x86/cpu: Uninline CR4 accessors

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cpu_tlbstate is exported because various TLB-related functions need
access to it, but cpu_tlbstate is sensitive information which should
only be accessed by well-contained kernel functions and not be directly
exposed to modules.

The various CR4 accessors require cpu_tlbstate as the CR4 shadow cache
is located there.

In preparation for unexporting cpu_tlbstate, create a builtin function
for manipulating CR4 and rework the various helpers to use it.

No functional change.

 [ bp: push the export of native_write_cr4() only when CONFIG_LKTDM=m to
   the last patch in the series. ]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200421092558.939985695@linutronix.de

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Thomas Gleixner 2020-04-21 11:20:29 +02:00 • committed by Borislav Petkov

parent 8c5cc19e94

commit d8f0b35331

3 changed files with 38 additions and 32 deletions

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36

arch/x86/include/asm/tlbflush.h

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23

arch/x86/kernel/cpu/common.c

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11

arch/x86/kernel/process.c

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