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accel/tcg: Move {set,clear}_helper_retaddr to cpu_ldst.h

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Use of these in helpers goes hand-in-hand with tlb_vaddr_to_host
and other probing functions.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2024-07-09 12:52:40 -07:00
parent a7ddb48bd1
commit 3d75856d1a
4 changed files with 34 additions and 32 deletions
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34
include/exec/cpu_ldst.h
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@ -379,4 +379,38 @@ void *tlb_vaddr_to_host(CPUArchState *env, abi_ptr addr,
MMUAccessType access_type, int mmu_idx);
#endif
/*
* 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 /* CPU_LDST_H */