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pc-bios/s390-ccw: Use reset_psw pointer instead of hard-coded null pointer

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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 <philmd@redhat.com>
Message-Id: <20210423142440.582188-1-thuth@redhat.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
This commit is contained in:
Thomas Huth 2021-04-23 10:30:51 +02:00
parent d08a649404
commit ff77712a8a
1 changed files with 2 additions and 2 deletions
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4
pc-bios/s390-ccw/jump2ipl.c
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@ -82,8 +82,8 @@ void jump_to_low_kernel(void)
jump_to_IPL_code(KERN_IMAGE_START); jump_to_IPL_code(KERN_IMAGE_START);
} }
/* Trying to get PSW at zero address */ /* Trying to get PSW at zero address (pointed to by reset_psw) */
if (*((uint64_t *)0) & RESET_PSW_MASK) { if (*reset_psw & RESET_PSW_MASK) {
/* /*
* Surely nobody will try running directly from lowcore, so * Surely nobody will try running directly from lowcore, so
* let's use 0 as an indication that we want to load the reset * let's use 0 as an indication that we want to load the reset