Commit 8f54bcac authored by Al Viro's avatar Al Viro
Browse files

mips: switch to generic kernel_thread() 



Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent ddffeb8c

arch/mips/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -40,6 +40,7 @@ config MIPS 
	select HAVE_MOD_ARCH_SPECIFIC

	select MODULES_USE_ELF_REL

	select MODULES_USE_ELF_RELA if 64BIT

	select GENERIC_KERNEL_THREAD



menu "Machine selection"

arch/mips/include/asm/processor.h

+0 −2
Original line number Diff line number Diff line
@@ -310,8 +310,6 @@ struct task_struct; 
/* Free all resources held by a thread. */

#define release_thread(thread) do { } while(0)



extern long kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);



extern unsigned long thread_saved_pc(struct task_struct *tsk);



/*

arch/mips/kernel/entry.S

+7 −0
Original line number Diff line number Diff line
@@ -65,6 +65,13 @@ need_resched: 
	b	need_resched

#endif



FEXPORT(ret_from_kernel_thread)

	jal	schedule_tail		# a0 = struct task_struct *prev

	move	a0, s1

	jal	s0

	li	a0, 0

	j	sys_exit



FEXPORT(ret_from_fork)

	jal	schedule_tail		# a0 = struct task_struct *prev

arch/mips/kernel/mips_ksyms.c

+0 −2
Original line number Diff line number Diff line
@@ -32,8 +32,6 @@ EXPORT_SYMBOL(memset); 
EXPORT_SYMBOL(memcpy);

EXPORT_SYMBOL(memmove);



EXPORT_SYMBOL(kernel_thread);



/*

 * Functions that operate on entire pages.  Mostly used by memory management.

 */

arch/mips/kernel/process.c

+22 −40
Original line number Diff line number Diff line
@@ -84,6 +84,7 @@ void __noreturn cpu_idle(void) 
}



asmlinkage void ret_from_fork(void);

asmlinkage void ret_from_kernel_thread(void);



void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)

{
@@ -113,7 +114,7 @@ void flush_thread(void) 
}



int copy_thread(unsigned long clone_flags, unsigned long usp,

	unsigned long unused, struct task_struct *p, struct pt_regs *regs)

	unsigned long arg, struct task_struct *p, struct pt_regs *regs)

{

	struct thread_info *ti = task_thread_info(p);

	struct pt_regs *childregs;
@@ -136,19 +137,30 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, 
	childregs = (struct pt_regs *) childksp - 1;

	/*  Put the stack after the struct pt_regs.  */

	childksp = (unsigned long) childregs;

	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);

	if (unlikely(p->flags & PF_KTHREAD)) {

		unsigned long status = p->thread.cp0_status;

		memset(childregs, 0, sizeof(struct pt_regs));

		ti->addr_limit = KERNEL_DS;

		p->thread.reg16 = usp; /* fn */

		p->thread.reg17 = arg;

		p->thread.reg29 = childksp;

		p->thread.reg31 = (unsigned long) ret_from_kernel_thread;

#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)

		status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |

			 ((status & (ST0_KUC | ST0_IEC)) << 2);

#else

		status |= ST0_EXL;

#endif

		childregs->cp0_status = status;

		return 0;

	}

	*childregs = *regs;

	childregs->regs[7] = 0;	/* Clear error flag */



	childregs->regs[2] = 0;	/* Child gets zero as return value */



	if (childregs->cp0_status & ST0_CU0) {

		childregs->regs[28] = (unsigned long) ti;

		childregs->regs[29] = childksp;

		ti->addr_limit = KERNEL_DS;

	} else {

	childregs->regs[29] = usp;

	ti->addr_limit = USER_DS;

	}



	p->thread.reg29 = (unsigned long) childregs;

	p->thread.reg31 = (unsigned long) ret_from_fork;
@@ -156,7 +168,6 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, 
	 * New tasks lose permission to use the fpu. This accelerates context

	 * switching for most programs since they don't use the fpu.

	 */

	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);

	childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);



#ifdef CONFIG_MIPS_MT_SMTC
@@ -221,35 +232,6 @@ int dump_task_fpu(struct task_struct *t, elf_fpregset_t *fpr) 
	return 1;

}



/*

 * Create a kernel thread

 */

static void __noreturn kernel_thread_helper(void *arg, int (*fn)(void *))

{

	do_exit(fn(arg));

}



long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)

{

	struct pt_regs regs;



	memset(&regs, 0, sizeof(regs));



	regs.regs[4] = (unsigned long) arg;

	regs.regs[5] = (unsigned long) fn;

	regs.cp0_epc = (unsigned long) kernel_thread_helper;

	regs.cp0_status = read_c0_status();

#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)

	regs.cp0_status = (regs.cp0_status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |

			  ((regs.cp0_status & (ST0_KUC | ST0_IEC)) << 2);

#else

	regs.cp0_status |= ST0_EXL;

#endif



	/* Ok, create the new process.. */

	return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);

}



/*

 *

 */