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 <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 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
 116 typedef struct {
 117         unsigned long seg;
 118 } mm_segment_t;
 119
 120 struct 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 */
 190 struct task_struct;
 191 struct 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
 203 extern 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
 225 static inline void set_er(unsigned long value, unsigned long addr)
 226 {
 227         asm volatile ("wer %0, %1" : : "a" (value), "a" (addr) : "memory");
 228 }
 229
 230 static 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 */