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
26namespace __sanitizer {
27
28void 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