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 // %o7 contains the address of the call instruction and not the 62 // return address, so we need to compensate. 63 uhwptr pc1 = GetNextInstructionPc(((uhwptr *)bp)[15]); 64 // Let's assume that any pointer in the 0th page is invalid and 65 // stop unwinding here. If we're adding support for a platform 66 // where this isn't true, we need to reconsider this check. 67 if (pc1 < kPageSize) 68 break; 69 if (pc1 != pc) 70 trace_buffer[size++] = pc1; 71 bottom = bp; 72 bp = (uptr)((uhwptr *)bp)[14] + STACK_BIAS; 73 } 74 } 75 76 } // namespace __sanitizer 77 78 #endif // !defined(__sparc__) 79