/hg/icedtea8-forest/hotspot: 8141491, PR3159, G592292: Unaligned...
andrew at icedtea.classpath.org
andrew at icedtea.classpath.org
Tue Nov 1 02:54:33 UTC 2016
changeset bca091274752 in /hg/icedtea8-forest/hotspot
details: http://icedtea.classpath.org/hg/icedtea8-forest/hotspot?cmd=changeset;node=bca091274752
author: mikael
date: Wed Oct 26 03:47:58 2016 +0100
8141491, PR3159, G592292: Unaligned memory access in Bits.c
Summary: Introduce alignment-safe Copy::conjoint_swap and j.i.m.Unsafe.copySwapMemory
Reviewed-by: jrose, dholmes, psandoz
diffstat:
src/share/vm/prims/unsafe.cpp | 31 +++++
src/share/vm/runtime/interfaceSupport.hpp | 18 ++-
src/share/vm/utilities/copy.cpp | 171 +++++++++++++++++++++++++++++-
src/share/vm/utilities/copy.hpp | 12 +-
4 files changed, 229 insertions(+), 3 deletions(-)
diffs (301 lines):
diff -r 3e73be729f73 -r bca091274752 src/share/vm/prims/unsafe.cpp
--- a/src/share/vm/prims/unsafe.cpp Tue Oct 25 22:16:45 2016 +0100
+++ b/src/share/vm/prims/unsafe.cpp Wed Oct 26 03:47:58 2016 +0100
@@ -740,6 +740,36 @@
Copy::conjoint_memory_atomic(src, dst, sz);
UNSAFE_END
+// This function is a leaf since if the source and destination are both in native memory
+// the copy may potentially be very large, and we don't want to disable GC if we can avoid it.
+// If either source or destination (or both) are on the heap, the function will enter VM using
+// JVM_ENTRY_FROM_LEAF
+JVM_LEAF(void, Unsafe_CopySwapMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size, jlong elemSize)) {
+ UnsafeWrapper("Unsafe_CopySwapMemory0");
+
+ size_t sz = (size_t)size;
+ size_t esz = (size_t)elemSize;
+
+ if (srcObj == NULL && dstObj == NULL) {
+ // Both src & dst are in native memory
+ address src = (address)srcOffset;
+ address dst = (address)dstOffset;
+
+ Copy::conjoint_swap(src, dst, sz, esz);
+ } else {
+ // At least one of src/dst are on heap, transition to VM to access raw pointers
+
+ JVM_ENTRY_FROM_LEAF(env, void, Unsafe_CopySwapMemory0) {
+ oop srcp = JNIHandles::resolve(srcObj);
+ oop dstp = JNIHandles::resolve(dstObj);
+
+ address src = (address)index_oop_from_field_offset_long(srcp, srcOffset);
+ address dst = (address)index_oop_from_field_offset_long(dstp, dstOffset);
+
+ Copy::conjoint_swap(src, dst, sz, esz);
+ } JVM_END
+ }
+} JVM_END
////// Random queries
@@ -1702,6 +1732,7 @@
JNINativeMethod memcopy_methods_17[] = {
{CC"copyMemory", CC"("OBJ"J"OBJ"JJ)V", FN_PTR(Unsafe_CopyMemory2)},
+ {CC"copySwapMemory0", CC "(" OBJ "J" OBJ "JJJ)V", FN_PTR(Unsafe_CopySwapMemory0)},
{CC"setMemory", CC"("OBJ"JJB)V", FN_PTR(Unsafe_SetMemory2)}
};
diff -r 3e73be729f73 -r bca091274752 src/share/vm/runtime/interfaceSupport.hpp
--- a/src/share/vm/runtime/interfaceSupport.hpp Tue Oct 25 22:16:45 2016 +0100
+++ b/src/share/vm/runtime/interfaceSupport.hpp Wed Oct 26 03:47:58 2016 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@@ -431,6 +431,14 @@
os::verify_stack_alignment(); \
/* begin of body */
+#define VM_ENTRY_BASE_FROM_LEAF(result_type, header, thread) \
+ TRACE_CALL(result_type, header) \
+ debug_only(ResetNoHandleMark __rnhm;) \
+ HandleMarkCleaner __hm(thread); \
+ Thread* THREAD = thread; \
+ os::verify_stack_alignment(); \
+ /* begin of body */
+
// ENTRY routines may lock, GC and throw exceptions
@@ -592,6 +600,14 @@
VM_LEAF_BASE(result_type, header)
+#define JVM_ENTRY_FROM_LEAF(env, result_type, header) \
+ { { \
+ JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
+ ThreadInVMfromNative __tiv(thread); \
+ debug_only(VMNativeEntryWrapper __vew;) \
+ VM_ENTRY_BASE_FROM_LEAF(result_type, header, thread)
+
+
#define JVM_END } }
#endif // SHARE_VM_RUNTIME_INTERFACESUPPORT_HPP
diff -r 3e73be729f73 -r bca091274752 src/share/vm/utilities/copy.cpp
--- a/src/share/vm/utilities/copy.cpp Tue Oct 25 22:16:45 2016 +0100
+++ b/src/share/vm/utilities/copy.cpp Wed Oct 26 03:47:58 2016 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2006, 2016, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@@ -53,6 +53,175 @@
}
}
+class CopySwap : AllStatic {
+public:
+ /**
+ * Copy and byte swap elements
+ *
+ * @param src address of source
+ * @param dst address of destination
+ * @param byte_count number of bytes to copy
+ * @param elem_size size of the elements to copy-swap
+ */
+ static void conjoint_swap(address src, address dst, size_t byte_count, size_t elem_size) {
+ assert(src != NULL, err_msg("address must not be NULL"));
+ assert(dst != NULL, err_msg("address must not be NULL"));
+ assert(elem_size == 2 || elem_size == 4 || elem_size == 8,
+ err_msg("incorrect element size: " SIZE_FORMAT, elem_size));
+ assert(is_size_aligned(byte_count, elem_size),
+ err_msg("byte_count " SIZE_FORMAT " must be multiple of element size " SIZE_FORMAT, byte_count, elem_size));
+
+ address src_end = src + byte_count;
+
+ if (dst <= src || dst >= src_end) {
+ do_conjoint_swap<RIGHT>(src, dst, byte_count, elem_size);
+ } else {
+ do_conjoint_swap<LEFT>(src, dst, byte_count, elem_size);
+ }
+ }
+
+private:
+ /**
+ * Byte swap a 16-bit value
+ */
+ static uint16_t byte_swap(uint16_t x) {
+ return (x << 8) | (x >> 8);
+ }
+
+ /**
+ * Byte swap a 32-bit value
+ */
+ static uint32_t byte_swap(uint32_t x) {
+ uint16_t lo = (uint16_t)x;
+ uint16_t hi = (uint16_t)(x >> 16);
+
+ return ((uint32_t)byte_swap(lo) << 16) | (uint32_t)byte_swap(hi);
+ }
+
+ /**
+ * Byte swap a 64-bit value
+ */
+ static uint64_t byte_swap(uint64_t x) {
+ uint32_t lo = (uint32_t)x;
+ uint32_t hi = (uint32_t)(x >> 32);
+
+ return ((uint64_t)byte_swap(lo) << 32) | (uint64_t)byte_swap(hi);
+ }
+
+ enum CopyDirection {
+ RIGHT, // lower -> higher address
+ LEFT // higher -> lower address
+ };
+
+ /**
+ * Copy and byte swap elements
+ *
+ * <T> - type of element to copy
+ * <D> - copy direction
+ * <is_src_aligned> - true if src argument is aligned to element size
+ * <is_dst_aligned> - true if dst argument is aligned to element size
+ *
+ * @param src address of source
+ * @param dst address of destination
+ * @param byte_count number of bytes to copy
+ */
+ template <typename T, CopyDirection D, bool is_src_aligned, bool is_dst_aligned>
+ static void do_conjoint_swap(address src, address dst, size_t byte_count) {
+ address cur_src, cur_dst;
+
+ switch (D) {
+ case RIGHT:
+ cur_src = src;
+ cur_dst = dst;
+ break;
+ case LEFT:
+ cur_src = src + byte_count - sizeof(T);
+ cur_dst = dst + byte_count - sizeof(T);
+ break;
+ }
+
+ for (size_t i = 0; i < byte_count / sizeof(T); i++) {
+ T tmp;
+
+ if (is_src_aligned) {
+ tmp = *(T*)cur_src;
+ } else {
+ memcpy(&tmp, cur_src, sizeof(T));
+ }
+
+ tmp = byte_swap(tmp);
+
+ if (is_dst_aligned) {
+ *(T*)cur_dst = tmp;
+ } else {
+ memcpy(cur_dst, &tmp, sizeof(T));
+ }
+
+ switch (D) {
+ case RIGHT:
+ cur_src += sizeof(T);
+ cur_dst += sizeof(T);
+ break;
+ case LEFT:
+ cur_src -= sizeof(T);
+ cur_dst -= sizeof(T);
+ break;
+ }
+ }
+ }
+
+ /**
+ * Copy and byte swap elements
+ *
+ * <T> - type of element to copy
+ * <D> - copy direction
+ *
+ * @param src address of source
+ * @param dst address of destination
+ * @param byte_count number of bytes to copy
+ */
+ template <typename T, CopyDirection direction>
+ static void do_conjoint_swap(address src, address dst, size_t byte_count) {
+ if (is_ptr_aligned(src, sizeof(T))) {
+ if (is_ptr_aligned(dst, sizeof(T))) {
+ do_conjoint_swap<T,direction,true,true>(src, dst, byte_count);
+ } else {
+ do_conjoint_swap<T,direction,true,false>(src, dst, byte_count);
+ }
+ } else {
+ if (is_ptr_aligned(dst, sizeof(T))) {
+ do_conjoint_swap<T,direction,false,true>(src, dst, byte_count);
+ } else {
+ do_conjoint_swap<T,direction,false,false>(src, dst, byte_count);
+ }
+ }
+ }
+
+
+ /**
+ * Copy and byte swap elements
+ *
+ * <D> - copy direction
+ *
+ * @param src address of source
+ * @param dst address of destination
+ * @param byte_count number of bytes to copy
+ * @param elem_size size of the elements to copy-swap
+ */
+ template <CopyDirection D>
+ static void do_conjoint_swap(address src, address dst, size_t byte_count, size_t elem_size) {
+ switch (elem_size) {
+ case 2: do_conjoint_swap<uint16_t,D>(src, dst, byte_count); break;
+ case 4: do_conjoint_swap<uint32_t,D>(src, dst, byte_count); break;
+ case 8: do_conjoint_swap<uint64_t,D>(src, dst, byte_count); break;
+ default: guarantee(false, err_msg("do_conjoint_swap: Invalid elem_size %zd\n", elem_size));
+ }
+ }
+};
+
+void Copy::conjoint_swap(address src, address dst, size_t byte_count, size_t elem_size) {
+ CopySwap::conjoint_swap(src, dst, byte_count, elem_size);
+}
// Fill bytes; larger units are filled atomically if everything is aligned.
void Copy::fill_to_memory_atomic(void* to, size_t size, jubyte value) {
diff -r 3e73be729f73 -r bca091274752 src/share/vm/utilities/copy.hpp
--- a/src/share/vm/utilities/copy.hpp Tue Oct 25 22:16:45 2016 +0100
+++ b/src/share/vm/utilities/copy.hpp Wed Oct 26 03:47:58 2016 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2016, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@@ -227,6 +227,16 @@
}
}
+ /**
+ * Copy and *unconditionally* byte swap elements
+ *
+ * @param src address of source
+ * @param dst address of destination
+ * @param byte_count number of bytes to copy
+ * @param elem_size size of the elements to copy-swap
+ */
+ static void conjoint_swap(address src, address dst, size_t byte_count, size_t elem_size);
+
// Fill methods
// Fill word-aligned words, not atomic on each word
More information about the distro-pkg-dev
mailing list