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authorAl Viro <viro@zeniv.linux.org.uk>2012-09-18 22:18:51 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2012-10-01 00:53:10 -0400
commit02ce496f152df87be081a64796498942c433a2fd (patch)
tree0e6bdae8a5c9b1538f45c198cae7715957b997ba /arch/frv
parentd878d6dacee2c862f02da20f7fa3e2c0e8820e71 (diff)
frv: split ret_from_fork, simplify kernel_thread() a lot
Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'arch/frv')
-rw-r--r--arch/frv/kernel/Makefile2
-rw-r--r--arch/frv/kernel/entry.S8
-rw-r--r--arch/frv/kernel/frv_ksyms.c1
-rw-r--r--arch/frv/kernel/kernel_thread.S77
-rw-r--r--arch/frv/kernel/process.c44
5 files changed, 32 insertions, 100 deletions
diff --git a/arch/frv/kernel/Makefile b/arch/frv/kernel/Makefile
index ad4087b6996..7b10bc19106 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 7d5e000fd32..7a886130ca1 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 a89803b58b9..86c516d96dc 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 f0e52943f92..00000000000
--- 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 <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
diff --git a/arch/frv/kernel/process.c b/arch/frv/kernel/process.c
index ff95f50efea..0f02dee25e2 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 <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;
-
- 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, &regs, 0, NULL, NULL);
+}