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// Copyright 2018 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"
// void runtime·asmstdcall(void *c);
TEXT runtime·asmstdcall(SB),NOSPLIT|NOFRAME,$0
MOVM.DB.W [R4, R5, R14], (R13) // push {r4, r5, lr}
MOVW R0, R4 // put libcall * in r4
MOVW R13, R5 // save stack pointer in r5
// SetLastError(0)
MOVW $0, R0
MRC 15, 0, R1, C13, C0, 2
MOVW R0, 0x34(R1)
MOVW 8(R4), R12 // libcall->args
// Do we have more than 4 arguments?
MOVW 4(R4), R0 // libcall->n
SUB.S $4, R0, R2
BLE loadregs
// Reserve stack space for remaining args
SUB R2<<2, R13
BIC $0x7, R13 // alignment for ABI
// R0: count of arguments
// R1:
// R2: loop counter, from 0 to (n-4)
// R3: scratch
// R4: pointer to libcall struct
// R12: libcall->args
MOVW $0, R2
ADD $4, R2, R3 // r3 = args[4 + i]
MOVW R3<<2(R12), R3
MOVW R3, R2<<2(R13) // stack[i] = r3
ADD $1, R2 // i++
SUB $4, R0, R3 // while (i < (n - 4))
CMP R3, R2
BLT stackargs
CMP $3, R0
MOVW.GT 12(R12), R3
CMP $2, R0
MOVW.GT 8(R12), R2
CMP $1, R0
MOVW.GT 4(R12), R1
CMP $0, R0
MOVW.GT 0(R12), R0
BIC $0x7, R13 // alignment for ABI
MOVW 0(R4), R12 // branch to libcall->fn
BL (R12)
MOVW R5, R13 // free stack space
MOVW R0, 12(R4) // save return value to libcall->r1
MOVW R1, 16(R4)
// GetLastError
MRC 15, 0, R1, C13, C0, 2
MOVW 0x34(R1), R0
MOVW R0, 20(R4) // store in libcall->err
MOVM.IA.W (R13), [R4, R5, R15]
TEXT runtime·badsignal2(SB),NOSPLIT|NOFRAME,$0
MOVM.DB.W [R4, R14], (R13) // push {r4, lr}
MOVW R13, R4 // save original stack pointer
SUB $8, R13 // space for 2 variables
BIC $0x7, R13 // alignment for ABI
// stderr
MOVW runtime·_GetStdHandle(SB), R1
MOVW $-12, R0
BL (R1)
MOVW $runtime·badsignalmsg(SB), R1 // lpBuffer
MOVW $runtime·badsignallen(SB), R2 // lpNumberOfBytesToWrite
MOVW (R2), R2
ADD $0x4, R13, R3 // lpNumberOfBytesWritten
MOVW $0, R12 // lpOverlapped
MOVW R12, (R13)
MOVW runtime·_WriteFile(SB), R12
BL (R12)
MOVW R4, R13 // restore SP
MOVM.IA.W (R13), [R4, R15] // pop {r4, pc}
TEXT runtime·getlasterror(SB),NOSPLIT,$0
MRC 15, 0, R0, C13, C0, 2
MOVW 0x34(R0), R0
MOVW R0, ret+0(FP)
TEXT runtime·setlasterror(SB),NOSPLIT|NOFRAME,$0
MRC 15, 0, R1, C13, C0, 2
MOVW R0, 0x34(R1)
// Called by Windows as a Vectored Exception Handler (VEH).
// First argument is pointer to struct containing
// exception record and context pointers.
// Handler function is stored in R1
// Return 0 for 'not handled', -1 for handled.
// int32_t sigtramp(
// func *GoExceptionHandler);
TEXT runtime·sigtramp(SB),NOSPLIT|NOFRAME,$0
MOVM.DB.W [R0, R4-R11, R14], (R13) // push {r0, r4-r11, lr} (SP-=40)
SUB $(8+20), R13 // reserve space for g, sp, and
// parameters/retval to go call
MOVW R0, R6 // Save param0
MOVW R1, R7 // Save param1
BL runtime·load_g(SB)
CMP $0, g // is there a current g?
BL.EQ runtime·badsignal2(SB)
// save g and SP in case of stack switch
MOVW R13, 24(R13)
MOVW g, 20(R13)
// do we need to switch to the g0 stack?
MOVW g, R5 // R5 = g
MOVW g_m(R5), R2 // R2 = m
MOVW m_g0(R2), R4 // R4 = g0
CMP R5, R4 // if curg == g0
BEQ g0
// switch to g0 stack
MOVW R4, g // g = g0
MOVW (g_sched+gobuf_sp)(g), R3 // R3 = g->gobuf.sp
BL runtime·save_g(SB)
// traceback will think that we've done PUSH and SUB
// on this stack, so subtract them here to match.
// (we need room for sighandler arguments anyway).
// and re-save old SP for restoring later.
SUB $(40+8+20), R3
MOVW R13, 24(R3) // save old stack pointer
MOVW R3, R13 // switch stack
MOVW 0(R6), R2 // R2 = ExceptionPointers->ExceptionRecord
MOVW 4(R6), R3 // R3 = ExceptionPointers->ContextRecord
// make it look like mstart called us on g0, to stop traceback
MOVW $runtime·mstart(SB), R4
MOVW R4, 0(R13) // Save link register for traceback
MOVW R2, 4(R13) // Move arg0 (ExceptionRecord) into position
MOVW R3, 8(R13) // Move arg1 (ContextRecord) into position
MOVW R5, 12(R13) // Move arg2 (original g) into position
BL (R7) // Call the go routine
MOVW 16(R13), R4 // Fetch return value from stack
// Compute the value of the g0 stack pointer after deallocating
// this frame, then allocating 8 bytes. We may need to store
// the resume SP and PC on the g0 stack to work around
// control flow guard when we resume from the exception.
ADD $(40+20), R13, R12
// switch back to original stack and g
MOVW 24(R13), R13
MOVW 20(R13), g
BL runtime·save_g(SB)
MOVW R4, R0 // move retval into position
ADD $(8 + 20), R13 // free locals
MOVM.IA.W (R13), [R3, R4-R11, R14] // pop {r3, r4-r11, lr}
// if return value is CONTINUE_SEARCH, do not set up control
// flow guard workaround
CMP $0, R0
BEQ return
// Check if we need to set up the control flow guard workaround.
// On Windows/ARM, the stack pointer must lie within system
// stack limits when we resume from exception.
// Store the resume SP and PC on the g0 stack,
// and return to returntramp on the g0 stack. returntramp
// pops the saved PC and SP from the g0 stack, resuming execution
// at the desired location.
// If returntramp has already been set up by a previous exception
// handler, don't clobber the stored SP and PC on the stack.
MOVW 0x40(R3), R2 // load PC from context record
MOVW $runtime·returntramp(SB), R1
CMP R1, R2
B.EQ return // do not clobber saved SP/PC
// Save resume SP and PC on g0 stack
MOVW 0x38(R3), R2 // load SP from context record
MOVW R2, 0(R12) // Store resume SP on g0 stack
MOVW 0x40(R3), R2 // load PC from context record
MOVW R2, 4(R12) // Store resume PC on g0 stack
// Set up context record to return to returntramp on g0 stack
MOVW R12, 0x38(R3) // save g0 stack pointer
// in context record
MOVW $runtime·returntramp(SB), R2 // save resume address
MOVW R2, 0x40(R3) // in context record
B (R14) // return
// 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.
TEXT runtime·returntramp(SB),NOSPLIT|NOFRAME,$0
MOVM.IA (R13), [R13, R15] // ldm sp, [sp, pc]
TEXT runtime·exceptiontramp(SB),NOSPLIT|NOFRAME,$0
MOVW $runtime·exceptionhandler(SB), R1
B runtime·sigtramp(SB)
TEXT runtime·firstcontinuetramp(SB),NOSPLIT|NOFRAME,$0
MOVW $runtime·firstcontinuehandler(SB), R1
B runtime·sigtramp(SB)
TEXT runtime·lastcontinuetramp(SB),NOSPLIT|NOFRAME,$0
MOVW $runtime·lastcontinuehandler(SB), R1
B runtime·sigtramp(SB)
TEXT runtime·ctrlhandler(SB),NOSPLIT|NOFRAME,$0
MOVW $runtime·ctrlhandler1(SB), R1
B runtime·externalthreadhandler(SB)
TEXT runtime·profileloop(SB),NOSPLIT|NOFRAME,$0
MOVW $runtime·profileloop1(SB), R1
B runtime·externalthreadhandler(SB)
// int32 externalthreadhandler(uint32 arg, int (*func)(uint32))
// stack layout:
// +----------------+
// | callee-save |
// | registers |
// +----------------+
// | m |
// +----------------+
// 20| g |
// +----------------+
// 16| func ptr (r1) |
// +----------------+
// 12| argument (r0) |
// 8 | param1 |
// +----------------+
// 4 | param0 |
// +----------------+
// 0 | retval |
// +----------------+
TEXT runtime·externalthreadhandler(SB),NOSPLIT|NOFRAME,$0
MOVM.DB.W [R4-R11, R14], (R13) // push {r4-r11, lr}
SUB $(m__size + g__size + 20), R13 // space for locals
MOVW R0, 12(R13)
MOVW R1, 16(R13)
// zero out m and g structures
ADD $20, R13, R0 // compute pointer to g
MOVW R0, 4(R13)
MOVW $(m__size + g__size), R0
MOVW R0, 8(R13)
BL runtime·memclrNoHeapPointers(SB)
// initialize m and g structures
ADD $20, R13, R2 // R2 = g
ADD $(20 + g__size), R13, R3 // R3 = m
MOVW R2, m_g0(R3) // m->g0 = g
MOVW R3, g_m(R2) // g->m = m
MOVW R2, m_curg(R3) // m->curg = g
MOVW R2, g
BL runtime·save_g(SB)
// set up stackguard stuff
MOVW R13, R0
MOVW R0, g_stack+stack_hi(g)
SUB $(32*1024), R0
MOVW R0, (g_stack+stack_lo)(g)
MOVW R0, g_stackguard0(g)
MOVW R0, g_stackguard1(g)
// move argument into position and call function
MOVW 12(R13), R0
MOVW R0, 4(R13)
MOVW 16(R13), R1
BL (R1)
// clear g
MOVW $0, g
BL runtime·save_g(SB)
MOVW 0(R13), R0 // load return value
ADD $(m__size + g__size + 20), R13 // free locals
MOVM.IA.W (R13), [R4-R11, R15] // pop {r4-r11, pc}
GLOBL runtime·cbctxts(SB), NOPTR, $4
TEXT runtime·callbackasm1(SB),NOSPLIT|NOFRAME,$0
MOVM.DB.W [R4-R11, R14], (R13) // push {r4-r11, lr}
SUB $36, R13 // space for locals
// save callback arguments to stack. We currently support up to 4 arguments
ADD $16, R13, R4
MOVM.IA [R0-R3], (R4)
// load cbctxts[i]. The trampoline in zcallback_windows.s puts the callback
// index in R12
MOVW runtime·cbctxts(SB), R4
MOVW R12<<2(R4), R4 // R4 holds pointer to wincallbackcontext structure
// extract callback context
MOVW wincallbackcontext_argsize(R4), R5
MOVW wincallbackcontext_gobody(R4), R4
// we currently support up to 4 arguments
CMP $(4 * 4), R5
BL.GT runtime·abort(SB)
// extend argsize by size of return value
ADD $4, R5
// Build 'type args struct'
MOVW R4, 4(R13) // fn
ADD $16, R13, R0 // arg (points to r0-r3, ret on stack)
MOVW R0, 8(R13)
MOVW R5, 12(R13) // argsize
BL runtime·load_g(SB)
BL runtime·cgocallback_gofunc(SB)
ADD $16, R13, R0 // load arg
MOVW 12(R13), R1 // load argsize
SUB $4, R1 // offset to return value
MOVW R1<<0(R0), R0 // load return value
ADD $36, R13 // free locals
MOVM.IA.W (R13), [R4-R11, R15] // pop {r4-r11, pc}
// uint32 tstart_stdcall(M *newm);
TEXT runtime·tstart_stdcall(SB),NOSPLIT|NOFRAME,$0
MOVM.DB.W [R4-R11, R14], (R13) // push {r4-r11, lr}
MOVW m_g0(R0), g
MOVW R0, g_m(g)
BL runtime·save_g(SB)
// do per-thread TLS initialization
BL runtime·init_thread_tls(SB)
// Layout new m scheduler stack on os stack.
MOVW R13, R0
MOVW R0, g_stack+stack_hi(g)
SUB $(64*1024), R0
MOVW R0, (g_stack+stack_lo)(g)
MOVW R0, g_stackguard0(g)
MOVW R0, g_stackguard1(g)
BL runtime·emptyfunc(SB) // fault if stack check is wrong
BL runtime·mstart(SB)
// Exit the thread.
MOVW $0, R0
MOVM.IA.W (R13), [R4-R11, R15] // pop {r4-r11, pc}
// onosstack calls fn on OS stack.
// adapted from asm_arm.s : systemstack
// func onosstack(fn unsafe.Pointer, arg uint32)
TEXT runtime·onosstack(SB),NOSPLIT,$0
MOVW fn+0(FP), R5 // R5 = fn
MOVW arg+4(FP), R6 // R6 = arg
// This function can be called when there is no g,
// for example, when we are handling a callback on a non-go thread.
// In this case we're already on the system stack.
CMP $0, g
BEQ noswitch
MOVW g_m(g), R1 // R1 = m
MOVW m_gsignal(R1), R2 // R2 = gsignal
CMP g, R2
B.EQ noswitch
MOVW m_g0(R1), R2 // R2 = g0
CMP g, R2
B.EQ noswitch
MOVW m_curg(R1), R3
CMP g, R3
B.EQ switch
// Bad: g is not gsignal, not g0, not curg. What is it?
// Hide call from linker nosplit analysis.
MOVW $runtime·badsystemstack(SB), R0
BL (R0)
B runtime·abort(SB)
// save our state in g->sched. Pretend to
// be systemstack_switch if the G stack is scanned.
MOVW $runtime·systemstack_switch(SB), R3
ADD $4, R3, R3 // get past push {lr}
MOVW R3, (g_sched+gobuf_pc)(g)
MOVW R13, (g_sched+gobuf_sp)(g)
MOVW LR, (g_sched+gobuf_lr)(g)
MOVW g, (g_sched+gobuf_g)(g)
// switch to g0
MOVW R2, g
MOVW (g_sched+gobuf_sp)(R2), R3
// make it look like mstart called systemstack on g0, to stop traceback
SUB $4, R3, R3
MOVW $runtime·mstart(SB), R4
MOVW R4, 0(R3)
MOVW R3, R13
// call target function
MOVW R6, R0 // arg
BL (R5)
// switch back to g
MOVW g_m(g), R1
MOVW m_curg(R1), g
MOVW (g_sched+gobuf_sp)(g), R13
MOVW $0, R3
MOVW R3, (g_sched+gobuf_sp)(g)
// Using a tail call here cleans up tracebacks since we won't stop
// at an intermediate systemstack.
MOVW.P 4(R13), R14 // restore LR
MOVW R6, R0 // arg
B (R5)
// Runs on OS stack. Duration (in 100ns units) is in R0.
TEXT runtime·usleep2(SB),NOSPLIT|NOFRAME,$0
MOVM.DB.W [R4, R14], (R13) // push {r4, lr}
MOVW R13, R4 // Save SP
SUB $8, R13 // R13 = R13 - 8
BIC $0x7, R13 // Align SP for ABI
RSB $0, R0, R3 // R3 = -R0
MOVW $0, R1 // R1 = FALSE (alertable)
MOVW $-1, R0 // R0 = handle
MOVW R13, R2 // R2 = pTime
MOVW R3, 0(R2) // time_lo
MOVW R0, 4(R2) // time_hi
MOVW runtime·_NtWaitForSingleObject(SB), R3
BL (R3)
MOVW R4, R13 // Restore SP
MOVM.IA.W (R13), [R4, R15] // pop {R4, pc}
// Runs on OS stack.
TEXT runtime·switchtothread(SB),NOSPLIT|NOFRAME,$0
MOVM.DB.W [R4, R14], (R13) // push {R4, lr}
MOVW R13, R4
BIC $0x7, R13 // alignment for ABI
MOVW runtime·_SwitchToThread(SB), R0
BL (R0)
MOVW R4, R13 // restore stack pointer
MOVM.IA.W (R13), [R4, R15] // pop {R4, pc}
TEXT ·publicationBarrier(SB),NOSPLIT|NOFRAME,$0-0
B runtime·armPublicationBarrier(SB)
// never called (cgo not supported)
TEXT runtime·read_tls_fallback(SB),NOSPLIT|NOFRAME,$0
MOVW $0xabcd, R0
MOVW R0, (R0)
TEXT runtime·nanotime(SB),NOSPLIT|NOFRAME,$0-8
B runtime·nanotimeQPC(SB) // tail call
B runtime·nowQPC(SB) // tail call
// save_g saves the g register (R10) into thread local memory
// so that we can call externally compiled
// ARM code that will overwrite those registers.
// NOTE: runtime.gogo assumes that R1 is preserved by this function.
// runtime.mcall assumes this function only clobbers R0 and R11.
// Returns with g in R0.
// Save the value in the _TEB->TlsSlots array.
// Effectively implements TlsSetValue().
// tls_g stores the TLS slot allocated TlsAlloc().
TEXT runtime·save_g(SB),NOSPLIT|NOFRAME,$0
MRC 15, 0, R0, C13, C0, 2
ADD $0xe10, R0
MOVW $runtime·tls_g(SB), R11
MOVW (R11), R11
MOVW g, R11<<2(R0)
MOVW g, R0 // preserve R0 across call to setg<>
// load_g loads the g register from thread-local memory,
// for use after calling externally compiled
// ARM code that overwrote those registers.
// Get the value from the _TEB->TlsSlots array.
// Effectively implements TlsGetValue().
TEXT runtime·load_g(SB),NOSPLIT|NOFRAME,$0
MRC 15, 0, R0, C13, C0, 2
ADD $0xe10, R0
MOVW $runtime·tls_g(SB), g
MOVW (g), g
MOVW g<<2(R0), g
// This is called from rt0_go, which runs on the system stack
// using the initial stack allocated by the OS.
// It calls back into standard C using the BL below.
// To do that, the stack pointer must be 8-byte-aligned.
TEXT runtime·_initcgo(SB),NOSPLIT|NOFRAME,$0
MOVM.DB.W [R4, R14], (R13) // push {r4, lr}
// Ensure stack is 8-byte aligned before calling C code
MOVW R13, R4
BIC $0x7, R13
// Allocate a TLS slot to hold g across calls to external code
MOVW $runtime·_TlsAlloc(SB), R0
MOVW (R0), R0
BL (R0)
// Assert that slot is less than 64 so we can use _TEB->TlsSlots
CMP $64, R0
MOVW $runtime·abort(SB), R1
BL.GE (R1)
// Save Slot into tls_g
MOVW $runtime·tls_g(SB), R1
MOVW R0, (R1)
BL runtime·init_thread_tls(SB)
MOVW R4, R13
MOVM.IA.W (R13), [R4, R15] // pop {r4, pc}
// void init_thread_tls()
// Does per-thread TLS initialization. Saves a pointer to the TLS slot
// holding G, in the current m.
// g->m->tls[0] = &_TEB->TlsSlots[tls_g]
// The purpose of this is to enable the profiling handler to get the
// current g associated with the thread. We cannot use m->curg because curg
// only holds the current user g. If the thread is executing system code or
// external code, m->curg will be NULL. The thread's TLS slot always holds
// the current g, so save a reference to this location so the profiling
// handler can get the real g from the thread's m.
// Clobbers R0-R3
TEXT runtime·init_thread_tls(SB),NOSPLIT|NOFRAME,$0
// compute &_TEB->TlsSlots[tls_g]
MRC 15, 0, R0, C13, C0, 2
ADD $0xe10, R0
MOVW $runtime·tls_g(SB), R1
MOVW (R1), R1
MOVW R1<<2, R1
ADD R1, R0
// save in g->m->tls[0]
MOVW g_m(g), R1
MOVW R0, m_tls(R1)
// Holds the TLS Slot, which was allocated by TlsAlloc()
GLOBL runtime·tls_g+0(SB), NOPTR, $4