libsanitizer/sanitizer_common/sanitizer_stacktrace_sparc.cpp

   1 //===-- sanitizer_stacktrace_sparc.cpp ------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file is shared between AddressSanitizer and ThreadSanitizer
  10 // run-time libraries.
  11 //
  12 // Implementation of fast stack unwinding for Sparc.
  13 //===----------------------------------------------------------------------===//
  14
  15 #if defined(__sparc__)
  16
  17 #if defined(__arch64__) || defined(__sparcv9)
  18 #define STACK_BIAS 2047
  19 #else
  20 #define STACK_BIAS 0
  21 #endif
  22
  23 #include "sanitizer_common.h"
  24 #include "sanitizer_stacktrace.h"
  25
  26 namespace __sanitizer {
  27
  28 void BufferedStackTrace::UnwindFast(uptr pc, uptr bp, uptr stack_top,
  29                                     uptr stack_bottom, u32 max_depth) {
  30   // TODO(yln): add arg sanity check for stack_top/stack_bottom
  31   CHECK_GE(max_depth, 2);
  32   const uptr kPageSize = GetPageSizeCached();
  33   trace_buffer[0] = pc;
  34   size = 1;
  35   if (stack_top < 4096) return;  // Sanity check for stack top.
  36   // Flush register windows to memory
  37 #if defined(__sparc_v9__) || defined(__sparcv9__) || defined(__sparcv9)
  38   asm volatile("flushw" ::: "memory");
  39 #else
  40   asm volatile("ta 3" ::: "memory");
  41 #endif
  42   // On the SPARC, the return address is not in the frame, it is in a
  43   // register.  There is no way to access it off of the current frame
  44   // pointer, but it can be accessed off the previous frame pointer by
  45   // reading the value from the register window save area.
  46   uptr prev_bp = GET_CURRENT_FRAME();
  47   uptr next_bp = prev_bp;
  48   unsigned int i = 0;
  49   while (next_bp != bp && IsAligned(next_bp, sizeof(uhwptr)) && i++ < 8) {
  50     prev_bp = next_bp;
  51     next_bp = (uptr)((uhwptr *)next_bp)[14] + STACK_BIAS;
  52   }
  53   if (next_bp == bp)
  54     bp = prev_bp;
  55   // Lowest possible address that makes sense as the next frame pointer.
  56   // Goes up as we walk the stack.
  57   uptr bottom = stack_bottom;
  58   // Avoid infinite loop when frame == frame[0] by using frame > prev_frame.
  59   while (IsValidFrame(bp, stack_top, bottom) && IsAligned(bp, sizeof(uhwptr)) &&
  60          size < max_depth) {
  61     uhwptr pc1 = ((uhwptr *)bp)[15];
  62     // Let's assume that any pointer in the 0th page is invalid and
  63     // stop unwinding here.  If we're adding support for a platform
  64     // where this isn't true, we need to reconsider this check.
  65     if (pc1 < kPageSize)
  66       break;
  67     if (pc1 != pc) {
  68       // %o7 contains the address of the call instruction and not the
  69       // return address, so we need to compensate.
  70       trace_buffer[size++] = GetNextInstructionPc((uptr)pc1);
  71     }
  72     bottom = bp;
  73     bp = (uptr)((uhwptr *)bp)[14] + STACK_BIAS;
  74   }
  75 }
  76
  77 }  // namespace __sanitizer
  78
  79 #endif  // !defined(__sparc__)