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authorBenjamin Gray <bgray@linux.ibm.com>2023-07-25 03:58:41 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2023-08-02 15:22:19 +0300
commitc3062ede9927053754ba27b280afe00b9b31b37a (patch)
tree4e0203e5987cd828c1d9d1586e5598664a8971ad /tools/testing/selftests/powerpc
parentfc6732a8556c1099b89f4777a96bd6a1ae5a4378 (diff)
downloadlinux-c3062ede9927053754ba27b280afe00b9b31b37a.tar.xz
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.c24
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;
}
}