From fe74290d51bc08e9b90ed7c145d74a22cd50b90e Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Mon, 2 Oct 2006 02:18:34 -0700
Subject: [PATCH] provide kernel_execve on all architectures

This adds the new kernel_execve function on all architectures that were using
_syscall3() to implement execve.

The implementation uses code from the _syscall3 macros provided in the
unistd.h header file.  I don't have cross-compilers for any of these
architectures, so the patch is untested with the exception of i386.

Most architectures can probably implement this in a nicer way in assembly or
by combining it with the sys_execve implementation itself, but this should do
it for now.

[bunk@stusta.de: m68knommu build fix]
[markh@osdl.org: build fix]
[bero@arklinux.org: build fix]
[ralf@linux-mips.org: mips fix]
[schwidefsky@de.ibm.com: s390 fix]
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Andi Kleen <ak@muc.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ian Molton <spyro@f2s.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Hirokazu Takata <takata.hirokazu@renesas.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Richard Curnow <rc@rc0.org.uk>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp>
Cc: Chris Zankel <chris@zankel.net>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Bernhard Rosenkraenzer <bero@arklinux.org>
Signed-off-by: Mark Haverkamp <markh@osdl.org>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
 arch/xtensa/kernel/syscalls.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

(limited to 'arch/xtensa')

diff --git a/arch/xtensa/kernel/syscalls.c b/arch/xtensa/kernel/syscalls.c
index 37c90ca5b98..d9285d4d556 100644
--- a/arch/xtensa/kernel/syscalls.c
+++ b/arch/xtensa/kernel/syscalls.c
@@ -266,3 +266,23 @@ void system_call (struct pt_regs *regs)
 	regs->areg[2] = res;
 	do_syscall_trace();
 }
+
+/*
+ * Do a system call from kernel instead of calling sys_execve so we
+ * end up with proper pt_regs.
+ */
+int kernel_execve(const char *filename, char *const argv[], char *const envp[])
+{
+	long __res;
+	asm volatile (
+		"  mov   a5, %2 \n"
+		"  mov   a4, %4 \n"
+		"  mov   a3, %3 \n"
+		"  movi  a2, %1 \n"
+		"  syscall      \n"
+		"  mov   %0, a2 \n"
+		: "=a" (__res)
+		: "i" (__NR_execve), "a" (filename), "a" (argv), "a" (envp)
+		: "a2", "a3", "a4", "a5");
+	return __res;
+}
-- 
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