frv: split ret_from_fork, simplify kernel_thread() a lot (02ce496f) · Commits · jan.koester / Linux

arch/frv/kernel/Makefile

+1 −1

Original line number	Diff line number	Diff line
		@@ -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

arch/frv/kernel/entry.S

+8 −0

Original line number	Diff line number	Diff line
		@@ -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,

arch/frv/kernel/frv_ksyms.c

+0 −1

Original line number	Diff line number	Diff line
		@@ -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);

arch/frv/kernel/kernel_thread.S

deleted100644 → 0

+0 −77

Original line number	Diff line number	Diff line
		/* 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 <linux/kern_levels.h>
		#include <asm/unistd.h>

		#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

arch/frv/kernel/process.c

+23 −21

Original line number	Diff line number	Diff line
		@@ -37,6 +37,7 @@
		#include "local.h"

		asmlinkage void ret_from_fork(void);
		asmlinkage void ret_from_kernel_thread(void);

		#include <asm/pgalloc.h>

		@@ -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;
		childregs = regs;

		childregs0->gr8 = 0;
		childregs0->sp = usp;
		childregs0->next_frame = NULL;
		childregs->sp = usp;
		childregs->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;
		}
		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, &regs, 0, NULL, NULL);
		}