
RET
// func cputicks() int64
TEXT runtime·cputicks(SB),NOSPLIT,$0-0
CMPB runtime·lfenceBeforeRdtsc(SB), $1
JNE mfence
LFENCE
JMP done
mfence:
MFENCE
done:
RDTSC
SHLQ $32, DX
ADDQ DX, AX
MOVQ AX, ret+0(FP)
RET
// func memhash(p unsafe.Pointer, h, s uintptr) uintptr
// hash function using AES hardware instructions
TEXT runtime·memhash(SB),NOSPLIT,$0-32
CMPB runtime·useAeshash(SB), $0
JEQ noaes
MOVQ p+0(FP), AX // ptr to data
MOVQ s+16(FP), CX // size
LEAQ ret+24(FP), DX
JMP aeshashbody<>(SB)
noaes:
JMP runtime·memhashFallback(SB)
// func strhash(p unsafe.Pointer, h uintptr) uintptr
TEXT runtime·strhash(SB),NOSPLIT,$0-24
CMPB runtime·useAeshash(SB), $0
JEQ noaes
MOVQ p+0(FP), AX // ptr to string struct
MOVQ 8(AX), CX // length of string
MOVQ (AX), AX // string data
LEAQ ret+16(FP), DX
JMP aeshashbody<>(SB)
noaes:
JMP runtime·strhashFallback(SB)
// AX: data
// CX: length
// DX: address to put return value
TEXT aeshashbody<>(SB),NOSPLIT,$0-0
// Fill an SSE register with our seeds.
MOVQ h+8(FP), X0 // 64 bits of per-table hash seed
PINSRW $4, CX, X0 // 16 bits of length
PSHUFHW $0, X0, X0 // repeat length 4 times total
MOVO X0, X1 // save unscrambled seed
PXOR runtime·aeskeysched(SB), X0 // xor in per-process seed
AESENC X0, X0 // scramble seed
CMPQ CX, $16
JB aes0to15
JE aes16
CMPQ CX, $32
JBE aes17to32
CMPQ CX, $64
JBE aes33to64
CMPQ CX, $128
JBE aes65to128
JMP aes129plus
aes0to15:
TESTQ CX, CX
JE aes0
ADDQ $16, AX
TESTW $0xff0, AX
JE endofpage
// 16 bytes loaded at this address won't cross
// a page boundary, so we can load it directly.
MOVOU -16(AX), X1
ADDQ CX, CX
MOVQ $masks<>(SB), AX
PAND (AX)(CX*8), X1
final1:
PXOR X0, X1 // xor data with seed
AESENC X1, X1 // scramble combo 3 times
AESENC X1, X1
AESENC X1, X1
MOVQ X1, (DX)
RET
endofpage:
// address ends in 1111xxxx. Might be up against
// a page boundary, so load ending at last byte.
// Then shift bytes down using pshufb.
MOVOU -32(AX)(CX*1), X1
ADDQ CX, CX
MOVQ $shifts<>(SB), AX
PSHUFB (AX)(CX*8), X1
JMP final1
aes0:
// Return scrambled input seed
AESENC X0, X0
MOVQ X0, (DX)
RET
aes16:
MOVOU (AX), X1
JMP final1
aes17to32:
// make second starting seed
PXOR runtime·aeskeysched+16(SB), X1
AESENC X1, X1
// load data to be hashed
MOVOU (AX), X2
MOVOU -16(AX)(CX*1), X3
// xor with seed
PXOR X0, X2
PXOR X1, X3
// scramble 3 times
AESENC X2, X2
AESENC X3, X3
AESENC X2, X2
AESENC X3, X3
AESENC X2, X2
AESENC X3, X3
// combine results
PXOR X3, X2
MOVQ X2, (DX)
RET
aes33to64:
// make 3 more starting seeds
MOVO X1, X2
MOVO X1, X3
PXOR runtime·aeskeysched+16(SB), X1
PXOR runtime·aeskeysched+32(SB), X2
PXOR runtime·aeskeysched+48(SB), X3
AESENC X1, X1
AESENC X2, X2
AESENC X3, X3
MOVOU (AX), X4
MOVOU 16(AX), X5
MOVOU -32(AX)(CX*1), X6
MOVOU -16(AX)(CX*1), X7
PXOR X0, X4
PXOR X1, X5
PXOR X2, X6
PXOR X3, X7
AESENC X4, X4
AESENC X5, X5
AESENC X6, X6
AESENC X7, X7
AESENC X4, X4
AESENC X5, X5
AESENC X6, X6
AESENC X7, X7
AESENC X4, X4
AESENC X5, X5
AESENC X6, X6
AESENC X7, X7
PXOR X6, X4
PXOR X7, X5
PXOR X5, X4
MOVQ X4, (DX)
RET
aes65to128:
// make 7 more starting seeds
MOVO X1, X2
MOVO X1, X3
MOVO X1, X4
MOVO X1, X5
MOVO X1, X6
MOVO X1, X7
PXOR runtime·aeskeysched+16(SB), X1
PXOR runtime·aeskeysched+32(SB), X2
PXOR runtime·aeskeysched+48(SB), X3
PXOR runtime·aeskeysched+64(SB), X4
PXOR runtime·aeskeysched+80(SB), X5
PXOR runtime·aeskeysched+96(SB), X6
PXOR runtime·aeskeysched+112(SB), X7
AESENC X1, X1
AESENC X2, X2
AESENC X3, X3
AESENC X4, X4
AESENC X5, X5
AESENC X6, X6
AESENC X7, X7
// load data
MOVOU (AX), X8
MOVOU 16(AX), X9
MOVOU 32(AX), X10
MOVOU 48(AX), X11
MOVOU -64(AX)(CX*1), X12
MOVOU -48(AX)(CX*1), X13
MOVOU -32(AX)(CX*1), X14
MOVOU -16(AX)(CX*1), X15
// xor with seed
PXOR X0, X8
PXOR X1, X9
PXOR X2, X10
PXOR X3, X11
PXOR X4, X12
PXOR X5, X13
PXOR X6, X14
PXOR X7, X15
// scramble 3 times
AESENC X8, X8
AESENC X9, X9
AESENC X10, X10
AESENC X11, X11
AESENC X12, X12
AESENC X13, X13
AESENC X14, X14
AESENC X15, X15
AESENC X8, X8
AESENC X9, X9
AESENC X10, X10
AESENC X11, X11
AESENC X12, X12
AESENC X13, X13
AESENC X14, X14
AESENC X15, X15
AESENC X8, X8
AESENC X9, X9
AESENC X10, X10
AESENC X11, X11
AESENC X12, X12
AESENC X13, X13
AESENC X14, X14
AESENC X15, X15
// combine results
PXOR X12, X8
PXOR X13, X9
PXOR X14, X10
PXOR X15, X11
PXOR X10, X8
PXOR X11, X9
PXOR X9, X8
MOVQ X8, (DX)
RET
aes129plus:
// make 7 more starting seeds
MOVO X1, X2
MOVO X1, X3
MOVO X1, X4
MOVO X1, X5
MOVO X1, X6
MOVO X1, X7
PXOR runtime·aeskeysched+16(SB), X1
PXOR runtime·aeskeysched+32(SB), X2
PXOR runtime·aeskeysched+48(SB), X3
PXOR runtime·aeskeysched+64(SB), X4
PXOR runtime·aeskeysched+80(SB), X5
PXOR runtime·aeskeysched+96(SB), X6
PXOR runtime·aeskeysched+112(SB), X7
AESENC X1, X1
AESENC X2, X2
AESENC X3, X3
AESENC X4, X4
AESENC X5, X5
AESENC X6, X6
AESENC X7, X7
// start with last (possibly overlapping) block
MOVOU -128(AX)(CX*1), X8
MOVOU -112(AX)(CX*1), X9
MOVOU -96(AX)(CX*1), X10
MOVOU -80(AX)(CX*1), X11
MOVOU -64(AX)(CX*1), X12
MOVOU -48(AX)(CX*1), X13
MOVOU -32(AX)(CX*1), X14
MOVOU -16(AX)(CX*1), X15
// xor in seed
PXOR X0, X8
PXOR X1, X9
PXOR X2, X10
PXOR X3, X11
PXOR X4, X12
PXOR X5, X13
PXOR X6, X14
PXOR X7, X15
// compute number of remaining 128-byte blocks
DECQ CX
SHRQ $7, CX
aesloop:
// scramble state
AESENC X8, X8
AESENC X9, X9
AESENC X10, X10
AESENC X11, X11
AESENC X12, X12
AESENC X13, X13
AESENC X14, X14
AESENC X15, X15
// scramble state, xor in a block
MOVOU (AX), X0
MOVOU 16(AX), X1
MOVOU 32(AX), X2
MOVOU 48(AX), X3
AESENC X0, X8
AESENC X1, X9
AESENC X2, X10
AESENC X3, X11
MOVOU 64(AX), X4
MOVOU 80(AX), X5
MOVOU 96(AX), X6
MOVOU 112(AX), X7
AESENC X4, X12
AESENC X5, X13
AESENC X6, X14
AESENC X7, X15
ADDQ $128, AX
DECQ CX
JNE aesloop
// 3 more scrambles to finish
AESENC X8, X8
AESENC X9, X9
AESENC X10, X10
AESENC X11, X11
AESENC X12, X12
AESENC X13, X13
AESENC X14, X14
AESENC X15, X15
AESENC X8, X8
AESENC X9, X9
AESENC X10, X10
AESENC X11, X11
AESENC X12, X12
AESENC X13, X13
AESENC X14, X14
AESENC X15, X15
AESENC X8, X8
AESENC X9, X9
AESENC X10, X10
AESENC X11, X11
AESENC X12, X12
AESENC X13, X13
AESENC X14, X14
AESENC X15, X15
PXOR X12, X8
PXOR X13, X9
PXOR X14, X10
PXOR X15, X11
PXOR X10, X8
PXOR X11, X9
PXOR X9, X8
MOVQ X8, (DX)
RET
// func memhash32(p unsafe.Pointer, h uintptr) uintptr
TEXT runtime·memhash32(SB),NOSPLIT,$0-24
CMPB runtime·useAeshash(SB), $0
JEQ noaes
MOVQ p+0(FP), AX // ptr to data
MOVQ h+8(FP), X0 // seed
PINSRD $2, (AX), X0 // data
AESENC runtime·aeskeysched+0(SB), X0
AESENC runtime·aeskeysched+16(SB), X0
AESENC runtime·aeskeysched+32(SB), X0
MOVQ X0, ret+16(FP)
RET
noaes:
JMP runtime·memhash32Fallback(SB)
// func memhash64(p unsafe.Pointer, h uintptr) uintptr
TEXT runtime·memhash64(SB),NOSPLIT,$0-24
CMPB runtime·useAeshash(SB), $0
JEQ noaes
MOVQ p+0(FP), AX // ptr to data
MOVQ h+8(FP), X0 // seed
PINSRQ $1, (AX), X0 // data
AESENC runtime·aeskeysched+0(SB), X0
AESENC runtime·aeskeysched+16(SB), X0
AESENC runtime·aeskeysched+32(SB), X0
MOVQ X0, ret+16(FP)
RET
noaes:
JMP runtime·memhash64Fallback(SB)
// simple mask to get rid of data in the high part of the register.
DATA masks<>+0x00(SB)/8, $0x0000000000000000
DATA masks<>+0x08(SB)/8, $0x0000000000000000
DATA masks<>+0x10(SB)/8, $0x00000000000000ff
DATA masks<>+0x18(SB)/8, $0x0000000000000000
DATA masks<>+0x20(SB)/8, $0x000000000000ffff
DATA masks<>+0x28(SB)/8, $0x0000000000000000
DATA masks<>+0x30(SB)/8, $0x0000000000ffffff
DATA masks<>+0x38(SB)/8, $0x0000000000000000
DATA masks<>+0x40(SB)/8, $0x00000000ffffffff
DATA masks<>+0x48(SB)/8, $0x0000000000000000
DATA masks<>+0x50(SB)/8, $0x000000ffffffffff
DATA masks<>+0x58(SB)/8, $0x0000000000000000
DATA masks<>+0x60(SB)/8, $0x0000ffffffffffff
DATA masks<>+0x68(SB)/8, $0x0000000000000000
DATA masks<>+0x70(SB)/8, $0x00ffffffffffffff
DATA masks<>+0x78(SB)/8, $0x0000000000000000
DATA masks<>+0x80(SB)/8, $0xffffffffffffffff
DATA masks<>+0x88(SB)/8, $0x0000000000000000
DATA masks<>+0x90(SB)/8, $0xffffffffffffffff
DATA masks<>+0x98(SB)/8, $0x00000000000000ff
DATA masks<>+0xa0(SB)/8, $0xffffffffffffffff
DATA masks<>+0xa8(SB)/8, $0x000000000000ffff
DATA masks<>+0xb0(SB)/8, $0xffffffffffffffff
DATA masks<>+0xb8(SB)/8, $0x0000000000ffffff
DATA masks<>+0xc0(SB)/8, $0xffffffffffffffff
DATA masks<>+0xc8(SB)/8, $0x00000000ffffffff
DATA masks<>+0xd0(SB)/8, $0xffffffffffffffff
DATA masks<>+0xd8(SB)/8, $0x000000ffffffffff
DATA masks<>+0xe0(SB)/8, $0xffffffffffffffff
DATA masks<>+0xe8(SB)/8, $0x0000ffffffffffff
DATA masks<>+0xf0(SB)/8, $0xffffffffffffffff
DATA masks<>+0xf8(SB)/8, $0x00ffffffffffffff
GLOBL masks<>(SB),RODATA,$256
// func checkASM() bool
TEXT ·checkASM(SB),NOSPLIT,$0-1
// check that masks<>(SB) and shifts<>(SB) are aligned to 16-byte
MOVQ $masks<>(SB), AX
MOVQ $shifts<>(SB), BX
ORQ BX, AX
TESTQ $15, AX
SETEQ ret+0(FP)
RET
// these are arguments to pshufb. They move data down from
// the high bytes of the register to the low bytes of the register.
// index is how many bytes to move.
DATA shifts<>+0x00(SB)/8, $0x0000000000000000
DATA shifts<>+0x08(SB)/8, $0x0000000000000000
DATA shifts<>+0x10(SB)/8, $0xffffffffffffff0f
DATA shifts<>+0x18(SB)/8, $0xffffffffffffffff
DATA shifts<>+0x20(SB)/8, $0xffffffffffff0f0e
DATA shifts<>+0x28(SB)/8, $0xffffffffffffffff
DATA shifts<>+0x30(SB)/8, $0xffffffffff0f0e0d
DATA shifts<>+0x38(SB)/8, $0xffffffffffffffff
DATA shifts<>+0x40(SB)/8, $0xffffffff0f0e0d0c
DATA shifts<>+0x48(SB)/8, $0xffffffffffffffff
DATA shifts<>+0x50(SB)/8, $0xffffff0f0e0d0c0b
DATA shifts<>+0x58(SB)/8, $0xffffffffffffffff
DATA shifts<>+0x60(SB)/8, $0xffff0f0e0d0c0b0a
DATA shifts<>+0x68(SB)/8, $0xffffffffffffffff
DATA shifts<>+0x70(SB)/8, $0xff0f0e0d0c0b0a09
DATA shifts<>+0x78(SB)/8, $0xffffffffffffffff
DATA shifts<>+0x80(SB)/8, $0x0f0e0d0c0b0a0908
DATA shifts<>+0x88(SB)/8, $0xffffffffffffffff
DATA shifts<>+0x90(SB)/8, $0x0e0d0c0b0a090807
DATA shifts<>+0x98(SB)/8, $0xffffffffffffff0f
DATA shifts<>+0xa0(SB)/8, $0x0d0c0b0a09080706
DATA shifts<>+0xa8(SB)/8, $0xffffffffffff0f0e
DATA shifts<>+0xb0(SB)/8, $0x0c0b0a0908070605
DATA shifts<>+0xb8(SB)/8, $0xffffffffff0f0e0d
DATA shifts<>+0xc0(SB)/8, $0x0b0a090807060504
DATA shifts<>+0xc8(SB)/8, $0xffffffff0f0e0d0c
DATA shifts<>+0xd0(SB)/8, $0x0a09080706050403
DATA shifts<>+0xd8(SB)/8, $0xffffff0f0e0d0c0b
DATA shifts<>+0xe0(SB)/8, $0x0908070605040302
DATA shifts<>+0xe8(SB)/8, $0xffff0f0e0d0c0b0a
DATA shifts<>+0xf0(SB)/8, $0x0807060504030201
DATA shifts<>+0xf8(SB)/8, $0xff0f0e0d0c0b0a09
GLOBL shifts<>(SB),RODATA,$256
TEXT runtime·return0(SB), NOSPLIT, $0
MOVL $0, AX
RET
// Called from cgo wrappers, this function returns g->m->curg.stack.hi.
// Must obey the gcc calling convention.
TEXT _cgo_topofstack(SB),NOSPLIT,$0
get_tls(CX)
MOVQ g(CX), AX
MOVQ g_m(AX), AX
MOVQ m_curg(AX), AX
MOVQ (g_stack+stack_hi)(AX), AX
RET
// The top-most function running on a goroutine
// returns to goexit+PCQuantum. Defined as ABIInternal
// so as to make it identifiable to traceback (this
// function it used as a sentinel; traceback wants to
// see the func PC, not a wrapper PC).
TEXT runtime·goexit<ABIInternal>(SB),NOSPLIT,$0-0
BYTE $0x90 // NOP
CALL runtime·goexit1(SB) // does not return
// traceback from goexit1 must hit code range of goexit
BYTE $0x90 // NOP
// This is called from .init_array and follows the platform, not Go, ABI.
TEXT runtime·addmoduledata(SB),NOSPLIT,$0-0
PUSHQ R15 // The access to global variables below implicitly uses R15, which is callee-save
MOVQ runtime·lastmoduledatap(SB), AX
MOVQ DI, moduledata_next(AX)
MOVQ DI, runtime·lastmoduledatap(SB)
POPQ R15
RET
// gcWriteBarrier performs a heap pointer write and informs the GC.
//
// gcWriteBarrier does NOT follow the Go ABI. It takes two arguments:
// - DI is the destination of the write
// - AX is the value being written at DI
// It clobbers FLAGS. It does not clobber any general-purpose registers,
// but may clobber others (e.g., SSE registers).
// Defined as ABIInternal since it does not use the stack-based Go ABI.
TEXT runtime·gcWriteBarrier<ABIInternal>(SB),NOSPLIT,$120
// Save the registers clobbered by the fast path. This is slightly
// faster than having the caller spill these.
MOVQ R14, 104(SP)
MOVQ R13, 112(SP)
// TODO: Consider passing g.m.p in as an argument so they can be shared
// across a sequence of write barriers.
get_tls(R13)
MOVQ g(R13), R13
MOVQ g_m(R13), R13
MOVQ m_p(R13), R13
MOVQ (p_wbBuf+wbBuf_next)(R13), R14
// Increment wbBuf.next position.
LEAQ 16(R14), R14
MOVQ R14, (p_wbBuf+wbBuf_next)(R13)
CMPQ R14, (p_wbBuf+wbBuf_end)(R13)
// Record the write.
MOVQ AX, -16(R14) // Record value
// Note: This turns bad pointer writes into bad
// pointer reads, which could be confusing. We could avoid
// reading from obviously bad pointers, which would
// take care of the vast majority of these. We could
// patch this up in the signal handler, or use XCHG to
// combine the read and the write.
MOVQ (DI), R13
MOVQ R13, -8(R14) // Record *slot
// Is the buffer full? (flags set in CMPQ above)
JEQ flush
ret:
MOVQ 104(SP), R14
MOVQ 112(SP), R13
// Do the write.
MOVQ AX, (DI)
RET
flush:
// Save all general purpose registers since these could be
// clobbered by wbBufFlush and were not saved by the caller.
// It is possible for wbBufFlush to clobber other registers
// (e.g., SSE registers), but the compiler takes care of saving
// those in the caller if necessary. This strikes a balance
// with registers that are likely to be used.
//
// We don't have type information for these, but all code under
// here is NOSPLIT, so nothing will observe these.
//
// TODO: We could strike a different balance; e.g., saving X0
// and not saving GP registers that are less likely to be used.
MOVQ DI, 0(SP) // Also first argument to wbBufFlush
MOVQ AX, 8(SP) // Also second argument to wbBufFlush
MOVQ BX, 16(SP)
MOVQ CX, 24(SP)
MOVQ DX, 32(SP)
// DI already saved
MOVQ SI, 40(SP)
MOVQ BP, 48(SP)
MOVQ R8, 56(SP)
MOVQ R9, 64(SP)
MOVQ R10, 72(SP)
MOVQ R11, 80(SP)
MOVQ R12, 88(SP)
// R13 already saved
// R14 already saved
MOVQ R15, 96(SP)
// This takes arguments DI and AX
CALL runtime·wbBufFlush(SB)
MOVQ 0(SP), DI
MOVQ 8(SP), AX
MOVQ 16(SP), BX
MOVQ 24(SP), CX
MOVQ 32(SP), DX
MOVQ 40(SP), SI
MOVQ 48(SP), BP
MOVQ 56(SP), R8
MOVQ 64(SP), R9
MOVQ 72(SP), R10
MOVQ 80(SP), R11
MOVQ 88(SP), R12
MOVQ 96(SP), R15
JMP ret
// gcWriteBarrierCX is gcWriteBarrier, but with args in DI and CX.
// Defined as ABIInternal since it does not use the stable Go ABI.
TEXT runtime·gcWriteBarrierCX<ABIInternal>(SB),NOSPLIT,$0
XCHGQ CX, AX
CALL runtime·gcWriteBarrier<ABIInternal>(SB)
XCHGQ CX, AX
RET
// gcWriteBarrierDX is gcWriteBarrier, but with args in DI and DX.
// Defined as ABIInternal since it does not use the stable Go ABI.
TEXT runtime·gcWriteBarrierDX<ABIInternal>(SB),NOSPLIT,$0
XCHGQ DX, AX
CALL runtime·gcWriteBarrier<ABIInternal>(SB)
XCHGQ DX, AX
RET
// gcWriteBarrierBX is gcWriteBarrier, but with args in DI and BX.
// Defined as ABIInternal since it does not use the stable Go ABI.
TEXT runtime·gcWriteBarrierBX<ABIInternal>(SB),NOSPLIT,$0
XCHGQ BX, AX
CALL runtime·gcWriteBarrier<ABIInternal>(SB)
XCHGQ BX, AX
RET
// gcWriteBarrierBP is gcWriteBarrier, but with args in DI and BP.
// Defined as ABIInternal since it does not use the stable Go ABI.
TEXT runtime·gcWriteBarrierBP<ABIInternal>(SB),NOSPLIT,$0
XCHGQ BP, AX
CALL runtime·gcWriteBarrier<ABIInternal>(SB)
XCHGQ BP, AX
RET
// gcWriteBarrierSI is gcWriteBarrier, but with args in DI and SI.
// Defined as ABIInternal since it does not use the stable Go ABI.
TEXT runtime·gcWriteBarrierSI<ABIInternal>(SB),NOSPLIT,$0
XCHGQ SI, AX
CALL runtime·gcWriteBarrier<ABIInternal>(SB)
XCHGQ SI, AX
RET
// gcWriteBarrierR8 is gcWriteBarrier, but with args in DI and R8.
// Defined as ABIInternal since it does not use the stable Go ABI.
TEXT runtime·gcWriteBarrierR8<ABIInternal>(SB),NOSPLIT,$0
XCHGQ R8, AX
CALL runtime·gcWriteBarrier<ABIInternal>(SB)
XCHGQ R8, AX
RET
// gcWriteBarrierR9 is gcWriteBarrier, but with args in DI and R9.
// Defined as ABIInternal since it does not use the stable Go ABI.
TEXT runtime·gcWriteBarrierR9<ABIInternal>(SB),NOSPLIT,$0
XCHGQ R9, AX
CALL runtime·gcWriteBarrier<ABIInternal>(SB)
XCHGQ R9, AX
RET
DATA debugCallFrameTooLarge<>+0x00(SB)/20, $"call frame too large"
GLOBL debugCallFrameTooLarge<>(SB), RODATA, $20 // Size duplicated below
// debugCallV1 is the entry point for debugger-injected function
// calls on running goroutines. It informs the runtime that a
// debug call has been injected and creates a call frame for the
// debugger to fill in.
//
// To inject a function call, a debugger should:
// 1. Check that the goroutine is in state _Grunning and that
// there are at least 256 bytes free on the stack.
// 2. Push the current PC on the stack (updating SP).
// 3. Write the desired argument frame size at SP-16 (using the SP
// after step 2).
// 4. Save all machine registers (including flags and XMM reigsters)
// so they can be restored later by the debugger.
// 5. Set the PC to debugCallV1 and resume execution.
//
// If the goroutine is in state _Grunnable, then it's not generally
// safe to inject a call because it may return out via other runtime
// operations. Instead, the debugger should unwind the stack to find
// the return to non-runtime code, add a temporary breakpoint there,
// and inject the call once that breakpoint is hit.
//
// If the goroutine is in any other state, it's not safe to inject a call.
//
// This function communicates back to the debugger by setting RAX and
// invoking INT3 to raise a breakpoint signal. See the comments in the
// implementation for the protocol the debugger is expected to
// follow. InjectDebugCall in the runtime tests demonstrates this protocol.
//
// The debugger must ensure that any pointers passed to the function
// obey escape analysis requirements. Specifically, it must not pass
// a stack pointer to an escaping argument. debugCallV1 cannot check
// this invariant.
//
// This is ABIInternal because Go code injects its PC directly into new
// goroutine stacks.
TEXT runtime·debugCallV1<ABIInternal>(SB),NOSPLIT,$152-0
// Save all registers that may contain pointers so they can be
// conservatively scanned.
//
// We can't do anything that might clobber any of these
// registers before this.
MOVQ R15, r15-(14*8+8)(SP)
MOVQ R14, r14-(13*8+8)(SP)
MOVQ R13, r13-(12*8+8)(SP)
MOVQ R12, r12-(11*8+8)(SP)
MOVQ R11, r11-(10*8+8)(SP)
MOVQ R10, r10-(9*8+8)(SP)
MOVQ R9, r9-(8*8+8)(SP)
MOVQ R8, r8-(7*8+8)(SP)
MOVQ DI, di-(6*8+8)(SP)
MOVQ SI, si-(5*8+8)(SP)
MOVQ BP, bp-(4*8+8)(SP)
MOVQ BX, bx-(3*8+8)(SP)
MOVQ DX, dx-(2*8+8)(SP)
// Save the frame size before we clobber it. Either of the last
// saves could clobber this depending on whether there's a saved BP.
MOVQ frameSize-24(FP), DX // aka -16(RSP) before prologue
MOVQ CX, cx-(1*8+8)(SP)
MOVQ AX, ax-(0*8+8)(SP)
// Save the argument frame size.
MOVQ DX, frameSize-128(SP)
// Perform a safe-point check.
MOVQ retpc-8(FP), AX // Caller's PC
MOVQ AX, 0(SP)
CALL runtime·debugCallCheck(SB)
MOVQ 8(SP), AX
TESTQ AX, AX
JZ good
// The safety check failed. Put the reason string at the top
// of the stack.
MOVQ AX, 0(SP)
MOVQ 16(SP), AX
MOVQ AX, 8(SP)
// Set AX to 8 and invoke INT3. The debugger should get the
// reason a call can't be injected from the top of the stack
// and resume execution.
MOVQ $8, AX
BYTE $0xcc
JMP restore
good:
// Registers are saved and it's safe to make a call.
// Open up a call frame, moving the stack if necessary.
//
// Once the frame is allocated, this will set AX to 0 and
// invoke INT3. The debugger should write the argument
// frame for the call at SP, push the trapping PC on the
// stack, set the PC to the function to call, set RCX to point
// to the closure (if a closure call), and resume execution.
//
// If the function returns, this will set AX to 1 and invoke
// INT3. The debugger can then inspect any return value saved
// on the stack at SP and resume execution again.
//
// If the function panics, this will set AX to 2 and invoke INT3.
// The interface{} value of the panic will be at SP. The debugger
// can inspect the panic value and resume execution again.
#define DEBUG_CALL_DISPATCH(NAME,MAXSIZE) \
CMPQ AX, $MAXSIZE; \
JA 5(PC); \
MOVQ $NAME(SB), AX; \
MOVQ AX, 0(SP); \
CALL runtime·debugCallWrap(SB); \
JMP restore
MOVQ frameSize-128(SP), AX
DEBUG_CALL_DISPATCH(debugCall32<>, 32)
DEBUG_CALL_DISPATCH(debugCall64<>, 64)
DEBUG_CALL_DISPATCH(debugCall128<>, 128)
DEBUG_CALL_DISPATCH(debugCall256<>, 256)
DEBUG_CALL_DISPATCH(debugCall512<>, 512)
DEBUG_CALL_DISPATCH(debugCall1024<>, 1024)
DEBUG_CALL_DISPATCH(debugCall2048<>, 2048)
DEBUG_CALL_DISPATCH(debugCall4096<>, 4096)
DEBUG_CALL_DISPATCH(debugCall8192<>, 8192)
DEBUG_CALL_DISPATCH(debugCall16384<>, 16384)
DEBUG_CALL_DISPATCH(debugCall32768<>, 32768)
DEBUG_CALL_DISPATCH(debugCall65536<>, 65536)
// The frame size is too large. Report the error.
MOVQ $debugCallFrameTooLarge<>(SB), AX
MOVQ AX, 0(SP)
MOVQ $20, 8(SP) // length of debugCallFrameTooLarge string
MOVQ $8, AX
BYTE $0xcc
JMP restore
restore:
// Calls and failures resume here.
//
// Set AX to 16 and invoke INT3. The debugger should restore
// all registers except RIP and RSP and resume execution.
MOVQ $16, AX
BYTE $0xcc
// We must not modify flags after this point.
// Restore pointer-containing registers, which may have been
// modified from the debugger's copy by stack copying.
MOVQ ax-(0*8+8)(SP), AX
MOVQ cx-(1*8+8)(SP), CX
MOVQ dx-(2*8+8)(SP), DX
MOVQ bx-(3*8+8)(SP), BX
MOVQ bp-(4*8+8)(SP), BP
MOVQ si-(5*8+8)(SP), SI
MOVQ di-(6*8+8)(SP), DI
MOVQ r8-(7*8+8)(SP), R8
MOVQ r9-(8*8+8)(SP), R9
MOVQ r10-(9*8+8)(SP), R10
MOVQ r11-(10*8+8)(SP), R11
MOVQ r12-(11*8+8)(SP), R12
MOVQ r13-(12*8+8)(SP), R13
MOVQ r14-(13*8+8)(SP), R14
MOVQ r15-(14*8+8)(SP), R15
RET
// runtime.debugCallCheck assumes that functions defined with the
// DEBUG_CALL_FN macro are safe points to inject calls.
#define DEBUG_CALL_FN(NAME,MAXSIZE) \
TEXT NAME(SB),WRAPPER,$MAXSIZE-0; \
NO_LOCAL_POINTERS; \
MOVQ $0, AX; \
BYTE $0xcc; \
MOVQ $1, AX; \
BYTE $0xcc; \
RET
DEBUG_CALL_FN(debugCall32<>, 32)
DEBUG_CALL_FN(debugCall64<>, 64)
DEBUG_CALL_FN(debugCall128<>, 128)
DEBUG_CALL_FN(debugCall256<>, 256)
DEBUG_CALL_FN(debugCall512<>, 512)
DEBUG_CALL_FN(debugCall1024<>, 1024)
DEBUG_CALL_FN(debugCall2048<>, 2048)
DEBUG_CALL_FN(debugCall4096<>, 4096)
DEBUG_CALL_FN(debugCall8192<>, 8192)
DEBUG_CALL_FN(debugCall16384<>, 16384)
DEBUG_CALL_FN(debugCall32768<>, 32768)
DEBUG_CALL_FN(debugCall65536<>, 65536)
// func debugCallPanicked(val interface{})
TEXT runtime·debugCallPanicked(SB),NOSPLIT,$16-16
// Copy the panic value to the top of stack.
MOVQ val_type+0(FP), AX
MOVQ AX, 0(SP)
MOVQ val_data+8(FP), AX
MOVQ AX, 8(SP)
MOVQ $2, AX
BYTE $0xcc
RET
// Note: these functions use a special calling convention to save generated code space.
// Arguments are passed in registers, but the space for those arguments are allocated
// in the caller's stack frame. These stubs write the args into that stack space and
// then tail call to the corresponding runtime handler.
// The tail call makes these stubs disappear in backtraces.
// Defined as ABIInternal since they do not use the stack-based Go ABI.
TEXT runtime·panicIndex<ABIInternal>(SB),NOSPLIT,$0-16
MOVQ AX, x+0(FP)
MOVQ CX, y+8(FP)
JMP runtime·goPanicIndex(SB)
TEXT runtime·panicIndexU<ABIInternal>(SB),NOSPLIT,$0-16
MOVQ AX, x+0(FP)
MOVQ CX, y+8(FP)
JMP runtime·goPanicIndexU(SB)
TEXT runtime·panicSliceAlen<ABIInternal>(SB),NOSPLIT,$0-16
MOVQ CX, x+0(FP)
MOVQ DX, y+8(FP)
JMP runtime·goPanicSliceAlen(SB)
TEXT runtime·panicSliceAlenU<ABIInternal>(SB),NOSPLIT,$0-16
MOVQ CX, x+0(FP)
MOVQ DX, y+8(FP)
JMP runtime·goPanicSliceAlenU(SB)
TEXT runtime·panicSliceAcap<ABIInternal>(SB),NOSPLIT,$0-16
MOVQ CX, x+0(FP)
MOVQ DX, y+8(FP)
JMP runtime·goPanicSliceAcap(SB)
TEXT runtime·panicSliceAcapU<ABIInternal>(SB),NOSPLIT,$0-16
MOVQ CX, x+0(FP)
MOVQ DX, y+8(FP)
JMP runtime·goPanicSliceAcapU(SB)
TEXT runtime·panicSliceB<ABIInternal>(SB),NOSPLIT,$0-16
MOVQ AX, x+0(FP)
MOVQ CX, y+8(FP)
JMP runtime·goPanicSliceB(SB)
TEXT runtime·panicSliceBU<ABIInternal>(SB),NOSPLIT,$0-16
MOVQ AX, x+0(FP)
MOVQ CX, y+8(FP)
JMP runtime·goPanicSliceBU(SB)
TEXT runtime·panicSlice3Alen<ABIInternal>(SB),NOSPLIT,$0-16
MOVQ DX, x+0(FP)
MOVQ BX, y+8(FP)
JMP runtime·goPanicSlice3Alen(SB)
TEXT runtime·panicSlice3AlenU<ABIInternal>(SB),NOSPLIT,$0-16
MOVQ DX, x+0(FP)
MOVQ BX, y+8(FP)
JMP runtime·goPanicSlice3AlenU(SB)
TEXT runtime·panicSlice3Acap<ABIInternal>(SB),NOSPLIT,$0-16
MOVQ DX, x+0(FP)
MOVQ BX, y+8(FP)
JMP runtime·goPanicSlice3Acap(SB)
TEXT runtime·panicSlice3AcapU<ABIInternal>(SB),NOSPLIT,$0-16
MOVQ DX, x+0(FP)
MOVQ BX, y+8(FP)
JMP runtime·goPanicSlice3AcapU(SB)
TEXT runtime·panicSlice3B<ABIInternal>(SB),NOSPLIT,$0-16
MOVQ CX, x+0(FP)
MOVQ DX, y+8(FP)
JMP runtime·goPanicSlice3B(SB)
TEXT runtime·panicSlice3BU<ABIInternal>(SB),NOSPLIT,$0-16
MOVQ CX, x+0(FP)
MOVQ DX, y+8(FP)
JMP runtime·goPanicSlice3BU(SB)
TEXT runtime·panicSlice3C<ABIInternal>(SB),NOSPLIT,$0-16
MOVQ AX, x+0(FP)
MOVQ CX, y+8(FP)
JMP runtime·goPanicSlice3C(SB)
TEXT runtime·panicSlice3CU<ABIInternal>(SB),NOSPLIT,$0-16
MOVQ AX, x+0(FP)
MOVQ CX, y+8(FP)
JMP runtime·goPanicSlice3CU(SB)
#ifdef GOOS_android
// Use the free TLS_SLOT_APP slot #2 on Android Q.
// Earlier androids are set up in gcc_android.c.
DATA runtime·tls_g+0(SB)/8, $16
GLOBL runtime·tls_g+0(SB), NOPTR, $8
#endif
// The compiler and assembler's -spectre=ret mode rewrites
// all indirect CALL AX / JMP AX instructions to be
// CALL retpolineAX / JMP retpolineAX.
// See https://support.google.com/faqs/answer/7625886.
#define RETPOLINE(reg) \
/* CALL setup */ BYTE $0xE8; BYTE $(2+2); BYTE $0; BYTE $0; BYTE $0; \
/* nospec: */ \
/* PAUSE */ BYTE $0xF3; BYTE $0x90; \
/* JMP nospec */ BYTE $0xEB; BYTE $-(2+2); \
/* setup: */ \
/* MOVQ AX, 0(SP) */ BYTE $0x48|((reg&8)>>1); BYTE $0x89; \
BYTE $0x04|((reg&7)<<3); BYTE $0x24; \
/* RET */ BYTE $0xC3
TEXT runtime·retpolineAX(SB),NOSPLIT,$0; RETPOLINE(0)
TEXT runtime·retpolineCX(SB),NOSPLIT,$0; RETPOLINE(1)
TEXT runtime·retpolineDX(SB),NOSPLIT,$0; RETPOLINE(2)
TEXT runtime·retpolineBX(SB),NOSPLIT,$0; RETPOLINE(3)
/* SP is 4, can't happen / magic encodings */
TEXT runtime·retpolineBP(SB),NOSPLIT,$0; RETPOLINE(5)
TEXT runtime·retpolineSI(SB),NOSPLIT,$0; RETPOLINE(6)
TEXT runtime·retpolineDI(SB),NOSPLIT,$0; RETPOLINE(7)
TEXT runtime·retpolineR8(SB),NOSPLIT,$0; RETPOLINE(8)
TEXT runtime·retpolineR9(SB),NOSPLIT,$0; RETPOLINE(9)
TEXT runtime·retpolineR10(SB),NOSPLIT,$0; RETPOLINE(10)
TEXT runtime·retpolineR11(SB),NOSPLIT,$0; RETPOLINE(11)
TEXT runtime·retpolineR12(SB),NOSPLIT,$0; RETPOLINE(12)
TEXT runtime·retpolineR13(SB),NOSPLIT,$0; RETPOLINE(13)
TEXT runtime·retpolineR14(SB),NOSPLIT,$0; RETPOLINE(14)
TEXT runtime·retpolineR15(SB),NOSPLIT,$0; RETPOLINE(15)
 |
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Golds is a Go 101 project developed by Tapir Liu.
PR and bug reports are welcome and can be submitted to the issue list.
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