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linux/arch/tile/include/asm/thread_info.h
Chris Metcalf 76c567fbba arch/tile: support 4KB page size as well as 64KB 
The Tilera architecture traditionally supports 64KB page sizes
to improve TLB utilization and improve performance when the
hardware is being used primarily to run a single application.

For more generic server scenarios, it can be beneficial to run
with 4KB page sizes, so this commit allows that to be specified
(by modifying the arch/tile/include/hv/pagesize.h header).

As part of this change, we also re-worked the PTE management
slightly so that PTE writes all go through a __set_pte() function
where we can do some additional validation.  The set_pte_order()
function was eliminated since the "order" argument wasn't being used.

One bug uncovered was in the PCI DMA code, which wasn't properly
flushing the specified range.  This was benign with 64KB pages,
but with 4KB pages we were getting some larger flushes wrong.

The per-cpu memory reservation code also needed updating to
conform with the newer percpu stuff; before it always chose 64KB,
and that was always correct, but with 4KB granularity we now have
to pay closer attention and reserve the amount of memory that will
be requested when the percpu code starts allocating.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-10 13:17:53 -05:00

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/*
* Copyright (C) 2002 David Howells (dhowells@redhat.com)
* Copyright 2010 Tilera Corporation. All Rights Reserved.
*
* 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, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#ifndef _ASM_TILE_THREAD_INFO_H
#define _ASM_TILE_THREAD_INFO_H
#include <asm/processor.h>
#include <asm/page.h>
#ifndef __ASSEMBLY__
/*
* Low level task data that assembly code needs immediate access to.
* The structure is placed at the bottom of the supervisor stack.
*/
struct thread_info {
struct task_struct *task; /* main task structure */
struct exec_domain *exec_domain; /* execution domain */
unsigned long flags; /* low level flags */
unsigned long status; /* thread-synchronous flags */
__u32 homecache_cpu; /* CPU we are homecached on */
__u32 cpu; /* current CPU */
int preempt_count; /* 0 => preemptable,
<0 => BUG */
mm_segment_t addr_limit; /* thread address space
(KERNEL_DS or USER_DS) */
struct restart_block restart_block;
struct single_step_state *step_state; /* single step state
(if non-zero) */
};
/*
* macros/functions for gaining access to the thread information structure.
*/
#define INIT_THREAD_INFO(tsk) \
{ \
.task = &tsk, \
.exec_domain = &default_exec_domain, \
.flags = 0, \
.cpu = 0, \
.preempt_count = INIT_PREEMPT_COUNT, \
.addr_limit = KERNEL_DS, \
.restart_block = { \
.fn = do_no_restart_syscall, \
}, \
.step_state = NULL, \
}
#define init_thread_info (init_thread_union.thread_info)
#define init_stack (init_thread_union.stack)
#endif /* !__ASSEMBLY__ */
#if PAGE_SIZE < 8192
#define THREAD_SIZE_ORDER (13 - PAGE_SHIFT)
#else
#define THREAD_SIZE_ORDER (0)
#endif
#define THREAD_SIZE_PAGES (1 << THREAD_SIZE_ORDER)
#define THREAD_SIZE (PAGE_SIZE << THREAD_SIZE_ORDER)
#define LOG2_THREAD_SIZE (PAGE_SHIFT + THREAD_SIZE_ORDER)
#define STACK_WARN (THREAD_SIZE/8)
#ifndef __ASSEMBLY__
/* How to get the thread information struct from C. */
register unsigned long stack_pointer __asm__("sp");
#define current_thread_info() \
((struct thread_info *)(stack_pointer & -THREAD_SIZE))
#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
extern struct thread_info *alloc_thread_info(struct task_struct *task);
extern void free_thread_info(struct thread_info *info);
/* Sit on a nap instruction until interrupted. */
extern void smp_nap(void);
/* Enable interrupts racelessly and nap forever: helper for cpu_idle(). */
extern void _cpu_idle(void);
/* Switch boot idle thread to a freshly-allocated stack and free old stack. */
extern void cpu_idle_on_new_stack(struct thread_info *old_ti,
unsigned long new_sp,
unsigned long new_ss10);
#else /* __ASSEMBLY__ */
/* how to get the thread information struct from ASM */
#ifdef __tilegx__
#define GET_THREAD_INFO(reg) move reg, sp; mm reg, zero, LOG2_THREAD_SIZE, 63
#else
#define GET_THREAD_INFO(reg) mm reg, sp, zero, LOG2_THREAD_SIZE, 31
#endif
#endif /* !__ASSEMBLY__ */
#define PREEMPT_ACTIVE 0x10000000
/*
* Thread information flags that various assembly files may need to access.
* Keep flags accessed frequently in low bits, particular since it makes
* it easier to build constants in assembly.
*/
#define TIF_SIGPENDING 0 /* signal pending */
#define TIF_NEED_RESCHED 1 /* rescheduling necessary */
#define TIF_SINGLESTEP 2 /* restore singlestep on return to
user mode */
#define TIF_ASYNC_TLB 3 /* got an async TLB fault in kernel */
#define TIF_SYSCALL_TRACE 4 /* syscall trace active */
#define TIF_SYSCALL_AUDIT 5 /* syscall auditing active */
#define TIF_SECCOMP 6 /* secure computing */
#define TIF_MEMDIE 7 /* OOM killer at work */
#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
#define _TIF_SINGLESTEP (1<<TIF_SINGLESTEP)
#define _TIF_ASYNC_TLB (1<<TIF_ASYNC_TLB)
#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
#define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
#define _TIF_SECCOMP (1<<TIF_SECCOMP)
#define _TIF_MEMDIE (1<<TIF_MEMDIE)
/* Work to do on any return to user space. */
#define _TIF_ALLWORK_MASK \
(_TIF_SIGPENDING|_TIF_NEED_RESCHED|_TIF_SINGLESTEP|_TIF_ASYNC_TLB)
/*
* Thread-synchronous status.
*
* This is different from the flags in that nobody else
* ever touches our thread-synchronous status, so we don't
* have to worry about atomic accesses.
*/
#ifdef __tilegx__
#define TS_COMPAT 0x0001 /* 32-bit compatibility mode */
#endif
#define TS_POLLING 0x0004 /* in idle loop but not sleeping */
#define TS_RESTORE_SIGMASK 0x0008 /* restore signal mask in do_signal */
#define tsk_is_polling(t) (task_thread_info(t)->status & TS_POLLING)
#ifndef __ASSEMBLY__
#define HAVE_SET_RESTORE_SIGMASK 1
static inline void set_restore_sigmask(void)
{
struct thread_info *ti = current_thread_info();
ti->status |= TS_RESTORE_SIGMASK;
set_bit(TIF_SIGPENDING, &ti->flags);
}
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_TILE_THREAD_INFO_H */
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