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 <asm/core.h>
14
15#include <linux/compiler.h>
16#include <linux/stringify.h>
17#include <asm/ptrace.h>
18#include <asm/types.h>
19#include <asm/regs.h>
20
21#define ARCH_SLAB_MINALIGN XTENSA_STACK_ALIGNMENT
22
23/*
24 * User space process size: 1 GB.
25 * Windowed call ABI requires caller and callee to be located within the same
26 * 1 GB region. The C compiler places trampoline code on the stack for sources
27 * that take the address of a nested C function (a feature used by glibc), so
28 * the 1 GB requirement applies to the stack as well.
29 */
30
31#ifdef CONFIG_MMU
32#define TASK_SIZE __XTENSA_UL_CONST(0x40000000)
33#else
34#define TASK_SIZE __XTENSA_UL_CONST(0xffffffff)
35#endif
36
37#define STACK_TOP TASK_SIZE
38#define STACK_TOP_MAX STACK_TOP
39
40/*
41 * General exception cause assigned to fake NMI. Fake NMI needs to be handled
42 * differently from other interrupts, but it uses common kernel entry/exit
43 * code.
44 */
45
46#define EXCCAUSE_MAPPED_NMI 62
47
48/*
49 * General exception cause assigned to debug exceptions. Debug exceptions go
50 * to their own vector, rather than the general exception vectors (user,
51 * kernel, double); and their specific causes are reported via DEBUGCAUSE
52 * rather than EXCCAUSE. However it is sometimes convenient to redirect debug
53 * exceptions to the general exception mechanism. To do this, an otherwise
54 * unused EXCCAUSE value was assigned to debug exceptions for this purpose.
55 */
56
57#define EXCCAUSE_MAPPED_DEBUG 63
58
59/*
60 * We use DEPC also as a flag to distinguish between double and regular
61 * exceptions. For performance reasons, DEPC might contain the value of
62 * EXCCAUSE for regular exceptions, so we use this definition to mark a
63 * valid double exception address.
64 * (Note: We use it in bgeui, so it should be 64, 128, or 256)
65 */
66
67#define VALID_DOUBLE_EXCEPTION_ADDRESS 64
68
69#define XTENSA_INT_LEVEL(intno) _XTENSA_INT_LEVEL(intno)
70#define _XTENSA_INT_LEVEL(intno) XCHAL_INT##intno##_LEVEL
71
72#define XTENSA_INTLEVEL_MASK(level) _XTENSA_INTLEVEL_MASK(level)
73#define _XTENSA_INTLEVEL_MASK(level) (XCHAL_INTLEVEL##level##_MASK)
74
75#define XTENSA_INTLEVEL_ANDBELOW_MASK(l) _XTENSA_INTLEVEL_ANDBELOW_MASK(l)
76#define _XTENSA_INTLEVEL_ANDBELOW_MASK(l) (XCHAL_INTLEVEL##l##_ANDBELOW_MASK)
77
78#define PROFILING_INTLEVEL XTENSA_INT_LEVEL(XCHAL_PROFILING_INTERRUPT)
79
80/* LOCKLEVEL defines the interrupt level that masks all
81 * general-purpose interrupts.
82 */
83#if defined(CONFIG_XTENSA_FAKE_NMI) && defined(XCHAL_PROFILING_INTERRUPT)
84#define LOCKLEVEL (PROFILING_INTLEVEL - 1)
85#else
86#define LOCKLEVEL XCHAL_EXCM_LEVEL
87#endif
88
89#define TOPLEVEL XCHAL_EXCM_LEVEL
90#define XTENSA_FAKE_NMI (LOCKLEVEL < TOPLEVEL)
91
92/* WSBITS and WBBITS are the width of the WINDOWSTART and WINDOWBASE
93 * registers
94 */
95#define WSBITS (XCHAL_NUM_AREGS / 4) /* width of WINDOWSTART in bits */
96#define WBBITS (XCHAL_NUM_AREGS_LOG2 - 2) /* width of WINDOWBASE in bits */
97
98#if defined(__XTENSA_WINDOWED_ABI__)
99#define KERNEL_PS_WOE_MASK PS_WOE_MASK
100#elif defined(__XTENSA_CALL0_ABI__)
101#define KERNEL_PS_WOE_MASK 0
102#else
103#error Unsupported xtensa ABI
104#endif
105
106#ifndef __ASSEMBLY__
107
108#if defined(__XTENSA_WINDOWED_ABI__)
109
110/* Build a valid return address for the specified call winsize.
111 * winsize must be 1 (call4), 2 (call8), or 3 (call12)
112 */
113#define MAKE_RA_FOR_CALL(ra,ws) (((ra) & 0x3fffffff) | (ws) << 30)
114
115/* Convert return address to a valid pc
116 * Note: We assume that the stack pointer is in the same 1GB ranges as the ra
117 */
118#define MAKE_PC_FROM_RA(ra,sp) (((ra) & 0x3fffffff) | ((sp) & 0xc0000000))
119
120#elif defined(__XTENSA_CALL0_ABI__)
121
122/* Build a valid return address for the specified call winsize.
123 * winsize must be 1 (call4), 2 (call8), or 3 (call12)
124 */
125#define MAKE_RA_FOR_CALL(ra, ws) (ra)
126
127/* Convert return address to a valid pc
128 * Note: We assume that the stack pointer is in the same 1GB ranges as the ra
129 */
130#define MAKE_PC_FROM_RA(ra, sp) (ra)
131
132#else
133#error Unsupported Xtensa ABI
134#endif
135
136/* Spill slot location for the register reg in the spill area under the stack
137 * pointer sp. reg must be in the range [0..4).
138 */
139#define SPILL_SLOT(sp, reg) (*(((unsigned long *)(sp)) - 4 + (reg)))
140
141/* Spill slot location for the register reg in the spill area under the stack
142 * pointer sp for the call8. reg must be in the range [4..8).
143 */
144#define SPILL_SLOT_CALL8(sp, reg) (*(((unsigned long *)(sp)) - 12 + (reg)))
145
146/* Spill slot location for the register reg in the spill area under the stack
147 * pointer sp for the call12. reg must be in the range [4..12).
148 */
149#define SPILL_SLOT_CALL12(sp, reg) (*(((unsigned long *)(sp)) - 16 + (reg)))
150
151struct thread_struct {
152
153 /* kernel's return address and stack pointer for context switching */
154 unsigned long ra; /* kernel's a0: return address and window call size */
155 unsigned long sp; /* kernel's a1: stack pointer */
156
157#ifdef CONFIG_HAVE_HW_BREAKPOINT
158 struct perf_event *ptrace_bp[XCHAL_NUM_IBREAK];
159 struct perf_event *ptrace_wp[XCHAL_NUM_DBREAK];
160#endif
161 /* Make structure 16 bytes aligned. */
162 int align[0] __attribute__ ((aligned(16)));
163};
164
165/* This decides where the kernel will search for a free chunk of vm
166 * space during mmap's.
167 */
168#define TASK_UNMAPPED_BASE (TASK_SIZE / 2)
169
170#define INIT_THREAD \
171{ \
172 ra: 0, \
173 sp: sizeof(init_stack) + (long) &init_stack, \
174}
175
176
177/*
178 * Do necessary setup to start up a newly executed thread.
179 * Note: When windowed ABI is used for userspace we set-up ps
180 * as if we did a call4 to the new pc.
181 * set_thread_state in signal.c depends on it.
182 */
183#if IS_ENABLED(CONFIG_USER_ABI_CALL0)
184#define USER_PS_VALUE ((USER_RING << PS_RING_SHIFT) | \
185 (1 << PS_UM_BIT) | \
186 (1 << PS_EXCM_BIT))
187#else
188#define USER_PS_VALUE (PS_WOE_MASK | \
189 (1 << PS_CALLINC_SHIFT) | \
190 (USER_RING << PS_RING_SHIFT) | \
191 (1 << PS_UM_BIT) | \
192 (1 << PS_EXCM_BIT))
193#endif
194
195/* Clearing a0 terminates the backtrace. */
196#define start_thread(regs, new_pc, new_sp) \
197 do { \
198 unsigned long syscall = (regs)->syscall; \
199 unsigned long current_aregs[16]; \
200 memcpy(current_aregs, (regs)->areg, sizeof(current_aregs)); \
201 memset((regs), 0, sizeof(*(regs))); \
202 (regs)->pc = (new_pc); \
203 (regs)->ps = USER_PS_VALUE; \
204 memcpy((regs)->areg, current_aregs, sizeof(current_aregs)); \
205 (regs)->areg[1] = (new_sp); \
206 (regs)->areg[0] = 0; \
207 (regs)->wmask = 1; \
208 (regs)->depc = 0; \
209 (regs)->windowbase = 0; \
210 (regs)->windowstart = 1; \
211 (regs)->syscall = syscall; \
212 } while (0)
213
214/* Forward declaration */
215struct task_struct;
216struct mm_struct;
217
218extern unsigned long __get_wchan(struct task_struct *p);
219
220#define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc)
221#define KSTK_ESP(tsk) (task_pt_regs(tsk)->areg[1])
222
223#define cpu_relax() barrier()
224
225/* Special register access. */
226
227#define xtensa_set_sr(x, sr) \
228 ({ \
229 __asm__ __volatile__ ("wsr %0, "__stringify(sr) :: \
230 "a"((unsigned int)(x))); \
231 })
232
233#define xtensa_get_sr(sr) \
234 ({ \
235 unsigned int v; \
236 __asm__ __volatile__ ("rsr %0, "__stringify(sr) : "=a"(v)); \
237 v; \
238 })
239
240#define xtensa_xsr(x, sr) \
241 ({ \
242 unsigned int __v__ = (unsigned int)(x); \
243 __asm__ __volatile__ ("xsr %0, " __stringify(sr) : "+a"(__v__)); \
244 __v__; \
245 })
246
247#if XCHAL_HAVE_EXTERN_REGS
248
249static inline void set_er(unsigned long value, unsigned long addr)
250{
251 asm volatile ("wer %0, %1" : : "a" (value), "a" (addr) : "memory");
252}
253
254static inline unsigned long get_er(unsigned long addr)
255{
256 register unsigned long value;
257 asm volatile ("rer %0, %1" : "=a" (value) : "a" (addr) : "memory");
258 return value;
259}
260
261#endif /* XCHAL_HAVE_EXTERN_REGS */
262
263#endif /* __ASSEMBLY__ */
264#endif /* _XTENSA_PROCESSOR_H */