From: Chris Hanson <org/chris-hanson/cph>
Date: Sun, 19 Jul 1998 20:40:10 +0000 (+0000)
Subject: Must call mprotect to set the "execute" bit on Scheme's memory, so
X-Git-Tag: 20090517-FFI~4767
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=0824174b981bafcebab12da1156ed1ed706de2e2;p=mit-scheme.git

Must call mprotect to set the "execute" bit on Scheme's memory, so
compiled code can run.  Also, implement mechanism to use mprotect to
flush the cache (which is disabled by default).
---

diff --git a/v7/src/microcode/cmpintmd/mips.h b/v7/src/microcode/cmpintmd/mips.h
index 2a32f7345..636e1a8f3 100644
--- a/v7/src/microcode/cmpintmd/mips.h
+++ b/v7/src/microcode/cmpintmd/mips.h
@@ -1,6 +1,6 @@
 /* -*-C-*-
 
-$Id: mips.h,v 1.20 1994/05/02 19:04:06 cph Exp $
+$Id: mips.h,v 1.21 1998/07/19 20:40:10 cph Exp $
 
 Copyright (c) 1989-1994 Massachusetts Institute of Technology
 
@@ -46,11 +46,18 @@ MIT in each case. */
 
 #include "cmptype.h"
 
-#ifdef _IRIX4
+#ifdef _IRIX
 
 #include <sys/cachectl.h>
+#include <unistd.h>
 
-#else /* not _IRIX4 */
+/* Define this to use the official method of flushing the cache: the
+   `mprotect' system call.  When not defined, we use `cacheflush',
+   which is more efficient. The mprotect method is known to work on
+   IRIX 6.3.  */
+/* #define USE_MPROTECT_CACHE_FLUSH */
+
+#else /* not _IRIX */
 #ifdef sonyrisc
 
 #include <sys/syscall.h>
@@ -83,7 +90,13 @@ extern void syscall();
 #endif /* not 0 */
 
 #endif /* not sonyrisc */
-#endif /* not _IRIX4 */
+#endif /* not _IRIX */
+
+#ifdef USE_MPROTECT_CACHE_FLUSH
+#define FLUSH_BOTH call_mprotect
+#else
+#define FLUSH_BOTH(addr, size) cacheflush ((addr), (size), BCACHE)
+#endif
 
 /* Machine parameters to be set by the user. */
 
@@ -340,7 +353,7 @@ do {									\
   PC[1] = JALR(COMP_REG_LINKAGE, COMP_REG_TEMPORARY);			\
   PC[2] = ADDI(COMP_REG_TRAMP_INDEX, 0, (4*index));			\
   /* assumes index fits in 16 bits */					\
-  cacheflush (PC, (3 * sizeof (unsigned long)), BCACHE);		\
+  FLUSH_BOTH (PC, (3 * sizeof (unsigned long)));			\
 }
 
 /* Execute cache entries.
@@ -461,10 +474,9 @@ do {									\
 
 #define FLUSH_I_CACHE() do						\
 {									\
-  cacheflush (Constant_Space,						\
+  FLUSH_BOTH (Constant_Space,						\
 	      (((unsigned long) Heap_Top)				\
-	       - ((unsigned long) Constant_Space)),			\
-	      BCACHE);							\
+	       - ((unsigned long) Constant_Space)));			\
 } while (0)
 
 /* This flushes a region of the I-cache.
@@ -474,7 +486,7 @@ do {									\
 
 #define FLUSH_I_CACHE_REGION(address, nwords) do			\
 {									\
-  cacheflush ((address), ((sizeof (long)) * (nwords)), BCACHE);		\
+  FLUSH_BOTH ((address), ((sizeof (long)) * (nwords)));			\
 } while (0)
 
 /* This guarantees that a newly-written section of address space
@@ -484,15 +496,26 @@ do {									\
    the written region overlaps with already-executed areas.
  */
 
+#ifdef USE_MPROTECT_CACHE_FLUSH
+
+#define PUSH_D_CACHE_REGION(address, nwords) do				\
+{									\
+  FLUSH_BOTH ((address), ((sizeof (long)) * (nwords)));			\
+} while (0)
+
+#else /* not USE_MPROTECT_CACHE_FLUSH */
+
 #define PUSH_D_CACHE_REGION(address, nwords) do				\
 {									\
   unsigned long _addr = ((unsigned long) (address));			\
   unsigned long _nbytes = ((sizeof (long)) * (nwords));			\
-  cacheflush (_addr, _nbytes, DCACHE);					\
-  cacheflush (_addr, 1, ICACHE);					\
-  cacheflush ((_addr + (_nbytes - 1)), 1, ICACHE);			\
+  cacheflush (((PTR) _addr), _nbytes, DCACHE);				\
+  cacheflush (((PTR) _addr), 1, ICACHE);				\
+  cacheflush (((PTR) (_addr + (_nbytes - 1))), 1, ICACHE);		\
 } while (0)
 
+#endif /* not USE_MPROTECT_CACHE_FLUSH */
+
 #ifdef IN_CMPINT_C
 
 static void
@@ -512,6 +535,57 @@ DEFUN_VOID (interface_initialize_C)
   return;
 }
 
+#ifdef _IRIX6
+
+#include <sys/mman.h>
+#include <sys/types.h>
+
+#define VM_PROT_SCHEME (PROT_READ | PROT_WRITE | PROT_EXEC)
+
+static void * mprotect_start;
+static unsigned long mprotect_size;
+
+static void
+DEFUN (call_mprotect_1, (start, size), void * start AND unsigned long size)
+{
+  if ((mprotect (start, size, VM_PROT_SCHEME)) != 0)
+    {
+      perror ("unable to change memory protection");
+      fprintf (stderr, "mprotect(0x%lx, %d (0x%lx), 0x%lx)\n",
+	       start, size, size, VM_PROT_SCHEME);
+      Microcode_Termination (TERM_EXIT);
+      /*NOTREACHED*/
+    }
+}
+
+#ifdef USE_MPROTECT_CACHE_FLUSH
+void
+DEFUN (call_mprotect, (start, size), void * start AND unsigned long size)
+{
+  unsigned long pagesize = (getpagesize ());
+  unsigned long istart = ((unsigned long) start);
+  unsigned long pstart = ((istart / pagesize) * pagesize);
+  call_mprotect_1 (((void *) pstart), (istart - pstart));
+}
+#endif /* USE_MPROTECT_CACHE_FLUSH */
+
+void *
+DEFUN (irix_heap_malloc, (size), long size)
+{
+  int pagesize = (getpagesize ());
+  void * area = (malloc (size + pagesize));
+  if (area == 0)
+    return (0);
+  mprotect_start
+    = ((void *)
+       (((((unsigned long) area) + (pagesize - 1)) / pagesize) * pagesize));
+  mprotect_size = size;
+  call_mprotect_1 (mprotect_start, mprotect_size);
+  return (mprotect_start);
+}
+
+#endif /* _IRIX6 */
+
 #define ASM_RESET_HOOK interface_initialize_C
 
 #define CLOSURE_ENTRY_WORDS			\