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//===-- sanitizer_stacktrace_sparc.cpp ------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is shared between AddressSanitizer and ThreadSanitizer
// run-time libraries.
//
// Implemention of fast stack unwinding for Sparc.
//===----------------------------------------------------------------------===//
#if defined(__sparc__)
#if defined(__arch64__) || defined(__sparcv9)
#define STACK_BIAS 2047
#else
#define STACK_BIAS 0
#endif
#include "sanitizer_common.h"
#include "sanitizer_stacktrace.h"
namespace __sanitizer {
void BufferedStackTrace::UnwindFast(uptr pc, uptr bp, uptr stack_top,
uptr stack_bottom, u32 max_depth) {
// TODO(yln): add arg sanity check for stack_top/stack_bottom
CHECK_GE(max_depth, 2);
const uptr kPageSize = GetPageSizeCached();
#if defined(__GNUC__)
// __builtin_return_address returns the address of the call instruction
// on the SPARC and not the return address, so we need to compensate.
trace_buffer[0] = GetNextInstructionPc(pc);
#else
trace_buffer[0] = pc;
#endif
size = 1;
if (stack_top < 4096) return; // Sanity check for stack top.
// Flush register windows to memory
#if defined(__sparc_v9__) || defined(__sparcv9__) || defined(__sparcv9)
asm volatile("flushw" ::: "memory");
#else
asm volatile("ta 3" ::: "memory");
#endif
// On the SPARC, the return address is not in the frame, it is in a
// register. There is no way to access it off of the current frame
// pointer, but it can be accessed off the previous frame pointer by
// reading the value from the register window save area.
uptr prev_bp = GET_CURRENT_FRAME();
uptr next_bp = prev_bp;
unsigned int i = 0;
while (next_bp != bp && IsAligned(next_bp, sizeof(uhwptr)) && i++ < 8) {
prev_bp = next_bp;
next_bp = (uptr)((uhwptr *)next_bp)[14] + STACK_BIAS;
}
if (next_bp == bp)
bp = prev_bp;
// Lowest possible address that makes sense as the next frame pointer.
// Goes up as we walk the stack.
uptr bottom = stack_bottom;
// Avoid infinite loop when frame == frame[0] by using frame > prev_frame.
while (IsValidFrame(bp, stack_top, bottom) && IsAligned(bp, sizeof(uhwptr)) &&
size < max_depth) {
uhwptr pc1 = ((uhwptr *)bp)[15];
// Let's assume that any pointer in the 0th page is invalid and
// stop unwinding here. If we're adding support for a platform
// where this isn't true, we need to reconsider this check.
if (pc1 < kPageSize)
break;
if (pc1 != pc) {
// %o7 contains the address of the call instruction and not the
// return address, so we need to compensate.
trace_buffer[size++] = GetNextInstructionPc((uptr)pc1);
}
bottom = bp;
bp = (uptr)((uhwptr *)bp)[14] + STACK_BIAS;
}
}
} // namespace __sanitizer
#endif // !defined(__sparc__)
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