erts: Add 'exec_alloc' for hipe code

that uses its own super carrier (erts_exec_mmapper)
to guarantee low addressed and executable memory (PROT_EXEC).

Currently only used on x86_64 that needs low memory
for HiPE/AMD64's small code model.

By initializing erts_exec_mapper early we secure
its low memory area before erts_literal_mmapper might
steal it.

4 files changed, 64 insertions, 8 deletions

diff --git a/erts/emulator/sys/common/erl_mmap.c b/erts/emulator/sys/common/erl_mmap.c
index f5f40b35a8..38970bd24e 100644
--- a/erts/emulator/sys/common/erl_mmap.c
+++ b/erts/emulator/sys/common/erl_mmap.c
@@ -356,6 +356,12 @@ char* erts_literals_start;
 UWord erts_literals_size;
 #endif
 
+#ifdef ERTS_ALC_A_EXEC
+ErtsMemMapper erts_exec_mmapper;
+#endif
+
+
+
 #define ERTS_MMAP_SIZE_SC_SA_INC(SZ) 						\
     do {									\
 	mm->size.supercarrier.used.total += (SZ);			\
@@ -1351,10 +1357,39 @@ os_unreserve_physical(char *ptr, UWord size)
 }
 
 static void *
-os_mmap_virtual(char *ptr, UWord size)
+os_mmap_virtual(char *ptr, UWord size, int exec)
 {
-    void *res = mmap((void *) ptr, (size_t) size, ERTS_MMAP_VIRTUAL_PROT,
-		     ERTS_MMAP_VIRTUAL_FLAGS, ERTS_MMAP_FD, 0);
+    int flags = ERTS_MMAP_VIRTUAL_FLAGS;
+    void* res;
+
+#ifdef ERTS_ALC_A_EXEC
+    if (exec) {
+        ASSERT(!ptr);
+        /* OTP-19.0: Nice hack below cut-and-pasted from hipe_amd64.c */
+
+#  ifdef MAP_32BIT
+        /* If we got MAP_32BIT (Linux), then use that to ask for low memory */
+        flags |= MAP_32BIT;
+#  else
+        /* FreeBSD doesn't have MAP_32BIT, and it doesn't respect
+           a plain map_hint (returns high mappings even though the
+           hint refers to a free area), so we have to use both map_hint
+           and MAP_FIXED to get addresses below the 2GB boundary.
+           This is even worse than the Linux/ppc64 case.
+           Similarly, Solaris 10 doesn't have MAP_32BIT,
+           and it doesn't respect a plain map_hint. */
+        ptr = (char*)(512*1024*1024); /* 0.5GB */
+
+#    if defined(__FreeBSD__) || defined(__sun__)
+        flags |= MAP_FIXED;
+#    endif
+#  endif /* !MAP_32BIT */
+    }
+#else /* !ERTS_ALC_A_EXEC */
+    ASSERT(!exec);
+#endif
+    res = mmap((void *) ptr, (size_t) size, ERTS_MMAP_VIRTUAL_PROT,
+               flags, ERTS_MMAP_FD, 0);
     if (res == (void *) MAP_FAILED)
 	return NULL;
     return res;
@@ -2177,7 +2212,7 @@ erts_mmap_init(ErtsMemMapper* mm, ErtsMMapInit *init, int executable)
 	ptr = (char *) ERTS_PAGEALIGNED_CEILING(init->virtual_range.start);
 	end = (char *) ERTS_PAGEALIGNED_FLOOR(init->virtual_range.end);
 	sz = end - ptr;
-	start = os_mmap_virtual(ptr, sz);
+	start = os_mmap_virtual(ptr, sz, executable);
 	if (!start || start > ptr || start >= end)
 	    erts_exit(1,
 		     "erts_mmap: Failed to create virtual range for super carrier\n");
@@ -2202,7 +2237,7 @@ erts_mmap_init(ErtsMemMapper* mm, ErtsMMapInit *init, int executable)
 	sz = ERTS_PAGEALIGNED_CEILING(init->scs);
 #ifdef ERTS_HAVE_OS_PHYSICAL_MEMORY_RESERVATION
 	if (!init->scrpm) {
-	    start = os_mmap_virtual(NULL, sz);
+	    start = os_mmap_virtual(NULL, sz, executable);
 	    mm->reserve_physical = os_reserve_physical;
 	    mm->unreserve_physical = os_unreserve_physical;
 	    virtual_map = 1;
diff --git a/erts/emulator/sys/common/erl_mmap.h b/erts/emulator/sys/common/erl_mmap.h
index 30548bd0b0..8a7530d943 100644
--- a/erts/emulator/sys/common/erl_mmap.h
+++ b/erts/emulator/sys/common/erl_mmap.h
@@ -55,6 +55,11 @@ typedef struct {
 #define ERTS_MMAP_INIT_LITERAL_INITER \
     {{NULL, NULL}, {NULL, NULL}, ERTS_LITERAL_VIRTUAL_AREA_SIZE, 1, (1 << 10), 0}
 
+#define ERTS_HIPE_EXEC_VIRTUAL_AREA_SIZE (UWORD_CONSTANT(512)*1024*1024)
+
+#define ERTS_MMAP_INIT_HIPE_EXEC_INITER \
+    {{NULL, NULL}, {NULL, NULL}, ERTS_HIPE_EXEC_VIRTUAL_AREA_SIZE, 1, (1 << 10), 0}
+
 typedef struct ErtsMemMapper_ ErtsMemMapper;
 
 void *erts_mmap(ErtsMemMapper*, Uint32 flags, UWord *sizep);
@@ -126,10 +131,17 @@ Eterm erts_mmap_debug_info(ErtsMemMapper*, struct process*);
 #  define ERTS_HAVE_OS_MMAP 1
 #endif
 
+#ifdef ERTS_WANT_MEM_MAPPERS
+#  include "erl_alloc_types.h"
+
 extern ErtsMemMapper erts_dflt_mmapper;
-#if defined(ARCH_64) && defined(ERTS_HAVE_OS_PHYSICAL_MEMORY_RESERVATION)
+#  if defined(ARCH_64) && defined(ERTS_HAVE_OS_PHYSICAL_MEMORY_RESERVATION)
 extern ErtsMemMapper erts_literal_mmapper;
-#endif
+#  endif
+#  ifdef ERTS_ALC_A_EXEC
+extern ErtsMemMapper erts_exec_mmapper;
+#  endif
+#endif /* ERTS_WANT_MEM_MAPPERS */
 
 /*#define HARD_DEBUG_MSEG*/
 #ifdef HARD_DEBUG_MSEG
diff --git a/erts/emulator/sys/common/erl_mseg.c b/erts/emulator/sys/common/erl_mseg.c
index f0fbb682b0..f373302e65 100644
--- a/erts/emulator/sys/common/erl_mseg.c
+++ b/erts/emulator/sys/common/erl_mseg.c
@@ -31,6 +31,7 @@
 #  include "config.h"
 #endif
 
+#define ERTS_WANT_MEM_MAPPERS
 #include "sys.h"
 #include "erl_mseg.h"
 #include "global.h"
@@ -1402,6 +1403,12 @@ erts_mseg_init(ErtsMsegInit_t *init)
 
     erts_mtx_init(&init_atoms_mutex, "mseg_init_atoms");
 
+#ifdef ERTS_ALC_A_EXEC
+    /* Initialize erts_exec_mapper *FIRST*, to increase probability
+     * of getting low memory for HiPE AMD64's small code model.
+     */
+    erts_mmap_init(&erts_exec_mmapper, &init->exec_mmap, 1);
+#endif
     erts_mmap_init(&erts_dflt_mmapper, &init->dflt_mmap, 0);
 #if defined(ARCH_64) && defined(ERTS_HAVE_OS_PHYSICAL_MEMORY_RESERVATION)
     erts_mmap_init(&erts_literal_mmapper, &init->literal_mmap, 0);
diff --git a/erts/emulator/sys/common/erl_mseg.h b/erts/emulator/sys/common/erl_mseg.h
index 2acd8f8505..556a135798 100644
--- a/erts/emulator/sys/common/erl_mseg.h
+++ b/erts/emulator/sys/common/erl_mseg.h
@@ -61,6 +61,7 @@ typedef struct {
     Uint nos;
     ErtsMMapInit dflt_mmap;
     ErtsMMapInit literal_mmap;
+    ErtsMMapInit exec_mmap;
 } ErtsMsegInit_t;
 
 #define ERTS_MSEG_INIT_DEFAULT_INITIALIZER				\
@@ -70,7 +71,8 @@ typedef struct {
     10,			/* mcs:   Max cache size		*/	\
     1000,		/* cci:   Cache check interval		*/	\
     ERTS_MMAP_INIT_DEFAULT_INITER,					\
-    ERTS_MMAP_INIT_LITERAL_INITER                                       \
+    ERTS_MMAP_INIT_LITERAL_INITER,                                      \
+    ERTS_MMAP_INIT_HIPE_EXEC_INITER                                     \
 }
 
 typedef struct {