Messages in this thread | | | Date | Thu, 10 Aug 2006 00:18:34 +0400 | From | Michael Tokarev <> | Subject | Re: [PATCH] arch/i386/kernel/cpu/transmeta.c, kernel 2.6.17.8 |
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Forrest Voight wrote: > Corrects warning: > > CC arch/i386/kernel/cpu/centaur.o > CC arch/i386/kernel/cpu/transmeta.o > arch/i386/kernel/cpu/transmeta.c: In function 'init_transmeta': > arch/i386/kernel/cpu/transmeta.c:12: warning: 'cpu_freq' may be used > uninitialized in this function > CC arch/i386/kernel/cpu/intel.o >
This is a false alarm. Here's the code (details omitted):
if ( max >= 0x80860001 ) { cpuid(0x80860001, &dummy, &cpu_rev, &cpu_freq, &cpu_flags); ^^^^^^^^^ } if ( max >= 0x80860002 ) { printk(KERN_INFO "CPU: Processor %u MHz\n", cpu_freq); }
Note the two conditions: if second is true, the first is true too, so both branches are executed, so first cpu_freq is initialized (by cpuid() call) and next it's used in printk.
The same thing will be done by the following code:
if ( max >= 0x80860001 ) { cpuid(0x80860001, &dummy, &cpu_rev, &cpu_freq, &cpu_flags); if ( max >= 0x80860002 ) { printk(KERN_INFO "CPU: Processor %u MHz\n", cpu_freq); } }
and in this case gcc will not (hopefully) issue the warning.
BTW, cpu_rev gets initialized to 0 here as well - looks like it's done also just to prevent warning message.
/mjt
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