runtime/cgo: rename crosscall_386 to crosscall1 and standardise API

Most architectures have a crosscall1 function that takes a function
pointer, a setg_gcc function pointer and a g pointer. However,
crosscall_386 only takes a function pointer and the call to setg_gcc
is performed in the thread entry function.

Rename crosscall_386 to crosscall1 for consistency with other
architectures, as well as standardising the API - while not strictly
necessary, it will allow for further deduplication as the calling
code becomes more consistent.

Change-Id: I77cf42e1e15e0a4c5802359849a849c32cebd92f
Reviewed-on: https://go-review.googlesource.com/c/go/+/518618
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Joel Sing <joel@sing.id.au>
Reviewed-by: Ian Lance Taylor <iant@google.com>

src/runtime/cgo/gcc_386.S

@@ -14,20 +14,26 @@
 #endif
 
 /*
- * void crosscall_386(void (*fn)(void))
+ * void crosscall1(void (*fn)(void), void (*setg_gcc)(void*), void *g)
  *
- * Calling into the 8c tool chain, where all registers are caller save.
+ * Calling into the gc tool chain, where all registers are caller save.
  * Called from standard x86 ABI, where %ebp, %ebx, %esi,
  * and %edi are callee-save, so they must be saved explicitly.
  */
-.globl EXT(crosscall_386)
-EXT(crosscall_386):
+.globl EXT(crosscall1)
+EXT(crosscall1):
 	pushl %ebp
 	movl %esp, %ebp
 	pushl %ebx
 	pushl %esi
 	pushl %edi
 
+	movl 16(%ebp), %eax	/* g */
+	pushl %eax
+	movl 12(%ebp), %eax	/* setg_gcc */
+	call *%eax
+	popl %eax
+
 	movl 8(%ebp), %eax	/* fn */
 	call *%eax
 

src/runtime/cgo/gcc_freebsd_386.c

@@ -47,6 +47,7 @@ _cgo_sys_thread_start(ThreadStart *ts)
 	}
 }
 
+extern void crosscall1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
 static void*
 threadentry(void *v)
 {
@@ -55,11 +56,6 @@ threadentry(void *v)
 	ts = *(ThreadStart*)v;
 	free(v);
 
-	/*
-	 * Set specific keys.
-	 */
-	setg_gcc((void*)ts.g);
-
-	crosscall_386(ts.fn);
+	crosscall1(ts.fn, setg_gcc, ts.g);
 	return nil;
 }

src/runtime/cgo/gcc_linux_386.c

@@ -50,6 +50,7 @@ _cgo_sys_thread_start(ThreadStart *ts)
 	}
 }
 
+extern void crosscall1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
 static void*
 threadentry(void *v)
 {
@@ -58,11 +59,6 @@ threadentry(void *v)
 	ts = *(ThreadStart*)v;
 	free(v);
 
-	/*
-	 * Set specific keys.
-	 */
-	setg_gcc((void*)ts.g);
-
-	crosscall_386(ts.fn);
+	crosscall1(ts.fn, setg_gcc, ts.g);
 	return nil;
 }

src/runtime/cgo/gcc_netbsd_386.c

@@ -46,6 +46,7 @@ _cgo_sys_thread_start(ThreadStart *ts)
 	}
 }
 
+extern void crosscall1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
 static void*
 threadentry(void *v)
 {
@@ -55,11 +56,6 @@ threadentry(void *v)
 	ts = *(ThreadStart*)v;
 	free(v);
 
-	/*
-	 * Set specific keys.
-	 */
-	setg_gcc((void*)ts.g);
-
 	// On NetBSD, a new thread inherits the signal stack of the
 	// creating thread. That confuses minit, so we remove that
 	// signal stack here before calling the regular mstart. It's
@@ -71,6 +67,6 @@ threadentry(void *v)
 	ss.ss_flags = SS_DISABLE;
 	sigaltstack(&ss, nil);
 
-	crosscall_386(ts.fn);
+	crosscall1(ts.fn, setg_gcc, ts.g);
 	return nil;
 }

src/runtime/cgo/gcc_openbsd_386.c

@@ -46,6 +46,7 @@ _cgo_sys_thread_start(ThreadStart *ts)
 	}
 }
 
+extern void crosscall1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
 static void*
 threadentry(void *v)
 {
@@ -54,11 +55,6 @@ threadentry(void *v)
 	ts = *(ThreadStart*)v;
 	free(v);
 
-	/*
-	 * Set specific keys.
-	 */
-	setg_gcc((void*)ts.g);
-
-	crosscall_386(ts.fn);
+	crosscall1(ts.fn, setg_gcc, ts.g);
 	return nil;
 }

src/runtime/cgo/gcc_windows_386.c

@@ -12,21 +12,23 @@
 #include "libcgo_windows.h"
 
 static void threadentry(void*);
+static void (*setg_gcc)(void*);
 static DWORD *tls_g;
 
 void
 x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
 {
+	setg_gcc = setg;
 	tls_g = (DWORD *)tlsg;
 }
 
-
 void
 _cgo_sys_thread_start(ThreadStart *ts)
 {
 	_cgo_beginthread(threadentry, ts);
 }
 
+extern void crosscall1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
 static void
 threadentry(void *v)
 {
@@ -47,5 +49,5 @@ threadentry(void *v)
 		:: "r"(ts.tls), "r"(*tls_g), "r"(ts.g) : "%eax"
 	);
 
-	crosscall_386(ts.fn);
+	crosscall1(ts.fn, setg_gcc, ts.g);
 }

src/runtime/cgo/libcgo.h

@@ -68,11 +68,6 @@ void _cgo_sys_thread_start(ThreadStart *ts);
  */
 uintptr_t _cgo_wait_runtime_init_done(void);
 
-/*
- * Call fn in the 8c world.
- */
-void crosscall_386(void (*fn)(void));
-
 /*
  * Prints error then calls abort. For linux and android.
  */