Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal

Pull pile 2 of execve and kernel_thread unification work from Al Viro:
 "Stuff in there: kernel_thread/kernel_execve/sys_execve conversions for
  several more architectures plus assorted signal fixes and cleanups.

  There'll be more (in particular, real fixes for the alpha
  do_notify_resume() irq mess)..."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (43 commits)
  alpha: don't open-code trace_report_syscall_{enter,exit}
  Uninclude linux/freezer.h
  m32r: trim masks
  avr32: trim masks
  tile: don't bother with SIGTRAP in setup_frame
  microblaze: don't bother with SIGTRAP in setup_rt_frame()
  mn10300: don't bother with SIGTRAP in setup_frame()
  frv: no need to raise SIGTRAP in setup_frame()
  x86: get rid of duplicate code in case of CONFIG_VM86
  unicore32: remove pointless test
  h8300: trim _TIF_WORK_MASK
  parisc: decide whether to go to slow path (tracesys) based on thread flags
  parisc: don't bother looping in do_signal()
  parisc: fix double restarts
  bury the rest of TIF_IRET
  sanitize tsk_is_polling()
  bury _TIF_RESTORE_SIGMASK
  unicore32: unobfuscate _TIF_WORK_MASK
  mips: NOTIFY_RESUME is not needed in TIF masks
  mips: merge the identical "return from syscall" per-ABI code
  ...

Conflicts:
	arch/arm/include/asm/thread_info.h

13 files changed, 54 insertions, 173 deletions

diff --git a/arch/mn10300/Kconfig b/arch/mn10300/Kconfig
index 5cfb086..ddbdc33 100644
--- a/arch/mn10300/Kconfig
+++ b/arch/mn10300/Kconfig
@@ -8,6 +8,7 @@ config MN10300
 	select HAVE_ARCH_KGDB
 	select HAVE_NMI_WATCHDOG if MN10300_WD_TIMER
 	select GENERIC_CLOCKEVENTS
+	select GENERIC_KERNEL_THREAD
 
 config AM33_2
 	def_bool n
diff --git a/arch/mn10300/include/asm/frame.inc b/arch/mn10300/include/asm/frame.inc
index 2ee58e3..1c3eb4f 100644
--- a/arch/mn10300/include/asm/frame.inc
+++ b/arch/mn10300/include/asm/frame.inc
@@ -61,7 +61,7 @@
 ###############################################################################
 .macro RESTORE_ALL
 	# peel back the stack to the calling frame
-	# - this permits execve() to discard extra frames due to kernel syscalls
+	# - we need that when returning from interrupts to kernel mode
 	GET_THREAD_INFO a0
 	mov	(TI_frame,a0),fp
 	mov	fp,sp
diff --git a/arch/mn10300/include/asm/processor.h b/arch/mn10300/include/asm/processor.h
index 247928c..8b80b19 100644
--- a/arch/mn10300/include/asm/processor.h
+++ b/arch/mn10300/include/asm/processor.h
@@ -119,20 +119,13 @@ struct thread_struct {
 
 /*
  * do necessary setup to start up a newly executed thread
- * - need to discard the frame stacked by the kernel thread invoking the execve
- *   syscall (see RESTORE_ALL macro)
  */
 static inline void start_thread(struct pt_regs *regs,
 				unsigned long new_pc, unsigned long new_sp)
 {
-	struct thread_info *ti = current_thread_info();
-	struct pt_regs *frame0;
-
-	frame0 = thread_info_to_uregs(ti);
-	frame0->epsw = EPSW_nSL | EPSW_IE | EPSW_IM;
-	frame0->pc = new_pc;
-	frame0->sp = new_sp;
-	ti->frame = frame0;
+	regs->epsw = EPSW_nSL | EPSW_IE | EPSW_IM;
+	regs->pc = new_pc;
+	regs->sp = new_sp;
 }
 
 
@@ -140,11 +133,6 @@ static inline void start_thread(struct pt_regs *regs,
 extern void release_thread(struct task_struct *);
 
 /*
- * create a kernel thread without removing it from tasklists
- */
-extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
-
-/*
  * Return saved PC of a blocked thread.
  */
 extern unsigned long thread_saved_pc(struct task_struct *tsk);
diff --git a/arch/mn10300/include/asm/ptrace.h b/arch/mn10300/include/asm/ptrace.h
index 44251b9..08ac856 100644
--- a/arch/mn10300/include/asm/ptrace.h
+++ b/arch/mn10300/include/asm/ptrace.h
@@ -86,6 +86,7 @@ struct pt_regs {
 #define user_mode(regs)			(((regs)->epsw & EPSW_nSL) == EPSW_nSL)
 #define instruction_pointer(regs)	((regs)->pc)
 #define user_stack_pointer(regs)	((regs)->sp)
+#define current_pt_regs()		current_frame()
 
 #define arch_has_single_step()	(1)
 
diff --git a/arch/mn10300/include/asm/thread_info.h b/arch/mn10300/include/asm/thread_info.h
index ac519bb..f90062b 100644
--- a/arch/mn10300/include/asm/thread_info.h
+++ b/arch/mn10300/include/asm/thread_info.h
@@ -160,12 +160,13 @@ void arch_release_thread_info(struct thread_info *ti);
 #define _TIF_SIGPENDING		+(1 << TIF_SIGPENDING)
 #define _TIF_NEED_RESCHED	+(1 << TIF_NEED_RESCHED)
 #define _TIF_SINGLESTEP		+(1 << TIF_SINGLESTEP)
-#define _TIF_RESTORE_SIGMASK	+(1 << TIF_RESTORE_SIGMASK)
 #define _TIF_POLLING_NRFLAG	+(1 << TIF_POLLING_NRFLAG)
 
 #define _TIF_WORK_MASK		0x0000FFFE	/* work to do on interrupt/exception return */
 #define _TIF_ALLWORK_MASK	0x0000FFFF	/* work to do on any return to u-space */
 
+#define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
+
 #endif /* __KERNEL__ */
 
 #endif /* _ASM_THREAD_INFO_H */
diff --git a/arch/mn10300/include/asm/unistd.h b/arch/mn10300/include/asm/unistd.h
index 866eb14..044c770 100644
--- a/arch/mn10300/include/asm/unistd.h
+++ b/arch/mn10300/include/asm/unistd.h
@@ -382,6 +382,8 @@
 #define __ARCH_WANT_SYS_SIGPROCMASK
 #define __ARCH_WANT_SYS_RT_SIGACTION
 #define __ARCH_WANT_SYS_RT_SIGSUSPEND
+#define __ARCH_WANT_SYS_EXECVE
+#define __ARCH_WANT_KERNEL_EXECVE
 
 /*
  * "Conditional" syscalls
diff --git a/arch/mn10300/kernel/Makefile b/arch/mn10300/kernel/Makefile
index d067491..561029f 100644
--- a/arch/mn10300/kernel/Makefile
+++ b/arch/mn10300/kernel/Makefile
@@ -7,8 +7,8 @@ fpu-obj-y := fpu-nofpu.o fpu-nofpu-low.o
 fpu-obj-$(CONFIG_FPU) := fpu.o fpu-low.o
 
 obj-y   := process.o signal.o entry.o traps.o irq.o \
-	   ptrace.o setup.o time.o sys_mn10300.o io.o kthread.o \
-	   switch_to.o mn10300_ksyms.o kernel_execve.o $(fpu-obj-y) \
+	   ptrace.o setup.o time.o sys_mn10300.o io.o \
+	   switch_to.o mn10300_ksyms.o $(fpu-obj-y) \
 	   csrc-mn10300.o cevt-mn10300.o
 
 obj-$(CONFIG_SMP) += smp.o smp-low.o
diff --git a/arch/mn10300/kernel/entry.S b/arch/mn10300/kernel/entry.S
index 8e11f9f..0c631d3 100644
--- a/arch/mn10300/kernel/entry.S
+++ b/arch/mn10300/kernel/entry.S
@@ -55,6 +55,20 @@ ENTRY(ret_from_fork)
 	mov	d0,(REG_D0,fp)
 	jmp	syscall_exit
 
+ENTRY(ret_from_kernel_thread)
+	call	schedule_tail[],0
+	mov	(REG_D0,fp),d0
+	mov	(REG_A0,fp),a0
+	calls	(a0)
+	jmp	sys_exit
+
+ENTRY(ret_from_kernel_execve)
+	add	-12,d0	/* pt_regs -> frame */
+	mov	d0,sp
+	GET_THREAD_INFO a2
+	clr	d0
+	jmp	syscall_exit
+
 ###############################################################################
 #
 # system call handler
@@ -94,6 +108,10 @@ restore_all:
 ###############################################################################
 	ALIGN
 syscall_exit_work:
+	mov	(REG_EPSW,fp),d0
+	and	EPSW_nSL,d0
+	beq	resume_kernel		# returning to supervisor mode
+
 	btst	_TIF_SYSCALL_TRACE,d2
 	beq	work_pending
 	LOCAL_IRQ_ENABLE		# could let syscall_trace_exit() call
diff --git a/arch/mn10300/kernel/internal.h b/arch/mn10300/kernel/internal.h
index 2df4401..5617855 100644
--- a/arch/mn10300/kernel/internal.h
+++ b/arch/mn10300/kernel/internal.h
@@ -15,14 +15,10 @@ struct clocksource;
 struct clock_event_device;
 
 /*
- * kthread.S
- */
-extern int kernel_thread_helper(int);
-
-/*
  * entry.S
  */
 extern void ret_from_fork(struct task_struct *) __attribute__((noreturn));
+extern void ret_from_kernel_thread(struct task_struct *) __attribute__((noreturn));
 
 /*
  * smp-low.S
diff --git a/arch/mn10300/kernel/kernel_execve.S b/arch/mn10300/kernel/kernel_execve.S
deleted file mode 100644
index 86039f1..0000000
--- a/arch/mn10300/kernel/kernel_execve.S
+++ /dev/null
@@ -1,37 +0,0 @@
-/* MN10300 In-kernel program execution
- *
- * Copyright (C) 2007 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 Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
- */
-#include <linux/linkage.h>
-#include <asm/unistd.h>
-
-###############################################################################
-#
-# Do a system call from kernel instead of calling sys_execve so we end up with
-# proper pt_regs.
-#
-# int kernel_execve(const char *filename, char *const argv[],
-#		    char *const envp[])
-#
-# On entry: D0/D1/8(SP): arguments to function
-# On return: D0: syscall return.
-#
-###############################################################################
-	.globl		kernel_execve
-	.type		kernel_execve,@function
-kernel_execve:
-	mov		a3,a1
-	mov		d0,a0
-	mov		(12,sp),a3
-	mov		+__NR_execve,d0
-	syscall		0
-	mov		a1,a3
-	rets
-
-	.size		kernel_execve,.-kernel_execve
diff --git a/arch/mn10300/kernel/kthread.S b/arch/mn10300/kernel/kthread.S
deleted file mode 100644
index b5ae467..0000000
--- a/arch/mn10300/kernel/kthread.S
+++ /dev/null
@@ -1,31 +0,0 @@
-/* MN10300 Kernel thread trampoline function
- *
- * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
- * Written by Mark Salter (msalter@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
- */
-	.text
-
-###############################################################################
-#
-# kernel_thread_helper - trampoline for kernel_thread()
-#
-# On entry:
-#   A2 = address of function to call
-#   D2 = function argument
-#
-###############################################################################
-	.globl	kernel_thread_helper
-	.type	kernel_thread_helper,@function
-kernel_thread_helper:
-	mov	do_exit,d1
-	mov	d1,(sp)
-	mov	d1,mdr
-	mov	d2,d0
-	jmp	(a2)
-
-	.size	kernel_thread_helper,.-kernel_thread_helper
diff --git a/arch/mn10300/kernel/process.c b/arch/mn10300/kernel/process.c
index e9cceba..d0c671b 100644
--- a/arch/mn10300/kernel/process.c
+++ b/arch/mn10300/kernel/process.c
@@ -165,27 +165,6 @@ void show_regs(struct pt_regs *regs)
 }
 
 /*
- * create a kernel thread
- */
-int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
-	struct pt_regs regs;
-
-	memset(&regs, 0, sizeof(regs));
-
-	regs.a2 = (unsigned long) fn;
-	regs.d2 = (unsigned long) arg;
-	regs.pc = (unsigned long) kernel_thread_helper;
-	local_save_flags(regs.epsw);
-	regs.epsw |= EPSW_IE | EPSW_IM_7;
-
-	/* Ok, create the new process.. */
-	return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0,
-		       NULL, NULL);
-}
-EXPORT_SYMBOL(kernel_thread);
-
-/*
  * free current thread data structures etc..
  */
 void exit_thread(void)
@@ -230,50 +209,42 @@ int copy_thread(unsigned long clone_flags,
 		struct task_struct *p, struct pt_regs *kregs)
 {
 	struct thread_info *ti = task_thread_info(p);
-	struct pt_regs *c_uregs, *c_kregs, *uregs;
+	struct pt_regs *c_regs;
 	unsigned long c_ksp;
 
-	uregs = current->thread.uregs;
-
 	c_ksp = (unsigned long) task_stack_page(p) + THREAD_SIZE;
 
 	/* allocate the userspace exception frame and set it up */
 	c_ksp -= sizeof(struct pt_regs);
-	c_uregs = (struct pt_regs *) c_ksp;
+	c_regs = (struct pt_regs *) c_ksp;
+	c_ksp -= 12; /* allocate function call ABI slack */
 
-	p->thread.uregs = c_uregs;
-	*c_uregs = *uregs;
-	c_uregs->sp = c_usp;
-	c_uregs->epsw &= ~EPSW_FE; /* my FPU */
+	/* set up things up so the scheduler can start the new task */
+	p->thread.uregs = c_regs;
+	ti->frame	= c_regs;
+	p->thread.a3	= (unsigned long) c_regs;
+	p->thread.sp	= c_ksp;
+	p->thread.wchan	= p->thread.pc;
+	p->thread.usp	= c_usp;
 
-	c_ksp -= 12; /* allocate function call ABI slack */
+	if (unlikely(!kregs)) {
+		memset(c_regs, 0, sizeof(struct pt_regs));
+		c_regs->a0 = c_usp; /* function */
+		c_regs->d0 = ustk_size; /* argument */
+		local_save_flags(c_regs->epsw);
+		c_regs->epsw |= EPSW_IE | EPSW_IM_7;
+		p->thread.pc	= (unsigned long) ret_from_kernel_thread;
+		return 0;
+	}
+	*c_regs = *kregs;
+	c_regs->sp = c_usp;
+	c_regs->epsw &= ~EPSW_FE; /* my FPU */
 
 	/* the new TLS pointer is passed in as arg #5 to sys_clone() */
 	if (clone_flags & CLONE_SETTLS)
-		c_uregs->e2 = current_frame()->d3;
-
-	/* set up the return kernel frame if called from kernel_thread() */
-	c_kregs = c_uregs;
-	if (kregs != uregs) {
-		c_ksp -= sizeof(struct pt_regs);
-		c_kregs = (struct pt_regs *) c_ksp;
-		*c_kregs = *kregs;
-		c_kregs->sp = c_usp;
-		c_kregs->next = c_uregs;
-#ifdef CONFIG_MN10300_CURRENT_IN_E2
-		c_kregs->e2 = (unsigned long) p; /* current */
-#endif
-
-		c_ksp -= 12; /* allocate function call ABI slack */
-	}
+		c_regs->e2 = current_frame()->d3;
 
-	/* set up things up so the scheduler can start the new task */
-	ti->frame	= c_kregs;
-	p->thread.a3	= (unsigned long) c_kregs;
-	p->thread.sp	= c_ksp;
 	p->thread.pc	= (unsigned long) ret_from_fork;
-	p->thread.wchan	= (unsigned long) ret_from_fork;
-	p->thread.usp	= c_usp;
 
 	return 0;
 }
@@ -302,22 +273,6 @@ asmlinkage long sys_vfork(void)
 		       current_frame(), 0, NULL, NULL);
 }
 
-asmlinkage long sys_execve(const char __user *name,
-			   const char __user *const __user *argv,
-			   const char __user *const __user *envp)
-{
-	char *filename;
-	int error;
-
-	filename = getname(name);
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		return error;
-	error = do_execve(filename, argv, envp, current_frame());
-	putname(filename);
-	return error;
-}
-
 unsigned long get_wchan(struct task_struct *p)
 {
 	return p->thread.wchan;
diff --git a/arch/mn10300/kernel/signal.c b/arch/mn10300/kernel/signal.c
index 4d584ae..f570b30 100644
--- a/arch/mn10300/kernel/signal.c
+++ b/arch/mn10300/kernel/signal.c
@@ -317,10 +317,6 @@ static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
 	regs->d0 = sig;
 	regs->d1 = (unsigned long) &frame->sc;
 
-	/* the tracer may want to single-step inside the handler */
-	if (test_thread_flag(TIF_SINGLESTEP))
-		ptrace_notify(SIGTRAP);
-
 #if DEBUG_SIG
 	printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 	       sig, current->comm, current->pid, frame, regs->pc,
@@ -398,10 +394,6 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 	regs->d0 = sig;
 	regs->d1 = (long) &frame->info;
 
-	/* the tracer may want to single-step inside the handler */
-	if (test_thread_flag(TIF_SINGLESTEP))
-		ptrace_notify(SIGTRAP);
-
 #if DEBUG_SIG
 	printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 	       sig, current->comm, current->pid, frame, regs->pc,
@@ -475,11 +467,6 @@ static void do_signal(struct pt_regs *regs)
 	siginfo_t info;
 	int signr;
 
-	/* we want the common case to go fast, which is why we may in certain
-	 * cases get here from kernel mode */
-	if (!user_mode(regs))
-		return;
-
 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 	if (signr > 0) {
 		if (handle_signal(signr, &info, &ka, regs) == 0) {