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author | Thomas Gleixner <tglx@linutronix.de> | 2019-11-11 23:03:28 +0100 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2019-11-16 11:24:05 +0100 |
commit | c8137ace56383688af911fea5934c71ad158135e (patch) | |
tree | 27f653f628e61a868ef0e4d9ece62185e1c24952 /crypto | |
parent | be9afb4b529d9e3a68da1212e33be677bbfc8d2c (diff) | |
download | linux-c8137ace56383688af911fea5934c71ad158135e.tar.bz2 |
x86/iopl: Restrict iopl() permission scope
The access to the full I/O port range can be also provided by the TSS I/O
bitmap, but that would require to copy 8k of data on scheduling in the
task. As shown with the sched out optimization TSS.io_bitmap_base can be
used to switch the incoming task to a preallocated I/O bitmap which has all
bits zero, i.e. allows access to all I/O ports.
Implementing this allows to provide an iopl() emulation mode which restricts
the IOPL level 3 permissions to I/O port access but removes the STI/CLI
permission which is coming with the hardware IOPL mechansim.
Provide a config option to switch IOPL to emulation mode, make it the
default and while at it also provide an option to disable IOPL completely.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Diffstat (limited to 'crypto')
0 files changed, 0 insertions, 0 deletions