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Re: [PATCH] pc-bios/s390-ccw: Use reset_psw pointer instead of hard-code
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From: |
Philippe Mathieu-Daudé |
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Subject: |
Re: [PATCH] pc-bios/s390-ccw: Use reset_psw pointer instead of hard-coded null pointer |
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Date: |
Fri, 23 Apr 2021 11:26:22 +0200 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 |
On 4/23/21 10:36 AM, Thomas Huth wrote:
> 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.
>
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
> pc-bios/s390-ccw/jump2ipl.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>