kernel-ark/include/asm-xtensa/thread_info.h
Chris Zankel c658eac628 [XTENSA] Add support for configurable registers and coprocessors
The Xtensa architecture allows to define custom instructions and
registers. Registers that are bound to a coprocessor are only
accessible if the corresponding enable bit is set, which allows
to implement a 'lazy' context switch mechanism. Other registers
needs to be saved and restore at the time of the context switch
or during interrupt handling.

This patch adds support for these additional states:

- save and restore registers that are used by the compiler upon
  interrupt entry and exit.
- context switch additional registers unbound to any coprocessor
- 'lazy' context switch of registers bound to a coprocessor
- ptrace interface to provide access to additional registers
- update configuration files in include/asm-xtensa/variant-fsf

Signed-off-by: Chris Zankel <chris@zankel.net>
2008-02-13 17:41:43 -08:00

166 lines
4.5 KiB
C

/*
* include/asm-xtensa/thread_info.h
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2001 - 2005 Tensilica Inc.
*/
#ifndef _XTENSA_THREAD_INFO_H
#define _XTENSA_THREAD_INFO_H
#ifdef __KERNEL__
#ifndef __ASSEMBLY__
# include <asm/processor.h>
#endif
/*
* low level task data that entry.S needs immediate access to
* - this struct should fit entirely inside of one cache line
* - this struct shares the supervisor stack pages
* - if the contents of this structure are changed, the assembly constants
* must also be changed
*/
#ifndef __ASSEMBLY__
#if XTENSA_HAVE_COPROCESSORS
typedef struct xtregs_coprocessor {
xtregs_cp0_t cp0;
xtregs_cp1_t cp1;
xtregs_cp2_t cp2;
xtregs_cp3_t cp3;
xtregs_cp4_t cp4;
xtregs_cp5_t cp5;
xtregs_cp6_t cp6;
xtregs_cp7_t cp7;
} xtregs_coprocessor_t;
#endif
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 cpu; /* current CPU */
__s32 preempt_count; /* 0 => preemptable,< 0 => BUG*/
mm_segment_t addr_limit; /* thread address space */
struct restart_block restart_block;
unsigned long cpenable;
/* Allocate storage for extra user states and coprocessor states. */
#if XTENSA_HAVE_COPROCESSORS
xtregs_coprocessor_t xtregs_cp;
#endif
xtregs_user_t xtregs_user;
};
#else /* !__ASSEMBLY__ */
/* offsets into the thread_info struct for assembly code access */
#define TI_TASK 0x00000000
#define TI_EXEC_DOMAIN 0x00000004
#define TI_FLAGS 0x00000008
#define TI_STATUS 0x0000000C
#define TI_CPU 0x00000010
#define TI_PRE_COUNT 0x00000014
#define TI_ADDR_LIMIT 0x00000018
#define TI_RESTART_BLOCK 0x000001C
#endif
#define PREEMPT_ACTIVE 0x10000000
/*
* macros/functions for gaining access to the thread information structure
*
* preempt_count needs to be 1 initially, until the scheduler is functional.
*/
#ifndef __ASSEMBLY__
#define INIT_THREAD_INFO(tsk) \
{ \
.task = &tsk, \
.exec_domain = &default_exec_domain, \
.flags = 0, \
.cpu = 0, \
.preempt_count = 1, \
.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)
{
struct thread_info *ti;
__asm__("extui %0,a1,0,13\n\t"
"xor %0, a1, %0" : "=&r" (ti) : );
return ti;
}
/* thread information allocation */
#define alloc_thread_info(tsk) ((struct thread_info *) __get_free_pages(GFP_KERNEL,1))
#define free_thread_info(ti) free_pages((unsigned long) (ti), 1)
#else /* !__ASSEMBLY__ */
/* how to get the thread information struct from ASM */
#define GET_THREAD_INFO(reg,sp) \
extui reg, sp, 0, 13; \
xor reg, sp, reg
#endif
/*
* thread information flags
* - these are process state flags that various assembly files may need to access
* - pending work-to-be-done flags are in LSW
* - other flags in MSW
*/
#define TIF_SYSCALL_TRACE 0 /* syscall trace active */
#define TIF_SIGPENDING 1 /* signal pending */
#define TIF_NEED_RESCHED 2 /* rescheduling necessary */
#define TIF_SINGLESTEP 3 /* restore singlestep on return to user mode */
#define TIF_IRET 4 /* return with iret */
#define TIF_MEMDIE 5
#define TIF_RESTORE_SIGMASK 6 /* restore signal mask in do_signal() */
#define TIF_POLLING_NRFLAG 16 /* true if poll_idle() is polling TIF_NEED_RESCHED */
#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
#define _TIF_SINGLESTEP (1<<TIF_SINGLESTEP)
#define _TIF_IRET (1<<TIF_IRET)
#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
#define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
#define _TIF_WORK_MASK 0x0000FFFE /* work to do on interrupt/exception return */
#define _TIF_ALLWORK_MASK 0x0000FFFF /* work to do on any return to u-space */
/*
* 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.
*/
#define TS_USEDFPU 0x0001 /* FPU was used by this task this quantum (SMP) */
#define THREAD_SIZE 8192 //(2*PAGE_SIZE)
#endif /* __KERNEL__ */
#endif /* _XTENSA_THREAD_INFO */