[dev.regabi] runtime: use g register in some assembly functions on AMD64

Now that we have a g register, just use it.

Note: functions that can be called from ABI0 context (e.g.
morestack) is unchanged. Functions that switch g is also
unchanged, because we need to set the new g in both the register
and TLS.

TODO: other OSes.

Change-Id: I692a82a7caa8417ff620a59676a6275f56747b94
Reviewed-on: https://go-review.googlesource.com/c/go/+/289718
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>

diff --git a/src/runtime/asm_amd64.s b/src/runtime/asm_amd64.s
index 83c08a52f742cf60a7336e62f639d91003afd3a3..93280eee4a6c5dd59472423c581bd83f737b3c9b 100644 (file)
--- a/src/runtime/asm_amd64.s
+++ b/src/runtime/asm_amd64.s
@@ -585,18 +585,20 @@ TEXT runtime·jmpdefer(SB), NOSPLIT, $0-16
        MOVQ    0(DX), BX
        JMP     BX      // but first run the deferred function
 
-// Save state of caller into g->sched. Smashes R8, R9.
+// Save state of caller into g->sched. Smashes R9.
 TEXT gosave<>(SB),NOSPLIT,$0
-       get_tls(R8)
-       MOVQ    g(R8), R8
+#ifndef GOEXPERIMENT_REGABI
+       get_tls(R14)
+       MOVQ    g(R14), R14
+#endif
        MOVQ    0(SP), R9
-       MOVQ    R9, (g_sched+gobuf_pc)(R8)
+       MOVQ    R9, (g_sched+gobuf_pc)(R14)
        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)
+       MOVQ    R9, (g_sched+gobuf_sp)(R14)
+       MOVQ    $0, (g_sched+gobuf_ret)(R14)
+       MOVQ    BP, (g_sched+gobuf_bp)(R14)
        // Assert ctxt is zero. See func save.
-       MOVQ    (g_sched+gobuf_ctxt)(R8), R9
+       MOVQ    (g_sched+gobuf_ctxt)(R14), R9
        TESTQ   R9, R9
        JZ      2(PC)
        CALL    runtime·badctxt(SB)
@@ -1391,9 +1393,13 @@ TEXT runtime·gcWriteBarrier<ABIInternal>(SB),NOSPLIT,$112
        MOVQ    R13, 104(SP)
        // TODO: Consider passing g.m.p in as an argument so they can be shared
        // across a sequence of write barriers.
+#ifdef GOEXPERIMENT_REGABI
+       MOVQ    g_m(R14), R13
+#else
        get_tls(R13)
        MOVQ    g(R13), R13
        MOVQ    g_m(R13), R13
+#endif
        MOVQ    m_p(R13), R13
        MOVQ    (p_wbBuf+wbBuf_next)(R13), R12
        // Increment wbBuf.next position.

diff --git a/src/runtime/race_amd64.s b/src/runtime/race_amd64.s
index 7f97025c1add85ca317a76a6c6d26fff91beecaa..c3b7bbfbfe2e8084780fa123c1b326252705a362 100644 (file)
--- a/src/runtime/race_amd64.s
+++ b/src/runtime/race_amd64.s
@@ -146,8 +146,10 @@ TEXT       runtime·racewriterangepc1(SB), NOSPLIT, $0-24
 // If addr (RARG1) is out of range, do nothing.
 // Otherwise, setup goroutine context and invoke racecall. Other arguments already set.
 TEXT   racecalladdr<>(SB), NOSPLIT, $0-0
+#ifndef GOEXPERIMENT_REGABI
        get_tls(R12)
        MOVQ    g(R12), R14
+#endif
        MOVQ    g_racectx(R14), RARG0   // goroutine context
        // Check that addr is within [arenastart, arenaend) or within [racedatastart, racedataend).
        CMPQ    RARG1, runtime·racearenastart(SB)
@@ -183,8 +185,10 @@ TEXT       runtime·racefuncenter(SB), NOSPLIT, $0-8
 // R11 = caller's return address
 TEXT   racefuncenter<>(SB), NOSPLIT, $0-0
        MOVQ    DX, R15         // save function entry context (for closures)
+#ifndef GOEXPERIMENT_REGABI
        get_tls(R12)
        MOVQ    g(R12), R14
+#endif
        MOVQ    g_racectx(R14), RARG0   // goroutine context
        MOVQ    R11, RARG1
        // void __tsan_func_enter(ThreadState *thr, void *pc);
@@ -197,8 +201,10 @@ TEXT       racefuncenter<>(SB), NOSPLIT, $0-0
 // func runtime·racefuncexit()
 // Called from instrumented code.
 TEXT   runtime·racefuncexit(SB), NOSPLIT, $0-0
+#ifndef GOEXPERIMENT_REGABI
        get_tls(R12)
        MOVQ    g(R12), R14
+#endif
        MOVQ    g_racectx(R14), RARG0   // goroutine context
        // void __tsan_func_exit(ThreadState *thr);
        MOVQ    $__tsan_func_exit(SB), AX
@@ -357,8 +363,10 @@ racecallatomic_data:
        JAE     racecallatomic_ignore
 racecallatomic_ok:
        // Addr is within the good range, call the atomic function.
+#ifndef GOEXPERIMENT_REGABI
        get_tls(R12)
        MOVQ    g(R12), R14
+#endif
        MOVQ    g_racectx(R14), RARG0   // goroutine context
        MOVQ    8(SP), RARG1    // caller pc
        MOVQ    (SP), RARG2     // pc
@@ -370,8 +378,10 @@ racecallatomic_ignore:
        // An attempt to synchronize on the address would cause crash.
        MOVQ    AX, R15 // remember the original function
        MOVQ    $__tsan_go_ignore_sync_begin(SB), AX
+#ifndef GOEXPERIMENT_REGABI
        get_tls(R12)
        MOVQ    g(R12), R14
+#endif
        MOVQ    g_racectx(R14), RARG0   // goroutine context
        CALL    racecall<>(SB)
        MOVQ    R15, AX // restore the original function
@@ -399,8 +409,10 @@ TEXT       runtime·racecall(SB), NOSPLIT, $0-0
 
 // Switches SP to g0 stack and calls (AX). Arguments already set.
 TEXT   racecall<>(SB), NOSPLIT, $0-0
+#ifndef GOEXPERIMENT_REGABI
        get_tls(R12)
        MOVQ    g(R12), R14
+#endif
        MOVQ    g_m(R14), R13
        // Switch to g0 stack.
        MOVQ    SP, R12         // callee-saved, preserved across the CALL

diff --git a/src/runtime/sys_linux_amd64.s b/src/runtime/sys_linux_amd64.s
index b0a201fc6f70cca77f83d1ce78cabfd9ac9f9a63..d48573c2c592258ee749a5cd3ec24270c2ae55a9 100644 (file)
--- a/src/runtime/sys_linux_amd64.s
+++ b/src/runtime/sys_linux_amd64.s
@@ -215,9 +215,13 @@ TEXT runtime·walltime1(SB),NOSPLIT,$16-12
 
        MOVQ    SP, R12 // Save old SP; R12 unchanged by C code.
 
+#ifdef GOEXPERIMENT_REGABI
+       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
 
        // Set vdsoPC and vdsoSP for SIGPROF traceback.
        // Save the old values on stack and restore them on exit,
@@ -232,7 +236,11 @@ TEXT runtime·walltime1(SB),NOSPLIT,$16-12
        MOVQ    CX, m_vdsoPC(BX)
        MOVQ    DX, m_vdsoSP(BX)
 
+#ifdef GOEXPERIMENT_REGABI
+       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
@@ -275,9 +283,13 @@ TEXT runtime·nanotime1(SB),NOSPLIT,$16-8
 
        MOVQ    SP, R12 // Save old SP; R12 unchanged by C code.
 
+#ifdef GOEXPERIMENT_REGABI
+       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
 
        // Set vdsoPC and vdsoSP for SIGPROF traceback.
        // Save the old values on stack and restore them on exit,
@@ -292,7 +304,11 @@ TEXT runtime·nanotime1(SB),NOSPLIT,$16-8
        MOVQ    CX, m_vdsoPC(BX)
        MOVQ    DX, m_vdsoSP(BX)
 
+#ifdef GOEXPERIMENT_REGABI
+       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