From 02ce496f152df87be081a64796498942c433a2fd Mon Sep 17 00:00:00 2001 From: Al Viro Date: Tue, 18 Sep 2012 22:18:51 -0400 Subject: frv: split ret_from_fork, simplify kernel_thread() a lot Acked-by: David Howells Signed-off-by: Al Viro diff --git a/arch/frv/kernel/Makefile b/arch/frv/kernel/Makefile index ad4087b..7b10bc1 100644 --- a/arch/frv/kernel/Makefile +++ b/arch/frv/kernel/Makefile @@ -7,7 +7,7 @@ heads-$(CONFIG_MMU) := head-mmu-fr451.o extra-y:= head.o vmlinux.lds -obj-y := $(heads-y) entry.o entry-table.o break.o switch_to.o kernel_thread.o \ +obj-y := $(heads-y) entry.o entry-table.o break.o switch_to.o \ kernel_execve.o process.o traps.o ptrace.o signal.o dma.o \ sys_frv.o time.o setup.o frv_ksyms.o \ debug-stub.o irq.o sleep.o uaccess.o diff --git a/arch/frv/kernel/entry.S b/arch/frv/kernel/entry.S index 7d5e000..7a88613 100644 --- a/arch/frv/kernel/entry.S +++ b/arch/frv/kernel/entry.S @@ -863,6 +863,14 @@ ret_from_fork: setlos.p #0,gr8 bra __syscall_exit + .globl ret_from_kernel_thread +ret_from_kernel_thread: + lddi.p @(gr28,#REG_GR(8)),gr20 + call schedule_tail + or.p gr20,gr20,gr8 + calll @(gr21,gr0) + bra sys_exit + ################################################################################################### # # Return to user mode is not as complex as all this looks, diff --git a/arch/frv/kernel/frv_ksyms.c b/arch/frv/kernel/frv_ksyms.c index a89803b..86c516d 100644 --- a/arch/frv/kernel/frv_ksyms.c +++ b/arch/frv/kernel/frv_ksyms.c @@ -30,7 +30,6 @@ EXPORT_SYMBOL(ip_fast_csum); EXPORT_SYMBOL(local_irq_count); EXPORT_SYMBOL(local_bh_count); #endif -EXPORT_SYMBOL(kernel_thread); EXPORT_SYMBOL(__res_bus_clock_speed_HZ); EXPORT_SYMBOL(__page_offset); diff --git a/arch/frv/kernel/kernel_thread.S b/arch/frv/kernel/kernel_thread.S deleted file mode 100644 index f0e5294..0000000 --- a/arch/frv/kernel/kernel_thread.S +++ /dev/null @@ -1,77 +0,0 @@ -/* 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 -#include -#include - -#define CLONE_VM 0x00000100 /* set if VM shared between processes */ - - .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 diff --git a/arch/frv/kernel/process.c b/arch/frv/kernel/process.c index ff95f50..0f02dee 100644 --- a/arch/frv/kernel/process.c +++ b/arch/frv/kernel/process.c @@ -37,6 +37,7 @@ #include "local.h" asmlinkage void ret_from_fork(void); +asmlinkage void ret_from_kernel_thread(void); #include @@ -172,29 +173,21 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long topstk, struct task_struct *p, struct pt_regs *regs) { - struct pt_regs *childregs0, *childregs, *regs0; + struct pt_regs *childregs; - regs0 = __kernel_frame0_ptr; - childregs0 = (struct pt_regs *) + childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE - FRV_FRAME0_SIZE); - childregs = childregs0; /* set up the userspace frame (the only place that the USP is stored) */ - *childregs0 = *regs0; - - childregs0->gr8 = 0; - childregs0->sp = usp; - childregs0->next_frame = NULL; - - /* set up the return kernel frame if called from kernel_thread() */ - if (regs != regs0) { - childregs--; - *childregs = *regs; - childregs->sp = (unsigned long) childregs0; - childregs->next_frame = childregs0; - childregs->gr15 = (unsigned long) task_thread_info(p); - childregs->gr29 = (unsigned long) p; - } + *childregs = *regs; + + childregs->sp = usp; + childregs->next_frame = NULL; + + if (unlikely(!user_mode(regs))) + p->thread.pc = (unsigned long) ret_from_kernel_thread; + else + p->thread.pc = (unsigned long) ret_from_fork; p->set_child_tid = p->clear_child_tid = NULL; @@ -203,8 +196,7 @@ int copy_thread(unsigned long clone_flags, p->thread.sp = (unsigned long) childregs; p->thread.fp = 0; p->thread.lr = 0; - p->thread.pc = (unsigned long) ret_from_fork; - p->thread.frame0 = childregs0; + p->thread.frame0 = childregs; /* the new TLS pointer is passed in as arg #5 to sys_clone() */ if (clone_flags & CLONE_SETTLS) @@ -347,3 +339,13 @@ int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpregs) sizeof(current->thread.user->f)); return 1; } + +int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) +{ + struct pt_regs regs = { + .gr8 = (unsigned long)arg; + .gr9 = (unsigned long)fn; + .psr = PSR_S; + }; + return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); +} -- cgit v0.10.2