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alpha: switch to generic kernel_thread()

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2012-09-09 22:03:42 -04:00
parent 756144f8ea
commit cba1ec7e88
5 changed files with 30 additions and 71 deletions
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1
arch/alpha/Kconfig
View file

@ -20,6 +20,7 @@ config ALPHA
select GENERIC_CMOS_UPDATE
select GENERIC_STRNCPY_FROM_USER
select GENERIC_STRNLEN_USER
select GENERIC_KERNEL_THREAD
help
The Alpha is a 64-bit general-purpose processor designed and
marketed by the Digital Equipment Corporation of blessed memory,

3
arch/alpha/include/asm/processor.h
View file

@ -49,9 +49,6 @@ extern void start_thread(struct pt_regs *, unsigned long, unsigned long);
/* Free all resources held by a thread. */
extern void release_thread(struct task_struct *);
/* Create a kernel thread without removing it from tasklists. */
extern long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
unsigned long get_wchan(struct task_struct *p);
#define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc)

3
arch/alpha/kernel/alpha_ksyms.c
View file

@ -50,9 +50,6 @@ EXPORT_SYMBOL(alpha_read_fp_reg_s);
EXPORT_SYMBOL(alpha_write_fp_reg);
EXPORT_SYMBOL(alpha_write_fp_reg_s);
/* entry.S */
EXPORT_SYMBOL(kernel_thread);
/* Networking helper routines. */
EXPORT_SYMBOL(csum_tcpudp_magic);
EXPORT_SYMBOL(ip_compute_csum);

57
arch/alpha/kernel/entry.S
View file

@ -609,59 +609,22 @@ ret_from_fork:
.end ret_from_fork
/*
* kernel_thread(fn, arg, clone_flags)
* ... and new kernel threads - here
*/
.align 4
.globl kernel_thread
.ent kernel_thread
kernel_thread:
/* We can be called from a module. */
ldgp $gp, 0($27)
.prologue 1
subq $sp, SP_OFF+6*8, $sp
br $1, 2f /* load start address */
/* We've now "returned" from a fake system call. */
unop
blt $0, 1f /* error? */
ldi $1, 0x3fff
beq $20, 1f /* parent or child? */
bic $sp, $1, $8 /* in child. */
jsr $26, ($27)
.globl ret_from_kernel_thread
.ent ret_from_kernel_thread
ret_from_kernel_thread:
mov $17, $16
jsr $26, schedule_tail
mov $9, $27
mov $10, $16
jsr $26, ($9)
ldgp $gp, 0($26)
mov $0, $16
mov $31, $26
jmp $31, sys_exit
1: ret /* in parent. */
.align 4
2: /* Fake a system call stack frame, as we can't do system calls
from kernel space. Note that we store FN and ARG as they
need to be set up in the child for the call. Also store $8
and $26 for use in the parent. */
stq $31, SP_OFF($sp) /* ps */
stq $1, SP_OFF+8($sp) /* pc */
stq $gp, SP_OFF+16($sp) /* gp */
stq $16, 136($sp) /* $27; FN for child */
stq $17, SP_OFF+24($sp) /* $16; ARG for child */
stq $8, 64($sp) /* $8 */
stq $26, 128($sp) /* $26 */
/* Avoid the HAE being gratuitously wrong, to avoid restoring it. */
ldq $2, alpha_mv+HAE_CACHE
stq $2, 152($sp) /* HAE */
/* Shuffle FLAGS to the front; add CLONE_VM. */
ldi $1, CLONE_VM|CLONE_UNTRACED
or $18, $1, $16
bsr $26, sys_clone
/* We don't actually care for a3 success widgetry in the kernel.
Not for positive errno values. */
stq $0, 0($sp) /* $0 */
br ret_to_kernel
.end kernel_thread
.end ret_from_kernel_thread
/*

37
arch/alpha/kernel/process.c
View file

@ -259,33 +259,35 @@ alpha_vfork(struct pt_regs *regs)
/*
* Copy an alpha thread..
*
* Note the "stack_offset" stuff: when returning to kernel mode, we need
* to have some extra stack-space for the kernel stack that still exists
* after the "ret_from_fork". When returning to user mode, we only want
* the space needed by the syscall stack frame (ie "struct pt_regs").
* Use the passed "regs" pointer to determine how much space we need
* for a kernel fork().
*/
int
copy_thread(unsigned long clone_flags, unsigned long usp,
unsigned long unused,
unsigned long arg,
struct task_struct * p, struct pt_regs * regs)
{
extern void ret_from_fork(void);
extern void ret_from_kernel_thread(void);
struct thread_info *childti = task_thread_info(p);
struct pt_regs * childregs;
struct switch_stack * childstack, *stack;
unsigned long stack_offset, settls;
struct pt_regs *childregs = task_pt_regs(p);
struct switch_stack *childstack, *stack;
unsigned long settls;
stack_offset = PAGE_SIZE - sizeof(struct pt_regs);
if (!(regs->ps & 8))
stack_offset = (PAGE_SIZE-1) & (unsigned long) regs;
childregs = (struct pt_regs *)
(stack_offset + PAGE_SIZE + task_stack_page(p));
childstack = ((struct switch_stack *) childregs) - 1;
if (unlikely(!regs)) {
/* kernel thread */
memset(childstack, 0,
sizeof(struct switch_stack) + sizeof(struct pt_regs));
childstack->r26 = (unsigned long) ret_from_kernel_thread;
childstack->r9 = usp; /* function */
childstack->r10 = arg;
childregs->hae = alpha_mv.hae_cache,
childti->pcb.usp = 0;
childti->pcb.ksp = (unsigned long) childstack;
childti->pcb.flags = 1; /* set FEN, clear everything else */
return 0;
}
*childregs = *regs;
settls = regs->r20;
childregs->r0 = 0;
@ -293,7 +295,6 @@ copy_thread(unsigned long clone_flags, unsigned long usp,
childregs->r20 = 1; /* OSF/1 has some strange fork() semantics. */
regs->r20 = 0;
stack = ((struct switch_stack *) regs) - 1;
childstack = ((struct switch_stack *) childregs) - 1;
*childstack = *stack;
childstack->r26 = (unsigned long) ret_from_fork;
childti->pcb.usp = usp;