diff options
| author | Roland McGrath <roland@hack.frob.com> | 2014-05-14 09:44:39 -0700 |
|---|---|---|
| committer | Roland McGrath <roland@hack.frob.com> | 2014-05-14 09:44:39 -0700 |
| commit | e27871374eda477318f5a694d26cc02fd1cf019e (patch) | |
| tree | 9f3a2a0d27cc8700a4ee0d92940ab572ed3f39ef /sysdeps/unix/sysv/linux/x86_64/vfork.S | |
| parent | 5675da1e845e4b651eb649639137310fd9b6b380 (diff) | |
| download | glibc-e27871374eda477318f5a694d26cc02fd1cf019e.tar.gz glibc-e27871374eda477318f5a694d26cc02fd1cf019e.tar.xz glibc-e27871374eda477318f5a694d26cc02fd1cf019e.zip | |
x86: Consolidate NPTL/non versions of vfork
Diffstat (limited to 'sysdeps/unix/sysv/linux/x86_64/vfork.S')
| -rw-r--r-- | sysdeps/unix/sysv/linux/x86_64/vfork.S | 25 |
1 files changed, 19 insertions, 6 deletions
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) |