linux/include/asm-xtensa/ptrace.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

135 lines
3.9 KiB
C

/*
* include/asm-xtensa/ptrace.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_PTRACE_H
#define _XTENSA_PTRACE_H
/*
* Kernel stack
*
* +-----------------------+ -------- STACK_SIZE
* | register file | |
* +-----------------------+ |
* | struct pt_regs | |
* +-----------------------+ | ------ PT_REGS_OFFSET
* double : 16 bytes spill area : | ^
* excetion :- - - - - - - - - - - -: | |
* frame : struct pt_regs : | |
* :- - - - - - - - - - - -: | |
* | | | |
* | memory stack | | |
* | | | |
* ~ ~ ~ ~
* ~ ~ ~ ~
* | | | |
* | | | |
* +-----------------------+ | | --- STACK_BIAS
* | struct task_struct | | | ^
* current --> +-----------------------+ | | |
* | struct thread_info | | | |
* +-----------------------+ --------
*/
#define KERNEL_STACK_SIZE (2 * PAGE_SIZE)
/* Offsets for exception_handlers[] (3 x 64-entries x 4-byte tables). */
#define EXC_TABLE_KSTK 0x004 /* Kernel Stack */
#define EXC_TABLE_DOUBLE_SAVE 0x008 /* Double exception save area for a0 */
#define EXC_TABLE_FIXUP 0x00c /* Fixup handler */
#define EXC_TABLE_PARAM 0x010 /* For passing a parameter to fixup */
#define EXC_TABLE_SYSCALL_SAVE 0x014 /* For fast syscall handler */
#define EXC_TABLE_FAST_USER 0x100 /* Fast user exception handler */
#define EXC_TABLE_FAST_KERNEL 0x200 /* Fast kernel exception handler */
#define EXC_TABLE_DEFAULT 0x300 /* Default C-Handler */
#define EXC_TABLE_SIZE 0x400
/* Registers used by strace */
#define REG_A_BASE 0x0000
#define REG_AR_BASE 0x0100
#define REG_PC 0x0020
#define REG_PS 0x02e6
#define REG_WB 0x0248
#define REG_WS 0x0249
#define REG_LBEG 0x0200
#define REG_LEND 0x0201
#define REG_LCOUNT 0x0202
#define REG_SAR 0x0203
#define SYSCALL_NR 0x00ff
/* Other PTRACE_ values defined in <linux/ptrace.h> using values 0-9,16,17,24 */
#define PTRACE_GETREGS 12
#define PTRACE_SETREGS 13
#define PTRACE_GETXTREGS 18
#define PTRACE_SETXTREGS 19
#ifndef __ASSEMBLY__
#ifdef __KERNEL__
/*
* This struct defines the way the registers are stored on the
* kernel stack during a system call or other kernel entry.
*/
struct pt_regs {
unsigned long pc; /* 4 */
unsigned long ps; /* 8 */
unsigned long depc; /* 12 */
unsigned long exccause; /* 16 */
unsigned long excvaddr; /* 20 */
unsigned long debugcause; /* 24 */
unsigned long wmask; /* 28 */
unsigned long lbeg; /* 32 */
unsigned long lend; /* 36 */
unsigned long lcount; /* 40 */
unsigned long sar; /* 44 */
unsigned long windowbase; /* 48 */
unsigned long windowstart; /* 52 */
unsigned long syscall; /* 56 */
unsigned long icountlevel; /* 60 */
int reserved[1]; /* 64 */
/* Additional configurable registers that are used by the compiler. */
xtregs_opt_t xtregs_opt;
/* Make sure the areg field is 16 bytes aligned. */
int align[0] __attribute__ ((aligned(16)));
/* current register frame.
* Note: The ESF for kernel exceptions ends after 16 registers!
*/
unsigned long areg[16]; /* 128 (64) */
};
#include <asm/variant/core.h>
# define task_pt_regs(tsk) ((struct pt_regs*) \
(task_stack_page(tsk) + KERNEL_STACK_SIZE - (XCHAL_NUM_AREGS-16)*4) - 1)
# define user_mode(regs) (((regs)->ps & 0x00000020)!=0)
# define instruction_pointer(regs) ((regs)->pc)
extern void show_regs(struct pt_regs *);
# ifndef CONFIG_SMP
# define profile_pc(regs) instruction_pointer(regs)
# endif
#endif /* __KERNEL__ */
#else /* __ASSEMBLY__ */
#ifdef __KERNEL__
# include <asm/asm-offsets.h>
#define PT_REGS_OFFSET (KERNEL_STACK_SIZE - PT_USER_SIZE)
#endif
#endif /* !__ASSEMBLY__ */
#endif /* _XTENSA_PTRACE_H */