x86_64: Implement execl{,e,p} without double stack allocation

3 files changed, 183 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/x86_64/64/execl.S b/sysdeps/unix/sysv/linux/x86_64/64/execl.S
new file mode 100644
index 0000000000..29b492393b
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86_64/64/execl.S
@@ -0,0 +1,65 @@
+/* Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   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, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+
+ENTRY(execl)
+	/* Move return address into a register.  */
+	pop	%rax
+	cfi_adjust_cfa_offset(-8)
+	cfi_register(%rip, %rax)
+
+	/* Save the portions of the argv argument list in registers.  */
+	push	%r9
+	cfi_adjust_cfa_offset(8)
+	push	%r8
+	cfi_adjust_cfa_offset(8)
+	push	%rcx
+	cfi_adjust_cfa_offset(8)
+	push	%rdx
+	cfi_adjust_cfa_offset(8)
+	push	%rsi
+	cfi_adjust_cfa_offset(8)
+
+	/* Load the address of the argv array.  */
+	mov	%rsp, %rsi
+
+	/* Restore return address to the stack.  */
+	push	%rax
+	cfi_adjust_cfa_offset(8)
+	cfi_rel_offset(%rip, 0)
+
+	/* Load __environ for the env parameter.  */
+#ifdef PIC
+	mov	__environ@GOTPCREL(%rip), %rdx
+	mov	(%rdx), %rdx
+#else
+	mov	__environ(%rip), %rdx
+#endif
+
+	DO_CALL (execve, 3)
+
+	/* All returns are errors.  */
+	SYSCALL_SET_ERRNO
+	or	$-1, %rax
+
+	/* Pop all of the extra stack space in one go.  */
+	ret	$40
+
+END(execl)
+
+libc_hidden_def (execl)
diff --git a/sysdeps/unix/sysv/linux/x86_64/64/execle.S b/sysdeps/unix/sysv/linux/x86_64/64/execle.S
new file mode 100644
index 0000000000..c2fc5c93d5
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86_64/64/execle.S
@@ -0,0 +1,66 @@
+/* Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   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, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+
+ENTRY(execle)
+	/* Move return address into a register.  */
+	pop	%rax
+	cfi_adjust_cfa_offset(-8)
+	cfi_register(%rip, %rax)
+
+	/* Save the portions of the argv argument list in registers.  */
+	push	%r9
+	cfi_adjust_cfa_offset(8)
+	push	%r8
+	cfi_adjust_cfa_offset(8)
+	push	%rcx
+	cfi_adjust_cfa_offset(8)
+	push	%rdx
+	cfi_adjust_cfa_offset(8)
+	push	%rsi
+	cfi_adjust_cfa_offset(8)
+
+	/* Load the address of the argv array.  */
+	mov	%rsp, %rsi
+
+	/* Restore return address to the stack.  */
+	push	%rax
+	cfi_adjust_cfa_offset(8)
+	cfi_rel_offset(%rip, 0)
+
+	/* Find the env argument.  It is the array element after the argv
+	   NULL terminator, which cannot be located before argv[1].  */
+	lea	8(%rsi), %rax
+	mov	(%rax), %rdx
+1:	add	$8, %rax
+	test	%rdx, %rdx
+	mov	(%rax), %rdx
+	jnz	1b
+
+	DO_CALL (execve, 3)
+
+	/* All returns are errors.  */
+	SYSCALL_SET_ERRNO
+	or	$-1, %rax
+
+	/* Pop all of the extra stack space in one go.  */
+	ret	$40
+
+END(execle)
+
+libc_hidden_def (execle)
diff --git a/sysdeps/unix/sysv/linux/x86_64/64/execlp.S b/sysdeps/unix/sysv/linux/x86_64/64/execlp.S
new file mode 100644
index 0000000000..caa08951e3
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86_64/64/execlp.S
@@ -0,0 +1,52 @@
+/* Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   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, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+
+ENTRY(execlp)
+	/* Move return address into a register.  */
+	pop	%rax
+	cfi_adjust_cfa_offset(-8)
+	cfi_register(%rip, %rax)
+
+	/* Save the portions of the argv argument list in registers.  */
+	push	%r9
+	cfi_adjust_cfa_offset(8)
+	push	%r8
+	cfi_adjust_cfa_offset(8)
+	push	%rcx
+	cfi_adjust_cfa_offset(8)
+	push	%rdx
+	cfi_adjust_cfa_offset(8)
+	push	%rsi
+	cfi_adjust_cfa_offset(8)
+
+	/* Load the address of the argv array.  */
+	mov	%rsp, %rsi
+
+	/* Restore return address to the stack.  */
+	push	%rax
+	cfi_adjust_cfa_offset(8)
+	cfi_rel_offset(%rip, 0)
+
+	call	HIDDEN_JUMPTARGET (execvp)
+
+	/* Pop all of the extra stack space in one go.  */
+	ret	$40
+END(execlp)
+
+libc_hidden_def (execlp)