am ae728099: Merge "enable clone system call for x86"

* commit 'ae7280994e7845037b667fd6ebdcb6f299ba1aab':
  enable clone system call for x86

libc/Android.mk

@@ -261,6 +261,7 @@ libc_common_src_files := \
 	tzcode/strftime.c \
 	tzcode/strptime.c \
 	bionic/__set_errno.c \
+	bionic/bionic_clone.c \
 	bionic/cpuacct.c \
 	bionic/arc4random.c \
 	bionic/basename.c \
@@ -361,7 +362,6 @@ libc_static_common_src_files := \
 # =========================================================
 ifeq ($(TARGET_ARCH),arm)
 libc_common_src_files += \
-	bionic/bionic_clone.c \
 	arch-arm/bionic/__get_pc.S \
 	arch-arm/bionic/__get_sp.S \
 	arch-arm/bionic/_exit_with_stack_teardown.S \
@@ -451,7 +451,6 @@ endif # x86
 
 ifeq ($(TARGET_ARCH),mips)
 libc_common_src_files += \
-	bionic/bionic_clone.c \
 	arch-mips/bionic/__get_sp.S \
 	arch-mips/bionic/__get_tls.c \
 	arch-mips/bionic/__set_tls.c \

libc/arch-x86/bionic/clone.S

@@ -33,7 +33,7 @@ __pthread_clone:
         test    %eax, %eax
         jns     1f
 
-        # an error occured, set errno and return -1
+        # an error occurred, set errno and return -1
         negl    %eax
         call    __set_errno
         orl     $-1, %eax
@@ -53,7 +53,60 @@ __pthread_clone:
         popl    %ebx
         ret
 
-/* XXX: TODO: Add __bionic_clone here
- *            See bionic/bionic_clone.c and arch-arm/bionic/clone.S
- *            for more details...
+
+/*
+ * int  __bionic_clone(unsigned long clone_flags,
+ *                     void*         newsp,
+ *                     int           *parent_tidptr,
+ *                     void          *new_tls,
+ *                     int           *child_tidptr,
+ *                     int           (*fn)(void *),
+ *                     void          *arg);
  */
+.text
+.globl __bionic_clone
+.type __bionic_clone, @function
+.align 4
+__bionic_clone:
+        pushl   %ebx
+        pushl   %esi
+        pushl   %edi
+
+        # insert arguments onto the child stack
+        movl    20(%esp), %ecx
+        andl    $~15, %ecx
+        movl    36(%esp), %eax
+        movl    %eax, -16(%ecx)
+        movl    40(%esp), %eax
+        movl    %eax, -12(%ecx)
+
+        subl    $16, %ecx
+        movl    16(%esp), %ebx
+        movl    24(%esp), %edx
+        movl    32(%esp), %esi
+        movl    28(%esp), %edi
+        movl    $__NR_clone, %eax
+        int     $0x80
+        test    %eax, %eax
+        jns     1f
+
+        # an error occurred, set errno and return -1
+        negl    %eax
+        call    __set_errno
+        orl     $-1, %eax
+        jmp     2f
+
+1:
+        jnz     2f
+
+        # we're in the child now, call __bionic_clone_entry
+        # with the appropriate arguments on the child stack
+        # we already placed most of them
+        call    __bionic_clone_entry
+        hlt
+
+2:
+        popl    %edi
+        popl    %esi
+        popl    %ebx
+        ret

libc/bionic/bionic_clone.c

@@ -31,9 +31,6 @@
 #include <stdarg.h>
 #include <stdio.h>
 
-/* WARNING: AT THE MOMENT, THIS IS ONLY SUPPORTED ON ARM
- */
-
 extern int  __bionic_clone(unsigned long   clone_flags,
                            void*           newsp,
                            int            *parent_tidptr,