diff options
| author | Benjamin Gray <bgray@linux.ibm.com> | 2023-07-25 10:58:41 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2023-08-02 22:22:19 +1000 |
| commit | c3062ede9927053754ba27b280afe00b9b31b37a (patch) | |
| tree | 4e0203e5987cd828c1d9d1586e5598664a8971ad /tools/testing/selftests/powerpc | |
| parent | fc6732a8556c1099b89f4777a96bd6a1ae5a4378 (diff) | |
selftests/powerpc/ptrace: Declare test temporary variables as volatile
While the target is volatile, the temporary variables used to access the
target cast away the volatile. This is undefined behaviour, and a
compiler may optimise away/reorder these accesses, breaking the test.
This was observed with GCC 13.1.1, but it can be difficult to reproduce
because of the dependency on compiler behaviour.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230725005841.28854-5-bgray@linux.ibm.com
Diffstat (limited to 'tools/testing/selftests/powerpc')
| -rw-r--r-- | tools/testing/selftests/powerpc/ptrace/ptrace-hwbreak.c | 24 |
1 files changed, 12 insertions, 12 deletions
diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace-hwbreak.c b/tools/testing/selftests/powerpc/ptrace/ptrace-hwbreak.c index a16239277a6f..75d30d61ab0e 100644 --- a/tools/testing/selftests/powerpc/ptrace/ptrace-hwbreak.c +++ b/tools/testing/selftests/powerpc/ptrace/ptrace-hwbreak.c @@ -64,26 +64,26 @@ static bool dawr_present(struct ppc_debug_info *dbginfo) static void write_var(int len) { - __u8 *pcvar; - __u16 *psvar; - __u32 *pivar; - __u64 *plvar; + volatile __u8 *pcvar; + volatile __u16 *psvar; + volatile __u32 *pivar; + volatile __u64 *plvar; switch (len) { case 1: - pcvar = (__u8 *)&glvar; + pcvar = (volatile __u8 *)&glvar; *pcvar = 0xff; break; case 2: - psvar = (__u16 *)&glvar; + psvar = (volatile __u16 *)&glvar; *psvar = 0xffff; break; case 4: - pivar = (__u32 *)&glvar; + pivar = (volatile __u32 *)&glvar; *pivar = 0xffffffff; break; case 8: - plvar = (__u64 *)&glvar; + plvar = (volatile __u64 *)&glvar; *plvar = 0xffffffffffffffffLL; break; } @@ -98,16 +98,16 @@ static void read_var(int len) switch (len) { case 1: - cvar = (__u8)glvar; + cvar = (volatile __u8)glvar; break; case 2: - svar = (__u16)glvar; + svar = (volatile __u16)glvar; break; case 4: - ivar = (__u32)glvar; + ivar = (volatile __u32)glvar; break; case 8: - lvar = (__u64)glvar; + lvar = (volatile __u64)glvar; break; } } |