linux/include/asm-arm26/thread_info.h
Adrian Bunk 96419b7c4d [PATCH] fix arm26 THREAD_SIZE
arm26 currently has a 256 kB THREAD_SIZE (sic).

Looking at the comment in the code, this seems to be based on a
misunderstanding.

The comment says:
this needs attention (see kernel/fork.c which gets a nice div by zero if
this is lower than 8*32768

kernel/fork.c does:
  max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE)

Therefore, a division by 0 is impossible for all reasonable cases with
THREAD_SIZE >= PAGE_SIZE.

Since the minimum PAGE_SIZE Linux uses on the arm26 architecture is 16k,
PAGE_SIZE should be sufficient for THREAD_SIZE.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Ian Molton <spyro@f2s.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-16 23:15:25 -08:00

141 lines
3.7 KiB
C

/*
* linux/include/asm-arm26/thread_info.h
*
* Copyright (C) 2002 Russell King.
* Copyright (C) 2003 Ian Molton.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef __ASM_ARM_THREAD_INFO_H
#define __ASM_ARM_THREAD_INFO_H
#ifdef __KERNEL__
#ifndef __ASSEMBLY__
struct task_struct;
struct exec_domain;
#include <linux/compiler.h>
#include <asm/fpstate.h>
#include <asm/ptrace.h>
#include <asm/types.h>
typedef unsigned long mm_segment_t;
struct cpu_context_save {
__u32 r4;
__u32 r5;
__u32 r6;
__u32 r7;
__u32 r8;
__u32 r9;
__u32 sl;
__u32 fp;
__u32 sp;
__u32 pc;
};
/*
* low level task data that entry.S needs immediate access to.
* We assume cpu_context follows immedately after cpu_domain.
*/
struct thread_info {
unsigned long flags; /* low level flags */
int preempt_count; /* 0 => preemptable, <0 => bug */
mm_segment_t addr_limit; /* address limit */
struct task_struct *task; /* main task structure */
struct exec_domain *exec_domain; /* execution domain */
__u32 cpu; /* cpu */
struct cpu_context_save cpu_context; /* cpu context */
struct restart_block restart_block;
union fp_state fpstate;
};
#define INIT_THREAD_INFO(tsk) \
{ \
.task &tsk, \
.exec_domain &default_exec_domain, \
.flags 0, \
.preempt_count 0, \
.addr_limit KERNEL_DS, \
.restart_block = { \
.fn = do_no_restart_syscall, \
}, \
}
#define init_thread_info (init_thread_union.thread_info)
#define init_stack (init_thread_union.stack)
/*
* how to get the thread information struct from C
*/
static inline struct thread_info *current_thread_info(void) __attribute_const__;
static inline struct thread_info *current_thread_info(void)
{
register unsigned long sp asm ("sp");
return (struct thread_info *)(sp & ~0x1fff);
}
#define THREAD_SIZE PAGE_SIZE
#define task_pt_regs(task) ((struct pt_regs *)(task_stack_page(task) + THREAD_SIZE - 8) - 1)
extern struct thread_info *alloc_thread_info(struct task_struct *task);
extern void free_thread_info(struct thread_info *);
#define thread_saved_pc(tsk) \
((unsigned long)(pc_pointer(task_thread_info(tsk)->cpu_context.pc)))
#define thread_saved_fp(tsk) \
((unsigned long)(task_thread_info(tsk)->cpu_context.fp))
#else /* !__ASSEMBLY__ */
#define TI_FLAGS 0
#define TI_PREEMPT 4
#define TI_ADDR_LIMIT 8
#define TI_TASK 12
#define TI_EXEC_DOMAIN 16
#define TI_CPU 20
#define TI_CPU_SAVE 24
#define TI_RESTART_BLOCK 28
#define TI_FPSTATE 68
#endif
#define PREEMPT_ACTIVE 0x04000000
/*
* thread information flags:
* TIF_SYSCALL_TRACE - syscall trace active
* TIF_NOTIFY_RESUME - resumption notification requested
* TIF_SIGPENDING - signal pending
* TIF_NEED_RESCHED - rescheduling necessary
* TIF_USEDFPU - FPU was used by this task this quantum (SMP)
* TIF_POLLING_NRFLAG - true if poll_idle() is polling TIF_NEED_RESCHED
*/
#define TIF_NOTIFY_RESUME 0
#define TIF_SIGPENDING 1
#define TIF_NEED_RESCHED 2
#define TIF_SYSCALL_TRACE 8
#define TIF_USED_FPU 16
#define TIF_POLLING_NRFLAG 17
#define TIF_MEMDIE 18
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
#define _TIF_USED_FPU (1 << TIF_USED_FPU)
#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
/*
* Change these and you break ASM code in entry-common.S
*/
#define _TIF_WORK_MASK 0x000000ff
#endif /* __KERNEL__ */
#endif /* __ASM_ARM_THREAD_INFO_H */