From e27871374eda477318f5a694d26cc02fd1cf019e Mon Sep 17 00:00:00 2001
From: Roland McGrath <roland@hack.frob.com>
Date: Wed, 14 May 2014 09:44:39 -0700
Subject: x86: Consolidate NPTL/non versions of vfork

---
 sysdeps/unix/sysv/linux/i386/vfork.S   | 26 ++++++++++++++++++++------
 sysdeps/unix/sysv/linux/x86_64/vfork.S | 25 +++++++++++++++++++------
 2 files changed, 39 insertions(+), 12 deletions(-)

(limited to 'sysdeps/unix/sysv')

diff --git a/sysdeps/unix/sysv/linux/i386/vfork.S b/sysdeps/unix/sysv/linux/i386/vfork.S
index d6e0ecfcad..2c3d4a3ee7 100644
--- a/sysdeps/unix/sysv/linux/i386/vfork.S
+++ b/sysdeps/unix/sysv/linux/i386/vfork.S
@@ -20,6 +20,8 @@
 #define _ERRNO_H	1
 #include <bits/errno.h>
 #include <kernel-features.h>
+#include <tcb-offsets.h>
+
 
 /* Clone the calling process, but without copying the whole address space.
    The calling process is suspended until the new process exits or is
@@ -33,9 +35,16 @@ ENTRY (__vfork)
 	cfi_adjust_cfa_offset (-4)
 	cfi_register (%eip, %ecx)
 
-#ifdef SAVE_PID
-	SAVE_PID
-#endif
+	/* Save the TCB-cached PID away in %edx, and then negate the TCB
+           field.  But if it's zero, set it to 0x80000000 instead.  See
+           raise.c for the logic that relies on this value.  */
+	movl	%gs:PID, %edx
+	movl	%edx, %eax
+	negl	%eax
+	jne	1f
+	movl	$0x80000000, %eax
+1:	movl	%eax, %gs:PID
+
 
 	/* Stuff the syscall number in EAX and enter into the kernel.  */
 	movl	$SYS_ify (vfork), %eax
@@ -47,9 +56,13 @@ ENTRY (__vfork)
 	pushl	%ecx
 	cfi_adjust_cfa_offset (4)
 
-#ifdef RESTORE_PID
-	RESTORE_PID
-#endif
+	/* Restore the original value of the TCB cache of the PID, if we're
+	   the parent.  But in the child (syscall return value equals zero),
+	   leave things as they are.  */
+	testl	%eax, %eax
+	je	1f
+	movl	%edx, %gs:PID
+1:
 
 	cmpl	$-4095, %eax
 	/* Branch forward if it failed.  */
@@ -61,3 +74,4 @@ PSEUDO_END (__vfork)
 libc_hidden_def (__vfork)
 
 weak_alias (__vfork, vfork)
+strong_alias (__vfork, __libc_vfork)
diff --git a/sysdeps/unix/sysv/linux/x86_64/vfork.S b/sysdeps/unix/sysv/linux/x86_64/vfork.S
index d3b450a48d..15ea281899 100644
--- a/sysdeps/unix/sysv/linux/x86_64/vfork.S
+++ b/sysdeps/unix/sysv/linux/x86_64/vfork.S
@@ -18,6 +18,8 @@
 #include <sysdep.h>
 #define _ERRNO_H	1
 #include <bits/errno.h>
+#include <tcb-offsets.h>
+
 
 /* Clone the calling process, but without copying the whole address space.
    The calling process is suspended until the new process exits or is
@@ -32,9 +34,15 @@ ENTRY (__vfork)
 	cfi_adjust_cfa_offset(-8)
 	cfi_register(%rip, %rdi)
 
-#ifdef SAVE_PID
-	SAVE_PID
-#endif
+	/* Save the TCB-cached PID away in %esi, and then negate the TCB
+           field.  But if it's zero, set it to 0x80000000 instead.  See
+           raise.c for the logic that relies on this value.  */
+	movl	%fs:PID, %esi
+	movl	$0x80000000, %ecx
+	movl	%esi, %edx
+	negl	%edx
+	cmove	%ecx, %edx
+	movl	%edx, %fs:PID
 
 	/* Stuff the syscall number in RAX and enter into the kernel.  */
 	movl	$SYS_ify (vfork), %eax
@@ -44,9 +52,13 @@ ENTRY (__vfork)
 	pushq	%rdi
 	cfi_adjust_cfa_offset(8)
 
-#ifdef RESTORE_PID
-	RESTORE_PID
-#endif
+	/* Restore the original value of the TCB cache of the PID, if we're
+	   the parent.  But in the child (syscall return value equals zero),
+	   leave things as they are.  */
+	testq	%rax, %rax
+	je	1f
+	movl	%esi, %fs:PID
+1:
 
 	cmpl	$-4095, %eax
 	jae SYSCALL_ERROR_LABEL		/* Branch forward if it failed.  */
@@ -58,3 +70,4 @@ PSEUDO_END (__vfork)
 libc_hidden_def (__vfork)
 
 weak_alias (__vfork, vfork)
+strong_alias (__vfork, __libc_vfork)
-- 
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