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 #if defined(__GNUC__) 34 // __builtin_return_address returns the address of the call instruction 35 // on the SPARC and not the return address, so we need to compensate. 36 trace_buffer[0] = GetNextInstructionPc(pc); 37 #else 38 trace_buffer[0] = pc; 39 #endif 40 size = 1; 41 if (stack_top < 4096) return; // Sanity check for stack top. 42 // Flush register windows to memory 43 #if defined(__sparc_v9__) || defined(__sparcv9__) || defined(__sparcv9) 44 asm volatile("flushw" ::: "memory"); 45 #else 46 asm volatile("ta 3" ::: "memory"); 47 #endif 48 // On the SPARC, the return address is not in the frame, it is in a 49 // register. There is no way to access it off of the current frame 50 // pointer, but it can be accessed off the previous frame pointer by 51 // reading the value from the register window save area. 52 uptr prev_bp = GET_CURRENT_FRAME(); 53 uptr next_bp = prev_bp; 54 unsigned int i = 0; 55 while (next_bp != bp && IsAligned(next_bp, sizeof(uhwptr)) && i++ < 8) { 56 prev_bp = next_bp; 57 next_bp = (uptr)((uhwptr *)next_bp)[14] + STACK_BIAS; 58 } 59 if (next_bp == bp) 60 bp = prev_bp; 61 // Lowest possible address that makes sense as the next frame pointer. 62 // Goes up as we walk the stack. 63 uptr bottom = stack_bottom; 64 // Avoid infinite loop when frame == frame[0] by using frame > prev_frame. 65 while (IsValidFrame(bp, stack_top, bottom) && IsAligned(bp, sizeof(uhwptr)) && 66 size < max_depth) { 67 uhwptr pc1 = ((uhwptr *)bp)[15]; 68 // Let's assume that any pointer in the 0th page is invalid and 69 // stop unwinding here. If we're adding support for a platform 70 // where this isn't true, we need to reconsider this check. 71 if (pc1 < kPageSize) 72 break; 73 if (pc1 != pc) { 74 // %o7 contains the address of the call instruction and not the 75 // return address, so we need to compensate. 76 trace_buffer[size++] = GetNextInstructionPc((uptr)pc1); 77 } 78 bottom = bp; 79 bp = (uptr)((uhwptr *)bp)[14] + STACK_BIAS; 80 } 81 } 82 83 } // namespace __sanitizer 84 85 #endif // !defined(__sparc__) 86