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Summary: ShadowCallStack on x86_64 suffered from the same racy security issues as Return Flow Guard and had performance overhead as high as 13% depending on the benchmark. x86_64 ShadowCallStack was always an experimental feature and never shipped a runtime required to support it, as such there are no expected downstream users. Reviewers: pcc Reviewed By: pcc Subscribers: mgorny, javed.absar, hiraditya, jdoerfert, cfe-commits, #sanitizers, llvm-commits Tags: #clang, #sanitizers, #llvm Differential Revision: https://reviews.llvm.org/D59034 llvm-svn: 355624
38 lines
950 B
C
38 lines
950 B
C
// This header provides replacements for certain libc functions. It is necessary
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// in order to safely run the tests on aarch64, because the system libc might
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// not have been compiled with -ffixed-x18.
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#pragma once
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#include <stddef.h>
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#include <stdint.h>
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#include <stdio.h>
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#ifdef __aarch64__
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size_t scs_strlen(const char *p) {
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size_t retval = 0;
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while (*p++)
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retval++;
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return retval;
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}
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// We mark this function as noinline to make sure that its callers do not
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// become leaf functions as a result of inlining. This is because we want to
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// make sure that we generate the correct code for non-leaf functions.
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__attribute__((noinline)) void scs_fputs_stdout(const char *p) {
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__asm__ __volatile__(
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"mov x0, #1\n" // stdout
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"mov x1, %0\n"
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"mov x2, %1\n"
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"mov x8, #64\n" // write
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"svc #0\n" ::"r"(p),
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"r"(scs_strlen(p))
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: "x0", "x1", "x2", "x8");
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}
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#else
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#error Unsupported platform
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#endif
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