Vector registers are zero initialized by the kernel. Stop accepting
"all ones" as a clean value.
Note that this was not working as expected given that
value == 0xff
can be assumed to be always false by the compiler as value's range is
[-128, 127]. Both GCC (-Wtype-limits) and clang
(-Wtautological-constant-out-of-range-compare) warn about this.
Signed-off-by: Ignacio Encinas <ignacio@xxxxxxxxxxxx>
---
I tried looking why "all ones" was previously deemed a "clean" value but
couldn't find any information. It looks like the kernel always
zero-initializes the vector registers.
If "all ones" is still acceptable for any reason, my intention is to
spin a v2 changing the types of `value` and `prev_value` to unsigned
char.
---
tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c b/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c
index 35c0812e32de0c82a54f84bd52c4272507121e35..b712c4d258a6cb045aa96de4a75299714866f5e6 100644
--- a/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c
+++ b/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c
@@ -6,7 +6,7 @@
* the values. To further ensure consistency, this file is compiled without
* libc and without auto-vectorization.
*
- * To be "clean" all values must be either all ones or all zeroes.
+ * To be "clean" all values must be all zeroes.
*/
#define __stringify_1(x...) #x
@@ -46,7 +46,7 @@ int main(int argc, char **argv)
: "=r" (value)); \
if (first) { \
first = 0; \
- } else if (value != prev_value || !(value == 0x00 || value == 0xff)) { \
+ } else if (value != prev_value || value != 0x00) { \
printf("Register " __stringify(register) \
" values not clean! value: %u\n", value); \
exit(-1); \
---
base-commit: 03d38806a902b36bf364cae8de6f1183c0a35a67
change-id: 20250301-fix-v_exec_initval_nolibc-498d976c372d
Best regards,
--
Ignacio Encinas <ignacio@xxxxxxxxxxxx>
