x86/debug: Change thread.debugreg6 to thread.virtual_dr6

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Current usage of thread.debugreg6 is convoluted at best. It starts life as
a copy of the hardware DR6 value, but then various bits are cleared and
set.

Replace this with a new variable thread.virtual_dr6 that is initialized to
0 when DR6 is read and only gains bits, at the same time the actual (on
stack) dr6 value which is read from the hardware only gets bits cleared.

Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20200902133201.415372940@infradead.org

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This commit is contained in:

Peter Zijlstra 2020-09-02 15:26:02 +02:00 • committed by Thomas Gleixner

parent f4956cf83e

commit d53d9bc0cf

5 changed files with 26 additions and 24 deletions

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2

arch/x86/include/asm/processor.h

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12

arch/x86/kernel/hw_breakpoint.c

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5

arch/x86/kernel/kgdb.c

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6

arch/x86/kernel/ptrace.c

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25

arch/x86/kernel/traps.c

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