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       __XTENSA_UL_CONST(0xffffffff)
  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 /* Spill slot location for the register reg in the spill area under the stack
 117  * pointer sp. reg must be in the range [0..4).
 118  */
 119 #define SPILL_SLOT(sp, reg) (*(((unsigned long *)(sp)) - 4 + (reg)))
 120
 121 /* Spill slot location for the register reg in the spill area under the stack
 122  * pointer sp for the call8. reg must be in the range [4..8).
 123  */
 124 #define SPILL_SLOT_CALL8(sp, reg) (*(((unsigned long *)(sp)) - 12 + (reg)))
 125
 126 /* Spill slot location for the register reg in the spill area under the stack
 127  * pointer sp for the call12. reg must be in the range [4..12).
 128  */
 129 #define SPILL_SLOT_CALL12(sp, reg) (*(((unsigned long *)(sp)) - 16 + (reg)))
 130
 131 typedef struct {
 132         unsigned long seg;
 133 } mm_segment_t;
 134
 135 struct thread_struct {
 136
 137         /* kernel's return address and stack pointer for context switching */
 138         unsigned long ra; /* kernel's a0: return address and window call size */
 139         unsigned long sp; /* kernel's a1: stack pointer */
 140
 141         mm_segment_t current_ds;    /* see uaccess.h for example uses */
 142
 143         /* struct xtensa_cpuinfo info; */
 144
 145         unsigned long bad_vaddr; /* last user fault */
 146         unsigned long bad_uaddr; /* last kernel fault accessing user space */
 147         unsigned long error_code;
 148 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 149         struct perf_event *ptrace_bp[XCHAL_NUM_IBREAK];
 150         struct perf_event *ptrace_wp[XCHAL_NUM_DBREAK];
 151 #endif
 152         /* Make structure 16 bytes aligned. */
 153         int align[0] __attribute__ ((aligned(16)));
 154 };
 155
 156
 157 /*
 158  * Default implementation of macro that returns current
 159  * instruction pointer ("program counter").
 160  */
 161 #define current_text_addr()  ({ __label__ _l; _l: &&_l;})
 162
 163
 164 /* This decides where the kernel will search for a free chunk of vm
 165  * space during mmap's.
 166  */
 167 #define TASK_UNMAPPED_BASE      (TASK_SIZE / 2)
 168
 169 #define INIT_THREAD  \
 170 {                                                                       \
 171         ra:             0,                                              \
 172         sp:             sizeof(init_stack) + (long) &init_stack,        \
 173         current_ds:     {0},                                            \
 174         /*info:         {0}, */                                         \
 175         bad_vaddr:      0,                                              \
 176         bad_uaddr:      0,                                              \
 177         error_code:     0,                                              \
 178 }
 179
 180
 181 /*
 182  * Do necessary setup to start up a newly executed thread.
 183  * Note: We set-up ps as if we did a call4 to the new pc.
 184  *       set_thread_state in signal.c depends on it.
 185  */
 186 #define USER_PS_VALUE ((1 << PS_WOE_BIT) |                              \
 187                        (1 << PS_CALLINC_SHIFT) |                        \
 188                        (USER_RING << PS_RING_SHIFT) |                   \
 189                        (1 << PS_UM_BIT) |                               \
 190                        (1 << PS_EXCM_BIT))
 191
 192 /* Clearing a0 terminates the backtrace. */
 193 #define start_thread(regs, new_pc, new_sp) \
 194         memset(regs, 0, sizeof(*regs)); \
 195         regs->pc = new_pc; \
 196         regs->ps = USER_PS_VALUE; \
 197         regs->areg[1] = new_sp; \
 198         regs->areg[0] = 0; \
 199         regs->wmask = 1; \
 200         regs->depc = 0; \
 201         regs->windowbase = 0; \
 202         regs->windowstart = 1;
 203
 204 /* Forward declaration */
 205 struct task_struct;
 206 struct mm_struct;
 207
 208 /* Free all resources held by a thread. */
 209 #define release_thread(thread) do { } while(0)
 210
 211 extern unsigned long get_wchan(struct task_struct *p);
 212
 213 #define KSTK_EIP(tsk)           (task_pt_regs(tsk)->pc)
 214 #define KSTK_ESP(tsk)           (task_pt_regs(tsk)->areg[1])
 215
 216 #define cpu_relax()  barrier()
 217
 218 /* Special register access. */
 219
 220 #define WSR(v,sr) __asm__ __volatile__ ("wsr %0,"__stringify(sr) :: "a"(v));
 221 #define RSR(v,sr) __asm__ __volatile__ ("rsr %0,"__stringify(sr) : "=a"(v));
 222
 223 #define set_sr(x,sr) ({unsigned int v=(unsigned int)x; WSR(v,sr);})
 224 #define get_sr(sr) ({unsigned int v; RSR(v,sr); v; })
 225
 226 #ifndef XCHAL_HAVE_EXTERN_REGS
 227 #define XCHAL_HAVE_EXTERN_REGS 0
 228 #endif
 229
 230 #if XCHAL_HAVE_EXTERN_REGS
 231
 232 static inline void set_er(unsigned long value, unsigned long addr)
 233 {
 234         asm volatile ("wer %0, %1" : : "a" (value), "a" (addr) : "memory");
 235 }
 236
 237 static inline unsigned long get_er(unsigned long addr)
 238 {
 239         register unsigned long value;
 240         asm volatile ("rer %0, %1" : "=a" (value) : "a" (addr) : "memory");
 241         return value;
 242 }
 243
 244 #endif /* XCHAL_HAVE_EXTERN_REGS */
 245
 246 #endif  /* __ASSEMBLY__ */
 247 #endif  /* _XTENSA_PROCESSOR_H */