Aaron Bieber <aa...@bolddaemon.com> writes:
Accidently only sent this to tedu@ :P
Ted Unangst <t...@tedunangst.com> writes:
On i386, it's better for a jit to ask for exec memory upfront, so uvm
knows to place it in the exec segment. Otherwise, if you mmap non-exec
and mprotect it, you wind up with a high mapping and the segment must
be enlarged to cover the whole process.
I sent Mike a slightly different diff; this is what he ended up
committing to git. I think we should add it to the port.
Here is the diff. I don't currently have an i386 box to test, so if
someone could try it, that would be awesome :D
OK?
Index: Makefile
===================================================================
RCS file: /cvs/ports/lang/luajit/Makefile,v
retrieving revision 1.14
diff -u -p -r1.14 Makefile
--- Makefile 2 Jun 2014 19:43:50 -0000 1.14
+++ Makefile 19 Jan 2015 17:23:40 -0000
@@ -11,7 +11,7 @@ COMMENT = just-in-time compiler for Lua
V = 2.0.3
DISTNAME = LuaJIT-${V}
PKGNAME = ${DISTNAME:L}
-REVISION = 1
+REVISION = 2
CATEGORIES = lang
Index: patches/patch-src_lj_mcode_c
===================================================================
RCS file: patches/patch-src_lj_mcode_c
diff -N patches/patch-src_lj_mcode_c
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ patches/patch-src_lj_mcode_c 19 Jan 2015 17:23:40 -0000
@@ -0,0 +1,34 @@
+$OpenBSD$
+--- src/lj_mcode.c.orig Wed Mar 12 06:10:00 2014
++++ src/lj_mcode.c Mon Jan 19 10:21:45 2015
+@@ -145,7 +145,7 @@ static void mcode_free(jit_State *J, void *p, size_t s
+
+ /* -- MCode area protection ----------------------------------------------- */
+
+-/* Define this ONLY if the page protection twiddling becomes a bottleneck. */
++/* Define this ONLY if page protection twiddling becomes a bottleneck. */
+ #ifdef LUAJIT_UNPROTECT_MCODE
+
+ /* It's generally considered to be a potential security risk to have
+@@ -252,7 +252,20 @@ static void *mcode_alloc(jit_State *J, size_t sz)
+ #else
+
+ /* All memory addresses are reachable by relative jumps. */
+-#define mcode_alloc(J, sz) mcode_alloc_at((J), 0, (sz), MCPROT_GEN)
++static void *mcode_alloc(jit_State *J, size_t sz)
++{
++#ifdef __OpenBSD__
++ /* Allow better executable memory allocation for OpenBSD W^X mode. */
++ void *p = mcode_alloc_at(J, 0, sz, MCPROT_RUN);
++ if (p && mcode_setprot(p, sz, MCPROT_GEN)) {
++ mcode_free(J, p, sz);
++ return NULL;
++ }
++ return p;
++#else
++ return mcode_alloc_at(J, 0, sz, MCPROT_GEN);
++#endif
++}
+
+ #endif
+
