Re: [PATCH v6 7/7] coresight: config: Add preloaded configuration

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@marvell.com

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)

Suzuki

• .nr_feat_refs = ARRAY_SIZE(pstop_ref_names),
• .feat_ref_names = pstop_ref_names,
• .nr_total_params = PSTOP_NR_PARAMS,

+};

+/* end of ETM4x configurations */ +#endif /* IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM4X) */