1// Copyright 2018 The Go Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style 3// license that can be found in the LICENSE file. 4 5#include "go_asm.h" 6#include "go_tls.h" 7#include "textflag.h" 8#include "funcdata.h" 9#include "time_windows.h" 10#include "cgo/abi_arm64.h" 11 12// Offsets into Thread Environment Block (pointer in R18) 13#define TEB_error 0x68 14#define TEB_TlsSlots 0x1480 15#define TEB_ArbitraryPtr 0x28 16 17// Note: R0-R7 are args, R8 is indirect return value address, 18// R9-R15 are caller-save, R19-R29 are callee-save. 19// 20// load_g and save_g (in tls_arm64.s) clobber R27 (REGTMP) and R0. 21 22TEXT runtime·asmstdcall_trampoline<ABIInternal>(SB),NOSPLIT,$0 23 B runtime·asmstdcall(SB) 24 25// void runtime·asmstdcall(void *c); 26TEXT runtime·asmstdcall(SB),NOSPLIT,$16 27 STP (R19, R20), 16(RSP) // save old R19, R20 28 MOVD R0, R19 // save libcall pointer 29 MOVD RSP, R20 // save stack pointer 30 31 // SetLastError(0) 32 MOVD $0, TEB_error(R18_PLATFORM) 33 MOVD libcall_args(R19), R12 // libcall->args 34 35 // Do we have more than 8 arguments? 36 MOVD libcall_n(R19), R0 37 CMP $0, R0; BEQ _0args 38 CMP $1, R0; BEQ _1args 39 CMP $2, R0; BEQ _2args 40 CMP $3, R0; BEQ _3args 41 CMP $4, R0; BEQ _4args 42 CMP $5, R0; BEQ _5args 43 CMP $6, R0; BEQ _6args 44 CMP $7, R0; BEQ _7args 45 CMP $8, R0; BEQ _8args 46 47 // Reserve stack space for remaining args 48 SUB $8, R0, R2 49 ADD $1, R2, R3 // make even number of words for stack alignment 50 AND $~1, R3 51 LSL $3, R3 52 SUB R3, RSP 53 54 // R4: size of stack arguments (n-8)*8 55 // R5: &args[8] 56 // R6: loop counter, from 0 to (n-8)*8 57 // R7: scratch 58 // R8: copy of RSP - (R2)(RSP) assembles as (R2)(ZR) 59 SUB $8, R0, R4 60 LSL $3, R4 61 ADD $(8*8), R12, R5 62 MOVD $0, R6 63 MOVD RSP, R8 64stackargs: 65 MOVD (R6)(R5), R7 66 MOVD R7, (R6)(R8) 67 ADD $8, R6 68 CMP R6, R4 69 BNE stackargs 70 71_8args: 72 MOVD (7*8)(R12), R7 73_7args: 74 MOVD (6*8)(R12), R6 75_6args: 76 MOVD (5*8)(R12), R5 77_5args: 78 MOVD (4*8)(R12), R4 79_4args: 80 MOVD (3*8)(R12), R3 81_3args: 82 MOVD (2*8)(R12), R2 83_2args: 84 MOVD (1*8)(R12), R1 85_1args: 86 MOVD (0*8)(R12), R0 87_0args: 88 89 MOVD libcall_fn(R19), R12 // branch to libcall->fn 90 BL (R12) 91 92 MOVD R20, RSP // free stack space 93 MOVD R0, libcall_r1(R19) // save return value to libcall->r1 94 // TODO(rsc) floating point like amd64 in libcall->r2? 95 96 // GetLastError 97 MOVD TEB_error(R18_PLATFORM), R0 98 MOVD R0, libcall_err(R19) 99 100 // Restore callee-saved registers. 101 LDP 16(RSP), (R19, R20) 102 RET 103 104TEXT runtime·getlasterror(SB),NOSPLIT,$0 105 MOVD TEB_error(R18_PLATFORM), R0 106 MOVD R0, ret+0(FP) 107 RET 108 109// Called by Windows as a Vectored Exception Handler (VEH). 110// R0 is pointer to struct containing 111// exception record and context pointers. 112// R1 is the kind of sigtramp function. 113// Return value of sigtrampgo is stored in R0. 114TEXT sigtramp<>(SB),NOSPLIT,$176 115 // Switch from the host ABI to the Go ABI, safe args and lr. 116 MOVD R0, R5 117 MOVD R1, R6 118 MOVD LR, R7 119 SAVE_R19_TO_R28(8*4) 120 SAVE_F8_TO_F15(8*14) 121 122 BL runtime·load_g(SB) // Clobers R0, R27, R28 (g) 123 124 MOVD R5, R0 125 MOVD R6, R1 126 // Calling ABIInternal because TLS might be nil. 127 BL runtime·sigtrampgo<ABIInternal>(SB) 128 // Return value is already stored in R0. 129 130 // Restore callee-save registers. 131 RESTORE_R19_TO_R28(8*4) 132 RESTORE_F8_TO_F15(8*14) 133 MOVD R7, LR 134 RET 135 136// Trampoline to resume execution from exception handler. 137// This is part of the control flow guard workaround. 138// It switches stacks and jumps to the continuation address. 139// R0 and R1 are set above at the end of sigtrampgo 140// in the context that starts executing at sigresume. 141TEXT runtime·sigresume(SB),NOSPLIT|NOFRAME,$0 142 // Important: do not smash LR, 143 // which is set to a live value when handling 144 // a signal by pushing a call to sigpanic onto the stack. 145 MOVD R0, RSP 146 B (R1) 147 148TEXT runtime·exceptiontramp(SB),NOSPLIT|NOFRAME,$0 149 MOVD $const_callbackVEH, R1 150 B sigtramp<>(SB) 151 152TEXT runtime·firstcontinuetramp(SB),NOSPLIT|NOFRAME,$0 153 MOVD $const_callbackFirstVCH, R1 154 B sigtramp<>(SB) 155 156TEXT runtime·lastcontinuetramp(SB),NOSPLIT|NOFRAME,$0 157 MOVD $const_callbackLastVCH, R1 158 B sigtramp<>(SB) 159 160TEXT runtime·callbackasm1(SB),NOSPLIT,$208-0 161 NO_LOCAL_POINTERS 162 163 // On entry, the trampoline in zcallback_windows_arm64.s left 164 // the callback index in R12 (which is volatile in the C ABI). 165 166 // Save callback register arguments R0-R7. 167 // We do this at the top of the frame so they're contiguous with stack arguments. 168 // The 7*8 setting up R14 looks like a bug but is not: the eighth word 169 // is the space the assembler reserved for our caller's frame pointer, 170 // but we are not called from Go so that space is ours to use, 171 // and we must to be contiguous with the stack arguments. 172 MOVD $arg0-(7*8)(SP), R14 173 STP (R0, R1), (0*8)(R14) 174 STP (R2, R3), (2*8)(R14) 175 STP (R4, R5), (4*8)(R14) 176 STP (R6, R7), (6*8)(R14) 177 178 // Push C callee-save registers R19-R28. 179 // LR, FP already saved. 180 SAVE_R19_TO_R28(8*9) 181 182 // Create a struct callbackArgs on our stack. 183 MOVD $cbargs-(18*8+callbackArgs__size)(SP), R13 184 MOVD R12, callbackArgs_index(R13) // callback index 185 MOVD R14, R0 186 MOVD R0, callbackArgs_args(R13) // address of args vector 187 MOVD $0, R0 188 MOVD R0, callbackArgs_result(R13) // result 189 190 // Call cgocallback, which will call callbackWrap(frame). 191 MOVD $·callbackWrap<ABIInternal>(SB), R0 // PC of function to call, cgocallback takes an ABIInternal entry-point 192 MOVD R13, R1 // frame (&callbackArgs{...}) 193 MOVD $0, R2 // context 194 STP (R0, R1), (1*8)(RSP) 195 MOVD R2, (3*8)(RSP) 196 BL runtime·cgocallback(SB) 197 198 // Get callback result. 199 MOVD $cbargs-(18*8+callbackArgs__size)(SP), R13 200 MOVD callbackArgs_result(R13), R0 201 202 RESTORE_R19_TO_R28(8*9) 203 204 RET 205 206// uint32 tstart_stdcall(M *newm); 207TEXT runtime·tstart_stdcall(SB),NOSPLIT,$96-0 208 SAVE_R19_TO_R28(8*3) 209 210 MOVD m_g0(R0), g 211 MOVD R0, g_m(g) 212 BL runtime·save_g(SB) 213 214 // Set up stack guards for OS stack. 215 MOVD RSP, R0 216 MOVD R0, g_stack+stack_hi(g) 217 SUB $(64*1024), R0 218 MOVD R0, (g_stack+stack_lo)(g) 219 MOVD R0, g_stackguard0(g) 220 MOVD R0, g_stackguard1(g) 221 222 BL runtime·emptyfunc(SB) // fault if stack check is wrong 223 BL runtime·mstart(SB) 224 225 RESTORE_R19_TO_R28(8*3) 226 227 // Exit the thread. 228 MOVD $0, R0 229 RET 230 231TEXT runtime·nanotime1(SB),NOSPLIT,$0-8 232 MOVD $_INTERRUPT_TIME, R3 233 MOVD time_lo(R3), R0 234 MOVD $100, R1 235 MUL R1, R0 236 MOVD R0, ret+0(FP) 237 RET 238 239// This is called from rt0_go, which runs on the system stack 240// using the initial stack allocated by the OS. 241// It calls back into standard C using the BL below. 242TEXT runtime·wintls(SB),NOSPLIT,$0 243 // Allocate a TLS slot to hold g across calls to external code 244 MOVD runtime·_TlsAlloc(SB), R0 245 SUB $16, RSP // skip over saved frame pointer below RSP 246 BL (R0) 247 ADD $16, RSP 248 249 // Assert that slot is less than 64 so we can use _TEB->TlsSlots 250 CMP $64, R0 251 BLT ok 252 // Fallback to the TEB arbitrary pointer. 253 // TODO: don't use the arbitrary pointer (see go.dev/issue/59824) 254 MOVD $TEB_ArbitraryPtr, R0 255 B settls 256ok: 257 258 // Save offset from R18 into tls_g. 259 LSL $3, R0 260 ADD $TEB_TlsSlots, R0 261settls: 262 MOVD R0, runtime·tls_g(SB) 263 RET 264