runtime: make StackSystem part of StackGuard

Fixes #1779

R=rsc
CC=golang-dev
https://golang.org/cl/4543052

diff --git a/src/cmd/8l/pass.c b/src/cmd/8l/pass.c
index 28589b66a16c158c5309ce2ba523acb595c7d9d9..72ae043d6416fe3c4334207739d471872c54bfbb 100644 (file)
--- a/src/cmd/8l/pass.c
+++ b/src/cmd/8l/pass.c
@@ -32,23 +32,10 @@
 
 #include       "l.h"
 #include       "../ld/lib.h"
+#include "../../pkg/runtime/stack.h"
 
 static void xfol(Prog*, Prog**);
 
-// see ../../pkg/runtime/proc.c:/StackGuard
-enum
-{
-#ifdef __WINDOWS__
-       // use larger stacks to compensate for larger stack guard,
-       // needed for exception handling.
-       StackSmall = 256,
-       StackBig = 8192,
-#else
-       StackSmall = 128,
-       StackBig = 4096,
-#endif
-};
-
 Prog*
 brchain(Prog *p)
 {

diff --git a/src/pkg/runtime/proc.c b/src/pkg/runtime/proc.c
index 61faa15594bea3dc05c3bd8a9b16757e969b5d20..c5af8b754adc17392b999cb9d8bb742394d6a361 100644 (file)
--- a/src/pkg/runtime/proc.c
+++ b/src/pkg/runtime/proc.c
@@ -714,7 +714,7 @@ runtime·oldstack(void)
        goid = old.gobuf.g->goid;       // fault if g is bad, before gogo
 
        if(old.free != 0)
-               runtime·stackfree(g1->stackguard - StackGuard - StackSystem, old.free);
+               runtime·stackfree(g1->stackguard - StackGuard, old.free);
        g1->stackbase = old.stackbase;
        g1->stackguard = old.stackguard;
 
@@ -756,7 +756,7 @@ runtime·newstack(void)
                // the new Stktop* is necessary to unwind, but
                // we don't need to create a new segment.
                top = (Stktop*)(m->morebuf.sp - sizeof(*top));
-               stk = g1->stackguard - StackGuard - StackSystem;
+               stk = g1->stackguard - StackGuard;
                free = 0;
        } else {
                // allocate new segment.
@@ -785,7 +785,7 @@ runtime·newstack(void)
        g1->ispanic = false;
 
        g1->stackbase = (byte*)top;
-       g1->stackguard = stk + StackGuard + StackSystem;
+       g1->stackguard = stk + StackGuard;
 
        sp = (byte*)top;
        if(argsize > 0) {
@@ -834,7 +834,7 @@ runtime·malg(int32 stacksize)
                        g->param = nil;
                }
                newg->stack0 = stk;
-               newg->stackguard = stk + StackSystem + StackGuard;
+               newg->stackguard = stk + StackGuard;
                newg->stackbase = stk + StackSystem + stacksize - sizeof(Stktop);
                runtime·memclr(newg->stackbase, sizeof(Stktop));
        }
@@ -880,7 +880,7 @@ runtime·newproc1(byte *fn, byte *argp, int32 narg, int32 nret, void *callerpc)
 
        if((newg = gfget()) != nil){
                newg->status = Gwaiting;
-               if(newg->stackguard - StackGuard - StackSystem != newg->stack0)
+               if(newg->stackguard - StackGuard != newg->stack0)
                        runtime·throw("invalid stack in newg");
        } else {
                newg = runtime·malg(StackMin);
@@ -1165,7 +1165,7 @@ nomatch:
 static void
 gfput(G *g)
 {
-       if(g->stackguard - StackGuard - StackSystem != g->stack0)
+       if(g->stackguard - StackGuard != g->stack0)
                runtime·throw("invalid stack in gfput");
        g->schedlink = runtime·sched.gfree;
        runtime·sched.gfree = g;

diff --git a/src/pkg/runtime/runtime.h b/src/pkg/runtime/runtime.h
index f9b404e1522d34f4535d2904de12f7ee1d6c1b4f..f2f8dcd5b98cff7c973a515c60311bab39a253f9 100644 (file)
--- a/src/pkg/runtime/runtime.h
+++ b/src/pkg/runtime/runtime.h
@@ -597,17 +597,3 @@ int32      runtime·chancap(Hchan*);
 
 void   runtime·ifaceE2I(struct InterfaceType*, Eface, Iface*);
 
-enum
-{
-       // StackSystem is a number of additional bytes to add
-       // to each stack below the usual guard area for OS-specific
-       // purposes like signal handling.
-       // TODO(rsc): This is only for Windows.  Can't Windows use
-       // a separate exception stack like every other operating system?
-#ifdef __WINDOWS__
-       StackSystem = 2048,
-#else
-       StackSystem = 0,
-#endif
-};
-

diff --git a/src/pkg/runtime/stack.h b/src/pkg/runtime/stack.h
index ebf0462b564093513deda38ba736a2cb3f08f6fa..2b6b0e38769f52cedc403ffa6ce704ea71da69ba 100644 (file)
--- a/src/pkg/runtime/stack.h
+++ b/src/pkg/runtime/stack.h
@@ -53,6 +53,16 @@ functions to make sure that this limit cannot be violated.
  */
 
 enum {
+       // StackSystem is a number of additional bytes to add
+       // to each stack below the usual guard area for OS-specific
+       // purposes like signal handling. Used on Windows because
+       // it does not use a separate stack.
+#ifdef __WINDOWS__
+       StackSystem = 2048,
+#else
+       StackSystem = 0,
+#endif
+
        // The amount of extra stack to allocate beyond the size
        // needed for the single frame that triggered the split.
        StackExtra = 1024,
@@ -73,7 +83,7 @@ enum {
 
        // The stack guard is a pointer this many bytes above the
        // bottom of the stack.
-       StackGuard = 256,
+       StackGuard = 256 + StackSystem,
 
        // After a stack split check the SP is allowed to be this
        // many bytes below the stack guard.  This saves an instruction
@@ -82,5 +92,5 @@ enum {
 
        // The maximum number of bytes that a chain of NOSPLIT
        // functions can use.
-       StackLimit = StackGuard - StackSmall,
+       StackLimit = StackGuard - StackSystem - StackSmall,
 };