lib/armflush.c

   1 /* armflush.c - flush the instruction cache
   2
   3    __clear_cache is used in tccrun.c,  It is a built-in
   4    intrinsic with gcc.  However tcc in order to compile
   5    itself needs this function */
   6
   7 #ifdef __TINYC__
   8
   9 /* syscall wrapper */
  10 unsigned syscall(unsigned syscall_nr, ...);
  11
  12 /* arm-tcc supports only fake asm currently */
  13 __asm__(
  14     ".global syscall\n"
  15     "syscall:\n"
  16     ".int 0xe92d4080\n"  // push    {r7, lr}
  17     ".int 0xe1a07000\n"  // mov     r7, r0
  18     ".int 0xe1a00001\n"  // mov     r0, r1
  19     ".int 0xe1a01002\n"  // mov     r1, r2
  20     ".int 0xe1a02003\n"  // mov     r2, r3
  21     ".int 0xef000000\n"  // svc     0x00000000
  22     ".int 0xe8bd8080\n"  // pop     {r7, pc}
  23     );
  24
  25 /* from unistd.h: */
  26 #if defined(__thumb__) || defined(__ARM_EABI__)
  27 # define __NR_SYSCALL_BASE      0x0
  28 #else
  29 # define __NR_SYSCALL_BASE      0x900000
  30 #endif
  31 #define __ARM_NR_BASE           (__NR_SYSCALL_BASE+0x0f0000)
  32 #define __ARM_NR_cacheflush     (__ARM_NR_BASE+2)
  33
  34 #else
  35
  36 #define _GNU_SOURCE
  37 #include <unistd.h>
  38 #include <sys/syscall.h>
  39 #include <stdio.h>
  40
  41 #endif
  42
  43 /* Flushing for tccrun */
  44 void __clear_cache(void *beginning, void *end)
  45 {
  46 /* __ARM_NR_cacheflush is kernel private and should not be used in user space.
  47  * However, there is no ARM asm parser in tcc so we use it for now */
  48 #if 1
  49     syscall(__ARM_NR_cacheflush, beginning, end, 0);
  50 #else
  51     __asm__ ("push {r7}\n\t"
  52              "mov r7, #0xf0002\n\t"
  53              "mov r2, #0\n\t"
  54              "swi 0\n\t"
  55              "pop {r7}\n\t"
  56              "ret");
  57 #endif
  58 }