| Message ID | 1436793967-7138-3-git-send-email-Dave.Martin@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Jul 13, 2015 at 02:25:49PM +0100, Dave P Martin wrote: > There are only 16 comment bits in a BRK instruction, which > correspond to ESR bits 15:0. Bits 24:16 of the ESR are RES0, > and might have weird meanings in the future. > > This code inserts 16 bits of comment in the ESR value instead of > 20 (almost certainly a typo in the original code). I'd guess that someone got confused with the instruction encoding where the immediate lives in bits 20:5, though the mask would be wrong anyway. > > Signed-off-by: Dave Martin <Dave.Martin@arm.com> Looks sane to me. Acked-by: Mark Rutland <mark.rutland@arm.com> Mark. > --- > arch/arm64/include/asm/debug-monitors.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/debug-monitors.h b/arch/arm64/include/asm/debug-monitors.h > index f3d2dbd..ab7d5a8 100644 > --- a/arch/arm64/include/asm/debug-monitors.h > +++ b/arch/arm64/include/asm/debug-monitors.h > @@ -45,7 +45,7 @@ > /* > * ESR values expected for dynamic and compile time BRK instruction > */ > -#define DBG_ESR_VAL_BRK(x) (0xf2000000 | ((x) & 0xfffff)) > +#define DBG_ESR_VAL_BRK(x) (0xf2000000 | ((x) & 0xffff)) > > /* > * #imm16 values used for BRK instruction generation > -- > 1.7.10.4 >
On Mon, Jul 13, 2015 at 03:14:40PM +0100, Mark Rutland wrote: > On Mon, Jul 13, 2015 at 02:25:49PM +0100, Dave P Martin wrote: > > There are only 16 comment bits in a BRK instruction, which > > correspond to ESR bits 15:0. Bits 24:16 of the ESR are RES0, > > and might have weird meanings in the future. > > > > This code inserts 16 bits of comment in the ESR value instead of > > 20 (almost certainly a typo in the original code). > > I'd guess that someone got confused with the instruction encoding where > the immediate lives in bits 20:5, though the mask would be wrong anyway. > > > > > Signed-off-by: Dave Martin <Dave.Martin@arm.com> > > Looks sane to me. > > Acked-by: Mark Rutland <mark.rutland@arm.com> Cheers. This was harmless up to now, anyway. It will only bite if someone passes x >= 0x10000, which they're not supposed to do. ---Dave > > Mark. > > > --- > > arch/arm64/include/asm/debug-monitors.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/arch/arm64/include/asm/debug-monitors.h b/arch/arm64/include/asm/debug-monitors.h > > index f3d2dbd..ab7d5a8 100644 > > --- a/arch/arm64/include/asm/debug-monitors.h > > +++ b/arch/arm64/include/asm/debug-monitors.h > > @@ -45,7 +45,7 @@ > > /* > > * ESR values expected for dynamic and compile time BRK instruction > > */ > > -#define DBG_ESR_VAL_BRK(x) (0xf2000000 | ((x) & 0xfffff)) > > +#define DBG_ESR_VAL_BRK(x) (0xf2000000 | ((x) & 0xffff)) > > > > /* > > * #imm16 values used for BRK instruction generation > > -- > > 1.7.10.4 > > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
diff --git a/arch/arm64/include/asm/debug-monitors.h b/arch/arm64/include/asm/debug-monitors.h index f3d2dbd..ab7d5a8 100644 --- a/arch/arm64/include/asm/debug-monitors.h +++ b/arch/arm64/include/asm/debug-monitors.h @@ -45,7 +45,7 @@ /* * ESR values expected for dynamic and compile time BRK instruction */ -#define DBG_ESR_VAL_BRK(x) (0xf2000000 | ((x) & 0xfffff)) +#define DBG_ESR_VAL_BRK(x) (0xf2000000 | ((x) & 0xffff)) /* * #imm16 values used for BRK instruction generation
There are only 16 comment bits in a BRK instruction, which correspond to ESR bits 15:0. Bits 24:16 of the ESR are RES0, and might have weird meanings in the future. This code inserts 16 bits of comment in the ESR value instead of 20 (almost certainly a typo in the original code). Signed-off-by: Dave Martin <Dave.Martin@arm.com> --- arch/arm64/include/asm/debug-monitors.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)