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powerpc/pkeys: Fix reading of ibm, processor-storage-keys property 

scan_pkey_feature() uses of_property_read_u32_array() to read the
ibm,processor-storage-keys property and calls be32_to_cpu() on the
value it gets. The problem is that of_property_read_u32_array() already
returns the value converted to the CPU byte order.

The value of pkeys_total ends up more or less sane because there's a min()
call in pkey_initialize() which reduces pkeys_total to 32. So in practice
the kernel ignores the fact that the hypervisor reserved one key for
itself (the device tree advertises 31 keys in my test VM).

This is wrong, but the effect in practice is that when a process tries to
allocate the 32nd key, it gets an -EINVAL error instead of -ENOSPC which
would indicate that there aren't any keys available

Fixes: cf43d3b264 ("powerpc: Enable pkey subsystem")
Cc: stable@vger.kernel.org # v4.16+
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Thiago Jung Bauermann 2018-09-20 01:38:58 -03:00 committed by Michael Ellerman
parent 85682a7e3b
commit c716a25b9b
1 changed files with 1 additions and 1 deletions
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2
arch/powerpc/mm/pkeys.c
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@ -45,7 +45,7 @@ static void scan_pkey_feature(void)
* Since any pkey can be used for data or execute, we will just treat * Since any pkey can be used for data or execute, we will just treat
* all keys as equal and track them as one entity. * all keys as equal and track them as one entity.
*/ */
pkeys_total = be32_to_cpu(vals[0]); pkeys_total = vals[0];
pkeys_devtree_defined = true; pkeys_devtree_defined = true;
} }