Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * include/asm-xtensa/processor.h
3 *
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License. See the file "COPYING" in the main directory of this archive
6 * for more details.
7 *
8 * Copyright (C) 2001 - 2005 Tensilica Inc.
9 */
10
11#ifndef _XTENSA_PROCESSOR_H
12#define _XTENSA_PROCESSOR_H
13
14#ifdef __ASSEMBLY__
15#define _ASMLANGUAGE
16#endif
17
18#include <xtensa/config/core.h>
19#include <xtensa/config/specreg.h>
20#include <xtensa/config/tie.h>
21#include <xtensa/config/system.h>
22
23#include <linux/compiler.h>
24#include <asm/ptrace.h>
25#include <asm/types.h>
26#include <asm/coprocessor.h>
27
28/* Assertions. */
29
30#if (XCHAL_HAVE_WINDOWED != 1)
31#error Linux requires the Xtensa Windowed Registers Option.
32#endif
33
34/*
35 * User space process size: 1 GB.
36 * Windowed call ABI requires caller and callee to be located within the same
37 * 1 GB region. The C compiler places trampoline code on the stack for sources
38 * that take the address of a nested C function (a feature used by glibc), so
39 * the 1 GB requirement applies to the stack as well.
40 */
41
42#define TASK_SIZE 0x40000000
43
44/*
45 * General exception cause assigned to debug exceptions. Debug exceptions go
46 * to their own vector, rather than the general exception vectors (user,
47 * kernel, double); and their specific causes are reported via DEBUGCAUSE
48 * rather than EXCCAUSE. However it is sometimes convenient to redirect debug
49 * exceptions to the general exception mechanism. To do this, an otherwise
50 * unused EXCCAUSE value was assigned to debug exceptions for this purpose.
51 */
52
53#define EXCCAUSE_MAPPED_DEBUG 63
54
55/*
56 * We use DEPC also as a flag to distinguish between double and regular
57 * exceptions. For performance reasons, DEPC might contain the value of
58 * EXCCAUSE for regular exceptions, so we use this definition to mark a
59 * valid double exception address.
60 * (Note: We use it in bgeui, so it should be 64, 128, or 256)
61 */
62
63#define VALID_DOUBLE_EXCEPTION_ADDRESS 64
64
65/* LOCKLEVEL defines the interrupt level that masks all
66 * general-purpose interrupts.
67 */
68#define LOCKLEVEL 1
69
70/* WSBITS and WBBITS are the width of the WINDOWSTART and WINDOWBASE
71 * registers
72 */
73#define WSBITS (XCHAL_NUM_AREGS / 4) /* width of WINDOWSTART in bits */
74#define WBBITS (XCHAL_NUM_AREGS_LOG2 - 2) /* width of WINDOWBASE in bits */
75
76#ifndef __ASSEMBLY__
77
78/* Build a valid return address for the specified call winsize.
79 * winsize must be 1 (call4), 2 (call8), or 3 (call12)
80 */
81#define MAKE_RA_FOR_CALL(ra,ws) (((ra) & 0x3fffffff) | (ws) << 30)
82
83/* Convert return address to a valid pc
84 * Note: We assume that the stack pointer is in the same 1GB ranges as the ra
85 */
86#define MAKE_PC_FROM_RA(ra,sp) (((ra) & 0x3fffffff) | ((sp) & 0xc0000000))
87
88typedef struct {
89 unsigned long seg;
90} mm_segment_t;
91
92struct thread_struct {
93
94 /* kernel's return address and stack pointer for context switching */
95 unsigned long ra; /* kernel's a0: return address and window call size */
96 unsigned long sp; /* kernel's a1: stack pointer */
97
98 mm_segment_t current_ds; /* see uaccess.h for example uses */
99
100 /* struct xtensa_cpuinfo info; */
101
102 unsigned long bad_vaddr; /* last user fault */
103 unsigned long bad_uaddr; /* last kernel fault accessing user space */
104 unsigned long error_code;
105
106 unsigned long ibreak[XCHAL_NUM_IBREAK];
107 unsigned long dbreaka[XCHAL_NUM_DBREAK];
108 unsigned long dbreakc[XCHAL_NUM_DBREAK];
109
110 /* Allocate storage for extra state and coprocessor state. */
111 unsigned char cp_save[XTENSA_CP_EXTRA_SIZE]
112 __attribute__ ((aligned(XTENSA_CP_EXTRA_ALIGN)));
113
114 /* Make structure 16 bytes aligned. */
115 int align[0] __attribute__ ((aligned(16)));
116};
117
118
119/*
120 * Default implementation of macro that returns current
121 * instruction pointer ("program counter").
122 */
123#define current_text_addr() ({ __label__ _l; _l: &&_l;})
124
125
126/* This decides where the kernel will search for a free chunk of vm
127 * space during mmap's.
128 */
129#define TASK_UNMAPPED_BASE (TASK_SIZE / 2)
130
131#define INIT_THREAD \
132{ \
133 ra: 0, \
134 sp: sizeof(init_stack) + (long) &init_stack, \
135 current_ds: {0}, \
136 /*info: {0}, */ \
137 bad_vaddr: 0, \
138 bad_uaddr: 0, \
139 error_code: 0, \
140}
141
142
143/*
144 * Do necessary setup to start up a newly executed thread.
145 * Note: We set-up ps as if we did a call4 to the new pc.
146 * set_thread_state in signal.c depends on it.
147 */
148#define USER_PS_VALUE ( (1 << XCHAL_PS_WOE_SHIFT) + \
149 (1 << XCHAL_PS_CALLINC_SHIFT) + \
150 (USER_RING << XCHAL_PS_RING_SHIFT) + \
151 (1 << XCHAL_PS_PROGSTACK_SHIFT) + \
152 (1 << XCHAL_PS_EXCM_SHIFT) )
153
154/* Clearing a0 terminates the backtrace. */
155#define start_thread(regs, new_pc, new_sp) \
156 regs->pc = new_pc; \
157 regs->ps = USER_PS_VALUE; \
158 regs->areg[1] = new_sp; \
159 regs->areg[0] = 0; \
160 regs->wmask = 1; \
161 regs->depc = 0; \
162 regs->windowbase = 0; \
163 regs->windowstart = 1;
164
165/* Forward declaration */
166struct task_struct;
167struct mm_struct;
168
169// FIXME: do we need release_thread for CP??
170/* Free all resources held by a thread. */
171#define release_thread(thread) do { } while(0)
172
173// FIXME: do we need prepare_to_copy (lazy status) for CP??
174/* Prepare to copy thread state - unlazy all lazy status */
175#define prepare_to_copy(tsk) do { } while (0)
176
177/*
178 * create a kernel thread without removing it from tasklists
179 */
180extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
181
182/* Copy and release all segment info associated with a VM */
183
184#define copy_segments(p, mm) do { } while(0)
185#define release_segments(mm) do { } while(0)
186#define forget_segments() do { } while (0)
187
188#define thread_saved_pc(tsk) (task_pt_regs(tsk)->pc)
189
190extern unsigned long get_wchan(struct task_struct *p);
191
192#define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc)
193#define KSTK_ESP(tsk) (task_pt_regs(tsk)->areg[1])
194
195#define cpu_relax() barrier()
196
197/* Special register access. */
198
199#define WSR(v,sr) __asm__ __volatile__ ("wsr %0,"__stringify(sr) :: "a"(v));
200#define RSR(v,sr) __asm__ __volatile__ ("rsr %0,"__stringify(sr) : "=a"(v));
201
202#define set_sr(x,sr) ({unsigned int v=(unsigned int)x; WSR(v,sr);})
203#define get_sr(sr) ({unsigned int v; RSR(v,sr); v; })
204
205#endif /* __ASSEMBLY__ */
206#endif /* _XTENSA_PROCESSOR_H */