// Copyright 2014 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.
// +build ppc64 ppc64le
#include "go_asm.h"
#include "go_tls.h"
#include "funcdata.h"
#include "textflag.h"
#include "asm_ppc64x.h"
#ifdef GOOS_aix
#define cgoCalleeStackSize 48
#else
#define cgoCalleeStackSize 32
#endif
TEXT runtime·rt0_go(SB),NOSPLIT,$0
// R1 = stack; R3 = argc; R4 = argv; R13 = C TLS base pointer
// initialize essential registers
BL runtime·reginit(SB)
SUB $(FIXED_FRAME+16), R1
MOVD R2, 24(R1) // stash the TOC pointer away again now we've created a new frame
MOVW R3, FIXED_FRAME+0(R1) // argc
MOVD R4, FIXED_FRAME+8(R1) // argv
// create istack out of the given (operating system) stack.
// _cgo_init may update stackguard.
MOVD $runtime·g0(SB), g
BL runtime·save_g(SB)
MOVD $(-64*1024), R31
ADD R31, R1, R3
MOVD R3, g_stackguard0(g)
MOVD R3, g_stackguard1(g)
MOVD R3, (g_stack+stack_lo)(g)
MOVD R1, (g_stack+stack_hi)(g)
// if there is a _cgo_init, call it using the gcc ABI.
MOVD _cgo_init(SB), R12
CMP R0, R12
BEQ nocgo
#ifdef GOARCH_ppc64
// ppc64 use elf ABI v1. we must get the real entry address from
// first slot of the function descriptor before call.
MOVD 8(R12), R2
MOVD (R12), R12
#endif
MOVD R12, CTR // r12 = "global function entry point"
MOVD R13, R5 // arg 2: TLS base pointer
MOVD $setg_gcc<>(SB), R4 // arg 1: setg
MOVD g, R3 // arg 0: G
// C functions expect 32 (48 for AIX) bytes of space on caller
// stack frame and a 16-byte aligned R1
MOVD R1, R14 // save current stack
SUB $cgoCalleeStackSize, R1 // reserve the callee area
RLDCR $0, R1, $~15, R1 // 16-byte align
BL (CTR) // may clobber R0, R3-R12
MOVD R14, R1 // restore stack
#ifndef GOOS_aix
MOVD 24(R1), R2
#endif
XOR R0, R0 // fix R0
nocgo:
// update stackguard after _cgo_init
MOVD (g_stack+stack_lo)(g), R3
ADD $const__StackGuard, R3
MOVD R3, g_stackguard0(g)
MOVD R3, g_stackguard1(g)
// set the per-goroutine and per-mach "registers"
MOVD $runtime·m0(SB), R3
// save m->g0 = g0
MOVD g, m_g0(R3)
// save m0 to g0->m
MOVD R3, g_m(g)
BL runtime·check(SB)
// args are already prepared
BL runtime·args(SB)
BL runtime·osinit(SB)
BL runtime·schedinit(SB)
// create a new goroutine to start program
MOVD $runtime·mainPC(SB), R3 // entry
MOVDU R3, -8(R1)
MOVDU R0, -8(R1)
MOVDU R0, -8(R1)
MOVDU R0, -8(R1)
MOVDU R0, -8(R1)
MOVDU R0, -8(R1)
BL runtime·newproc(SB)
ADD $(16+FIXED_FRAME), R1
// start this M
BL runtime·mstart(SB)
MOVD R0, 0(R0)
RET
DATA runtime·mainPC+0(SB)/8,$runtime·main(SB)
GLOBL runtime·mainPC(SB),RODATA,$8
TEXT runtime·breakpoint(SB),NOSPLIT|NOFRAME,$0-0
MOVD R0, 0(R0) // TODO: TD
RET
TEXT runtime·asminit(SB),NOSPLIT|NOFRAME,$0-0
RET
// Any changes must be reflected to runtime/cgo/gcc_aix_ppc64.S:.crosscall_ppc64
TEXT _cgo_reginit(SB),NOSPLIT|NOFRAME,$0-0
// crosscall_ppc64 and crosscall2 need to reginit, but can't
// get at the 'runtime.reginit' symbol.
BR runtime·reginit(SB)
TEXT runtime·reginit(SB),NOSPLIT|NOFRAME,$0-0
// set R0 to zero, it's expected by the toolchain
XOR R0, R0
RET
/*
* go-routine
*/
// void gosave(Gobuf*)
// save state in Gobuf; setjmp
TEXT runtime·gosave(SB), NOSPLIT|NOFRAME, $0-8
MOVD buf+0(FP), R3
MOVD R1, gobuf_sp(R3)
MOVD LR, R31
MOVD R31, gobuf_pc(R3)
MOVD g, gobuf_g(R3)
MOVD R0, gobuf_lr(R3)
MOVD R0, gobuf_ret(R3)
// Assert ctxt is zero. See func save.
MOVD gobuf_ctxt(R3), R3
CMP R0, R3
BEQ 2(PC)
BL runtime·badctxt(SB)
RET
// void gogo(Gobuf*)
// restore state from Gobuf; longjmp
TEXT runtime·gogo(SB), NOSPLIT, $16-8
MOVD buf+0(FP), R5
MOVD gobuf_g(R5), g // make sure g is not nil
BL runtime·save_g(SB)
MOVD 0(g), R4
MOVD gobuf_sp(R5), R1
MOVD gobuf_lr(R5), R31
#ifndef GOOS_aix
MOVD 24(R1), R2 // restore R2
#endif
MOVD R31, LR
MOVD gobuf_ret(R5), R3
MOVD gobuf_ctxt(R5), R11
MOVD R0, gobuf_sp(R5)
MOVD R0, gobuf_ret(R5)
MOVD R0, gobuf_lr(R5)
MOVD R0, gobuf_ctxt(R5)
CMP R0, R0 // set condition codes for == test, needed by stack split
MOVD gobuf_pc(R5), R12
MOVD R12, CTR
BR (CTR)
// void 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|NOFRAME, $0-8
// Save caller state in g->sched
MOVD R1, (g_sched+gobuf_sp)(g)
MOVD LR, R31
MOVD R31, (g_sched+gobuf_pc)(g)
MOVD R0, (g_sched+gobuf_lr)(g)
MOVD g, (g_sched+gobuf_g)(g)
// Switch to m->g0 & its stack, call fn.
MOVD g, R3
MOVD g_m(g), R8
MOVD m_g0(R8), g
BL runtime·save_g(SB)
CMP g, R3
BNE 2(PC)
BR runtime·badmcall(SB)
MOVD fn+0(FP), R11 // context
MOVD 0(R11), R12 // code pointer
MOVD R12, CTR
MOVD (g_sched+gobuf_sp)(g), R1 // sp = m->g0->sched.sp
MOVDU R3, -8(R1)
MOVDU R0, -8(R1)
MOVDU R0, -8(R1)
MOVDU R0, -8(R1)
MOVDU R0, -8(R1)
BL (CTR)
MOVD 24(R1), R2
BR runtime·badmcall2(SB)
// 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
// We have several undefs here so that 16 bytes past
// $runtime·systemstack_switch lies within them whether or not the
// instructions that derive r2 from r12 are there.
UNDEF
UNDEF
UNDEF
BL (LR) // make sure this function is not leaf
RET
// func systemstack(fn func())
TEXT runtime·systemstack(SB), NOSPLIT, $0-8
MOVD fn+0(FP), R3 // R3 = fn
MOVD R3, R11 // context
MOVD g_m(g), R4 // R4 = m
MOVD m_gsignal(R4), R5 // R5 = gsignal
CMP g, R5
BEQ noswitch
MOVD m_g0(R4), R5 // R5 = g0
CMP g, R5
BEQ noswitch
MOVD m_curg(R4), R6
CMP g, R6
BEQ switch
// Bad: g is not gsignal, not g0, not curg. What is it?
// Hide call from linker nosplit analysis.
MOVD $runtime·badsystemstack(SB), R12
MOVD R12, CTR
BL (CTR)
BL runtime·abort(SB)
switch:
// save our state in g->sched. Pretend to
// be systemstack_switch if the G stack is scanned.
MOVD $runtime·systemstack_switch(SB), R6
ADD $16, R6 // get past prologue (including r2-setting instructions when they're there)
MOVD R6, (g_sched+gobuf_pc)(g)
MOVD R1, (g_sched+gobuf_sp)(g)
MOVD R0, (g_sched+gobuf_lr)(g)
MOVD g, (g_sched+gobuf_g)(g)
// switch to g0
MOVD R5, g
BL runtime·save_g(SB)
MOVD (g_sched+gobuf_sp)(g), R3
// make it look like mstart called systemstack on g0, to stop traceback
SUB $FIXED_FRAME, R3
MOVD $runtime·mstart(SB), R4
MOVD R4, 0(R3)
MOVD R3, R1
// call target function
MOVD 0(R11), R12 // code pointer
MOVD R12, CTR
BL (CTR)
// restore TOC pointer. It seems unlikely that we will use systemstack
// to call a function defined in another module, but the results of
// doing so would be so confusing that it's worth doing this.
MOVD g_m(g), R3
MOVD m_curg(R3), g
MOVD (g_sched+gobuf_sp)(g), R3
#ifndef GOOS_aix
MOVD 24(R3), R2
#endif
// switch back to g
MOVD g_m(g), R3
MOVD m_curg(R3), g
BL runtime·save_g(SB)
MOVD (g_sched+gobuf_sp)(g), R1
MOVD R0, (g_sched+gobuf_sp)(g)
RET
noswitch:
// already on m stack, just call directly
// On other arches we do a tail call here, but it appears to be
// impossible to tail call a function pointer in shared mode on
// ppc64 because the caller is responsible for restoring the TOC.
MOVD 0(R11), R12 // code pointer
MOVD R12, CTR
BL (CTR)
#ifndef GOOS_aix
MOVD 24(R1), R2
#endif
RET
/*
* support for morestack
*/
// Called during function prolog when more stack is needed.
// Caller has already loaded:
// R3: framesize, R4: argsize, R5: LR
//
// 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|NOFRAME,$0-0
// Cannot grow scheduler stack (m->g0).
MOVD g_m(g), R7
MOVD m_g0(R7), R8
CMP g, R8
BNE 3(PC)
BL runtime·badmorestackg0(SB)
BL runtime·abort(SB)
// Cannot grow signal stack (m->gsignal).
MOVD m_gsignal(R7), R8
CMP g, R8
BNE 3(PC)
BL runtime·badmorestackgsignal(SB)
BL runtime·abort(SB)
// Called from f.
// Set g->sched to context in f.
MOVD R1, (g_sched+gobuf_sp)(g)
MOVD LR, R8
MOVD R8, (g_sched+gobuf_pc)(g)
MOVD R5, (g_sched+gobuf_lr)(g)
MOVD R11, (g_sched+gobuf_ctxt)(g)
// Called from f.
// Set m->morebuf to f's caller.
MOVD R5, (m_morebuf+gobuf_pc)(R7) // f's caller's PC
MOVD R1, (m_morebuf+gobuf_sp)(R7) // f's caller's SP
MOVD g, (m_morebuf+gobuf_g)(R7)
// Call newstack on m->g0's stack.
MOVD m_g0(R7), g
BL runtime·save_g(SB)
MOVD (g_sched+gobuf_sp)(g), R1
MOVDU R0, -(FIXED_FRAME+0)(R1) // create a call frame on g0
BL runtime·newstack(SB)
// Not reached, but make sure the return PC from the call to newstack
// is still in this function, and not the beginning of the next.
UNDEF
TEXT runtime·morestack_noctxt(SB),NOSPLIT|NOFRAME,$0-0
MOVD R0, R11
BR 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) \
MOVD $MAXSIZE, R31; \
CMP R3, R31; \
BGT 4(PC); \
MOVD $NAME(SB), R12; \
MOVD R12, CTR; \
BR (CTR)
// Note: can't just "BR NAME(SB)" - bad inlining results.
TEXT ·reflectcall(SB), NOSPLIT|NOFRAME, $0-32
MOVWZ argsize+24(FP), R3
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)
MOVD $runtime·badreflectcall(SB), R12
MOVD R12, CTR
BR (CTR)
#define CALLFN(NAME,MAXSIZE) \
TEXT NAME(SB), WRAPPER, $MAXSIZE-24; \
NO_LOCAL_POINTERS; \
/* copy arguments to stack */ \
MOVD arg+16(FP), R3; \
MOVWZ argsize+24(FP), R4; \
MOVD R1, R5; \
CMP R4, $8; \
BLT tailsetup; \
/* copy 8 at a time if possible */ \
ADD $(FIXED_FRAME-8), R5; \
SUB $8, R3; \
top: \
MOVDU 8(R3), R7; \
MOVDU R7, 8(R5); \
SUB $8, R4; \
CMP R4, $8; \
BGE top; \
/* handle remaining bytes */ \
CMP $0, R4; \
BEQ callfn; \
ADD $7, R3; \
ADD $7, R5; \
BR tail; \
tailsetup: \
CMP $0, R4; \
BEQ callfn; \
ADD $(FIXED_FRAME-1), R5; \
SUB $1, R3; \
tail: \
MOVBU 1(R3), R6; \
MOVBU R6, 1(R5); \
SUB $1, R4; \
CMP $0, R4; \
BGT tail; \
callfn: \
/* call function */ \
MOVD f+8(FP), R11; \
#ifdef GOOS_aix \
/* AIX won't trigger a SIGSEGV if R11 = nil */ \
/* So it manually triggers it */ \
CMP R0, R11 \
BNE 2(PC) \
MOVD R0, 0(R0) \
#endif \
MOVD (R11), R12; \
MOVD R12, CTR; \
PCDATA $PCDATA_StackMapIndex, $0; \
BL (CTR); \
#ifndef GOOS_aix \
MOVD 24(R1), R2; \
#endif \
/* copy return values back */ \
MOVD argtype+0(FP), R7; \
MOVD arg+16(FP), R3; \
MOVWZ n+24(FP), R4; \
MOVWZ retoffset+28(FP), R6; \
ADD $FIXED_FRAME, R1, R5; \
ADD R6, R5; \
ADD R6, R3; \
SUB R6, R4; \
BL 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
MOVD R7, FIXED_FRAME+0(R1)
MOVD R3, FIXED_FRAME+8(R1)
MOVD R5, FIXED_FRAME+16(R1)
MOVD R4, FIXED_FRAME+24(R1)
BL runtime·reflectcallmove(SB)
RET
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|NOFRAME,$0-4
MOVW cycles+0(FP), R7
// POWER does not have a pause/yield instruction equivalent.
// Instead, we can lower the program priority by setting the
// Program Priority Register prior to the wait loop and set it
// back to default afterwards. On Linux, the default priority is
// medium-low. For details, see page 837 of the ISA 3.0.
OR R1, R1, R1 // Set PPR priority to low
again:
SUB $1, R7
CMP $0, R7
BNE again
OR R6, R6, R6 // Set PPR priority back to medium-low
RET
// void jmpdefer(fv, sp);
// called from deferreturn.
// 1. grab stored LR for caller
// 2. sub 8 bytes to get back to either nop or toc reload before deferreturn
// 3. BR to fn
// When dynamically linking Go, it is not sufficient to rewind to the BL
// deferreturn -- we might be jumping between modules and so we need to reset
// the TOC pointer in r2. To do this, codegen inserts MOVD 24(R1), R2 *before*
// the BL deferreturn and jmpdefer rewinds to that.
TEXT runtime·jmpdefer(SB), NOSPLIT|NOFRAME, $0-16
MOVD 0(R1), R31
SUB $8, R31
MOVD R31, LR
MOVD fv+0(FP), R11
MOVD argp+8(FP), R1
SUB $FIXED_FRAME, R1
#ifdef GOOS_aix
// AIX won't trigger a SIGSEGV if R11 = nil
// So it manually triggers it
CMP R0, R11
BNE 2(PC)
MOVD R0, 0(R0)
#endif
MOVD 0(R11), R12
MOVD R12, CTR
BR (CTR)
// Save state of caller into g->sched. Smashes R31.
TEXT gosave<>(SB),NOSPLIT|NOFRAME,$0
MOVD LR, R31
MOVD R31, (g_sched+gobuf_pc)(g)
MOVD R1, (g_sched+gobuf_sp)(g)
MOVD R0, (g_sched+gobuf_lr)(g)
MOVD R0, (g_sched+gobuf_ret)(g)
// Assert ctxt is zero. See func save.
MOVD (g_sched+gobuf_ctxt)(g), R31
CMP R0, R31
BEQ 2(PC)
BL runtime·badctxt(SB)
RET
#ifdef GOOS_aix
#define asmcgocallSaveOffset cgoCalleeStackSize + 8
#else
#define asmcgocallSaveOffset cgoCalleeStackSize
#endif
// 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
MOVD fn+0(FP), R3
MOVD arg+8(FP), R4
MOVD R1, R7 // save original stack pointer
MOVD g, R5
// 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.
// Moreover, if it's called inside the signal handler, it must not switch
// to g0 as it can be in use by another syscall.
MOVD g_m(g), R8
MOVD m_gsignal(R8), R6
CMP R6, g
BEQ g0
MOVD m_g0(R8), R6
CMP R6, g
BEQ g0
BL gosave<>(SB)
MOVD R6, g
BL runtime·save_g(SB)
MOVD (g_sched+gobuf_sp)(g), R1
// Now on a scheduling stack (a pthread-created stack).
g0:
#ifdef GOOS_aix
// Create a fake LR to improve backtrace.
MOVD $runtime·asmcgocall(SB), R6
MOVD R6, 16(R1)
// AIX also save one argument on the stack.
SUB $8, R1
#endif
// Save room for two of our pointers, plus the callee
// save area that lives on the caller stack.
SUB $(asmcgocallSaveOffset+16), R1
RLDCR $0, R1, $~15, R1 // 16-byte alignment for gcc ABI
MOVD R5, (asmcgocallSaveOffset+8)(R1)// save old g on stack
MOVD (g_stack+stack_hi)(R5), R5
SUB R7, R5
MOVD R5, asmcgocallSaveOffset(R1) // save depth in old g stack (can't just save SP, as stack might be copied during a callback)
#ifdef GOOS_aix
MOVD R7, 0(R1) // Save frame pointer to allow manual backtrace with gdb
#else
MOVD R0, 0(R1) // clear back chain pointer (TODO can we give it real back trace information?)
#endif
// This is a "global call", so put the global entry point in r12
MOVD R3, R12
#ifdef GOARCH_ppc64
// ppc64 use elf ABI v1. we must get the real entry address from
// first slot of the function descriptor before call.
// Same for AIX.
MOVD 8(R12), R2
MOVD (R12), R12
#endif
MOVD R12, CTR
MOVD R4, R3 // arg in r3
BL (CTR)
// C code can clobber R0, so set it back to 0. F27-F31 are
// callee save, so we don't need to recover those.
XOR R0, R0
// Restore g, stack pointer, toc pointer.
// R3 is errno, so don't touch it
MOVD (asmcgocallSaveOffset+8)(R1), g
MOVD (g_stack+stack_hi)(g), R5
MOVD asmcgocallSaveOffset(R1), R6
SUB R6, R5
#ifndef GOOS_aix
MOVD 24(R5), R2
#endif
MOVD R5, R1
BL runtime·save_g(SB)
MOVW R3, ret+16(FP)
RET
// cgocallback(void (*fn)(void*), void *frame, uintptr framesize, uintptr ctxt)
// Turn the fn into a Go func (by taking its address) and call
// cgocallback_gofunc.
TEXT runtime·cgocallback(SB),NOSPLIT,$32-32
MOVD $fn+0(FP), R3
MOVD R3, FIXED_FRAME+0(R1)
MOVD frame+8(FP), R3
MOVD R3, FIXED_FRAME+8(R1)
MOVD framesize+16(FP), R3
MOVD R3, FIXED_FRAME+16(R1)
MOVD ctxt+24(FP), R3
MOVD R3, FIXED_FRAME+24(R1)
MOVD $runtime·cgocallback_gofunc(SB), R12
MOVD R12, CTR
BL (CTR)
RET
// cgocallback_gofunc(FuncVal*, void *frame, uintptr framesize, uintptr ctxt)
// See cgocall.go for more details.
TEXT ·cgocallback_gofunc(SB),NOSPLIT,$16-32
NO_LOCAL_POINTERS
// Load m and g from thread-local storage.
MOVBZ runtime·iscgo(SB), R3
CMP R3, $0
BEQ nocgo
BL runtime·load_g(SB)
nocgo:
// If g is nil, Go did not create the current thread.
// Call needm to obtain one 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.
CMP g, $0
BEQ needm
MOVD g_m(g), R8
MOVD R8, savedm-8(SP)
BR havem
needm:
MOVD g, savedm-8(SP) // g is zero, so is m.
MOVD $runtime·needm(SB), R12
MOVD R12, CTR
BL (CTR)
// 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.
MOVD g_m(g), R8
MOVD m_g0(R8), R3
MOVD R1, (g_sched+gobuf_sp)(R3)
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 8(R1) aka savedsp-16(SP).
MOVD m_g0(R8), R3
MOVD (g_sched+gobuf_sp)(R3), R4
MOVD R4, savedsp-16(SP)
MOVD R1, (g_sched+gobuf_sp)(R3)
// 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 stack.
// This has the added benefit that it looks to the traceback
// routine like cgocallbackg is going to return to that
// PC (because the frame we allocate below has the same
// size as cgocallback_gofunc's frame declared above)
// so that the traceback will seamlessly trace back into
// the earlier calls.
//
// In the new goroutine, -8(SP) is unused (where SP refers to
// m->curg's SP while we're setting it up, before we've adjusted it).
MOVD m_curg(R8), g
BL runtime·save_g(SB)
MOVD (g_sched+gobuf_sp)(g), R4 // prepare stack as R4
MOVD (g_sched+gobuf_pc)(g), R5
MOVD R5, -(FIXED_FRAME+16)(R4)
MOVD ctxt+24(FP), R3
MOVD R3, -16(R4)
MOVD $-(FIXED_FRAME+16)(R4), R1
BL runtime·cgocallbackg(SB)
// Restore g->sched (== m->curg->sched) from saved values.
MOVD 0(R1), R5
MOVD R5, (g_sched+gobuf_pc)(g)
MOVD $(FIXED_FRAME+16)(R1), R4
MOVD R4, (g_sched+gobuf_sp)(g)
// 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.)
MOVD g_m(g), R8
MOVD m_g0(R8), g
BL runtime·save_g(SB)
MOVD (g_sched+gobuf_sp)(g), R1
MOVD savedsp-16(SP), R4
MOVD R4, (g_sched+gobuf_sp)(g)
// 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.
MOVD savedm-8(SP), R6
CMP R6, $0
BNE droppedm
MOVD $runtime·dropm(SB), R12
MOVD R12, CTR
BL (CTR)
droppedm:
// Done!
RET
// void setg(G*); set g. for use by needm.
TEXT runtime·setg(SB), NOSPLIT, $0-8
MOVD gg+0(FP), g
// This only happens if iscgo, so jump straight to save_g
BL runtime·save_g(SB)
RET
#ifdef GOARCH_ppc64
#ifdef GOOS_aix
DATA setg_gcc<>+0(SB)/8, $_setg_gcc<>(SB)
DATA setg_gcc<>+8(SB)/8, $TOC(SB)
DATA setg_gcc<>+16(SB)/8, $0
GLOBL setg_gcc<>(SB), NOPTR, $24
#else
TEXT setg_gcc<>(SB),NOSPLIT|NOFRAME,$0-0
DWORD $_setg_gcc<>(SB)
DWORD $0
DWORD $0
#endif
#endif
// void setg_gcc(G*); set g in C TLS.
// Must obey the gcc calling convention.
#ifdef GOARCH_ppc64le
TEXT setg_gcc<>(SB),NOSPLIT|NOFRAME,$0-0
#else
TEXT _setg_gcc<>(SB),NOSPLIT|NOFRAME,$0-0
#endif
// The standard prologue clobbers R31, which is callee-save in
// the C ABI, so we have to use $-8-0 and save LR ourselves.
MOVD LR, R4
// Also save g and R31, since they're callee-save in C ABI
MOVD R31, R5
MOVD g, R6
MOVD R3, g
BL runtime·save_g(SB)
MOVD R6, g
MOVD R5, R31
MOVD R4, LR
RET
TEXT runtime·abort(SB),NOSPLIT|NOFRAME,$0-0
MOVW (R0), R0
UNDEF
#define TBR 268
// int64 runtime·cputicks(void)
TEXT runtime·cputicks(SB),NOSPLIT,$0-8
MOVD SPR(TBR), R3
MOVD R3, ret+0(FP)
RET
// AES hashing not implemented for ppc64
TEXT runtime·aeshash(SB),NOSPLIT|NOFRAME,$0-0
MOVW (R0), R1
TEXT runtime·aeshash32(SB),NOSPLIT|NOFRAME,$0-0
MOVW (R0), R1
TEXT runtime·aeshash64(SB),NOSPLIT|NOFRAME,$0-0
MOVW (R0), R1
TEXT runtime·aeshashstr(SB),NOSPLIT|NOFRAME,$0-0
MOVW (R0), R1
TEXT runtime·return0(SB), NOSPLIT, $0
MOVW $0, R3
RET
// Called from cgo wrappers, this function returns g->m->curg.stack.hi.
// Must obey the gcc calling convention.
#ifdef GOOS_aix
// On AIX, _cgo_topofstack is defined in runtime/cgo, because it must
// be a longcall in order to prevent trampolines from ld.
TEXT __cgo_topofstack(SB),NOSPLIT|NOFRAME,$0
#else
TEXT _cgo_topofstack(SB),NOSPLIT|NOFRAME,$0
#endif
// g (R30) and R31 are callee-save in the C ABI, so save them
MOVD g, R4
MOVD R31, R5
MOVD LR, R6
BL runtime·load_g(SB) // clobbers g (R30), R31
MOVD g_m(g), R3
MOVD m_curg(R3), R3
MOVD (g_stack+stack_hi)(R3), R3
MOVD R4, g
MOVD R5, R31
MOVD R6, LR
RET
// The top-most function running on a goroutine
// returns to goexit+PCQuantum.
//
// When dynamically linking Go, it can be returned to from a function
// implemented in a different module and so needs to reload the TOC pointer
// from the stack (although this function declares that it does not set up x-a
// frame, newproc1 does in fact allocate one for goexit and saves the TOC
// pointer in the correct place).
// goexit+_PCQuantum is halfway through the usual global entry point prologue
// that derives r2 from r12 which is a bit silly, but not harmful.
TEXT runtime·goexit(SB),NOSPLIT|NOFRAME|TOPFRAME,$0-0
MOVD 24(R1), R2
BL runtime·goexit1(SB) // does not return
// traceback from goexit1 must hit code range of goexit
MOVD R0, R0 // NOP
// prepGoExitFrame saves the current TOC pointer (i.e. the TOC pointer for the
// module containing runtime) to the frame that goexit will execute in when
// the goroutine exits. It's implemented in assembly mainly because that's the
// easiest way to get access to R2.
TEXT runtime·prepGoExitFrame(SB),NOSPLIT,$0-8
MOVD sp+0(FP), R3
MOVD R2, 24(R3)
RET
TEXT runtime·addmoduledata(SB),NOSPLIT|NOFRAME,$0-0
ADD $-8, R1
MOVD R31, 0(R1)
MOVD runtime·lastmoduledatap(SB), R4
MOVD R3, moduledata_next(R4)
MOVD R3, runtime·lastmoduledatap(SB)
MOVD 0(R1), R31
ADD $8, R1
RET
TEXT ·checkASM(SB),NOSPLIT,$0-1
MOVW $1, R3
MOVB R3, ret+0(FP)
RET
// gcWriteBarrier performs a heap pointer write and informs the GC.
//
// gcWriteBarrier does NOT follow the Go ABI. It takes two arguments:
// - R20 is the destination of the write
// - R21 is the value being written at R20.
// It clobbers condition codes.
// It does not clobber R0 through R15,
// but may clobber any other register, *including* R31.
TEXT runtime·gcWriteBarrier(SB),NOSPLIT,$112
// The standard prologue clobbers R31.
// We use R16 and R17 as scratch registers.
MOVD g_m(g), R16
MOVD m_p(R16), R16
MOVD (p_wbBuf+wbBuf_next)(R16), R17
// Increment wbBuf.next position.
ADD $16, R17
MOVD R17, (p_wbBuf+wbBuf_next)(R16)
MOVD (p_wbBuf+wbBuf_end)(R16), R16
CMP R16, R17
// Record the write.
MOVD R21, -16(R17) // Record value
MOVD (R20), R16 // TODO: This turns bad writes into bad reads.
MOVD R16, -8(R17) // Record *slot
// Is the buffer full? (flags set in CMP above)
BEQ flush
ret:
// Do the write.
MOVD R21, (R20)
RET
flush:
// Save registers R0 through R15 since these were not saved by the caller.
// We don't save all registers on ppc64 because it takes too much space.
MOVD R20, (FIXED_FRAME+0)(R1) // Also first argument to wbBufFlush
MOVD R21, (FIXED_FRAME+8)(R1) // Also second argument to wbBufFlush
// R0 is always 0, so no need to spill.
// R1 is SP.
// R2 is SB.
MOVD R3, (FIXED_FRAME+16)(R1)
MOVD R4, (FIXED_FRAME+24)(R1)
MOVD R5, (FIXED_FRAME+32)(R1)
MOVD R6, (FIXED_FRAME+40)(R1)
MOVD R7, (FIXED_FRAME+48)(R1)
MOVD R8, (FIXED_FRAME+56)(R1)
MOVD R9, (FIXED_FRAME+64)(R1)
MOVD R10, (FIXED_FRAME+72)(R1)
MOVD R11, (FIXED_FRAME+80)(R1)
MOVD R12, (FIXED_FRAME+88)(R1)
// R13 is REGTLS
MOVD R14, (FIXED_FRAME+96)(R1)
MOVD R15, (FIXED_FRAME+104)(R1)
// This takes arguments R20 and R21.
CALL runtime·wbBufFlush(SB)
MOVD (FIXED_FRAME+0)(R1), R20
MOVD (FIXED_FRAME+8)(R1), R21
MOVD (FIXED_FRAME+16)(R1), R3
MOVD (FIXED_FRAME+24)(R1), R4
MOVD (FIXED_FRAME+32)(R1), R5
MOVD (FIXED_FRAME+40)(R1), R6
MOVD (FIXED_FRAME+48)(R1), R7
MOVD (FIXED_FRAME+56)(R1), R8
MOVD (FIXED_FRAME+64)(R1), R9
MOVD (FIXED_FRAME+72)(R1), R10
MOVD (FIXED_FRAME+80)(R1), R11
MOVD (FIXED_FRAME+88)(R1), R12
MOVD (FIXED_FRAME+96)(R1), R14
MOVD (FIXED_FRAME+104)(R1), R15
JMP 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.
TEXT runtime·panicIndex(SB),NOSPLIT,$0-16
MOVD R3, x+0(FP)
MOVD R4, y+8(FP)
JMP runtime·goPanicIndex(SB)
TEXT runtime·panicIndexU(SB),NOSPLIT,$0-16
MOVD R3, x+0(FP)
MOVD R4, y+8(FP)
JMP runtime·goPanicIndexU(SB)
TEXT runtime·panicSliceAlen(SB),NOSPLIT,$0-16
MOVD R4, x+0(FP)
MOVD R5, y+8(FP)
JMP runtime·goPanicSliceAlen(SB)
TEXT runtime·panicSliceAlenU(SB),NOSPLIT,$0-16
MOVD R4, x+0(FP)
MOVD R5, y+8(FP)
JMP runtime·goPanicSliceAlenU(SB)
TEXT runtime·panicSliceAcap(SB),NOSPLIT,$0-16
MOVD R4, x+0(FP)
MOVD R5, y+8(FP)
JMP runtime·goPanicSliceAcap(SB)
TEXT runtime·panicSliceAcapU(SB),NOSPLIT,$0-16
MOVD R4, x+0(FP)
MOVD R5, y+8(FP)
JMP runtime·goPanicSliceAcapU(SB)
TEXT runtime·panicSliceB(SB),NOSPLIT,$0-16
MOVD R3, x+0(FP)
MOVD R4, y+8(FP)
JMP runtime·goPanicSliceB(SB)
TEXT runtime·panicSliceBU(SB),NOSPLIT,$0-16
MOVD R3, x+0(FP)
MOVD R4, y+8(FP)
JMP runtime·goPanicSliceBU(SB)
TEXT runtime·panicSlice3Alen(SB),NOSPLIT,$0-16
MOVD R5, x+0(FP)
MOVD R6, y+8(FP)
JMP runtime·goPanicSlice3Alen(SB)
TEXT runtime·panicSlice3AlenU(SB),NOSPLIT,$0-16
MOVD R5, x+0(FP)
MOVD R6, y+8(FP)
JMP runtime·goPanicSlice3AlenU(SB)
TEXT runtime·panicSlice3Acap(SB),NOSPLIT,$0-16
MOVD R5, x+0(FP)
MOVD R6, y+8(FP)
JMP runtime·goPanicSlice3Acap(SB)
TEXT runtime·panicSlice3AcapU(SB),NOSPLIT,$0-16
MOVD R5, x+0(FP)
MOVD R6, y+8(FP)
JMP runtime·goPanicSlice3AcapU(SB)
TEXT runtime·panicSlice3B(SB),NOSPLIT,$0-16
MOVD R4, x+0(FP)
MOVD R5, y+8(FP)
JMP runtime·goPanicSlice3B(SB)
TEXT runtime·panicSlice3BU(SB),NOSPLIT,$0-16
MOVD R4, x+0(FP)
MOVD R5, y+8(FP)
JMP runtime·goPanicSlice3BU(SB)
TEXT runtime·panicSlice3C(SB),NOSPLIT,$0-16
MOVD R3, x+0(FP)
MOVD R4, y+8(FP)
JMP runtime·goPanicSlice3C(SB)
TEXT runtime·panicSlice3CU(SB),NOSPLIT,$0-16
MOVD R3, x+0(FP)
MOVD R4, y+8(FP)
JMP runtime·goPanicSlice3CU(SB)
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