runtime: add stackguard0 to G

This is part of preemptive scheduler.
stackguard0 is checked in split stack checks and can be set to StackPreempt.
stackguard is not set to StackPreempt (holds the original value).

R=golang-dev, daniel.morsing, iant
CC=golang-dev
https://golang.org/cl/9875043

diff --git a/src/pkg/runtime/asm_386.s b/src/pkg/runtime/asm_386.s
index 58fa6d69ac277b4a9620bdb2b7d63b5688f940e2..85b500807e14d082e9886387dbbedde7a33fbbc7 100644 (file)
--- a/src/pkg/runtime/asm_386.s
+++ b/src/pkg/runtime/asm_386.s
@@ -18,6 +18,7 @@ TEXT _rt0_386(SB),7,$0
        MOVL    $runtime·g0(SB), BP
        LEAL    (-64*1024+104)(SP), BX
        MOVL    BX, g_stackguard(BP)
+       MOVL    BX, g_stackguard0(BP)
        MOVL    SP, g_stackbase(BP)
        
        // find out information about the processor we're on
@@ -41,6 +42,10 @@ nocpuinfo:
        MOVL    BX, 4(SP)
        MOVL    BP, 0(SP)
        CALL    AX
+       // update stackguard after _cgo_init
+       MOVL    $runtime·g0(SB), CX
+       MOVL    g_stackguard0(CX), AX
+       MOVL    AX, g_stackguard(CX)
        // skip runtime·ldt0setup(SB) and tls test after _cgo_init for non-windows
        CMPL runtime·iswindows(SB), $0
        JEQ ok

diff --git a/src/pkg/runtime/asm_amd64.s b/src/pkg/runtime/asm_amd64.s
index f779b94517afb6c0fc71f2f74300ffac26f0464d..af83c0393c729ec7d27f5307d78828a9669edbdf 100644 (file)
--- a/src/pkg/runtime/asm_amd64.s
+++ b/src/pkg/runtime/asm_amd64.s
@@ -18,6 +18,7 @@ TEXT _rt0_amd64(SB),7,$-8
        MOVQ    $runtime·g0(SB), DI
        LEAQ    (-64*1024+104)(SP), BX
        MOVQ    BX, g_stackguard(DI)
+       MOVQ    BX, g_stackguard0(DI)
        MOVQ    SP, g_stackbase(DI)
 
        // find out information about the processor we're on
@@ -39,6 +40,10 @@ nocpuinfo:
        MOVQ    DI, CX  // Win64 uses CX for first parameter
        MOVQ    $setmg_gcc<>(SB), SI
        CALL    AX
+       // update stackguard after _cgo_init
+       MOVQ    $runtime·g0(SB), CX
+       MOVQ    g_stackguard0(CX), AX
+       MOVQ    AX, g_stackguard(CX)
        CMPL    runtime·iswindows(SB), $0
        JEQ ok
 

diff --git a/src/pkg/runtime/asm_arm.s b/src/pkg/runtime/asm_arm.s
index fed9b30215ee3da7d9a5d67b1ad33380abf1c610..d4bcbd5a91778a63d233b3a12cb2716060b9cef2 100644 (file)
--- a/src/pkg/runtime/asm_arm.s
+++ b/src/pkg/runtime/asm_arm.s
@@ -28,6 +28,7 @@ TEXT _rt0_arm(SB),7,$-4
        // create istack out of the OS stack
        MOVW    $(-8192+104)(R13), R0
        MOVW    R0, g_stackguard(g)     // (w 104b guard)
+       MOVW    R0, g_stackguard0(g)
        MOVW    R13, g_stackbase(g)
        BL      runtime·emptyfunc(SB)  // fault if stack check is wrong
 
@@ -36,6 +37,9 @@ TEXT _rt0_arm(SB),7,$-4
        CMP     $0, R2
        MOVW.NE g, R0 // first argument of _cgo_init is g
        BL.NE   (R2) // will clobber R0-R3
+       // update stackguard after _cgo_init
+       MOVW    g_stackguard0(g), R0
+       MOVW    R0, g_stackguard(g)
 
        BL      runtime·checkgoarm(SB)
        BL      runtime·check(SB)

diff --git a/src/pkg/runtime/panic.c b/src/pkg/runtime/panic.c
index ecce93ff16345cadf4f5e5a9e5224421f0723dee..18e4779540a9568fa8ede1d58f0c60353ba9f34b 100644 (file)
--- a/src/pkg/runtime/panic.c
+++ b/src/pkg/runtime/panic.c
@@ -298,6 +298,7 @@ runtime·unwindstack(G *gp, byte *sp)
                        break;
                gp->stackbase = (uintptr)top->stackbase;
                gp->stackguard = (uintptr)top->stackguard;
+               gp->stackguard0 = gp->stackguard;
                if(top->free != 0)
                        runtime·stackfree(stk, top->free);
        }

diff --git a/src/pkg/runtime/proc.c b/src/pkg/runtime/proc.c
index c7a8d2418257e5465a6f2996c2a5cae19ca2cad9..206a3cba19368f6384d8564cc7b726e270edc9a9 100644 (file)
--- a/src/pkg/runtime/proc.c
+++ b/src/pkg/runtime/proc.c
@@ -468,6 +468,7 @@ runtime·mstart(void)
        // so other calls can reuse this stack space.
        runtime·gosave(&m->g0->sched);
        m->g0->sched.pc = (void*)-1;  // make sure it is never used
+       m->g0->stackguard = m->g0->stackguard0;  // cgo sets only stackguard0, copy it to stackguard
        m->seh = &seh;
        runtime·asminit();
        runtime·minit();
@@ -615,6 +616,7 @@ runtime·needm(byte x)
        runtime·setmg(mp, mp->g0);
        g->stackbase = (uintptr)(&x + 1024);
        g->stackguard = (uintptr)(&x - 32*1024);
+       g->stackguard0 = g->stackguard;
 
        // On windows/386, we need to put an SEH frame (two words)
        // somewhere on the current stack. We are called
@@ -979,6 +981,7 @@ execute(G *gp)
                runtime·throw("execute: bad g status");
        }
        gp->status = Grunning;
+       gp->stackguard0 = gp->stackguard;
        m->p->tick++;
        m->curg = gp;
        gp->m = m;
@@ -1465,6 +1468,7 @@ runtime·malg(int32 stacksize)
                }
                newg->stack0 = (uintptr)stk;
                newg->stackguard = (uintptr)stk + StackGuard;
+               newg->stackguard0 = newg->stackguard;
                newg->stackbase = (uintptr)stk + StackSystem + stacksize - sizeof(Stktop);
                runtime·memclr((byte*)newg->stackbase, sizeof(Stktop));
        }

diff --git a/src/pkg/runtime/runtime.h b/src/pkg/runtime/runtime.h
index 2d918f4cff57735e028deb404a56e076e3858fab..e616990ccf2eebe8327634fa8ef5e60490727cb1 100644 (file)
--- a/src/pkg/runtime/runtime.h
+++ b/src/pkg/runtime/runtime.h
@@ -226,7 +226,8 @@ struct      GCStats
 };
 struct G
 {
-       uintptr stackguard;     // cannot move - also known to linker, libmach, runtime/cgo
+       // stackguard0 can be set to StackPreempt as opposed to stackguard
+       uintptr stackguard0;    // cannot move - also known to linker, libmach, runtime/cgo
        uintptr stackbase;      // cannot move - also known to libmach, runtime/cgo
        Defer*  defer;
        Panic*  panic;
@@ -235,6 +236,7 @@ struct      G
        uintptr gcsp;           // if status==Gsyscall, gcsp = sched.sp to use during gc
        byte*   gcpc;           // if status==Gsyscall, gcpc = sched.pc to use during gc
        uintptr gcguard;                // if status==Gsyscall, gcguard = stackguard to use during gc
+       uintptr stackguard;     // same as stackguard0, but not set to StackPreempt
        uintptr stack0;
        FuncVal*        fnstart;                // initial function
        G*      alllink;        // on allg

diff --git a/src/pkg/runtime/stack.c b/src/pkg/runtime/stack.c
index b6f64aa7664864363fc70da6d4a870007aa238b0..a033d6b01250fa0100c1568fb6f5381d7afd408c 100644 (file)
--- a/src/pkg/runtime/stack.c
+++ b/src/pkg/runtime/stack.c
@@ -157,6 +157,7 @@ runtime·oldstack(void)
        label = top->gobuf;
        gp->stackbase = (uintptr)top->stackbase;
        gp->stackguard = (uintptr)top->stackguard;
+       gp->stackguard0 = gp->stackguard;
        if(top->free != 0)
                runtime·stackfree(old, top->free);
 
@@ -249,6 +250,7 @@ runtime·newstack(void)
 
        gp->stackbase = (uintptr)top;
        gp->stackguard = (uintptr)stk + StackGuard;
+       gp->stackguard0 = gp->stackguard;
 
        sp = (byte*)top;
        if(argsize > 0) {