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authorAl Viro <viro@zeniv.linux.org.uk>2012-10-03 14:46:55 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2012-10-14 23:12:25 -0400
commit69b58a67213506f98835b0ee8cf24324f59a1442 (patch)
tree554e56ac841e958398b0967784db8628dbbf48a3 /arch/cris/arch-v10
parentddffeb8c4d0331609ef2581d84de4d763607bd37 (diff)
downloadlinux-69b58a67213506f98835b0ee8cf24324f59a1442.tar.gz
cris: switch to generic kernel_thread()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'arch/cris/arch-v10')
-rw-r--r--arch/cris/arch-v10/kernel/entry.S10
-rw-r--r--arch/cris/arch-v10/kernel/process.c83
2 files changed, 33 insertions, 60 deletions
diff --git a/arch/cris/arch-v10/kernel/entry.S b/arch/cris/arch-v10/kernel/entry.S
index 592fbe9dfb6..b8e39e00acb 100644
--- a/arch/cris/arch-v10/kernel/entry.S
+++ b/arch/cris/arch-v10/kernel/entry.S
@@ -35,6 +35,7 @@
.globl system_call
.globl ret_from_intr
.globl ret_from_fork
+ .globl ret_from_kernel_thread
.globl resume
.globl multiple_interrupt
.globl hwbreakpoint
@@ -81,7 +82,14 @@ ret_from_fork:
jsr schedule_tail
ba ret_from_sys_call
nop
-
+
+ret_from_kernel_thread:
+ jsr schedule_tail
+ move.d $r2, $r10 ; argument is here
+ jsr $r1 ; call the payload
+ moveq 0, $r10
+ jsr sys_exit ; never returns
+
ret_from_intr:
;; check for resched if preemptive kernel or if we're going back to user-mode
;; this test matches the user_regs(regs) macro
diff --git a/arch/cris/arch-v10/kernel/process.c b/arch/cris/arch-v10/kernel/process.c
index 15ac7150371..8a673aa81cd 100644
--- a/arch/cris/arch-v10/kernel/process.c
+++ b/arch/cris/arch-v10/kernel/process.c
@@ -17,6 +17,7 @@
#include <arch/svinto.h>
#include <linux/init.h>
#include <arch/system.h>
+#include <asm/ptrace.h>
#ifdef CONFIG_ETRAX_GPIO
void etrax_gpio_wake_up_check(void); /* drivers/gpio.c */
@@ -81,31 +82,6 @@ unsigned long thread_saved_pc(struct task_struct *t)
return task_pt_regs(t)->irp;
}
-static void kernel_thread_helper(void* dummy, int (*fn)(void *), void * arg)
-{
- fn(arg);
- do_exit(-1); /* Should never be called, return bad exit value */
-}
-
-/*
- * Create a kernel thread
- */
-int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
-{
- struct pt_regs regs;
-
- memset(&regs, 0, sizeof(regs));
-
- /* Don't use r10 since that is set to 0 in copy_thread */
- regs.r11 = (unsigned long)fn;
- regs.r12 = (unsigned long)arg;
- regs.irp = (unsigned long)kernel_thread_helper;
- regs.dccr = 1 << I_DCCR_BITNR;
-
- /* Ok, create the new process.. */
- return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
-}
-
/* setup the child's kernel stack with a pt_regs and switch_stack on it.
* it will be un-nested during _resume and _ret_from_sys_call when the
* new thread is scheduled.
@@ -115,29 +91,35 @@ int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
*
*/
asmlinkage void ret_from_fork(void);
+asmlinkage void ret_from_kernel_thread(void);
int copy_thread(unsigned long clone_flags, unsigned long usp,
- unsigned long unused,
+ unsigned long arg,
struct task_struct *p, struct pt_regs *regs)
{
- struct pt_regs * childregs;
- struct switch_stack *swstack;
+ struct pt_regs *childregs = task_pt_regs(p);
+ struct switch_stack *swstack = ((struct switch_stack *)childregs) - 1;
/* put the pt_regs structure at the end of the new kernel stack page and fix it up
* remember that the task_struct doubles as the kernel stack for the task
*/
- childregs = task_pt_regs(p);
-
+ if (unlikely(p->flags & PF_KTHREAD)) {
+ memset(swstack, 0,
+ sizeof(struct switch_stack) + sizeof(struct pt_regs));
+ swstack->r1 = usp;
+ swstack->r2 = arg;
+ childregs->dccr = 1 << I_DCCR_BITNR;
+ swstack->return_ip = (unsigned long) ret_from_kernel_thread;
+ p->thread.ksp = (unsigned long) swstack;
+ p->thread.usp = 0;
+ return 0;
+ }
*childregs = *regs; /* struct copy of pt_regs */
-
- p->set_child_tid = p->clear_child_tid = NULL;
childregs->r10 = 0; /* child returns 0 after a fork/clone */
-
- /* put the switch stack right below the pt_regs */
- swstack = ((struct switch_stack *)childregs) - 1;
+ /* put the switch stack right below the pt_regs */
swstack->r9 = 0; /* parameter to ret_from_sys_call, 0 == dont restart the syscall */
@@ -147,7 +129,7 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
/* fix the user-mode stackpointer */
- p->thread.usp = usp;
+ p->thread.usp = usp;
/* and the kernel-mode one */
@@ -161,45 +143,28 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
return 0;
}
-/*
- * Be aware of the "magic" 7th argument in the four system-calls below.
- * They need the latest stackframe, which is put as the 7th argument by
- * entry.S. The previous arguments are dummies or actually used, but need
- * to be defined to reach the 7th argument.
- *
- * N.B.: Another method to get the stackframe is to use current_regs(). But
- * it returns the latest stack-frame stacked when going from _user mode_ and
- * some of these (at least sys_clone) are called from kernel-mode sometimes
- * (for example during kernel_thread, above) and thus cannot use it. Thus,
- * to be sure not to get any surprises, we use the method for the other calls
- * as well.
- */
-
-asmlinkage int sys_fork(long r10, long r11, long r12, long r13, long mof, long srp,
- struct pt_regs *regs)
+asmlinkage int sys_fork(void)
{
- return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
+ return do_fork(SIGCHLD, rdusp(), current_pt_regs(), 0, NULL, NULL);
}
/* if newusp is 0, we just grab the old usp */
/* FIXME: Is parent_tid/child_tid really third/fourth argument? Update lib? */
asmlinkage int sys_clone(unsigned long newusp, unsigned long flags,
- int* parent_tid, int* child_tid, long mof, long srp,
- struct pt_regs *regs)
+ int* parent_tid, int* child_tid)
{
if (!newusp)
newusp = rdusp();
- return do_fork(flags, newusp, regs, 0, parent_tid, child_tid);
+ return do_fork(flags, newusp, current_pt_regs(), 0, parent_tid, child_tid);
}
/* vfork is a system call in i386 because of register-pressure - maybe
* we can remove it and handle it in libc but we put it here until then.
*/
-asmlinkage int sys_vfork(long r10, long r11, long r12, long r13, long mof, long srp,
- struct pt_regs *regs)
+asmlinkage int sys_vfork(void)
{
- return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL, NULL);
+ return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), current_pt_regs(), 0, NULL, NULL);
}
/*