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Date: Fri, 18 Jan 2013 17:54:54 +0530
From: Vineet Gupta <Vineet.Gupta1@...opsys.com>
To: <linux-arch@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC: <arnd@...db.de>, Vineet Gupta <Vineet.Gupta1@...opsys.com>,
Al Viro <viro@...IV.linux.org.uk>
Subject: [PATCH v2 40/76] ARC: Switch to generic sys_clone, fork, vfork
We still need the low level asm wrappers to save CALLEE regs, however
the core handlers sys_xxx now come from generic code
Signed-off-by: Vineet Gupta <vgupta@...opsys.com>
Cc: Al Viro <viro@...IV.linux.org.uk>
---
arch/arc/Kconfig | 1 +
arch/arc/include/asm/unistd.h | 3 +++
arch/arc/kernel/entry.S | 10 ----------
arch/arc/kernel/process.c | 40 +++++-----------------------------------
4 files changed, 9 insertions(+), 45 deletions(-)
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index 3d5f940..8fb9264 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -9,6 +9,7 @@
config ARC
def_bool y
select ARCH_NO_VIRT_TO_BUS
+ select CLONE_BACKWARDS
# ARC Busybox based initramfs absolutely relies on DEVTMPFS for /dev
# DEVTMPS in turn needs HOTPLUG
select DEVTMPFS if !INITRAMFS_SOURCE=""
diff --git a/arch/arc/include/asm/unistd.h b/arch/arc/include/asm/unistd.h
index 7841827..6f30484 100644
--- a/arch/arc/include/asm/unistd.h
+++ b/arch/arc/include/asm/unistd.h
@@ -9,6 +9,9 @@
/******** no-legacy-syscalls-ABI *******/
#define __ARCH_WANT_SYS_EXECVE
+#define __ARCH_WANT_SYS_CLONE
+#define __ARCH_WANT_SYS_VFORK
+#define __ARCH_WANT_SYS_FORK
#define sys_mmap2 sys_mmap_pgoff
diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S
index 69a0c9f..6823f30 100644
--- a/arch/arc/kernel/entry.S
+++ b/arch/arc/kernel/entry.S
@@ -594,8 +594,6 @@ ARC_EXIT ret_from_fork
; TBD: call do_fork directly from here
ARC_ENTRY sys_fork_wrapper
- ; copy pointer to pt_regs as a parameter
- mov r0, sp
SAVE_CALLEE_SAVED_USER
bl @sys_fork
DISCARD_CALLEE_SAVED_USER
@@ -604,8 +602,6 @@ ARC_ENTRY sys_fork_wrapper
ARC_EXIT sys_fork_wrapper
ARC_ENTRY sys_vfork_wrapper
- ; copy pointer to pt_regs as a parameter
- mov r0, sp
SAVE_CALLEE_SAVED_USER
bl @sys_vfork
DISCARD_CALLEE_SAVED_USER
@@ -614,12 +610,6 @@ ARC_ENTRY sys_vfork_wrapper
ARC_EXIT sys_vfork_wrapper
ARC_ENTRY sys_clone_wrapper
- ; clone sys-call takes 2 mandatary args: @flags and @child-stack
- ; and it can take 3 var-args, depending on flags
- ; To keep sys_clone( ) signature constant, we assume all 5 args
- ; and set the helper @prtegs in next free reg
- ; this is cheap since our args are in regs, not on stack
- mov r5, sp ; pt_regs
SAVE_CALLEE_SAVED_USER
bl @sys_clone
DISCARD_CALLEE_SAVED_USER
diff --git a/arch/arc/kernel/process.c b/arch/arc/kernel/process.c
index 403de7e..e2b119d 100644
--- a/arch/arc/kernel/process.c
+++ b/arch/arc/kernel/process.c
@@ -20,39 +20,6 @@
#include <linux/elf.h>
#include <linux/tick.h>
-asmlinkage int sys_fork(struct pt_regs *regs)
-{
- return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);
-}
-
-asmlinkage int sys_vfork(struct pt_regs *regs)
-{
- return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs, 0,
- NULL, NULL);
-}
-
-/* Per man, C-lib clone( ) is as follows
- *
- * int clone(int (*fn)(void *), void *child_stack,
- * int flags, void *arg, ...
- * pid_t *ptid, struct user_desc *tls, pid_t *ctid);
- *
- * @fn and @arg are of userland thread-hnalder and thus of no use
- * in sys-call, hence excluded in sys_clone arg list.
- * The only addition is ptregs, needed by fork core, although now-a-days
- * task_pt_regs() can be called anywhere to get that.
- */
-asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
- int __user *parent_tidptr, void *tls,
- int __user *child_tidptr, struct pt_regs *regs)
-{
- if (!newsp)
- newsp = regs->sp;
-
- return do_fork(clone_flags, newsp, regs, 0, parent_tidptr,
- child_tidptr);
-}
-
SYSCALL_DEFINE1(arc_settls, void *, user_tls_data_ptr)
{
task_thread_info(current)->thr_ptr = (unsigned int)user_tls_data_ptr;
@@ -132,12 +99,13 @@ asmlinkage void ret_from_fork(void);
*/
int copy_thread(unsigned long clone_flags,
unsigned long usp, unsigned long arg,
- struct task_struct *p, struct pt_regs *regs)
+ struct task_struct *p)
{
struct pt_regs *c_regs; /* child's pt_regs */
unsigned long *childksp; /* to unwind out of __switch_to() */
struct callee_regs *c_callee; /* child's callee regs */
struct callee_regs *parent_callee; /* paren't callee */
+ struct pt_regs *regs = current_pt_regs();
/* Mark the specific anchors to begin with (see pic above) */
c_regs = task_pt_regs(p);
@@ -176,7 +144,9 @@ int copy_thread(unsigned long clone_flags,
/* Copy parents pt regs on child's kernel mode stack */
*c_regs = *regs;
- c_regs->sp = usp;
+ if (usp)
+ c_regs->sp = usp;
+
c_regs->r0 = 0; /* fork returns 0 in child */
parent_callee = ((struct callee_regs *)regs) - 1;
--
1.7.4.1
--
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