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The kernel currently clears the tag bits (i.e. bits 56-63) in the fault address exposed via siginfo.si_addr and sigcontext.fault_address. However, the tag bits may be needed by tools in order to accurately diagnose memory errors, such as HWASan [1] or future tools based on the Memory Tagging Extension (MTE). Expose these bits via the arch_untagged_si_addr mechanism, so that they are only exposed to signal handlers with the SA_EXPOSE_TAGBITS flag set. [1] http://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html Signed-off-by: Peter Collingbourne <pcc@google.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Link: https://linux-review.googlesource.com/id/Ia8876bad8c798e0a32df7c2ce1256c4771c81446 Link: https://lore.kernel.org/r/0010296597784267472fa13b39f8238d87a72cf8.1605904350.git.pcc@google.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
25 lines
650 B
C
25 lines
650 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __ARM64_ASM_SIGNAL_H
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#define __ARM64_ASM_SIGNAL_H
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#include <asm/memory.h>
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#include <uapi/asm/signal.h>
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#include <uapi/asm/siginfo.h>
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static inline void __user *arch_untagged_si_addr(void __user *addr,
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unsigned long sig,
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unsigned long si_code)
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{
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/*
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* For historical reasons, all bits of the fault address are exposed as
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* address bits for watchpoint exceptions. New architectures should
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* handle the tag bits consistently.
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*/
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if (sig == SIGTRAP && si_code == TRAP_BRKPT)
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return addr;
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return untagged_addr(addr);
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}
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#define arch_untagged_si_addr arch_untagged_si_addr
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#endif
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