x86/mpx: Fix 32-bit address space calculation

I received a bug report that running 32-bit MPX binaries on
64-bit kernels was broken.  I traced it down to this little code
snippet.  We were switching our "number of bounds directory
entries" calculation correctly.  But, we didn't switch the other
side of the calculation: the virtual space size.

This meant that we were calculating an absurd size for
bd_entry_virt_space() on 32-bit because we used the 64-bit
virt_space.

This was _also_ broken for 32-bit kernels running on 64-bit
hardware since boot_cpu_data.x86_virt_bits=48 even when running
in 32-bit mode.

Correct that and properly handle all 3 possible cases:

 1. 32-bit binary on 64-bit kernel
 2. 64-bit binary on 64-bit kernel
 3. 32-bit binary on 32-bit kernel

This manifested in having bounds tables not properly unmapped.
It "leaked" memory but had no functional impact otherwise.

Signed-off-by: Dave Hansen <[email protected]>
Cc: <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions