Linux kernel mirror (for testing)
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linux
1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 2001 - 2008 Tensilica Inc.
7 * Copyright (C) 2015 Cadence Design Systems Inc.
8 */
9
10#ifndef _XTENSA_PROCESSOR_H
11#define _XTENSA_PROCESSOR_H
12
13#include <variant/core.h>
14#include <platform/hardware.h>
15
16#include <linux/compiler.h>
17#include <asm/ptrace.h>
18#include <asm/types.h>
19#include <asm/regs.h>
20
21/* Assertions. */
22
23#if (XCHAL_HAVE_WINDOWED != 1)
24# error Linux requires the Xtensa Windowed Registers Option.
25#endif
26
27#define ARCH_SLAB_MINALIGN XCHAL_DATA_WIDTH
28
29/*
30 * User space process size: 1 GB.
31 * Windowed call ABI requires caller and callee to be located within the same
32 * 1 GB region. The C compiler places trampoline code on the stack for sources
33 * that take the address of a nested C function (a feature used by glibc), so
34 * the 1 GB requirement applies to the stack as well.
35 */
36
37#ifdef CONFIG_MMU
38#define TASK_SIZE __XTENSA_UL_CONST(0x40000000)
39#else
40#define TASK_SIZE __XTENSA_UL_CONST(0xffffffff)
41#endif
42
43#define STACK_TOP TASK_SIZE
44#define STACK_TOP_MAX STACK_TOP
45
46/*
47 * General exception cause assigned to fake NMI. Fake NMI needs to be handled
48 * differently from other interrupts, but it uses common kernel entry/exit
49 * code.
50 */
51
52#define EXCCAUSE_MAPPED_NMI 62
53
54/*
55 * General exception cause assigned to debug exceptions. Debug exceptions go
56 * to their own vector, rather than the general exception vectors (user,
57 * kernel, double); and their specific causes are reported via DEBUGCAUSE
58 * rather than EXCCAUSE. However it is sometimes convenient to redirect debug
59 * exceptions to the general exception mechanism. To do this, an otherwise
60 * unused EXCCAUSE value was assigned to debug exceptions for this purpose.
61 */
62
63#define EXCCAUSE_MAPPED_DEBUG 63
64
65/*
66 * We use DEPC also as a flag to distinguish between double and regular
67 * exceptions. For performance reasons, DEPC might contain the value of
68 * EXCCAUSE for regular exceptions, so we use this definition to mark a
69 * valid double exception address.
70 * (Note: We use it in bgeui, so it should be 64, 128, or 256)
71 */
72
73#define VALID_DOUBLE_EXCEPTION_ADDRESS 64
74
75#define XTENSA_INT_LEVEL(intno) _XTENSA_INT_LEVEL(intno)
76#define _XTENSA_INT_LEVEL(intno) XCHAL_INT##intno##_LEVEL
77
78#define XTENSA_INTLEVEL_MASK(level) _XTENSA_INTLEVEL_MASK(level)
79#define _XTENSA_INTLEVEL_MASK(level) (XCHAL_INTLEVEL##level##_MASK)
80
81#define XTENSA_INTLEVEL_ANDBELOW_MASK(l) _XTENSA_INTLEVEL_ANDBELOW_MASK(l)
82#define _XTENSA_INTLEVEL_ANDBELOW_MASK(l) (XCHAL_INTLEVEL##l##_ANDBELOW_MASK)
83
84#define PROFILING_INTLEVEL XTENSA_INT_LEVEL(XCHAL_PROFILING_INTERRUPT)
85
86/* LOCKLEVEL defines the interrupt level that masks all
87 * general-purpose interrupts.
88 */
89#if defined(CONFIG_XTENSA_FAKE_NMI) && defined(XCHAL_PROFILING_INTERRUPT)
90#define LOCKLEVEL (PROFILING_INTLEVEL - 1)
91#else
92#define LOCKLEVEL XCHAL_EXCM_LEVEL
93#endif
94
95#define TOPLEVEL XCHAL_EXCM_LEVEL
96#define XTENSA_FAKE_NMI (LOCKLEVEL < TOPLEVEL)
97
98/* WSBITS and WBBITS are the width of the WINDOWSTART and WINDOWBASE
99 * registers
100 */
101#define WSBITS (XCHAL_NUM_AREGS / 4) /* width of WINDOWSTART in bits */
102#define WBBITS (XCHAL_NUM_AREGS_LOG2 - 2) /* width of WINDOWBASE in bits */
103
104#ifndef __ASSEMBLY__
105
106/* Build a valid return address for the specified call winsize.
107 * winsize must be 1 (call4), 2 (call8), or 3 (call12)
108 */
109#define MAKE_RA_FOR_CALL(ra,ws) (((ra) & 0x3fffffff) | (ws) << 30)
110
111/* Convert return address to a valid pc
112 * Note: We assume that the stack pointer is in the same 1GB ranges as the ra
113 */
114#define MAKE_PC_FROM_RA(ra,sp) (((ra) & 0x3fffffff) | ((sp) & 0xc0000000))
115
116typedef struct {
117 unsigned long seg;
118} mm_segment_t;
119
120struct thread_struct {
121
122 /* kernel's return address and stack pointer for context switching */
123 unsigned long ra; /* kernel's a0: return address and window call size */
124 unsigned long sp; /* kernel's a1: stack pointer */
125
126 mm_segment_t current_ds; /* see uaccess.h for example uses */
127
128 /* struct xtensa_cpuinfo info; */
129
130 unsigned long bad_vaddr; /* last user fault */
131 unsigned long bad_uaddr; /* last kernel fault accessing user space */
132 unsigned long error_code;
133#ifdef CONFIG_HAVE_HW_BREAKPOINT
134 struct perf_event *ptrace_bp[XCHAL_NUM_IBREAK];
135 struct perf_event *ptrace_wp[XCHAL_NUM_DBREAK];
136#endif
137 /* Make structure 16 bytes aligned. */
138 int align[0] __attribute__ ((aligned(16)));
139};
140
141
142/*
143 * Default implementation of macro that returns current
144 * instruction pointer ("program counter").
145 */
146#define current_text_addr() ({ __label__ _l; _l: &&_l;})
147
148
149/* This decides where the kernel will search for a free chunk of vm
150 * space during mmap's.
151 */
152#define TASK_UNMAPPED_BASE (TASK_SIZE / 2)
153
154#define INIT_THREAD \
155{ \
156 ra: 0, \
157 sp: sizeof(init_stack) + (long) &init_stack, \
158 current_ds: {0}, \
159 /*info: {0}, */ \
160 bad_vaddr: 0, \
161 bad_uaddr: 0, \
162 error_code: 0, \
163}
164
165
166/*
167 * Do necessary setup to start up a newly executed thread.
168 * Note: We set-up ps as if we did a call4 to the new pc.
169 * set_thread_state in signal.c depends on it.
170 */
171#define USER_PS_VALUE ((1 << PS_WOE_BIT) | \
172 (1 << PS_CALLINC_SHIFT) | \
173 (USER_RING << PS_RING_SHIFT) | \
174 (1 << PS_UM_BIT) | \
175 (1 << PS_EXCM_BIT))
176
177/* Clearing a0 terminates the backtrace. */
178#define start_thread(regs, new_pc, new_sp) \
179 memset(regs, 0, sizeof(*regs)); \
180 regs->pc = new_pc; \
181 regs->ps = USER_PS_VALUE; \
182 regs->areg[1] = new_sp; \
183 regs->areg[0] = 0; \
184 regs->wmask = 1; \
185 regs->depc = 0; \
186 regs->windowbase = 0; \
187 regs->windowstart = 1;
188
189/* Forward declaration */
190struct task_struct;
191struct mm_struct;
192
193/* Free all resources held by a thread. */
194#define release_thread(thread) do { } while(0)
195
196/* Copy and release all segment info associated with a VM */
197#define copy_segments(p, mm) do { } while(0)
198#define release_segments(mm) do { } while(0)
199#define forget_segments() do { } while (0)
200
201#define thread_saved_pc(tsk) (task_pt_regs(tsk)->pc)
202
203extern unsigned long get_wchan(struct task_struct *p);
204
205#define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc)
206#define KSTK_ESP(tsk) (task_pt_regs(tsk)->areg[1])
207
208#define cpu_relax() barrier()
209#define cpu_relax_lowlatency() cpu_relax()
210
211/* Special register access. */
212
213#define WSR(v,sr) __asm__ __volatile__ ("wsr %0,"__stringify(sr) :: "a"(v));
214#define RSR(v,sr) __asm__ __volatile__ ("rsr %0,"__stringify(sr) : "=a"(v));
215
216#define set_sr(x,sr) ({unsigned int v=(unsigned int)x; WSR(v,sr);})
217#define get_sr(sr) ({unsigned int v; RSR(v,sr); v; })
218
219#ifndef XCHAL_HAVE_EXTERN_REGS
220#define XCHAL_HAVE_EXTERN_REGS 0
221#endif
222
223#if XCHAL_HAVE_EXTERN_REGS
224
225static inline void set_er(unsigned long value, unsigned long addr)
226{
227 asm volatile ("wer %0, %1" : : "a" (value), "a" (addr) : "memory");
228}
229
230static inline unsigned long get_er(unsigned long addr)
231{
232 register unsigned long value;
233 asm volatile ("rer %0, %1" : "=a" (value) : "a" (addr) : "memory");
234 return value;
235}
236
237#endif /* XCHAL_HAVE_EXTERN_REGS */
238
239#endif /* __ASSEMBLY__ */
240#endif /* _XTENSA_PROCESSOR_H */