avr32: sanitize copy_thread(), switch to generic fork/vfork/clone, kill wrappers

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/avr32/include/asm/unistd.h

@@ -40,6 +40,9 @@
 #define __ARCH_WANT_SYS_RT_SIGACTION
 #define __ARCH_WANT_SYS_RT_SIGSUSPEND
 #define __ARCH_WANT_SYS_EXECVE
+#define __ARCH_WANT_SYS_FORK
+#define __ARCH_WANT_SYS_VFORK
+#define __ARCH_WANT_SYS_CLONE
 
 /*
  * "Conditional" syscalls

arch/avr32/kernel/process.c

@@ -299,11 +299,11 @@ asmlinkage void syscall_return(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 *unused)
 {
 	struct pt_regs *childregs = task_pt_regs(p);
 
-	if (unlikely(!regs)) {
+	if (unlikely(p->flags & PF_KTHREAD)) {
 		memset(childregs, 0, sizeof(struct pt_regs));
 		p->thread.cpu_context.r0 = arg;
 		p->thread.cpu_context.r1 = usp; /* fn */
@@ -311,8 +311,9 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
 		p->thread.cpu_context.pc = (unsigned long)ret_from_kernel_thread;
 		childregs->sr = MODE_SUPERVISOR;
 	} else {
-		*childregs = *regs;
-		childregs->sp = usp;
+		*childregs = *current_pt_regs();
+		if (usp)
+			childregs->sp = usp;
 		childregs->r12 = 0; /* Set return value for child */
 		p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
 	}
@@ -327,28 +328,6 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
 	return 0;
 }
 
-/* r12-r8 are dummy parameters to force the compiler to use the stack */
-asmlinkage int sys_fork(struct pt_regs *regs)
-{
-	return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);
-}
-
-asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
-		void __user *parent_tidptr, void __user *child_tidptr,
-		struct pt_regs *regs)
-{
-	if (!newsp)
-		newsp = regs->sp;
-	return do_fork(clone_flags, newsp, regs, 0, parent_tidptr,
-			child_tidptr);
-}
-
-asmlinkage int sys_vfork(struct pt_regs *regs)
-{
-	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs,
-		       0, NULL, NULL);
-}
-
 /*
  * This function is supposed to answer the question "who called
  * schedule()?"

arch/avr32/kernel/syscall-stubs.S

@@ -32,24 +32,6 @@ __sys_rt_sigreturn:
 	mov	r12, sp
 	rjmp	sys_rt_sigreturn
 
-	.global	__sys_fork
-	.type	__sys_fork,@function
-__sys_fork:
-	mov	r12, sp
-	rjmp	sys_fork
-
-	.global	__sys_clone
-	.type	__sys_clone,@function
-__sys_clone:
-	mov	r8, sp
-	rjmp	sys_clone
-
-	.global	__sys_vfork
-	.type	__sys_vfork,@function
-__sys_vfork:
-	mov	r12, sp
-	rjmp	sys_vfork
-
 	.global	__sys_mmap2
 	.type	__sys_mmap2,@function
 __sys_mmap2:

arch/avr32/kernel/syscall_table.S

@@ -15,7 +15,7 @@
 sys_call_table:
 	.long	sys_restart_syscall
 	.long	sys_exit
-	.long	__sys_fork
+	.long	sys_fork
 	.long	sys_read
 	.long	sys_write
 	.long	sys_open		/* 5 */
@@ -57,7 +57,7 @@ sys_call_table:
 	.long	sys_dup
 	.long	sys_pipe
 	.long	sys_times
-	.long	__sys_clone
+	.long	sys_clone
 	.long	sys_brk			/* 45 */
 	.long	sys_setgid
 	.long	sys_getgid
@@ -127,7 +127,7 @@ sys_call_table:
 	.long	sys_newuname
 	.long	sys_adjtimex
 	.long	sys_mprotect
-	.long	__sys_vfork
+	.long	sys_vfork
 	.long	sys_init_module		/* 115 */
 	.long	sys_delete_module
 	.long	sys_quotactl