Messages in this thread | | | Date | Fri, 8 May 2020 10:59:09 +0200 | From | Peter Zijlstra <> | Subject | Re: [patch V4 part 4 15/24] x86/db: Split out dr6/7 handling |
| |
On Thu, May 07, 2020 at 07:18:45PM +0200, Alexandre Chartre wrote: > > On 5/5/20 3:49 PM, Thomas Gleixner wrote: > > From: Peter Zijlstra <peterz@infradead.org> > > > > 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> > > --- > > arch/x86/kernel/hw_breakpoint.c | 6 --- > > arch/x86/kernel/traps.c | 62 +++++++++++++++++++++++++++------------- > > 2 files changed, 44 insertions(+), 24 deletions(-) > > > ... > > --- a/arch/x86/kernel/traps.c > > +++ b/arch/x86/kernel/traps.c > > @@ -691,6 +691,44 @@ static bool is_sysenter_singlestep(struc > > #endif > > } > > +static __always_inline void debug_enter(unsigned long *dr6, unsigned long *dr7) > > +{ > > + /* > > + * Disable breakpoints during exception handling; recursive exceptions > > + * are exceedingly 'fun'. > > + * > > + * Since this function is NOKPROBE, and that also applies to > > + * HW_BREAKPOINT_X, we can't hit a breakpoint before this (XXX except a > > + * HW_BREAKPOINT_W on our stack) > > + * > > + * Entry text is excluded for HW_BP_X and cpu_entry_area, which > > + * includes the entry stack is excluded for everything. > > + */ > > + get_debugreg(*dr7, 6); > > Do you mean get_debugreg(*dr7, 7); ?
Shees, I have to go buy a new stack of brown paper bags at this rate, don't I :/
| |