LXR linux/arch/xtensa/include/asm/processor.h

   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/* Assertions. */
  22
  23#if (XCHAL_HAVE_WINDOWED != 1)
  24# error Linux requires the Xtensa Windowed Registers Option.
  25#endif
  26
  27/* Xtensa ABI requires stack alignment to be at least 16 */
  28
  29#define STACK_ALIGN (XCHAL_DATA_WIDTH > 16 ? XCHAL_DATA_WIDTH : 16)
  30
  31#define ARCH_SLAB_MINALIGN STACK_ALIGN
  32
  33/*
  34 * User space process size: 1 GB.
  35 * Windowed call ABI requires caller and callee to be located within the same
  36 * 1 GB region. The C compiler places trampoline code on the stack for sources
  37 * that take the address of a nested C function (a feature used by glibc), so
  38 * the 1 GB requirement applies to the stack as well.
  39 */
  40
  41#ifdef CONFIG_MMU
  42#define TASK_SIZE       __XTENSA_UL_CONST(0x40000000)
  43#else
  44#define TASK_SIZE       __XTENSA_UL_CONST(0xffffffff)
  45#endif
  46
  47#define STACK_TOP       TASK_SIZE
  48#define STACK_TOP_MAX   STACK_TOP
  49
  50/*
  51 * General exception cause assigned to fake NMI. Fake NMI needs to be handled
  52 * differently from other interrupts, but it uses common kernel entry/exit
  53 * code.
  54 */
  55
  56#define EXCCAUSE_MAPPED_NMI     62
  57
  58/*
  59 * General exception cause assigned to debug exceptions. Debug exceptions go
  60 * to their own vector, rather than the general exception vectors (user,
  61 * kernel, double); and their specific causes are reported via DEBUGCAUSE
  62 * rather than EXCCAUSE.  However it is sometimes convenient to redirect debug
  63 * exceptions to the general exception mechanism.  To do this, an otherwise
  64 * unused EXCCAUSE value was assigned to debug exceptions for this purpose.
  65 */
  66
  67#define EXCCAUSE_MAPPED_DEBUG   63
  68
  69/*
  70 * We use DEPC also as a flag to distinguish between double and regular
  71 * exceptions. For performance reasons, DEPC might contain the value of
  72 * EXCCAUSE for regular exceptions, so we use this definition to mark a
  73 * valid double exception address.
  74 * (Note: We use it in bgeui, so it should be 64, 128, or 256)
  75 */
  76
  77#define VALID_DOUBLE_EXCEPTION_ADDRESS  64
  78
  79#define XTENSA_INT_LEVEL(intno) _XTENSA_INT_LEVEL(intno)
  80#define _XTENSA_INT_LEVEL(intno) XCHAL_INT##intno##_LEVEL
  81
  82#define XTENSA_INTLEVEL_MASK(level) _XTENSA_INTLEVEL_MASK(level)
  83#define _XTENSA_INTLEVEL_MASK(level) (XCHAL_INTLEVEL##level##_MASK)
  84
  85#define XTENSA_INTLEVEL_ANDBELOW_MASK(l) _XTENSA_INTLEVEL_ANDBELOW_MASK(l)
  86#define _XTENSA_INTLEVEL_ANDBELOW_MASK(l) (XCHAL_INTLEVEL##l##_ANDBELOW_MASK)
  87
  88#define PROFILING_INTLEVEL XTENSA_INT_LEVEL(XCHAL_PROFILING_INTERRUPT)
  89
  90/* LOCKLEVEL defines the interrupt level that masks all
  91 * general-purpose interrupts.
  92 */
  93#if defined(CONFIG_XTENSA_FAKE_NMI) && defined(XCHAL_PROFILING_INTERRUPT)
  94#define LOCKLEVEL (PROFILING_INTLEVEL - 1)
  95#else
  96#define LOCKLEVEL XCHAL_EXCM_LEVEL
  97#endif
  98
  99#define TOPLEVEL XCHAL_EXCM_LEVEL
 100#define XTENSA_FAKE_NMI (LOCKLEVEL < TOPLEVEL)
 101
 102/* WSBITS and WBBITS are the width of the WINDOWSTART and WINDOWBASE
 103 * registers
 104 */
 105#define WSBITS  (XCHAL_NUM_AREGS / 4)      /* width of WINDOWSTART in bits */
 106#define WBBITS  (XCHAL_NUM_AREGS_LOG2 - 2) /* width of WINDOWBASE in bits */
 107
 108#ifndef __ASSEMBLY__
 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/* Spill slot location for the register reg in the spill area under the stack
 121 * pointer sp. reg must be in the range [0..4).
 122 */
 123#define SPILL_SLOT(sp, reg) (*(((unsigned long *)(sp)) - 4 + (reg)))
 124
 125/* Spill slot location for the register reg in the spill area under the stack
 126 * pointer sp for the call8. reg must be in the range [4..8).
 127 */
 128#define SPILL_SLOT_CALL8(sp, reg) (*(((unsigned long *)(sp)) - 12 + (reg)))
 129
 130/* Spill slot location for the register reg in the spill area under the stack
 131 * pointer sp for the call12. reg must be in the range [4..12).
 132 */
 133#define SPILL_SLOT_CALL12(sp, reg) (*(((unsigned long *)(sp)) - 16 + (reg)))
 134
 135typedef struct {
 136        unsigned long seg;
 137} mm_segment_t;
 138
 139struct thread_struct {
 140
 141        /* kernel's return address and stack pointer for context switching */
 142        unsigned long ra; /* kernel's a0: return address and window call size */
 143        unsigned long sp; /* kernel's a1: stack pointer */
 144
 145        mm_segment_t current_ds;    /* see uaccess.h for example uses */
 146
 147        /* struct xtensa_cpuinfo info; */
 148
 149        unsigned long bad_vaddr; /* last user fault */
 150        unsigned long bad_uaddr; /* last kernel fault accessing user space */
 151        unsigned long error_code;
 152#ifdef CONFIG_HAVE_HW_BREAKPOINT
 153        struct perf_event *ptrace_bp[XCHAL_NUM_IBREAK];
 154        struct perf_event *ptrace_wp[XCHAL_NUM_DBREAK];
 155#endif
 156        /* Make structure 16 bytes aligned. */
 157        int align[0] __attribute__ ((aligned(16)));
 158};
 159
 160/* This decides where the kernel will search for a free chunk of vm
 161 * space during mmap's.
 162 */
 163#define TASK_UNMAPPED_BASE      (TASK_SIZE / 2)
 164
 165#define INIT_THREAD  \
 166{                                                                       \
 167        ra:             0,                                              \
 168        sp:             sizeof(init_stack) + (long) &init_stack,        \
 169        current_ds:     {0},                                            \
 170        /*info:         {0}, */                                         \
 171        bad_vaddr:      0,                                              \
 172        bad_uaddr:      0,                                              \
 173        error_code:     0,                                              \
 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                memset((regs), 0, sizeof(*(regs))); \
 200                (regs)->pc = (new_pc); \
 201                (regs)->ps = USER_PS_VALUE; \
 202                (regs)->areg[1] = (new_sp); \
 203                (regs)->areg[0] = 0; \
 204                (regs)->wmask = 1; \
 205                (regs)->depc = 0; \
 206                (regs)->windowbase = 0; \
 207                (regs)->windowstart = 1; \
 208                (regs)->syscall = syscall; \
 209        } while (0)
 210
 211/* Forward declaration */
 212struct task_struct;
 213struct mm_struct;
 214
 215/* Free all resources held by a thread. */
 216#define release_thread(thread) do { } while(0)
 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         unsigned int v = (unsigned int)(x); \
 230         __asm__ __volatile__ ("wsr %0, "__stringify(sr) :: "a"(v)); \
 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#ifndef XCHAL_HAVE_EXTERN_REGS
 241#define XCHAL_HAVE_EXTERN_REGS 0
 242#endif
 243
 244#if XCHAL_HAVE_EXTERN_REGS
 245
 246static inline void set_er(unsigned long value, unsigned long addr)
 247{
 248        asm volatile ("wer %0, %1" : : "a" (value), "a" (addr) : "memory");
 249}
 250
 251static inline unsigned long get_er(unsigned long addr)
 252{
 253        register unsigned long value;
 254        asm volatile ("rer %0, %1" : "=a" (value) : "a" (addr) : "memory");
 255        return value;
 256}
 257
 258#endif /* XCHAL_HAVE_EXTERN_REGS */
 259
 260#endif  /* __ASSEMBLY__ */
 261#endif  /* _XTENSA_PROCESSOR_H */
 262