| // Copyright 2021 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. |
| |
| //go:build !faketime |
| // +build !faketime |
| |
| #include "go_asm.h" |
| #include "go_tls.h" |
| #include "textflag.h" |
| |
| #define SYS_clock_gettime 228 |
| |
| // func time.now() (sec int64, nsec int32, mono int64) |
| TEXT time·now(SB),NOSPLIT,$16-24 |
| MOVQ SP, R12 // Save old SP; R12 unchanged by C code. |
| |
| #ifdef GOEXPERIMENT_regabig |
| MOVQ g_m(R14), BX // BX unchanged by C code. |
| #else |
| get_tls(CX) |
| MOVQ g(CX), AX |
| MOVQ g_m(AX), BX // BX unchanged by C code. |
| #endif |
| |
| // Store CLOCK_REALTIME results directly to return space. |
| LEAQ sec+0(FP), SI |
| |
| // Set vdsoPC and vdsoSP for SIGPROF traceback. |
| // Save the old values on stack and restore them on exit, |
| // so this function is reentrant. |
| MOVQ m_vdsoPC(BX), CX |
| MOVQ m_vdsoSP(BX), DX |
| MOVQ CX, 0(SP) |
| MOVQ DX, 8(SP) |
| |
| MOVQ -8(SI), CX // Sets CX to function return address. |
| MOVQ CX, m_vdsoPC(BX) |
| MOVQ SI, m_vdsoSP(BX) |
| |
| #ifdef GOEXPERIMENT_regabig |
| CMPQ R14, m_curg(BX) // Only switch if on curg. |
| #else |
| CMPQ AX, m_curg(BX) // Only switch if on curg. |
| #endif |
| JNE noswitch |
| |
| MOVQ m_g0(BX), DX |
| MOVQ (g_sched+gobuf_sp)(DX), SP // Set SP to g0 stack |
| |
| noswitch: |
| SUBQ $16, SP // Space for monotonic time results |
| ANDQ $~15, SP // Align for C code |
| |
| MOVL $0, DI // CLOCK_REALTIME |
| MOVQ runtime·vdsoClockgettimeSym(SB), AX |
| CMPQ AX, $0 |
| JEQ fallback |
| CALL AX |
| |
| MOVL $1, DI // CLOCK_MONOTONIC |
| LEAQ 0(SP), SI |
| MOVQ runtime·vdsoClockgettimeSym(SB), AX |
| CALL AX |
| |
| ret: |
| MOVQ 0(SP), AX // sec |
| MOVQ 8(SP), DX // nsec |
| |
| MOVQ R12, SP // Restore real SP |
| // Restore vdsoPC, vdsoSP |
| // We don't worry about being signaled between the two stores. |
| // If we are not in a signal handler, we'll restore vdsoSP to 0, |
| // and no one will care about vdsoPC. If we are in a signal handler, |
| // we cannot receive another signal. |
| MOVQ 8(SP), CX |
| MOVQ CX, m_vdsoSP(BX) |
| MOVQ 0(SP), CX |
| MOVQ CX, m_vdsoPC(BX) |
| |
| // sec is in AX, nsec in DX |
| // return nsec in AX |
| IMULQ $1000000000, AX |
| ADDQ DX, AX |
| MOVQ AX, mono+16(FP) |
| RET |
| |
| fallback: |
| MOVQ $SYS_clock_gettime, AX |
| SYSCALL |
| |
| MOVL $1, DI // CLOCK_MONOTONIC |
| LEAQ 0(SP), SI |
| MOVQ $SYS_clock_gettime, AX |
| SYSCALL |
| |
| JMP ret |
