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[thirdparty/glibc.git] / sysdeps / unix / sysv / linux / i386 / clone.S

diff --git a/sysdeps/unix/sysv/linux/i386/clone.S b/sysdeps/unix/sysv/linux/i386/clone.S
index cf8120ba8f71101ffdd96dbaaba4263cf2ad9262..9d47a3c5161271bb45b407d62cf24832f41332d7 100644 (file)
--- a/sysdeps/unix/sysv/linux/i386/clone.S
+++ b/sysdeps/unix/sysv/linux/i386/clone.S
@@ -1,4 +1,4 @@
-/* Copyright (C) 1996, 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
+/* Copyright (C) 1996-2019 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Richard Henderson (rth@tamu.edu)
 
@@ -13,9 +13,8 @@
    Lesser General Public License for more details.
 
    You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, write to the Free
-   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
-   02111-1307 USA.  */
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
 
 /* clone() is even more special than fork() as it mucks with stacks
    and invokes a function in the right context after its all over.  */
@@ -24,62 +23,88 @@
 #define _ERRNO_H       1
 #include <bits/errno.h>
 #include <asm-syntax.h>
-#include <bp-sym.h>
-#include <bp-asm.h>
 
-/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg); */
+/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg,
+            pid_t *ptid, struct user_desc *tls, pid_t *ctid); */
 
-#define PARMS  LINKAGE         /* no space for saved regs */
+#define PARMS  4               /* no space for saved regs */
 #define FUNC   PARMS
 #define STACK  FUNC+4
-#define FLAGS  STACK+PTR_SIZE
+#define FLAGS  STACK+4
 #define ARG    FLAGS+4
+#define PTID   ARG+4
+#define TLS    PTID+4
+#define CTID   TLS+4
+
+#define __NR_clone 120
+#define SYS_clone 120
 
         .text
-ENTRY (BP_SYM (__clone))
+ENTRY (__clone)
        /* Sanity check arguments.  */
        movl    $-EINVAL,%eax
        movl    FUNC(%esp),%ecx         /* no NULL function pointers */
-#ifdef PIC
-       jecxz   SYSCALL_ERROR_LABEL
-#else
        testl   %ecx,%ecx
        jz      SYSCALL_ERROR_LABEL
-#endif
        movl    STACK(%esp),%ecx        /* no NULL stack pointers */
-#ifdef PIC
-       jecxz   SYSCALL_ERROR_LABEL
-#else
        testl   %ecx,%ecx
        jz      SYSCALL_ERROR_LABEL
-#endif
 
-       /* Insert the argument onto the new stack.  */
-       subl    $8,%ecx
+       /* Insert the argument onto the new stack.  Make sure the new
+          thread is started with an alignment of (mod 16).  */
+       andl    $0xfffffff0, %ecx
+       subl    $28,%ecx
        movl    ARG(%esp),%eax          /* no negative argument counts */
-       movl    %eax,4(%ecx)
+       movl    %eax,12(%ecx)
 
        /* Save the function pointer as the zeroth argument.
           It will be popped off in the child in the ebx frobbing below.  */
        movl    FUNC(%esp),%eax
-       movl    %eax,0(%ecx)
+       movl    %eax,8(%ecx)
+       /* Don't leak any information.  */
+       movl    $0,4(%ecx)
 
        /* Do the system call */
        pushl   %ebx
-       movl    FLAGS+4(%esp),%ebx
+       cfi_adjust_cfa_offset (4)
+       pushl   %esi
+       cfi_adjust_cfa_offset (4)
+       pushl   %edi
+       cfi_adjust_cfa_offset (4)
+
+       movl    TLS+12(%esp),%esi
+       cfi_rel_offset (esi, 4)
+       movl    PTID+12(%esp),%edx
+       movl    FLAGS+12(%esp),%ebx
+       cfi_rel_offset (ebx, 8)
+       movl    CTID+12(%esp),%edi
+       cfi_rel_offset (edi, 0)
        movl    $SYS_ify(clone),%eax
+
+       /* Remember the flag value.  */
+       movl    %ebx, (%ecx)
+
+       /* End FDE now, because in the child the unwind info will be
+          wrong.  */
+       cfi_endproc
+
        int     $0x80
+       popl    %edi
+       popl    %esi
        popl    %ebx
 
        test    %eax,%eax
        jl      SYSCALL_ERROR_LABEL
-       jz      thread_start
+       jz      L(thread_start)
 
-L(pseudo_end):
        ret
 
-thread_start:
-       subl    %ebp,%ebp       /* terminate the stack frame */
+L(thread_start):
+       cfi_startproc;
+       /* Clearing frame pointer is insufficient, use CFI.  */
+       cfi_undefined (eip);
+       /* Note: %esi is zero.  */
+       movl    %esi,%ebp       /* terminate the stack frame */
        call    *%ebx
 #ifdef PIC
        call    L(here)
@@ -87,9 +112,11 @@ L(here):
        popl    %ebx
        addl    $_GLOBAL_OFFSET_TABLE_+[.-L(here)], %ebx
 #endif
-       pushl   %eax
-       call    JUMPTARGET (_exit)
+       movl    %eax, %ebx
+       movl    $SYS_ify(exit), %eax
+       ENTER_KERNEL
 
-PSEUDO_END (BP_SYM (__clone))
+PSEUDO_END (__clone)
 
-weak_alias (BP_SYM (__clone), BP_SYM (clone))
+libc_hidden_def (__clone)
+weak_alias (__clone, clone)