components/python/python39/patches/18-obmalloc-adi.patch

   1 This patch was developed in house for Bug 21658934. Python PyObject_Free()
   2 implementation relies on being able to read memory that might not belong to
   3 the current buffer. When ADIHEAP is enabled, this is detected as a violation.
   4 Use an explicit nonfaulting load to ignore the ADI tag.
   5
   6 This patch should now work with both Studio and gcc compilers (and possibly
   7 many others). It might be pushed upstream.
   8
   9 --- Python-3.9.0/Objects/obmalloc.c
  10 +++ Python-3.9.0/Objects/obmalloc.c
  11 @@ -1407,6 +1407,38 @@ obmalloc controls.  Since this test is n
  12  extremely desirable that it be this fast.
  13  */
  14
  15 +#ifdef __sparcv9
  16 +/*
  17 + * Py_ADDRESS_IN_RANGE needs to access memory that might be arbitrarily
  18 + * tagged by an ADI aware allocator. The use of a nonfaulting load
  19 + * guarantees that the read will succeed.
  20 + */
  21 +#ifdef __SUNPRO_C
  22 +
  23 +/* Studio can use built-in nonfaulting load instruction for vis.h */
  24 +#include <vis.h>
  25 +#define POOL_INDEX(x)   __vis_ldswa_ASI_PNF((void*)x)
  26 +
  27 +#else  /* __SUNPRO_C */
  28 +/*
  29 + * GCC doesn't have similar instruction built-in, but it can use
  30 + * following assembly code to do the same.
  31 + */
  32 +
  33 +static inline int vis_ldswa_ASI_PNF(void *arg);
  34 +
  35 +int vis_ldswa_ASI_PNF(void *arg) {
  36 +  int res;
  37 +  __asm__ ("ldswa  [%1]0x82,%0" : "=r" (res) : "r" (arg));
  38 +  return res;
  39 +}
  40 +#define POOL_INDEX(x)   vis_ldswa_ASI_PNF((void*)x)
  41 +
  42 +#endif  /* __SUNPRO_C */
  43 +#else   /* __sparcv9 */
  44 +#define POOL_INDEX(x)   (*(x))
  45 +#endif  /* __sparcv9 */
  46 +
  47  static bool _Py_NO_SANITIZE_ADDRESS
  48              _Py_NO_SANITIZE_THREAD
  49              _Py_NO_SANITIZE_MEMORY
  50 @@ -1417,7 +1449,7 @@ address_in_range(void *p, poolp pool)
  51      // another thread may be concurrently modifying the value without holding
  52      // the GIL. The following dance forces the compiler to read pool->arenaindex
  53      // only once.
  54 -    uint arenaindex = *((volatile uint *)&pool->arenaindex);
  55 +    uint arenaindex = (uint)POOL_INDEX((volatile uint *)&pool->arenaindex);
  56      return arenaindex < maxarenas &&
  57          (uintptr_t)p - arenas[arenaindex].address < ARENA_SIZE &&
  58          arenas[arenaindex].address != 0;