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
 135 typedef struct {
 136         unsigned long seg;
 137 } mm_segment_t;
 138
 139 struct 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 */
 212 struct task_struct;
 213 struct mm_struct;
 214
 215 /* Free all resources held by a thread. */
 216 #define release_thread(thread) do { } while(0)
 217
 218 extern 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 #if XCHAL_HAVE_EXTERN_REGS
 241
 242 static inline void set_er(unsigned long value, unsigned long addr)
 243 {
 244         asm volatile ("wer %0, %1" : : "a" (value), "a" (addr) : "memory");
 245 }
 246
 247 static inline unsigned long get_er(unsigned long addr)
 248 {
 249         register unsigned long value;
 250         asm volatile ("rer %0, %1" : "=a" (value) : "a" (addr) : "memory");
 251         return value;
 252 }
 253
 254 #endif /* XCHAL_HAVE_EXTERN_REGS */
 255
 256 #endif  /* __ASSEMBLY__ */
 257 #endif  /* _XTENSA_PROCESSOR_H */