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x86/intel/cacheinfo: Shut up last long-standing warning
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arch/x86/kernel/cpu/intel_cacheinfo.c: In function ‘init_intel_cacheinfo’:
arch/x86/kernel/cpu/intel_cacheinfo.c:642:28: warning: ‘this_leaf.size’ may be used uninitialized in this function [-Wmaybe-uninitialized] arch/x86/kernel/cpu/intel_cacheinfo.c:643:29: warning: ‘this_leaf.eax.split.num_threads_sharing’ may be used uninitialized in this function [-Wmaybe-uninitialized]

This keeps on happening during randbuilds and the compiler is
wrong here:

In the case where cpuid4_cache_lookup_regs() returns 0, both
this_leaf.size and this_leaf.eax get initialized. In the case
where the CPUID leaf doesn't contain valid cache info, we error
out which init_intel_cacheinfo() handles correctly without
touching the abovementioned fields.

So shut up the warning by clearing out the struct which we hand
down.

While at it, reverse error handling and gain one indentation
level.

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1370710095-20547-1-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Borislav Petkov authored and Ingo Molnar committed Jun 20, 2013
1 parent 4d067d8 commit 719038d
Showing 1 changed file with 25 additions and 27 deletions.
52 changes: 25 additions & 27 deletions arch/x86/kernel/cpu/intel_cacheinfo.c
Original file line number Diff line number Diff line change
Expand Up @@ -618,36 +618,34 @@ unsigned int __cpuinit init_intel_cacheinfo(struct cpuinfo_x86 *c)
* parameters cpuid leaf to find the cache details
*/
for (i = 0; i < num_cache_leaves; i++) {
struct _cpuid4_info_regs this_leaf;
struct _cpuid4_info_regs this_leaf = {};
int retval;

retval = cpuid4_cache_lookup_regs(i, &this_leaf);
if (retval >= 0) {
switch (this_leaf.eax.split.level) {
case 1:
if (this_leaf.eax.split.type ==
CACHE_TYPE_DATA)
new_l1d = this_leaf.size/1024;
else if (this_leaf.eax.split.type ==
CACHE_TYPE_INST)
new_l1i = this_leaf.size/1024;
break;
case 2:
new_l2 = this_leaf.size/1024;
num_threads_sharing = 1 + this_leaf.eax.split.num_threads_sharing;
index_msb = get_count_order(num_threads_sharing);
l2_id = c->apicid & ~((1 << index_msb) - 1);
break;
case 3:
new_l3 = this_leaf.size/1024;
num_threads_sharing = 1 + this_leaf.eax.split.num_threads_sharing;
index_msb = get_count_order(
num_threads_sharing);
l3_id = c->apicid & ~((1 << index_msb) - 1);
break;
default:
break;
}
if (retval < 0)
continue;

switch (this_leaf.eax.split.level) {
case 1:
if (this_leaf.eax.split.type == CACHE_TYPE_DATA)
new_l1d = this_leaf.size/1024;
else if (this_leaf.eax.split.type == CACHE_TYPE_INST)
new_l1i = this_leaf.size/1024;
break;
case 2:
new_l2 = this_leaf.size/1024;
num_threads_sharing = 1 + this_leaf.eax.split.num_threads_sharing;
index_msb = get_count_order(num_threads_sharing);
l2_id = c->apicid & ~((1 << index_msb) - 1);
break;
case 3:
new_l3 = this_leaf.size/1024;
num_threads_sharing = 1 + this_leaf.eax.split.num_threads_sharing;
index_msb = get_count_order(num_threads_sharing);
l3_id = c->apicid & ~((1 << index_msb) - 1);
break;
default:
break;
}
}
}
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