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| author | Peter Zijlstra <peterz@infradead.org> | 2020-09-02 15:26:02 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-09-04 15:12:58 +0200 |
| commit | d53d9bc0cf783e93b374de3895145c7375e570ba (patch) | |
| tree | fb95a9c74cba7e6a7d93f58f80f542e941f99997 /arch/x86/kernel/ptrace.c | |
| parent | f4956cf83ed12271bdbd5b547f3378add72bbffb (diff) | |
| download | linux-d53d9bc0cf783e93b374de3895145c7375e570ba.tar.gz linux-d53d9bc0cf783e93b374de3895145c7375e570ba.tar.bz2 linux-d53d9bc0cf783e93b374de3895145c7375e570ba.zip | |
x86/debug: Change thread.debugreg6 to thread.virtual_dr6
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
Diffstat (limited to 'arch/x86/kernel/ptrace.c')
| -rw-r--r-- | arch/x86/kernel/ptrace.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 5f982896dc0b..bedca011459c 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -465,7 +465,7 @@ static void ptrace_triggered(struct perf_event *bp, break; } - thread->debugreg6 |= (DR_TRAP0 << i); + thread->virtual_dr6 |= (DR_TRAP0 << i); } /* @@ -601,7 +601,7 @@ static unsigned long ptrace_get_debugreg(struct task_struct *tsk, int n) if (bp) val = bp->hw.info.address; } else if (n == 6) { - val = thread->debugreg6 ^ DR6_RESERVED; /* Flip back to arch polarity */ + val = thread->virtual_dr6 ^ DR6_RESERVED; /* Flip back to arch polarity */ } else if (n == 7) { val = thread->ptrace_dr7; } @@ -657,7 +657,7 @@ static int ptrace_set_debugreg(struct task_struct *tsk, int n, if (n < HBP_NUM) { rc = ptrace_set_breakpoint_addr(tsk, n, val); } else if (n == 6) { - thread->debugreg6 = val ^ DR6_RESERVED; /* Flip to positive polarity */ + thread->virtual_dr6 = val ^ DR6_RESERVED; /* Flip to positive polarity */ rc = 0; } else if (n == 7) { rc = ptrace_write_dr7(tsk, val); |