From c01bd008dba6dadfda37e1964a1cc3359ed4ff50 Mon Sep 17 00:00:00 2001
From: Dan Sumorok <dsumorok@gmail.com>
Date: Sat, 6 Jul 2013 17:09:37 -0400
Subject: [PATCH] Hack to load code below 4GB, and to make 32-bit vm allocates
 work.

---
 BasiliskII/src/Unix/configure.ac | 26 +++++++++++++++++++-------
 BasiliskII/src/Unix/sigsegv.h    |  2 +-
 BasiliskII/src/Unix/vm_alloc.cpp | 32 ++++++++++++++++++--------------
 3 files changed, 38 insertions(+), 22 deletions(-)

diff --git a/BasiliskII/src/Unix/configure.ac b/BasiliskII/src/Unix/configure.ac
index 095ee4c5..e5c3cd27 100644
--- a/BasiliskII/src/Unix/configure.ac
+++ b/BasiliskII/src/Unix/configure.ac
@@ -772,18 +772,20 @@ if [[ "x$WANT_SDL" = "xyes" ]]; then
     EXTRASYSSRCS="$EXTRASYSSRCS ../SDL/SDLMain.m"
   fi
 fi
+
+AC_MSG_CHECKING([whether __LP64__ is defined])
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#if !defined(__LP64__)
+                                     # error __LP64__ not defined
+                                     #endif
+                                   ]])],
+                  [AC_MSG_RESULT(yes); LP64_DEFINED=yes],
+                  [AC_MSG_RESULT(no)])
+
 if [[ "x$WANT_SDL_VIDEO" = "xyes" ]]; then
   AC_DEFINE(USE_SDL_VIDEO, 1, [Define to enable SDL video graphics support])
   VIDEOSRCS="../SDL/video_sdl.cpp"
   KEYCODES="../SDL/keycodes"
   if [[ "x$ac_cv_framework_Carbon" = "xyes" ]]; then
-    AC_MSG_CHECKING([whether __LP64__ is defined])
-    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#if !defined(__LP64__)
-                                         # error __LP64__ not defined
-                                         #endif
-                                       ]])],
-                      [AC_MSG_RESULT(yes); LP64_DEFINED=yes],
-                      [AC_MSG_RESULT(no)])
     if [[ "x$LP64_DEFINED" = "xyes" ]]; then
       EXTRASYSSRCS="$EXTRASYSSRCS ../MacOSX/clip_macosx64.mm ../pict.c"
     else
@@ -1774,6 +1776,16 @@ if [[ "x$HAVE_IPA" = "xyes" ]]; then
   LDFLAGS="$LDFLAGS -O3 -OPT:Olimit=0 -IPA"
 fi
 
+if [[ "x$LP64_DEFINED" = "xyes" ] && [ "x$have_mach_vm" = "xyes" ]]; then
+LIBS+=" -Wl,-pagezero_size,0x20000000"
+LIBS+=" -Wl,-segaddr,__TEXT,0x60000000"
+LIBS+=" -Wl,-segaddr,__PAGEZERO,0x20000000"
+fi
+
+if [[ ${OS_TYPE} = darwin ]]; then
+LIBS+=" -Wl,-no_pie"
+fi
+
 dnl Generate Makefile.
 AC_SUBST(DEFINES)
 AC_SUBST(SYSSRCS)
diff --git a/BasiliskII/src/Unix/sigsegv.h b/BasiliskII/src/Unix/sigsegv.h
index 8fdada9e..26a9e5eb 100644
--- a/BasiliskII/src/Unix/sigsegv.h
+++ b/BasiliskII/src/Unix/sigsegv.h
@@ -106,7 +106,7 @@ extern "C" {
 #define SIGSEGV_REGISTER_FILE			((SIGSEGV_REGISTER_TYPE *)&SIP->thr_state.MACH_FIELD_NAME(rax)) /* RAX is the first GPR we consider */
 #endif
 #ifdef __x86_64__
-#define SIGSEGV_FAULT_ADDRESS_FAST		(((uint64_t)code[1])|0x100000000)
+#define SIGSEGV_FAULT_ADDRESS_FAST		code[1]
 #else
 #define SIGSEGV_FAULT_ADDRESS_FAST		code[1]
 #endif
diff --git a/BasiliskII/src/Unix/vm_alloc.cpp b/BasiliskII/src/Unix/vm_alloc.cpp
index 57dd8169..4d3569c0 100644
--- a/BasiliskII/src/Unix/vm_alloc.cpp
+++ b/BasiliskII/src/Unix/vm_alloc.cpp
@@ -221,6 +221,9 @@ void vm_exit(void)
 /* Allocate zero-filled memory of SIZE bytes. The mapping is private
    and default protection bits are read / write. The return value
    is the actual mapping address chosen or VM_MAP_FAILED for errors.  */
+#if defined(HAVE_MACH_VM)
+static void *last_alloc = NULL;
+#endif
 
 void * vm_acquire(size_t size, int options)
 {
@@ -238,24 +241,18 @@ void * vm_acquire(size_t size, int options)
 #endif
 
 #if defined(HAVE_MACH_VM)
-	static size_t addrOffset = 0x80000000;
+	static size_t addrOffset = 0x20000000;
 	kern_return_t ret_code;
 	static uint8 *base32 = NULL;
 
 	if(options & VM_MAP_32BIT) {
 #ifdef __LP64__
-		if((size < 0x08000000) && (addrOffset < 0x100000000ULL) && (base32 != NULL)) {
-			addr = (void *)(base32 + addrOffset);
-			ret_code = vm_allocate(mach_task_self(), (vm_address_t *)&addr, 
-					       size, VM_FLAGS_FIXED);
-			addrOffset += 0x08000000;
-		} else {
-			ret_code = vm_allocate(mach_task_self(), (vm_address_t *)&addr, 
-					       size, VM_FLAGS_ANYWHERE);
-			if((ret_code == KERN_SUCCESS) && (base32 == NULL)) {
-			  base32 = (uint8_t *)addr;
-			}
-
+		addr = base32 + addrOffset;
+		ret_code = vm_allocate(mach_task_self(), (vm_address_t *)&addr, 
+				       size, VM_FLAGS_FIXED | VM_FLAGS_OVERWRITE);
+		if(ret_code == KERN_SUCCESS) {
+			last_alloc = addr;
+			base32 = base32 + size;
 		}
 #else
 		// vm_allocate() returns a zero-filled memory region
@@ -325,9 +322,16 @@ int vm_acquire_fixed(void * addr, size_t size, int options)
 
 #if defined(HAVE_MACH_VM)
 	// vm_allocate() returns a zero-filled memory region
+
 #ifdef __LP64__
-	kern_return_t ret_code = vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 
+	if(addr != last_alloc) {
+		return -1;
+	}
+
+	kern_return_t ret_code = vm_allocate(mach_task_self(), 
+					     (vm_address_t *)&addr, size, 
 					     VM_FLAGS_FIXED | VM_FLAGS_OVERWRITE);
+
 #else
 	kern_return_t ret_code = vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 
 					     VM_FLAGS_FIXED);