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authorMark Salter <msalter@redhat.com>2012-09-21 12:26:37 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2012-10-01 00:59:08 -0400
commit46f15067c020a0ce712cb2d3ef38c0589a521c15 (patch)
treef980e4faf9dccc1be052fdbbb1dbd785c6238cc6 /arch/c6x
parent61b7fbc3f4ebdcfd34f9438adfab8df936a19e33 (diff)
c6x: add ret_from_kernel_thread(), simplify kernel_thread()
Signed-off-by: Mark Salter <msalter@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'arch/c6x')
-rw-r--r--arch/c6x/kernel/entry.S20
-rw-r--r--arch/c6x/kernel/process.c38
2 files changed, 32 insertions, 26 deletions
diff --git a/arch/c6x/kernel/entry.S b/arch/c6x/kernel/entry.S
index 30b37e5f4a61..6e6bd9d3d9cc 100644
--- a/arch/c6x/kernel/entry.S
+++ b/arch/c6x/kernel/entry.S
@@ -400,6 +400,26 @@ ret_from_fork_2:
STW .D2T2 B0,*+SP(REGS_A4+8)
ENDPROC(ret_from_fork)
+ENTRY(ret_from_kernel_thread)
+#ifdef CONFIG_C6X_BIG_KERNEL
+ MVKL .S1 schedule_tail,A0
+ MVKH .S1 schedule_tail,A0
+ B .S2X A0
+#else
+ B .S2 schedule_tail
+#endif
+ LDW .D2T2 *+SP(REGS_A0+8),B10 /* get fn */
+ ADDKPC .S2 0f,B3,3
+0:
+ B .S2 B10 /* call fn */
+ LDW .D2T1 *+SP(REGS_A1+8),A4 /* get arg */
+ MVKL .S2 sys_exit,B11
+ MVKH .S2 sys_exit,B11
+ ADDKPC .S2 0f,B3,1
+0:
+ BNOP .S2 B11,5 /* jump to sys_exit */
+ENDPROC(ret_from_kernel_thread)
+
;;
;; These are the interrupt handlers, responsible for calling __do_IRQ()
;; int6 is used for syscalls (see _system_call entry)
diff --git a/arch/c6x/kernel/process.c b/arch/c6x/kernel/process.c
index 45e924a636a0..d2ffc9bdaba1 100644
--- a/arch/c6x/kernel/process.c
+++ b/arch/c6x/kernel/process.c
@@ -25,6 +25,7 @@ void (*c6x_restart)(void);
void (*c6x_halt)(void);
extern asmlinkage void ret_from_fork(void);
+extern asmlinkage void ret_from_kernel_thread(void);
/*
* power off function, if any
@@ -103,36 +104,21 @@ void machine_power_off(void)
halt_loop();
}
-static void kernel_thread_helper(int dummy, void *arg, int (*fn)(void *))
-{
- do_exit(fn(arg));
-}
-
/*
* Create a kernel thread
*/
int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{
- struct pt_regs regs;
-
- /*
- * copy_thread sets a4 to zero (child return from fork)
- * so we can't just set things up to directly return to
- * fn.
- */
- memset(&regs, 0, sizeof(regs));
- regs.b4 = (unsigned long) arg;
- regs.a6 = (unsigned long) fn;
- regs.pc = (unsigned long) kernel_thread_helper;
- local_save_flags(regs.csr);
- regs.csr |= 1;
- regs.tsr = 5; /* Set GEE and GIE in TSR */
+ struct pt_regs regs = {
+ .a0 = (unsigned long)fn,
+ .a1 = (unsigned long)arg,
+ .tsr = 0, /* kernel mode */
+ };
/* Ok, create the new process.. */
return do_fork(flags | CLONE_VM | CLONE_UNTRACED, -1, &regs,
0, NULL, NULL);
}
-EXPORT_SYMBOL(kernel_thread);
void flush_thread(void)
{
@@ -192,21 +178,21 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
childregs = task_pt_regs(p);
*childregs = *regs;
- childregs->a4 = 0;
- if (usp == -1)
+ if (usp == -1) {
/* case of __kernel_thread: we return to supervisor space */
childregs->sp = (unsigned long)(childregs + 1);
- else
+ p->thread.pc = (unsigned long) ret_from_kernel_thread;
+ } else {
/* Otherwise use the given stack */
childregs->sp = usp;
+ p->thread.pc = (unsigned long) ret_from_fork;
+ }
/* Set usp/ksp */
p->thread.usp = childregs->sp;
- /* switch_to uses stack to save/restore 14 callee-saved regs */
thread_saved_ksp(p) = (unsigned long)childregs - 8;
- p->thread.pc = (unsigned int) ret_from_fork;
- p->thread.wchan = (unsigned long) ret_from_fork;
+ p->thread.wchan = p->thread.pc;
#ifdef __DSBT__
{
unsigned long dp;

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