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 (PLATFORM_DEFAULT_MEM_START + PLATFORM_DEFAULT_MEM_SIZE) 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 IS_POW2(v) (((v) & ((v) - 1)) == 0) 82 83 #define PROFILING_INTLEVEL XTENSA_INT_LEVEL(XCHAL_PROFILING_INTERRUPT) 84 85 /* LOCKLEVEL defines the interrupt level that masks all 86 * general-purpose interrupts. 87 */ 88 #if defined(CONFIG_XTENSA_VARIANT_HAVE_PERF_EVENTS) && \ 89 defined(XCHAL_PROFILING_INTERRUPT) && \ 90 PROFILING_INTLEVEL == XCHAL_EXCM_LEVEL && \ 91 XCHAL_EXCM_LEVEL > 1 && \ 92 IS_POW2(XTENSA_INTLEVEL_MASK(PROFILING_INTLEVEL)) 93 #define LOCKLEVEL (XCHAL_EXCM_LEVEL - 1) 94 #else 95 #define LOCKLEVEL XCHAL_EXCM_LEVEL 96 #endif 97 #define TOPLEVEL XCHAL_EXCM_LEVEL 98 #define XTENSA_FAKE_NMI (LOCKLEVEL < TOPLEVEL) 99 100 /* WSBITS and WBBITS are the width of the WINDOWSTART and WINDOWBASE 101 * registers 102 */ 103 #define WSBITS (XCHAL_NUM_AREGS / 4) /* width of WINDOWSTART in bits */ 104 #define WBBITS (XCHAL_NUM_AREGS_LOG2 - 2) /* width of WINDOWBASE in bits */ 105 106 #ifndef __ASSEMBLY__ 107 108 /* Build a valid return address for the specified call winsize. 109 * winsize must be 1 (call4), 2 (call8), or 3 (call12) 110 */ 111 #define MAKE_RA_FOR_CALL(ra,ws) (((ra) & 0x3fffffff) | (ws) << 30) 112 113 /* Convert return address to a valid pc 114 * Note: We assume that the stack pointer is in the same 1GB ranges as the ra 115 */ 116 #define MAKE_PC_FROM_RA(ra,sp) (((ra) & 0x3fffffff) | ((sp) & 0xc0000000)) 117 118 typedef struct { 119 unsigned long seg; 120 } mm_segment_t; 121 122 struct thread_struct { 123 124 /* kernel's return address and stack pointer for context switching */ 125 unsigned long ra; /* kernel's a0: return address and window call size */ 126 unsigned long sp; /* kernel's a1: stack pointer */ 127 128 mm_segment_t current_ds; /* see uaccess.h for example uses */ 129 130 /* struct xtensa_cpuinfo info; */ 131 132 unsigned long bad_vaddr; /* last user fault */ 133 unsigned long bad_uaddr; /* last kernel fault accessing user space */ 134 unsigned long error_code; 135 136 unsigned long ibreak[XCHAL_NUM_IBREAK]; 137 unsigned long dbreaka[XCHAL_NUM_DBREAK]; 138 unsigned long dbreakc[XCHAL_NUM_DBREAK]; 139 140 /* Make structure 16 bytes aligned. */ 141 int align[0] __attribute__ ((aligned(16))); 142 }; 143 144 145 /* 146 * Default implementation of macro that returns current 147 * instruction pointer ("program counter"). 148 */ 149 #define current_text_addr() ({ __label__ _l; _l: &&_l;}) 150 151 152 /* This decides where the kernel will search for a free chunk of vm 153 * space during mmap's. 154 */ 155 #define TASK_UNMAPPED_BASE (TASK_SIZE / 2) 156 157 #define INIT_THREAD \ 158 { \ 159 ra: 0, \ 160 sp: sizeof(init_stack) + (long) &init_stack, \ 161 current_ds: {0}, \ 162 /*info: {0}, */ \ 163 bad_vaddr: 0, \ 164 bad_uaddr: 0, \ 165 error_code: 0, \ 166 } 167 168 169 /* 170 * Do necessary setup to start up a newly executed thread. 171 * Note: We set-up ps as if we did a call4 to the new pc. 172 * set_thread_state in signal.c depends on it. 173 */ 174 #define USER_PS_VALUE ((1 << PS_WOE_BIT) | \ 175 (1 << PS_CALLINC_SHIFT) | \ 176 (USER_RING << PS_RING_SHIFT) | \ 177 (1 << PS_UM_BIT) | \ 178 (1 << PS_EXCM_BIT)) 179 180 /* Clearing a0 terminates the backtrace. */ 181 #define start_thread(regs, new_pc, new_sp) \ 182 memset(regs, 0, sizeof(*regs)); \ 183 regs->pc = new_pc; \ 184 regs->ps = USER_PS_VALUE; \ 185 regs->areg[1] = new_sp; \ 186 regs->areg[0] = 0; \ 187 regs->wmask = 1; \ 188 regs->depc = 0; \ 189 regs->windowbase = 0; \ 190 regs->windowstart = 1; 191 192 /* Forward declaration */ 193 struct task_struct; 194 struct mm_struct; 195 196 /* Free all resources held by a thread. */ 197 #define release_thread(thread) do { } while(0) 198 199 /* Copy and release all segment info associated with a VM */ 200 #define copy_segments(p, mm) do { } while(0) 201 #define release_segments(mm) do { } while(0) 202 #define forget_segments() do { } while (0) 203 204 #define thread_saved_pc(tsk) (task_pt_regs(tsk)->pc) 205 206 extern unsigned long get_wchan(struct task_struct *p); 207 208 #define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc) 209 #define KSTK_ESP(tsk) (task_pt_regs(tsk)->areg[1]) 210 211 #define cpu_relax() barrier() 212 #define cpu_relax_lowlatency() cpu_relax() 213 214 /* Special register access. */ 215 216 #define WSR(v,sr) __asm__ __volatile__ ("wsr %0,"__stringify(sr) :: "a"(v)); 217 #define RSR(v,sr) __asm__ __volatile__ ("rsr %0,"__stringify(sr) : "=a"(v)); 218 219 #define set_sr(x,sr) ({unsigned int v=(unsigned int)x; WSR(v,sr);}) 220 #define get_sr(sr) ({unsigned int v; RSR(v,sr); v; }) 221 222 #ifndef XCHAL_HAVE_EXTERN_REGS 223 #define XCHAL_HAVE_EXTERN_REGS 0 224 #endif 225 226 #if XCHAL_HAVE_EXTERN_REGS 227 228 static inline void set_er(unsigned long value, unsigned long addr) 229 { 230 asm volatile ("wer %0, %1" : : "a" (value), "a" (addr) : "memory"); 231 } 232 233 static inline unsigned long get_er(unsigned long addr) 234 { 235 register unsigned long value; 236 asm volatile ("rer %0, %1" : "=a" (value) : "a" (addr) : "memory"); 237 return value; 238 } 239 240 #endif /* XCHAL_HAVE_EXTERN_REGS */ 241 242 #endif /* __ASSEMBLY__ */ 243 #endif /* _XTENSA_PROCESSOR_H */ 244