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| author |  Peter Zijlstra <peterz@infradead.org>
| 2020-04-06 21:02:56 +0200 |
|---|---|---|
| committer |  Thomas Gleixner <tglx@linutronix.de>
| 2020-06-11 15:14:59 +0200 |
| commit | 9f58fdde95c9509a4ded27a6d0035e79294002b4 (patch) | |
| tree | 52051e8aa46fb1962af8f97c4d6eb8876ca33936 /arch/x86/kernel/hw_breakpoint.c | |
| parent | x86/nmi: Protect NMI entry against instrumentation (diff) | |
| download | linux-9f58fdde95c9509a4ded27a6d0035e79294002b4.tar.gz linux-9f58fdde95c9509a4ded27a6d0035e79294002b4.tar.bz2 linux-9f58fdde95c9509a4ded27a6d0035e79294002b4.zip | |
x86/db: Split out dr6/7 handling
DR6/7 should be handled before nmi_enter() is invoked and restore after
nmi_exit() to minimize the exposure.
Split it out into helper inlines and bring it into the correct order.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505135314.808628211@linutronix.de
Diffstat (limited to 'arch/x86/kernel/hw_breakpoint.c')
| -rw-r--r-- | arch/x86/kernel/hw_breakpoint.c | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c index d42fc0eaf193..9ddf441ccaa8 100644 --- a/arch/x86/kernel/hw_breakpoint.c +++ b/arch/x86/kernel/hw_breakpoint.c @@ -464,7 +464,7 @@ static int hw_breakpoint_handler(struct die_args *args) { int i, cpu, rc = NOTIFY_STOP; struct perf_event *bp; - unsigned long dr7, dr6; + unsigned long dr6; unsigned long *dr6_p; /* The DR6 value is pointed by args->err */ @@ -479,9 +479,6 @@ static int hw_breakpoint_handler(struct die_args *args) if ((dr6 & DR_TRAP_BITS) == 0) return NOTIFY_DONE; - get_debugreg(dr7, 7); - /* Disable breakpoints during exception handling */ - set_debugreg(0UL, 7); /* * Assert that local interrupts are disabled * Reset the DRn bits in the virtualized register value. @@ -538,7 +535,6 @@ static int hw_breakpoint_handler(struct die_args *args) (dr6 & (~DR_TRAP_BITS))) rc = NOTIFY_DONE; - set_debugreg(dr7, 7); put_cpu(); return rc; |