Yaya48
cf256aa081
Upstream: https://gitlab.com/qemu-project/qemu.git Upstream-Commit: d2e570cc0f97b936902a5b1b86b73c0f5998b475
48 lines
1.2 KiB
C
48 lines
1.2 KiB
C
/*
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* Get user helper pc for memory unwinding.
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* SPDX-License-Identifier: LGPL-2.1-or-later
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*/
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#ifndef ACCEL_TCG_HELPER_RETADDR_H
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#define ACCEL_TCG_HELPER_RETADDR_H
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#ifndef CONFIG_TCG
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#error Can only include this header with TCG
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#endif
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/*
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* For user-only, helpers that use guest to host address translation
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* must protect the actual host memory access by recording 'retaddr'
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* for the signal handler. This is required for a race condition in
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* which another thread unmaps the page between a probe and the
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* actual access.
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*/
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#ifdef CONFIG_USER_ONLY
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extern __thread uintptr_t helper_retaddr;
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static inline void set_helper_retaddr(uintptr_t ra)
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{
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helper_retaddr = ra;
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/*
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* Ensure that this write is visible to the SIGSEGV handler that
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* may be invoked due to a subsequent invalid memory operation.
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*/
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signal_barrier();
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}
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static inline void clear_helper_retaddr(void)
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{
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/*
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* Ensure that previous memory operations have succeeded before
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* removing the data visible to the signal handler.
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*/
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signal_barrier();
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helper_retaddr = 0;
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}
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#else
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#define set_helper_retaddr(ra) do { } while (0)
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#define clear_helper_retaddr() do { } while (0)
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#endif
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#endif /* ACCEL_TCG_HELPER_RETADDR_H */
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