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bsd-user/mmap: use TSA_NO_TSA to suppress clang TSA warnings in FreeBSD 

FreeBSD implements pthread headers using TSA (thread safety analysis)
annotations, therefore when an application is compiled with
-Wthread-safety there are some locking/annotation requirements that the
user of the pthread API has to follow.

This will also be the case in QEMU, since bsd-user/mmap.c uses the
pthread API. Therefore when building it with -Wthread-safety the
compiler will throw warnings because the functions are not properly
annotated. We need TSA to be enabled because it ensures that the
critical sections of an annotated variable are properly locked.

In order to make the compiler happy and avoid adding all the necessary
macros to all callers (lock functions should use TSA_ACQUIRE, while
unlock TSA_RELEASE, and this applies to all users of pthread_mutex_lock
and pthread_mutex_unlock), simply use TSA_NO_TSA to supppress such
warnings.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20230117135203.3049709-3-eesposit@redhat.com>
Reviewed-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Emanuele Giuseppe Esposito 2023-01-17 08:52:02 -05:00 committed by Kevin Wolf
parent deb9c2ad0b
commit e022d9cab7
2 changed files with 6 additions and 4 deletions
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5
bsd-user/qemu.h
View File

@ -36,6 +36,7 @@ extern char **environ;
#include "target_os_signal.h"
#include "target.h"
#include "exec/gdbstub.h"
#include "qemu/clang-tsa.h"
/*
* This struct is used to hold certain information about the image. Basically,
@ -234,8 +235,8 @@ int target_msync(abi_ulong start, abi_ulong len, int flags);
extern unsigned long last_brk;
extern abi_ulong mmap_next_start;
abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size);
void mmap_fork_start(void);
void mmap_fork_end(int child);
void TSA_NO_TSA mmap_fork_start(void);
void TSA_NO_TSA mmap_fork_end(int child);
/* main.c */
extern char qemu_proc_pathname[];

5
include/exec/exec-all.h
View File

@ -25,6 +25,7 @@
#include "exec/cpu_ldst.h"
#endif
#include "qemu/interval-tree.h"
#include "qemu/clang-tsa.h"
/* allow to see translation results - the slowdown should be negligible, so we leave it */
#define DEBUG_DISAS
@ -759,8 +760,8 @@ static inline tb_page_addr_t get_page_addr_code(CPUArchState *env,
}
#if defined(CONFIG_USER_ONLY)
void mmap_lock(void);
void mmap_unlock(void);
void TSA_NO_TSA mmap_lock(void);
void TSA_NO_TSA mmap_unlock(void);
bool have_mmap_lock(void);
/**