This commit implements a shared library, where native functions are
rewritten as special instructions. At runtime, user programs load
the shared library, and special instructions are executed when
native functions are called.
Signed-off-by: Yeqi Fu
---
Makefile| 2 +
common-user/native/Makefile.include | 9
common-user/native/Makefile.target | 22 +
common-user/native/libnative.S | 69 +
configure | 39
5 files changed, 141 insertions(+)
create mode 100644 common-user/native/Makefile.include
create mode 100644 common-user/native/Makefile.target
create mode 100644 common-user/native/libnative.S
diff --git a/Makefile b/Makefile
index 5d48dfac18..6f6147b40f 100644
--- a/Makefile
+++ b/Makefile
@@ -182,6 +182,8 @@ SUBDIR_MAKEFLAGS=$(if $(V),,--no-print-directory --quiet)
include $(SRC_PATH)/tests/Makefile.include
+include $(SRC_PATH)/common-user/native/Makefile.include
+
all: recurse-all
ROMS_RULES=$(foreach t, all clean distclean, $(addsuffix /$(t), $(ROMS)))
diff --git a/common-user/native/Makefile.include
b/common-user/native/Makefile.include
new file mode 100644
index 00..40d20bcd4c
--- /dev/null
+++ b/common-user/native/Makefile.include
@@ -0,0 +1,9 @@
+.PHONY: build-native
+build-native: $(NATIVE_TARGETS:%=build-native-library-%)
+$(NATIVE_TARGETS:%=build-native-library-%): build-native-library-%:
+ $(call quiet-command, \
+ $(MAKE) -C common-user/native/$* $(SUBDIR_MAKEFLAGS), \
+ "BUILD","$* native library")
+# endif
+
+all: build-native
diff --git a/common-user/native/Makefile.target
b/common-user/native/Makefile.target
new file mode 100644
index 00..65d90102e2
--- /dev/null
+++ b/common-user/native/Makefile.target
@@ -0,0 +1,22 @@
+# -*- Mode: makefile -*-
+#
+# Library for native calls
+#
+
+all:
+-include ../../../config-host.mak
+-include config-target.mak
+
+CFLAGS+=-shared -D $(TARGET_NAME)
+LDFLAGS+=
+
+SRC = $(SRC_PATH)/common-user/native/libnative.S
+LIBNATIVE = libnative.so
+
+all: $(LIBNATIVE)
+
+$(LIBNATIVE): $(SRC)
+ $(CC) $(CFLAGS) $(EXTRA_CFLAGS) $(EXTRA_NATIVE_CALL_FLAGS) $< -o $@
$(LDFLAGS)
+
+clean:
+ rm -f $(LIBNATIVE)
diff --git a/common-user/native/libnative.S b/common-user/native/libnative.S
new file mode 100644
index 00..3692eaa3cf
--- /dev/null
+++ b/common-user/native/libnative.S
@@ -0,0 +1,69 @@
+#if defined(i386) || defined(x86_64)
+/*
+ * An unused instruction is utilized to mark a native call.
+ */
+#define __SPECIAL_INSTR .byte 0x0f, 0xff;
+#define __RET_INSTR ret;
+#endif
+
+#if defined(arm) || defined(aarch64)
+/*
+ * HLT is an invalid instruction for userspace programs,
+ * and is used to mark a native call.
+ */
+#define __SPECIAL_INSTR hlt 0x;
+#if defined(aarch64)
+#define __RET_INSTR ret;
+#else
+#define __RET_INSTR bx lr;
+#endif
+#endif
+
+
+#if defined(mips) || defined(mips64)
+/*
+ * The syscall instruction contains 20 unused bits, which are typically
+ * set to 0. These bits can be used to store non-zero data,
+ * distinguishing them from a regular syscall instruction.
+ */
+#define __SPECIAL_INSTR syscall 0x;
+#define __RET_INSTR jr $ra;
+#endif
+
+/* Symbols of native functions */
+.section .data
+sym_memset: .asciz "memset"
+sym_memcpy: .asciz "memcpy"
+sym_strncpy: .asciz "strncpy"
+sym_memcmp: .asciz "memcmp"
+sym_strncmp: .asciz "strncmp"
+sym_strcpy: .asciz "strcpy"
+sym_strcat: .asciz "strcat"
+sym_strcmp: .asciz "strcmp"
+
+.macro define_function name
+\name:
+#if defined(x86_64) || defined(aarch64)
+__SPECIAL_INSTR
+.quad sym_\name
+__RET_INSTR
+#elif defined(mips64)
+.align 4
+__SPECIAL_INSTR
+.quad sym_\name
+__RET_INSTR
+#elif defined(i386) || defined(mips) || defined(arm)
+__SPECIAL_INSTR
+.long sym_\name
+__RET_INSTR
+#endif
+.endm
+
+define_function memcpy
+define_function strncpy
+define_function memset
+define_function memcmp
+define_function strncmp
+define_function strcpy
+define_function strcat
+define_function strcmp
diff --git a/configure b/configure
index 7a1e463d9c..de533b27a2 100755
--- a/configure
+++ b/configure
@@ -1826,6 +1826,45 @@ if test "$tcg" = "enabled"; then
fi
)
+# common-user/native configuration
+(mkdir -p common-user/native
+
+native_targets=
+for target in $target_list; do
+ case $target in
+*-softmmu)
+continue
+;;
+ esac
+
+ # native call is only supported on these architectures
+ arch=${target%%-*}
+ config_target_mak=common-user/native/${target}/config-target.mak
+ case $arch in
+i386|x86_64|arm|aarch64|mips|mips64)
+ if test -f cross-build/${target}/config-target.mak; then
+mkdir -p "common-user/native/${target}"
+ln -srf cross-build/${target}/config-target.mak "$config_target_mak"
+if test $arch = arm; then
+ echo "EXTRA_NATIVE_CALL_FLAGS=-marm" >> "$config_target_mak"
+fi
+if test $arch =
