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