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 #include <variant/core.h> 15 #include <asm/coprocessor.h> 16 #include <platform/hardware.h> 17 18 #include <linux/compiler.h> 19 #include <asm/ptrace.h> 20 #include <asm/types.h> 21 #include <asm/regs.h> 22 23 /* Assertions. */ 24 25 #if (XCHAL_HAVE_WINDOWED != 1) 26 # error Linux requires the Xtensa Windowed Registers Option. 27 #endif 28 29 #define ARCH_SLAB_MINALIGN XCHAL_DATA_WIDTH 30 31 /* 32 * User space process size: 1 GB. 33 * Windowed call ABI requires caller and callee to be located within the same 34 * 1 GB region. The C compiler places trampoline code on the stack for sources 35 * that take the address of a nested C function (a feature used by glibc), so 36 * the 1 GB requirement applies to the stack as well. 37 */ 38 39 #ifdef CONFIG_MMU 40 #define TASK_SIZE __XTENSA_UL_CONST(0x40000000) 41 #else 42 #define TASK_SIZE (PLATFORM_DEFAULT_MEM_START + PLATFORM_DEFAULT_MEM_SIZE) 43 #endif 44 45 #define STACK_TOP TASK_SIZE 46 #define STACK_TOP_MAX STACK_TOP 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 /* LOCKLEVEL defines the interrupt level that masks all 70 * general-purpose interrupts. 71 */ 72 #define LOCKLEVEL 1 73 74 /* WSBITS and WBBITS are the width of the WINDOWSTART and WINDOWBASE 75 * registers 76 */ 77 #define WSBITS (XCHAL_NUM_AREGS / 4) /* width of WINDOWSTART in bits */ 78 #define WBBITS (XCHAL_NUM_AREGS_LOG2 - 2) /* width of WINDOWBASE in bits */ 79 80 #ifndef __ASSEMBLY__ 81 82 /* Build a valid return address for the specified call winsize. 83 * winsize must be 1 (call4), 2 (call8), or 3 (call12) 84 */ 85 #define MAKE_RA_FOR_CALL(ra,ws) (((ra) & 0x3fffffff) | (ws) << 30) 86 87 /* Convert return address to a valid pc 88 * Note: We assume that the stack pointer is in the same 1GB ranges as the ra 89 */ 90 #define MAKE_PC_FROM_RA(ra,sp) (((ra) & 0x3fffffff) | ((sp) & 0xc0000000)) 91 92 typedef struct { 93 unsigned long seg; 94 } mm_segment_t; 95 96 struct thread_struct { 97 98 /* kernel's return address and stack pointer for context switching */ 99 unsigned long ra; /* kernel's a0: return address and window call size */ 100 unsigned long sp; /* kernel's a1: stack pointer */ 101 102 mm_segment_t current_ds; /* see uaccess.h for example uses */ 103 104 /* struct xtensa_cpuinfo info; */ 105 106 unsigned long bad_vaddr; /* last user fault */ 107 unsigned long bad_uaddr; /* last kernel fault accessing user space */ 108 unsigned long error_code; 109 110 unsigned long ibreak[XCHAL_NUM_IBREAK]; 111 unsigned long dbreaka[XCHAL_NUM_DBREAK]; 112 unsigned long dbreakc[XCHAL_NUM_DBREAK]; 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 << PS_WOE_BIT) | \ 149 (1 << PS_CALLINC_SHIFT) | \ 150 (USER_RING << PS_RING_SHIFT) | \ 151 (1 << PS_UM_BIT) | \ 152 (1 << PS_EXCM_BIT)) 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 */ 166 struct task_struct; 167 struct mm_struct; 168 169 /* Free all resources held by a thread. */ 170 #define release_thread(thread) do { } while(0) 171 172 /* Prepare to copy thread state - unlazy all lazy status */ 173 extern void prepare_to_copy(struct task_struct*); 174 175 /* Create a kernel thread without removing it from tasklists */ 176 extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags); 177 178 /* Copy and release all segment info associated with a VM */ 179 #define copy_segments(p, mm) do { } while(0) 180 #define release_segments(mm) do { } while(0) 181 #define forget_segments() do { } while (0) 182 183 #define thread_saved_pc(tsk) (task_pt_regs(tsk)->pc) 184 185 extern unsigned long get_wchan(struct task_struct *p); 186 187 #define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc) 188 #define KSTK_ESP(tsk) (task_pt_regs(tsk)->areg[1]) 189 190 #define cpu_relax() barrier() 191 192 /* Special register access. */ 193 194 #define WSR(v,sr) __asm__ __volatile__ ("wsr %0,"__stringify(sr) :: "a"(v)); 195 #define RSR(v,sr) __asm__ __volatile__ ("rsr %0,"__stringify(sr) : "=a"(v)); 196 197 #define set_sr(x,sr) ({unsigned int v=(unsigned int)x; WSR(v,sr);}) 198 #define get_sr(sr) ({unsigned int v; RSR(v,sr); v; }) 199 200 #endif /* __ASSEMBLY__ */ 201 #endif /* _XTENSA_PROCESSOR_H */ 202