Re: [Xen-devel] KEXEC fix 32/64bit issues with KEXEC_CMD_kexec_get_range

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 14.12.11 at 15:02, Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote:
>To fix 32bit Xen which uses 32bit intergers for addresses and sizes,
>change the internals to use xen_kexec64_range_t which will use 64bit
>integers instead.  This also invovles changing several casts to
>explicitly use uint64_ts rather than unsigned longs.

I don't think fixing 32-bit Xen is really necessary: Neither does anyone
care much, nor should any address be beyond 4Gb in that case. Not
playing with this will likely simplify the patch quite a bit.

>--- a/xen/arch/ia64/xen/machine_kexec.c
>+++ b/xen/arch/ia64/xen/machine_kexec.c
>@@ -102,10 +102,10 @@ void machine_reboot_kexec(xen_kexec_imag
>       machine_kexec(image);
> }
> 
>-int machine_kexec_get_xen(xen_kexec_range_t *range)
>+int machine_kexec_get_xen(xen_kexec64_range_t *range)
> {
>       range->start = ia64_tpa(_text);
>-      range->size = (unsigned long)_end - (unsigned long)_text;
>+      range->size = (uint64_t)_end - (uint64_t)_text;

This is bogus and pointless (same thing a few lines down the patch).

>       return 0;
> }
> 
>--- a/xen/arch/x86/x86_32/machine_kexec.c
>+++ b/xen/arch/x86/x86_32/machine_kexec.c
>@@ -11,11 +11,11 @@
> #include <asm/page.h>
> #include <public/kexec.h>
> 
>-int machine_kexec_get_xen(xen_kexec_range_t *range)
>+int machine_kexec_get_xen(xen_kexec64_range_t *range)
> {
>         range->start = virt_to_maddr(_start);
>-        range->size = (unsigned long)xenheap_phys_end -
>-                      (unsigned long)range->start;
>+        range->size = (uint64_t)xenheap_phys_end -

And here it's even wrong, and I doubt it compiles without warning
across the supported range of compilers.

>+                      (uint64_t)range->start;

Casting range->start here and elsewhere shouldn't be necessary at
all (the pre-existing cast was bogus too).

>         return 0;
> }
> 

Jan


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