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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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3
accel/tcg/cpu-exec.c
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@ -41,9 +41,6 @@
#include "tb-context.h" #include "tb-context.h"
#include "internal-common.h" #include "internal-common.h"
#include "internal-target.h" #include "internal-target.h"
#if defined(CONFIG_USER_ONLY)
#include "user-retaddr.h"
#endif
/* -icount align implementation. */ /* -icount align implementation. */

1
accel/tcg/user-exec.c
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@ -33,7 +33,6 @@
#include "tcg/tcg-ldst.h" #include "tcg/tcg-ldst.h"
#include "internal-common.h" #include "internal-common.h"
#include "internal-target.h" #include "internal-target.h"
#include "user-retaddr.h"
__thread uintptr_t helper_retaddr; __thread uintptr_t helper_retaddr;

28
accel/tcg/user-retaddr.h
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@ -1,28 +0,0 @@
#ifndef ACCEL_TCG_USER_RETADDR_H
#define ACCEL_TCG_USER_RETADDR_H
#include "qemu/atomic.h"
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;
}
#endif

34
include/exec/cpu_ldst.h
View File

@ -379,4 +379,38 @@ void *tlb_vaddr_to_host(CPUArchState *env, abi_ptr addr,
MMUAccessType access_type, int mmu_idx); MMUAccessType access_type, int mmu_idx);
#endif #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 */ #endif /* CPU_LDST_H */