linux/include/asm-xtensa/variant-fsf/tie-asm.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

70 lines
2.5 KiB
C

/*
* This header file contains assembly-language definitions (assembly
* macros, etc.) for this specific Xtensa processor's TIE extensions
* and options. It is customized to this Xtensa processor configuration.
*
* 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) 1999-2008 Tensilica Inc.
*/
#ifndef _XTENSA_CORE_TIE_ASM_H
#define _XTENSA_CORE_TIE_ASM_H
/* Selection parameter values for save-area save/restore macros: */
/* Option vs. TIE: */
#define XTHAL_SAS_TIE 0x0001 /* custom extension or coprocessor */
#define XTHAL_SAS_OPT 0x0002 /* optional (and not a coprocessor) */
/* Whether used automatically by compiler: */
#define XTHAL_SAS_NOCC 0x0004 /* not used by compiler w/o special opts/code */
#define XTHAL_SAS_CC 0x0008 /* used by compiler without special opts/code */
/* ABI handling across function calls: */
#define XTHAL_SAS_CALR 0x0010 /* caller-saved */
#define XTHAL_SAS_CALE 0x0020 /* callee-saved */
#define XTHAL_SAS_GLOB 0x0040 /* global across function calls (in thread) */
/* Misc */
#define XTHAL_SAS_ALL 0xFFFF /* include all default NCP contents */
/* Macro to save all non-coprocessor (extra) custom TIE and optional state
* (not including zero-overhead loop registers).
* Save area ptr (clobbered): ptr (1 byte aligned)
* Scratch regs (clobbered): at1..at4 (only first XCHAL_NCP_NUM_ATMPS needed)
*/
.macro xchal_ncp_store ptr at1 at2 at3 at4 continue=0 ofs=-1 select=XTHAL_SAS_ALL
xchal_sa_start \continue, \ofs
.ifeq (XTHAL_SAS_OPT | XTHAL_SAS_CC | XTHAL_SAS_GLOB) & ~\select
xchal_sa_align \ptr, 0, 1024-4, 4, 4
rur \at1, THREADPTR // threadptr option
s32i \at1, \ptr, .Lxchal_ofs_ + 0
.set .Lxchal_ofs_, .Lxchal_ofs_ + 4
.endif
.endm // xchal_ncp_store
/* Macro to save all non-coprocessor (extra) custom TIE and optional state
* (not including zero-overhead loop registers).
* Save area ptr (clobbered): ptr (1 byte aligned)
* Scratch regs (clobbered): at1..at4 (only first XCHAL_NCP_NUM_ATMPS needed)
*/
.macro xchal_ncp_load ptr at1 at2 at3 at4 continue=0 ofs=-1 select=XTHAL_SAS_ALL
xchal_sa_start \continue, \ofs
.ifeq (XTHAL_SAS_OPT | XTHAL_SAS_CC | XTHAL_SAS_GLOB) & ~\select
xchal_sa_align \ptr, 0, 1024-4, 4, 4
l32i \at1, \ptr, .Lxchal_ofs_ + 0
wur \at1, THREADPTR // threadptr option
.set .Lxchal_ofs_, .Lxchal_ofs_ + 4
.endif
.endm // xchal_ncp_load
#define XCHAL_NCP_NUM_ATMPS 1
#define XCHAL_SA_NUM_ATMPS 1
#endif /*_XTENSA_CORE_TIE_ASM_H*/