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-rw-r--r--arch/frv/kernel/kernel_thread.S77
1 files changed, 77 insertions, 0 deletions
diff --git a/arch/frv/kernel/kernel_thread.S b/arch/frv/kernel/kernel_thread.S
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+++ b/arch/frv/kernel/kernel_thread.S
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+/* kernel_thread.S: kernel thread creation
+ *
+ * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/linkage.h>
+#include <asm/unistd.h>
+
+#define CLONE_VM 0x00000100 /* set if VM shared between processes */
+#define KERN_ERR "<3>"
+
+ .section .rodata
+kernel_thread_emsg:
+ .asciz KERN_ERR "failed to create kernel thread: error=%d\n"
+
+ .text
+ .balign 4
+
+###############################################################################
+#
+# Create a kernel thread
+#
+# int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
+#
+###############################################################################
+ .globl kernel_thread
+ .type kernel_thread,@function
+kernel_thread:
+ or.p gr8,gr0,gr4
+ or gr9,gr0,gr5
+
+ # start by forking the current process, but with shared VM
+ setlos.p #__NR_clone,gr7 ; syscall number
+ ori gr10,#CLONE_VM,gr8 ; first syscall arg [clone_flags]
+ sethi.p #0xe4e4,gr9 ; second syscall arg [newsp]
+ setlo #0xe4e4,gr9
+ setlos.p #0,gr10 ; third syscall arg [parent_tidptr]
+ setlos #0,gr11 ; fourth syscall arg [child_tidptr]
+ tira gr0,#0
+ setlos.p #4095,gr7
+ andcc gr8,gr8,gr0,icc0
+ addcc.p gr8,gr7,gr0,icc1
+ bnelr icc0,#2
+ bc icc1,#0,kernel_thread_error
+
+ # now invoke the work function
+ or gr5,gr0,gr8
+ calll @(gr4,gr0)
+
+ # and finally exit the thread
+ setlos #__NR_exit,gr7 ; syscall number
+ tira gr0,#0
+
+kernel_thread_error:
+ subi sp,#8,sp
+ movsg lr,gr4
+ sti gr8,@(sp,#0)
+ sti.p gr4,@(sp,#4)
+
+ or gr8,gr0,gr9
+ sethi.p %hi(kernel_thread_emsg),gr8
+ setlo %lo(kernel_thread_emsg),gr8
+
+ call printk
+
+ ldi @(sp,#4),gr4
+ ldi @(sp,#0),gr8
+ subi sp,#8,sp
+ jmpl @(gr4,gr0)
+
+ .size kernel_thread,.-kernel_thread