When compiling the s390-ccw bios with clang, it emits a warning like this:
pc-bios/s390-ccw/jump2ipl.c:86:9: warning: indirection of non-volatile null
pointer will be deleted, not trap [-Wnull-dereference]
if (*((uint64_t *)0) & RESET_PSW_MASK) {
^~~~~~~~~~~~~~~~
pc-bios/s390-ccw/jump2ipl.c:86:9: note: consider using __builtin_trap() or
qualifying pointer with 'volatile'
We could add a "volatile" here to shut it up, but on the other hand,
we also have a pointer variable called "reset_psw" in this file already
that points to the PSW at address 0, so we can simply use that pointer
variable instead.
Reviewed-by: Philippe Mathieu-Daudé <phi...@redhat.com>
Message-Id: <20210423142440.582188-1-th...@redhat.com>
Reviewed-by: Janosch Frank <fran...@linux.ibm.com>
Signed-off-by: Thomas Huth <th...@redhat.com>
---
pc-bios/s390-ccw/jump2ipl.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/pc-bios/s390-ccw/jump2ipl.c b/pc-bios/s390-ccw/jump2ipl.c
index b9c70d64a5..73e4367e09 100644
--- a/pc-bios/s390-ccw/jump2ipl.c
+++ b/pc-bios/s390-ccw/jump2ipl.c
@@ -82,8 +82,8 @@ void jump_to_low_kernel(void)
jump_to_IPL_code(KERN_IMAGE_START);
}
- /* Trying to get PSW at zero address */
- if (*((uint64_t *)0) & RESET_PSW_MASK) {
+ /* Trying to get PSW at zero address (pointed to by reset_psw) */
+ if (*reset_psw & RESET_PSW_MASK) {
/*
* Surely nobody will try running directly from lowcore, so
* let's use 0 as an indication that we want to load the reset
--
2.27.0
