[GIT PULL] L3 CID fix for 3.5

From: Borislav Petkov
Date: Thu Apr 19 2012 - 12:53:53 EST

Hi guys,

please pull the following fix for L3 cache index disable into tip. Since
there's no real breakage but simply a correctness issue, it can wait for
3.5. I've also removed the stable tag I had in the previous version.


The following changes since commit e816b57a337ea3b755de72bec38c10c864f23015:

Linux 3.4-rc3 (2012-04-15 18:28:29 -0700)

are available in the git repository at:

git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp.git tags/l3-fix-for-3.5

for you to fetch changes up to a720b2dd2470a52345df11dca8d6c1466599f812:

x86, intel_cacheinfo: Fix error return code in amd_set_l3_disable_slot() (2012-04-19 18:30:28 +0200)

A small L3 cache index disable fix from Srivatsa Bhat which unifies the
way the code checks for already disabled indices.

Srivatsa S. Bhat (1):
x86, intel_cacheinfo: Fix error return code in amd_set_l3_disable_slot()

arch/x86/kernel/cpu/intel_cacheinfo.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

Appending patch here too:

commit a720b2dd2470a52345df11dca8d6c1466599f812
Author: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
Date: Thu Apr 19 12:35:08 2012 +0200

x86, intel_cacheinfo: Fix error return code in amd_set_l3_disable_slot()

If the L3 disable slot is already in use, return -EEXIST instead of
-EINVAL. The caller, store_cache_disable(), checks this return value to
print an appropriate warning.

Also, we want to signal with -EEXIST that the current index we're
disabling has actually been already disabled on the node:

$ echo 12 > /sys/devices/system/cpu/cpu3/cache/index3/cache_disable_0
$ echo 12 > /sys/devices/system/cpu/cpu3/cache/index3/cache_disable_0
-bash: echo: write error: File exists
$ echo 12 > /sys/devices/system/cpu/cpu3/cache/index3/cache_disable_1
-bash: echo: write error: File exists
$ echo 12 > /sys/devices/system/cpu/cpu5/cache/index3/cache_disable_1
-bash: echo: write error: File exists

The old code would say

-bash: echo: write error: Invalid argument

for disable slot 1 when playing the example above with no output in
dmesg, which is clearly misleading.

Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20120419070053.GB16645@xxxxxxxxxxxxxx
[Boris: add testing for the other index too]
Signed-off-by: Borislav Petkov <borislav.petkov@xxxxxxx>

diff --git a/arch/x86/kernel/cpu/intel_cacheinfo.c b/arch/x86/kernel/cpu/intel_cacheinfo.c
index 73d08ed98a64..b8f3653dddbc 100644
--- a/arch/x86/kernel/cpu/intel_cacheinfo.c
+++ b/arch/x86/kernel/cpu/intel_cacheinfo.c
@@ -433,14 +433,14 @@ int amd_set_l3_disable_slot(struct amd_northbridge *nb, int cpu, unsigned slot,
/* check if @slot is already used or the index is already disabled */
ret = amd_get_l3_disable_slot(nb, slot);
if (ret >= 0)
- return -EINVAL;
+ return -EEXIST;

if (index > nb->l3_cache.indices)
return -EINVAL;

/* check whether the other slot has disabled the same index already */
if (index == amd_get_l3_disable_slot(nb, !slot))
- return -EINVAL;
+ return -EEXIST;

amd_l3_disable_index(nb, cpu, slot, index);

@@ -468,8 +468,8 @@ static ssize_t store_cache_disable(struct _cpuid4_info *this_leaf,
err = amd_set_l3_disable_slot(this_leaf->base.nb, cpu, slot, val);
if (err) {
if (err == -EEXIST)
- printk(KERN_WARNING "L3 disable slot %d in use!\n",
- slot);
+ pr_warning("L3 slot %d in use/index already disabled!\n",
+ slot);
return err;
return count;


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