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authorSverker Eriksson <[email protected]>2015-05-26 20:12:08 +0200
committerSverker Eriksson <[email protected]>2015-06-01 19:44:15 +0200
commit957f619382923be72835500f56e75d8bbe553892 (patch)
tree6c2c555083d48c8342dd31ec01c8ef239f448538 /erts/emulator/beam
parent9c34c2544981ff2df6ddf94b36f4a9db5d6da6b5 (diff)
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erts: Fix magic binary alignment on 32-bit
Caused bus error on 32-bit sparc from unaligned 64-bit word in binary_to_term trap context. Also add _UNALIGNED_ magic macros to avoid double alignment padding in NIF resources.
Diffstat (limited to 'erts/emulator/beam')
-rw-r--r--erts/emulator/beam/erl_binary.h18
-rw-r--r--erts/emulator/beam/erl_bits.c8
-rw-r--r--erts/emulator/beam/erl_nif.c26
-rw-r--r--erts/emulator/beam/global.h45
4 files changed, 77 insertions, 20 deletions
diff --git a/erts/emulator/beam/erl_binary.h b/erts/emulator/beam/erl_binary.h
index 8d264d166e..6b96787d40 100644
--- a/erts/emulator/beam/erl_binary.h
+++ b/erts/emulator/beam/erl_binary.h
@@ -194,6 +194,9 @@ ERTS_GLB_INLINE Binary *erts_bin_nrml_alloc(Uint size);
ERTS_GLB_INLINE Binary *erts_bin_realloc_fnf(Binary *bp, Uint size);
ERTS_GLB_INLINE Binary *erts_bin_realloc(Binary *bp, Uint size);
ERTS_GLB_INLINE void erts_bin_free(Binary *bp);
+ERTS_GLB_INLINE Binary *erts_create_magic_binary_x(Uint size,
+ void (*destructor)(Binary *),
+ int unaligned);
ERTS_GLB_INLINE Binary *erts_create_magic_binary(Uint size,
void (*destructor)(Binary *));
@@ -332,21 +335,30 @@ erts_bin_free(Binary *bp)
}
ERTS_GLB_INLINE Binary *
-erts_create_magic_binary(Uint size, void (*destructor)(Binary *))
+erts_create_magic_binary_x(Uint size, void (*destructor)(Binary *),
+ int unaligned)
{
- Uint bsize = ERTS_MAGIC_BIN_SIZE(size);
+ Uint bsize = unaligned ? ERTS_MAGIC_BIN_UNALIGNED_SIZE(size)
+ : ERTS_MAGIC_BIN_SIZE(size);
Binary* bptr = erts_alloc_fnf(ERTS_ALC_T_BINARY, bsize);
ASSERT(bsize > size);
if (!bptr)
erts_alloc_n_enomem(ERTS_ALC_T2N(ERTS_ALC_T_BINARY), bsize);
ERTS_CHK_BIN_ALIGNMENT(bptr);
bptr->flags = BIN_FLAG_MAGIC;
- bptr->orig_size = ERTS_MAGIC_BIN_ORIG_SIZE(size);
+ bptr->orig_size = unaligned ? ERTS_MAGIC_BIN_UNALIGNED_ORIG_SIZE(size)
+ : ERTS_MAGIC_BIN_ORIG_SIZE(size);
erts_refc_init(&bptr->refc, 0);
ERTS_MAGIC_BIN_DESTRUCTOR(bptr) = destructor;
return bptr;
}
+ERTS_GLB_INLINE Binary *
+erts_create_magic_binary(Uint size, void (*destructor)(Binary *))
+{
+ return erts_create_magic_binary_x(size, destructor, 0);
+}
+
#endif /* #if ERTS_GLB_INLINE_INCL_FUNC_DEF */
#endif /* !__ERL_BINARY_H */
diff --git a/erts/emulator/beam/erl_bits.c b/erts/emulator/beam/erl_bits.c
index b8ae93fa58..2e29bf8895 100644
--- a/erts/emulator/beam/erl_bits.c
+++ b/erts/emulator/beam/erl_bits.c
@@ -107,6 +107,14 @@ erts_bits_destroy_state(ERL_BITS_PROTO_0)
void
erts_init_bits(void)
{
+ ERTS_CT_ASSERT(offsetof(Binary,orig_bytes) % 8 == 0);
+ ERTS_CT_ASSERT(offsetof(ErtsMagicBinary,u.aligned.data) % 8 == 0);
+ ERTS_CT_ASSERT(ERTS_MAGIC_BIN_BYTES_TO_ALIGN ==
+ (offsetof(ErtsMagicBinary,u.aligned.data)
+ - offsetof(ErtsMagicBinary,u.unaligned.data)));
+ ERTS_CT_ASSERT(offsetof(ErtsBinary,driver.binary.orig_bytes)
+ == offsetof(Binary,orig_bytes));
+
erts_smp_atomic_init_nob(&bits_bufs_size, 0);
#if defined(ERTS_SMP)
/* erl_process.c calls erts_bits_init_state() on all state instances */
diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c
index 426a00304e..f42ccf23c2 100644
--- a/erts/emulator/beam/erl_nif.c
+++ b/erts/emulator/beam/erl_nif.c
@@ -1199,7 +1199,11 @@ typedef struct enif_resource_t
struct enif_resource_type_t* type;
#ifdef DEBUG
erts_refc_t nif_refc;
+# ifdef ARCH_32
+ byte align__[4];
+# endif
#endif
+
char data[1];
}ErlNifResource;
@@ -1375,7 +1379,7 @@ static void rollback_opened_resource_types(void)
static void nif_resource_dtor(Binary* bin)
{
- ErlNifResource* resource = (ErlNifResource*) ERTS_MAGIC_BIN_DATA(bin);
+ ErlNifResource* resource = (ErlNifResource*) ERTS_MAGIC_BIN_UNALIGNED_DATA(bin);
ErlNifResourceType* type = resource->type;
ASSERT(ERTS_MAGIC_BIN_DESTRUCTOR(bin) == &nif_resource_dtor);
@@ -1396,8 +1400,10 @@ static void nif_resource_dtor(Binary* bin)
void* enif_alloc_resource(ErlNifResourceType* type, size_t size)
{
- Binary* bin = erts_create_magic_binary(SIZEOF_ErlNifResource(size), &nif_resource_dtor);
- ErlNifResource* resource = ERTS_MAGIC_BIN_DATA(bin);
+ Binary* bin = erts_create_magic_binary_x(SIZEOF_ErlNifResource(size),
+ &nif_resource_dtor,
+ 1); /* unaligned */
+ ErlNifResource* resource = ERTS_MAGIC_BIN_UNALIGNED_DATA(bin);
ASSERT(type->owner && type->next && type->prev); /* not allowed in load/upgrade */
resource->type = type;
@@ -1412,7 +1418,7 @@ void* enif_alloc_resource(ErlNifResourceType* type, size_t size)
void enif_release_resource(void* obj)
{
ErlNifResource* resource = DATA_TO_RESOURCE(obj);
- ErtsBinary* bin = ERTS_MAGIC_BIN_FROM_DATA(resource);
+ ErtsBinary* bin = ERTS_MAGIC_BIN_FROM_UNALIGNED_DATA(resource);
ASSERT(ERTS_MAGIC_BIN_DESTRUCTOR(bin) == &nif_resource_dtor);
#ifdef DEBUG
@@ -1426,7 +1432,7 @@ void enif_release_resource(void* obj)
void enif_keep_resource(void* obj)
{
ErlNifResource* resource = DATA_TO_RESOURCE(obj);
- ErtsBinary* bin = ERTS_MAGIC_BIN_FROM_DATA(resource);
+ ErtsBinary* bin = ERTS_MAGIC_BIN_FROM_UNALIGNED_DATA(resource);
ASSERT(ERTS_MAGIC_BIN_DESTRUCTOR(bin) == &nif_resource_dtor);
#ifdef DEBUG
@@ -1438,7 +1444,7 @@ void enif_keep_resource(void* obj)
ERL_NIF_TERM enif_make_resource(ErlNifEnv* env, void* obj)
{
ErlNifResource* resource = DATA_TO_RESOURCE(obj);
- ErtsBinary* bin = ERTS_MAGIC_BIN_FROM_DATA(resource);
+ ErtsBinary* bin = ERTS_MAGIC_BIN_FROM_UNALIGNED_DATA(resource);
Eterm* hp = alloc_heap(env,PROC_BIN_SIZE);
return erts_mk_magic_binary_term(&hp, &MSO(env->proc), &bin->binary);
}
@@ -1467,7 +1473,7 @@ int enif_get_resource(ErlNifEnv* env, ERL_NIF_TERM term, ErlNifResourceType* typ
return 0; / * Or should we allow "resource binaries" as handles? * /
}*/
mbin = pb->val;
- resource = (ErlNifResource*) ERTS_MAGIC_BIN_DATA(mbin);
+ resource = (ErlNifResource*) ERTS_MAGIC_BIN_UNALIGNED_DATA(mbin);
if (ERTS_MAGIC_BIN_DESTRUCTOR(mbin) != &nif_resource_dtor
|| resource->type != type) {
return 0;
@@ -1479,8 +1485,8 @@ int enif_get_resource(ErlNifEnv* env, ERL_NIF_TERM term, ErlNifResourceType* typ
size_t enif_sizeof_resource(void* obj)
{
ErlNifResource* resource = DATA_TO_RESOURCE(obj);
- Binary* bin = &ERTS_MAGIC_BIN_FROM_DATA(resource)->binary;
- return ERTS_MAGIC_BIN_DATA_SIZE(bin) - offsetof(ErlNifResource,data);
+ Binary* bin = &ERTS_MAGIC_BIN_FROM_UNALIGNED_DATA(resource)->binary;
+ return ERTS_MAGIC_BIN_UNALIGNED_DATA_SIZE(bin) - offsetof(ErlNifResource,data);
}
@@ -2689,6 +2695,8 @@ erts_unload_nif(struct erl_module_nif* lib)
void erl_nif_init()
{
+ ERTS_CT_ASSERT((offsetof(ErlNifResource,data) % 8) == ERTS_MAGIC_BIN_BYTES_TO_ALIGN);
+
resource_type_list.next = &resource_type_list;
resource_type_list.prev = &resource_type_list;
resource_type_list.dtor = NULL;
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index 340c7033ab..ee1f70b748 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -230,9 +230,23 @@ typedef struct {
ERTS_INTERNAL_BINARY_FIELDS
SWord orig_size;
void (*destructor)(Binary *);
- char magic_bin_data[1];
+ union {
+ struct {
+ ERTS_BINARY_STRUCT_ALIGNMENT
+ char data[1];
+ } aligned;
+ struct {
+ char data[1];
+ } unaligned;
+ } u;
} ErtsMagicBinary;
+#ifdef ARCH_32
+#define ERTS_MAGIC_BIN_BYTES_TO_ALIGN 4
+#else
+#define ERTS_MAGIC_BIN_BYTES_TO_ALIGN 0
+#endif
+
typedef union {
Binary binary;
ErtsMagicBinary magic_binary;
@@ -252,15 +266,30 @@ typedef union {
#define ERTS_MAGIC_BIN_DESTRUCTOR(BP) \
((ErtsBinary *) (BP))->magic_binary.destructor
#define ERTS_MAGIC_BIN_DATA(BP) \
- ((void *) ((ErtsBinary *) (BP))->magic_binary.magic_bin_data)
-#define ERTS_MAGIC_BIN_DATA_SIZE(BP) \
- ((BP)->orig_size - sizeof(void (*)(Binary *)))
+ ((void *) ((ErtsBinary *) (BP))->magic_binary.u.aligned.data)
+#define ERTS_MAGIC_DATA_OFFSET \
+ (offsetof(ErtsMagicBinary,u.aligned.data) - offsetof(Binary,orig_bytes))
#define ERTS_MAGIC_BIN_ORIG_SIZE(Sz) \
- (sizeof(void (*)(Binary *)) + (Sz))
+ (ERTS_MAGIC_DATA_OFFSET + (Sz))
#define ERTS_MAGIC_BIN_SIZE(Sz) \
- (offsetof(ErtsMagicBinary,magic_bin_data) + (Sz))
-#define ERTS_MAGIC_BIN_FROM_DATA(DATA) \
- ((ErtsBinary*)((char*)(DATA) - offsetof(ErtsMagicBinary,magic_bin_data)))
+ (offsetof(ErtsMagicBinary,u.aligned.data) + (Sz))
+
+/* On 32-bit arch these macro variants will save memory
+ by not forcing 8-byte alignment for the magic payload.
+*/
+#define ERTS_MAGIC_BIN_UNALIGNED_DATA(BP) \
+ ((void *) ((ErtsBinary *) (BP))->magic_binary.u.unaligned.data)
+#define ERTS_MAGIC_UNALIGNED_DATA_OFFSET \
+ (offsetof(ErtsMagicBinary,u.unaligned.data) - offsetof(Binary,orig_bytes))
+#define ERTS_MAGIC_BIN_UNALIGNED_DATA_SIZE(BP) \
+ ((BP)->orig_size - ERTS_MAGIC_UNALIGNED_DATA_OFFSET)
+#define ERTS_MAGIC_BIN_UNALIGNED_ORIG_SIZE(Sz) \
+ (ERTS_MAGIC_UNALIGNED_DATA_OFFSET + (Sz))
+#define ERTS_MAGIC_BIN_UNALIGNED_SIZE(Sz) \
+ (offsetof(ErtsMagicBinary,u.unaligned.data) + (Sz))
+#define ERTS_MAGIC_BIN_FROM_UNALIGNED_DATA(DATA) \
+ ((ErtsBinary*)((char*)(DATA) - offsetof(ErtsMagicBinary,u.unaligned.data)))
+
#define Binary2ErlDrvBinary(B) (&((ErtsBinary *) (B))->driver.binary)
#define ErlDrvBinary2Binary(D) ((Binary *) \