From 533e6903bea0440816a0f517b0845ccea4cc7917 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 16 Sep 2012 12:05:09 -0400 Subject: m68k: split ret_from_fork(), simplify kernel_thread() Signed-off-by: Al Viro --- arch/m68k/kernel/entry.S | 11 ++++++ arch/m68k/kernel/process.c | 84 +++++++++++++--------------------------------- 2 files changed, 35 insertions(+), 60 deletions(-) (limited to 'arch/m68k/kernel') diff --git a/arch/m68k/kernel/entry.S b/arch/m68k/kernel/entry.S index 165ee9f..8a01f58 100644 --- a/arch/m68k/kernel/entry.S +++ b/arch/m68k/kernel/entry.S @@ -111,6 +111,17 @@ ENTRY(ret_from_fork) addql #4,%sp jra ret_from_exception +ENTRY(ret_from_kernel_thread) + | a3 contains the kernel thread payload, d7 - its argument + movel %d1,%sp@- + jsr schedule_tail + GET_CURRENT(%d0) + movel %d7,(%sp) + jsr %a3@ + addql #4,%sp + movel %d0,(%sp) + jra sys_exit + #if defined(CONFIG_COLDFIRE) || !defined(CONFIG_MMU) #ifdef TRAP_DBG_INTERRUPT diff --git a/arch/m68k/kernel/process.c b/arch/m68k/kernel/process.c index c488e3c..b3d4760 100644 --- a/arch/m68k/kernel/process.c +++ b/arch/m68k/kernel/process.c @@ -34,6 +34,7 @@ asmlinkage void ret_from_fork(void); +asmlinkage void ret_from_kernel_thread(void); /* @@ -120,51 +121,6 @@ void show_regs(struct pt_regs * regs) printk("USP: %08lx\n", rdusp()); } -/* - * Create a kernel thread - */ -int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) -{ - int pid; - mm_segment_t fs; - - fs = get_fs(); - set_fs (KERNEL_DS); - - { - register long retval __asm__ ("d0"); - register long clone_arg __asm__ ("d1") = flags | CLONE_VM | CLONE_UNTRACED; - - retval = __NR_clone; - __asm__ __volatile__ - ("clrl %%d2\n\t" - "trap #0\n\t" /* Linux/m68k system call */ - "tstl %0\n\t" /* child or parent */ - "jne 1f\n\t" /* parent - jump */ -#ifdef CONFIG_MMU - "lea %%sp@(%c7),%6\n\t" /* reload current */ - "movel %6@,%6\n\t" -#endif - "movel %3,%%sp@-\n\t" /* push argument */ - "jsr %4@\n\t" /* call fn */ - "movel %0,%%d1\n\t" /* pass exit value */ - "movel %2,%%d0\n\t" /* exit */ - "trap #0\n" - "1:" - : "+d" (retval) - : "i" (__NR_clone), "i" (__NR_exit), - "r" (arg), "a" (fn), "d" (clone_arg), "r" (current), - "i" (-THREAD_SIZE) - : "d2"); - - pid = retval; - } - - set_fs (fs); - return pid; -} -EXPORT_SYMBOL(kernel_thread); - void flush_thread(void) { current->thread.fs = __USER_DS; @@ -216,30 +172,18 @@ asmlinkage int m68k_clone(struct pt_regs *regs) } 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 * childstack, *stack; - unsigned long *retp; + struct switch_stack *childstack; childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1; - - *childregs = *regs; - childregs->d0 = 0; - - retp = ((unsigned long *) regs); - stack = ((struct switch_stack *) retp) - 1; - childstack = ((struct switch_stack *) childregs) - 1; - *childstack = *stack; - childstack->retpc = (unsigned long)ret_from_fork; p->thread.usp = usp; p->thread.ksp = (unsigned long)childstack; - - if (clone_flags & CLONE_SETTLS) - task_thread_info(p)->tp_value = regs->d5; + p->thread.esp0 = (unsigned long)childregs; /* * Must save the current SFC/DFC value, NOT the value when @@ -247,6 +191,26 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, */ p->thread.fs = get_fs().seg; + if (unlikely(!regs)) { + /* kernel thread */ + memset(childstack, 0, + sizeof(struct switch_stack) + sizeof(struct pt_regs)); + childregs->sr = PS_S; + childstack->a3 = usp; /* function */ + childstack->d7 = arg; + childstack->retpc = (unsigned long)ret_from_kernel_thread; + p->thread.usp = 0; + return 0; + } + *childregs = *regs; + childregs->d0 = 0; + + *childstack = ((struct switch_stack *) regs)[-1]; + childstack->retpc = (unsigned long)ret_from_fork; + + if (clone_flags & CLONE_SETTLS) + task_thread_info(p)->tp_value = regs->d5; + #ifdef CONFIG_FPU if (!FPU_IS_EMU) { /* Copy the current fpu state */ -- cgit v1.1 From d878d6dacee2c862f02da20f7fa3e2c0e8820e71 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 16 Sep 2012 12:06:34 -0400 Subject: m68k: switch to generic sys_execve()/kernel_execve() The tricky part here is that task_pt_regs() on m68k works *only* for process inside do_signal(). However, we need something much simpler - pt_regs of a process inside do_signal() may be at different offsets from the stack bottom, depending on the way we'd entered the kernel, but for a task inside sys_execve() it *is* at constant offset. Moreover, for a kernel thread about to become a userland process the same location is also fine - setting sp to that will leave the kernel stack pointer at the very bottom of the kernel stack when we finally switch to userland. Signed-off-by: Al Viro --- arch/m68k/kernel/entry.S | 5 +++++ arch/m68k/kernel/process.c | 20 -------------------- arch/m68k/kernel/sys_m68k.c | 17 ----------------- 3 files changed, 5 insertions(+), 37 deletions(-) (limited to 'arch/m68k/kernel') diff --git a/arch/m68k/kernel/entry.S b/arch/m68k/kernel/entry.S index 8a01f58..946cb01 100644 --- a/arch/m68k/kernel/entry.S +++ b/arch/m68k/kernel/entry.S @@ -122,6 +122,11 @@ ENTRY(ret_from_kernel_thread) movel %d0,(%sp) jra sys_exit +ENTRY(ret_from_kernel_execve) + movel 4(%sp), %sp + GET_CURRENT(%d0) + jra ret_from_exception + #if defined(CONFIG_COLDFIRE) || !defined(CONFIG_MMU) #ifdef TRAP_DBG_INTERRUPT diff --git a/arch/m68k/kernel/process.c b/arch/m68k/kernel/process.c index b3d4760..4e54b4c 100644 --- a/arch/m68k/kernel/process.c +++ b/arch/m68k/kernel/process.c @@ -298,26 +298,6 @@ int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu) EXPORT_SYMBOL(dump_fpu); #endif /* CONFIG_FPU */ -/* - * sys_execve() executes a new program. - */ -asmlinkage int sys_execve(const char __user *name, - const char __user *const __user *argv, - const char __user *const __user *envp) -{ - int error; - char * filename; - struct pt_regs *regs = (struct pt_regs *) &name; - - filename = getname(name); - error = PTR_ERR(filename); - if (IS_ERR(filename)) - return error; - error = do_execve(filename, argv, envp, regs); - putname(filename); - return error; -} - unsigned long get_wchan(struct task_struct *p) { unsigned long fp, pc; diff --git a/arch/m68k/kernel/sys_m68k.c b/arch/m68k/kernel/sys_m68k.c index 9a5932e..3a480b3 100644 --- a/arch/m68k/kernel/sys_m68k.c +++ b/arch/m68k/kernel/sys_m68k.c @@ -549,23 +549,6 @@ asmlinkage int sys_getpagesize(void) return PAGE_SIZE; } -/* - * 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, - const char *const argv[], - const char *const envp[]) -{ - register long __res asm ("%d0") = __NR_execve; - register long __a asm ("%d1") = (long)(filename); - register long __b asm ("%d2") = (long)(argv); - register long __c asm ("%d3") = (long)(envp); - asm volatile ("trap #0" : "+d" (__res) - : "d" (__a), "d" (__b), "d" (__c)); - return __res; -} - asmlinkage unsigned long sys_get_thread_area(void) { return current_thread_info()->tp_value; -- cgit v1.1