Hi Suzuki,
> -----Original Message-----
> From: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> Sent: Friday, January 12, 2024 7:34 PM
> To: Linu Cherian <lcherian@xxxxxxxxxxx>; mike.leach@xxxxxxxxxx;
> james.clark@xxxxxxx; leo.yan@xxxxxxxxxx
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; coresight@xxxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; robh+dt@xxxxxxxxxx;
> krzysztof.kozlowski+dt@xxxxxxxxxx; conor+dt@xxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; Sunil Kovvuri Goutham
> <sgoutham@xxxxxxxxxxx>; George Cherian <gcherian@xxxxxxxxxxx>
> Subject: [EXT] Re: [PATCH v6 7/7] coresight: config: Add preloaded
> configuration
>
> External Email
>
> ----------------------------------------------------------------------
> On 05/01/2024 05:58, Linu Cherian wrote:
> > Add a preloaded configuration for generating external trigger on
> > address match. This can be used by CTI and ETR blocks to stop trace
> > capture on kernel panic.
> >
> > Kernel address for panic function to be programmed as below.
> >
> > $cd /config/cs-syscfg/features/gen_etrig/params
> > $echo <panic_address> > address/value
> >
> > Signed-off-by: Linu Cherian <lcherian@xxxxxxxxxxx>
> > ---
> > Changelog from v5:
> > * No changes
> >
> > drivers/hwtracing/coresight/Makefile | 2 +-
> > .../coresight/coresight-cfg-preload.c | 2 +
> > .../coresight/coresight-cfg-preload.h | 2 +
> > .../hwtracing/coresight/coresight-cfg-pstop.c | 83 +++++++++++++++++++
> > 4 files changed, 88 insertions(+), 1 deletion(-)
> > create mode 100644 drivers/hwtracing/coresight/coresight-cfg-pstop.c
> >
> > diff --git a/drivers/hwtracing/coresight/Makefile
> > b/drivers/hwtracing/coresight/Makefile
> > index 995d3b2c76df..68b15c8d9462 100644
> > --- a/drivers/hwtracing/coresight/Makefile
> > +++ b/drivers/hwtracing/coresight/Makefile
> > @@ -5,7 +5,7 @@
> > obj-$(CONFIG_CORESIGHT) += coresight.o
> > coresight-y := coresight-core.o coresight-etm-perf.o coresight-platform.o \
> > coresight-sysfs.o coresight-syscfg.o coresight-config.o \
> > - coresight-cfg-preload.o coresight-cfg-afdo.o \
> > + coresight-cfg-preload.o coresight-cfg-afdo.o coresight-cfg-
> pstop.o
> > +\
> > coresight-syscfg-configfs.o coresight-trace-id.o
> > obj-$(CONFIG_CORESIGHT_LINK_AND_SINK_TMC) += coresight-tmc.o
> > coresight-tmc-y := coresight-tmc-core.o coresight-tmc-etf.o \ diff
> > --git a/drivers/hwtracing/coresight/coresight-cfg-preload.c
> > b/drivers/hwtracing/coresight/coresight-cfg-preload.c
> > index e237a4edfa09..4980e68483c5 100644
> > --- a/drivers/hwtracing/coresight/coresight-cfg-preload.c
> > +++ b/drivers/hwtracing/coresight/coresight-cfg-preload.c
> > @@ -13,6 +13,7 @@
> > static struct cscfg_feature_desc *preload_feats[] = {
> > #if IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM4X)
> > &strobe_etm4x,
> > + &gen_etrig_etm4x,
> > #endif
> > NULL
> > };
> > @@ -20,6 +21,7 @@ static struct cscfg_feature_desc *preload_feats[] = {
> > static struct cscfg_config_desc *preload_cfgs[] = {
> > #if IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM4X)
> > &afdo_etm4x,
> > + &pstop_etm4x,
> > #endif
> > NULL
> > };
> > diff --git a/drivers/hwtracing/coresight/coresight-cfg-preload.h
> > b/drivers/hwtracing/coresight/coresight-cfg-preload.h
> > index 21299e175477..291ba530a6a5 100644
> > --- a/drivers/hwtracing/coresight/coresight-cfg-preload.h
> > +++ b/drivers/hwtracing/coresight/coresight-cfg-preload.h
> > @@ -10,4 +10,6 @@
> > #if IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM4X)
> > extern struct cscfg_feature_desc strobe_etm4x;
> > extern struct cscfg_config_desc afdo_etm4x;
> > +extern struct cscfg_feature_desc gen_etrig_etm4x; extern struct
> > +cscfg_config_desc pstop_etm4x;
> > #endif
> > diff --git a/drivers/hwtracing/coresight/coresight-cfg-pstop.c
> > b/drivers/hwtracing/coresight/coresight-cfg-pstop.c
> > new file mode 100644
> > index 000000000000..037d6773fab8
> > --- /dev/null
> > +++ b/drivers/hwtracing/coresight/coresight-cfg-pstop.c
> > @@ -0,0 +1,83 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright(C) 2023 Marvell.
> > + * Based on coresight-cfg-afdo.c
> > + */
> > +
> > +#include "coresight-config.h"
> > +
> > +/* ETMv4 includes and features */
> > +#if IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM4X)
> > +#include "coresight-etm4x-cfg.h"
> > +
> > +/* preload configurations and features */
> > +
> > +/* preload in features for ETMv4 */
> > +
> > +/* panic_stop feature */
> > +static struct cscfg_parameter_desc gen_etrig_params[] = {
> > + {
> > + .name = "address",
> > + .value = 0x0,
> > + },
> > +};
> > +
> > +static struct cscfg_regval_desc gen_etrig_regs[] = {
> > + /* resource selector */
> > + {
> > + .type = CS_CFG_REG_TYPE_RESOURCE,
> > + .offset = TRCRSCTLRn(2),
> > + .hw_info = ETM4_CFG_RES_SEL,
> > + .val32 = 0x40001,
> > + },
> > + /* single address comparator */
> > + {
> > + .type = CS_CFG_REG_TYPE_RESOURCE |
> CS_CFG_REG_TYPE_VAL_64BIT |
> > + CS_CFG_REG_TYPE_VAL_PARAM,
> > + .offset = TRCACVRn(0),
> > + .val32 = 0x0,
> > + },
> > + {
> > + .type = CS_CFG_REG_TYPE_RESOURCE,
> > + .offset = TRCACATRn(0),
> > + .val64 = 0xf00,
> > + },
> > + /* Driver external output[0] with comparator out */
> > + {
> > + .type = CS_CFG_REG_TYPE_RESOURCE,
> > + .offset = TRCEVENTCTL0R,
> > + .val32 = 0x2,
> > + },
> > + /* end of regs */
> > +};
> > +
> > +struct cscfg_feature_desc gen_etrig_etm4x = {
> > + .name = "gen_etrig",
> > + .description = "Generate external trigger on address match\n"
> > + "parameter \'address\': address of kernel address\n",
> > + .match_flags = CS_CFG_MATCH_CLASS_SRC_ETM4,
> > + .nr_params = ARRAY_SIZE(gen_etrig_params),
> > + .params_desc = gen_etrig_params,
> > + .nr_regs = ARRAY_SIZE(gen_etrig_regs),
> > + .regs_desc = gen_etrig_regs,
> > +};
> > +
> > +/* create a panic stop configuration */
> > +
> > +/* the total number of parameters in used features */
> > +#define PSTOP_NR_PARAMS ARRAY_SIZE(gen_etrig_params)
> > +
> > +static const char *pstop_ref_names[] = {
> > + "gen_etrig",
> > +};
> > +
> > +struct cscfg_config_desc pstop_etm4x = {
> > + .name = "panicstop",
> > + .description = "Stop ETM on kernel panic\n",
>
> Since this is actually generic, i.e., Stop trace on a Kernel address, we could
> rename this ? Or why don't we pre-populate the address of "panic"
> at load time. That way the user doesn't have to figure out the kernel address
> (e.g., if KASLR is enabled)
>
Yeah, will hardcode that parameter value to panic symbol. That will avoid the hassle of user figuring out the kernel address for panic.
diff --git a/drivers/hwtracing/coresight/coresight-cfg-pstop.c b/drivers/hwtracing/coresight/coresight-cfg-pstop.c
index 037d6773fab8..c2bfbd07bfaf 100644
--- a/drivers/hwtracing/coresight/coresight-cfg-pstop.c
+++ b/drivers/hwtracing/coresight/coresight-cfg-pstop.c
@@ -18,7 +18,7 @@
static struct cscfg_parameter_desc gen_etrig_params[] = {
{
.name = "address",
- .value = 0x0,
+ .value = (u64)panic,
},
};
Linu Cherian.
