Messages in this thread | | | Date | Wed, 01 Jul 2015 17:00:28 -0700 | From | Stephen Boyd <> | Subject | Re: [PATCH 4/4] hvc_dcc: disable user-space access to DCC |
| |
On 06/30/2015 02:23 PM, Timur Tabi wrote: > diff --git a/arch/arm/include/asm/dcc.h b/arch/arm/include/asm/dcc.h > index b74899d..c50056b 100644 > --- a/arch/arm/include/asm/dcc.h > +++ b/arch/arm/include/asm/dcc.h > @@ -9,8 +9,11 @@ > * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > * GNU General Public License for more details. > */ > +#ifndef __ASM_DCC_H > +#define __ASM_DCC_H > > #include <asm/barrier.h> > +#include <asm/hardware/cp14.h>
That's new.
> > static inline u32 __dcc_getstatus(void) > { > @@ -39,3 +42,15 @@ static inline void __dcc_putchar(char c) > : "r" (c)); > isb(); > } > + > +static inline void __dcc_initialize(void) > +{ > + u32 val; > + > + /* Disable user-space access to DCC */ > + val = MRC14(0, c0, c1, 0); > + val |= 1 << 12; /* DSCR[Comms] */ > + MCR14(val, 0, c0, c1, 0); > +}
Nitpick: We do raw cp14 accesses for other functions in this file, so it would be nice to be consistent throughout.
> + > +#endif > diff --git a/arch/arm64/include/asm/dcc.h b/arch/arm64/include/asm/dcc.h > index fcb8d7d..7843e62 100644 > --- a/arch/arm64/include/asm/dcc.h > +++ b/arch/arm64/include/asm/dcc.h > @@ -49,4 +49,15 @@ static inline void __dcc_putchar(char c) > isb(); > } > > +static inline void __dcc_initialize(void) > +{ > + u32 val; > + > + /* Disable user-space access to DCC */ > + asm ("mrs %0, mdscr_el1\n"
shouldn't this be volatile?
> + " orr %0, %0, #4096\n" /* Set the TDCC bit */
arm64 has some #defines in debug-monitors.h which we should probably extend to have this bit as a #define too.
> + " msr mdscr_el1, %0\n" > + : "=r" (val)); > +} > + > #endif >
-- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
| |