Re: [PATCH v2 4/6] coresight: samples: Add an example config writer for configfs load

Good morning Mike,

On Tue, Nov 30, 2021 at 10:00:58PM +0000, Mike Leach wrote:

Add an example file generator to test loading configurations via a binary attribute in configfs.

Provides a file buffer writer function that can be re-used in other userspace programs.

Buffer write format matches that expected by the corresponding reader in the configfs driver code.

Despite trying quite hard I haven't found a single bug in this patchset, which is a feat for user space code.

Please see comments below...

Signed-off-by: Mike Leach mike.leach@linaro.org

samples/coresight/Makefile | 7 + samples/coresight/coresight-cfg-bufw.c | 302 ++++++++++++++++++++++ samples/coresight/coresight-cfg-bufw.h | 24 ++ samples/coresight/coresight-cfg-filegen.c | 89 +++++++ 4 files changed, 422 insertions(+) create mode 100644 samples/coresight/coresight-cfg-bufw.c create mode 100644 samples/coresight/coresight-cfg-bufw.h create mode 100644 samples/coresight/coresight-cfg-filegen.c

diff --git a/samples/coresight/Makefile b/samples/coresight/Makefile index b3fce4af2347..07bfd99d7a68 100644 --- a/samples/coresight/Makefile +++ b/samples/coresight/Makefile @@ -1,4 +1,11 @@ # SPDX-License-Identifier: GPL-2.0-only +# coresight config - loadable module configuration. obj-$(CONFIG_SAMPLE_CORESIGHT_SYSCFG) += coresight-cfg-sample.o ccflags-y += -I$(srctree)/drivers/hwtracing/coresight

+# coresight config - configfs loadable binary config generator +userprogs-always-y += coresight-cfg-filegen

+coresight-cfg-filegen-objs := coresight-cfg-filegen.o coresight-cfg-bufw.o +userccflags += -I$(srctree)/drivers/hwtracing/coresight diff --git a/samples/coresight/coresight-cfg-bufw.c b/samples/coresight/coresight-cfg-bufw.c new file mode 100644 index 000000000000..8c32a8509eef --- /dev/null +++ b/samples/coresight/coresight-cfg-bufw.c @@ -0,0 +1,302 @@ +// SPDX-License-Identifier: GPL-2.0 +/*

• • Copyright (c) 2020 Linaro Limited, All rights reserved.

Are you sure you want to keep this to 2020? Here and in all other files.

• • Author: Mike Leach mike.leach@linaro.org
• */

+#include <string.h>

+#include "coresight-cfg-bufw.h"

+/*

• • Set of macros to make writing the buffer code easier.
• *.

Extra '.'

• • Uses naming convention as 'buffer' for the buffer pointer and
• • 'used' as the current bytes used by the encosing function.
• */

+#define cscfg_write_u64(val64) { \

• *(u64 *)(buffer + used) = val64; \
• used += sizeof(u64); \
• }

+#define cscfg_write_u32(val32) { \

• *(u32 *)(buffer + used) = val32; \
• used += sizeof(u32); \
• }

+#define cscfg_write_u16(val16) { \

• *(u16 *)(buffer + used) = val16; \
• used += sizeof(u16); \
• }

+#define cscfg_write_u8(val8) { \

• *(buffer + used) = val8; \
• used++; \
• }

+#define CHECK_WRET(rval) { \

• if (rval < 0) \

• return rval;	   \
  

• used += rval; \
• }

+/* write the header at the start of the buffer */ +static int cscfg_file_write_fhdr(u8 *buffer, const int buflen,

• 		 const struct cscfg_file_header *fhdr)
  

+{

• int used = 0;
• cscfg_write_u32(fhdr->magic_version);
• cscfg_write_u16(fhdr->length);
• cscfg_write_u16(fhdr->nr_features);
• return used;

+}

+static int cscfg_file_write_string(u8 *buffer, const int buflen, const char *string) +{

• int len, used = 0;
• len = strlen(string);
• if (len > CSCFG_FILE_STR_MAXSIZE)

• return -EINVAL;
  

• if (buflen < (len + 1 + sizeof(u16)))

• return -EINVAL;
  

• cscfg_write_u16((u16)(len + 1));
• strcpy((char *)(buffer + used), string);
• used += (len + 1);
• return used;

+}

+static int cscfg_file_write_elem_hdr(u8 *buffer, const int buflen,

• 		     struct cscfg_file_elem_header *ehdr)
  

+{

• int used = 0;
• if (buflen < (sizeof(u16) + sizeof(u8)))

• return -EINVAL;
  

• cscfg_write_u16(ehdr->elem_length);
• cscfg_write_u8(ehdr->elem_type);
• return used;

+}

Extra newline

+static int cscfg_file_write_config(u8 *buffer, const int buflen,

• 		   struct cscfg_config_desc *config_desc)
  

+{

• int used = 0, bytes_w, space_req, preset_bytes, i;
• struct cscfg_file_elem_header ehdr;
• ehdr.elem_length = 0;
• ehdr.elem_type = CSCFG_FILE_ELEM_TYPE_CFG;
• /* write element header at current buffer location */
• bytes_w = cscfg_file_write_elem_hdr(buffer, buflen, &ehdr);
• CHECK_WRET(bytes_w);
• /* write out the configuration name */
• bytes_w = cscfg_file_write_string(buffer + used, buflen - used,

• 			  config_desc->name);
  

• CHECK_WRET(bytes_w);
• /* write out the description string */
• bytes_w = cscfg_file_write_string(buffer + used, buflen - used,

• 			  config_desc->description);
  

• CHECK_WRET(bytes_w);
• /*

• * calculate the space needed for variables + presets
  

• * [u16 value - nr_presets]
  

• * [u32 value - nr_total_params]
  

• * [u16 value - nr_feat_refs]
  

• * [u64 values] * (nr_presets * nr_total_params)
  

• */
  

• preset_bytes = sizeof(u64) * config_desc->nr_presets * config_desc->nr_total_params;
• space_req = (sizeof(u16) * 2) + sizeof(u32) + preset_bytes;
• if ((buflen - used) < space_req)

• return -EINVAL;
  

• cscfg_write_u16((u16)config_desc->nr_presets);
• cscfg_write_u32((u32)config_desc->nr_total_params);
• cscfg_write_u16((u16)config_desc->nr_feat_refs);
• if (preset_bytes) {

• memcpy(buffer + used, (u8 *)config_desc->presets, preset_bytes);
  

• used += preset_bytes;
  

• }
• /* now write the feature ref names */
• for (i = 0; i < config_desc->nr_feat_refs; i++) {

• bytes_w = cscfg_file_write_string(buffer + used, buflen - used,
  

• 				  config_desc->feat_ref_names[i]);
  

• CHECK_WRET(bytes_w);
  

• }
• /* rewrite the element header with the correct length */
• ehdr.elem_length = used;
• bytes_w = cscfg_file_write_elem_hdr(buffer, buflen, &ehdr);
• /* no CHECK_WRET as used must not be updated */
• if (bytes_w < 0)

• return bytes_w;
  

• return used;

+}

+/*

• • write a parameter structure into the buffer in following format:
• • [cscfg_file_elem_str] - parameter name.
• • [u64 value: param_value] - initial value.
• */

+static int cscfg_file_write_param(u8 *buffer, const int buflen,

• 		  struct cscfg_parameter_desc *param_desc)
  

+{

• int used = 0, bytes_w;
• bytes_w = cscfg_file_write_string(buffer + used, buflen - used,

• 			  param_desc->name);
  

• CHECK_WRET(bytes_w);
• if ((buflen - used) < sizeof(u64))

• return -EINVAL;
  

• cscfg_write_u64(param_desc->value);
• return used;

+} +/*

• • Write a feature element from cscfg_feature_desc in following format:
• • [cscfg_file_elem_header] - header length is total bytes to end of param structures.
• • [cscfg_file_elem_str] - feature name.
• • [cscfg_file_elem_str] - feature description.
• • [u32 value: match_flags]
• • [u16 value: nr_regs] - number of registers.
• • [u16 value: nr_params] - number of parameters.
• • [cscfg_regval_desc struct] * nr_regs
• • [PARAM_ELEM] * nr_params

Extra newlines

• */

+static int cscfg_file_write_feat(u8 *buffer, const int buflen,

• 		 struct cscfg_feature_desc *feat_desc)
  

+{

• struct cscfg_file_elem_header ehdr;
• struct cscfg_regval_desc *p_reg_desc;
• int used = 0, bytes_w, i, space_req;
• u32 val32;
• ehdr.elem_length = 0;
• ehdr.elem_type = CSCFG_FILE_ELEM_TYPE_FEAT;
• /* write element header at current buffer location */
• bytes_w = cscfg_file_write_elem_hdr(buffer, buflen, &ehdr);
• CHECK_WRET(bytes_w);
• /* write out the name string */
• bytes_w = cscfg_file_write_string(buffer + used, buflen - used,

• 			  feat_desc->name);
  

• CHECK_WRET(bytes_w)
• /* write out the description string */
• bytes_w = cscfg_file_write_string(buffer + used, buflen - used,

• 			  feat_desc->description);
  

• CHECK_WRET(bytes_w);
• /* check for space for variables and register structures */
• space_req = (sizeof(u16) * 2) + sizeof(u32) +

• (sizeof(struct cscfg_regval_desc) * feat_desc->nr_regs);
  

• if ((buflen - used) < space_req)

• return -EINVAL;
  

• /* write the variables */
• cscfg_write_u32((u32)feat_desc->match_flags);
• cscfg_write_u16((u16)feat_desc->nr_regs);
• cscfg_write_u16((u16)feat_desc->nr_params);
• /*write the registers */
• for (i = 0; i < feat_desc->nr_regs; i++) {

• p_reg_desc = (struct cscfg_regval_desc *)&feat_desc->regs_desc[i];
  

• CSCFG_FILE_REG_DESC_INFO_TO_U32(val32, p_reg_desc);
  

• cscfg_write_u32(val32);
  

• cscfg_write_u64(feat_desc->regs_desc[i].val64);
  

• }
• /* write any parameters */
• for (i = 0; i < feat_desc->nr_params; i++) {

• bytes_w = cscfg_file_write_param(buffer + used, buflen - used,
  

• 				 &feat_desc->params_desc[i]);
  

• CHECK_WRET(bytes_w);
  

• }
• /*

• * rewrite the element header at the start of the buffer block
  

• * with the correct length
  

• */
  

• ehdr.elem_length = used;
• bytes_w = cscfg_file_write_elem_hdr(buffer, buflen, &ehdr);
• /* no CHECK_WRET as used must not be updated */
• if (bytes_w < 0)

• return bytes_w;
  

• return used;

+}

+/*

• • write a buffer from the configuration and feature
• • descriptors to write into a file for configfs.
• • Will only write one config, and/or a number of features,
• • per the file standard.
• */

+int cscfg_file_write_buffer(u8 *buffer, const int buflen,

• 	    struct cscfg_config_desc *config_desc,
  

• 	    struct cscfg_feature_desc **feat_descs)
  

+{

• struct cscfg_file_header fhdr;
• int used = 0, bytes_w, i;
• /* init the file header */
• fhdr.magic_version = CSCFG_FILE_MAGIC_VERSION;
• fhdr.length = 0;
• fhdr.nr_features = 0;
• /* count the features */
• if (feat_descs) {

• while (feat_descs[fhdr.nr_features])
  

• 	fhdr.nr_features++;
  

• }
• /* need a buffer and at least one config or feature */
• if ((!config_desc && !fhdr.nr_features) ||

•    !buffer || (buflen > CSCFG_FILE_MAXSIZE))
  

• return -EINVAL;
  

• /* write a header at the start to get the length of the header */
• bytes_w = cscfg_file_write_fhdr(buffer, buflen, &fhdr);
• CHECK_WRET(bytes_w);
• /* write a single config */
• if (config_desc) {

• bytes_w = cscfg_file_write_config(buffer + used, buflen - used,
  

• 				  config_desc);
  

• CHECK_WRET(bytes_w);
  

• }
• /* write any features */
• for (i = 0; i < fhdr.nr_features; i++) {

• bytes_w = cscfg_file_write_feat(buffer + used, buflen - used,
  

• 				feat_descs[i]);
  

• CHECK_WRET(bytes_w);
  

• }
• /* finally re-write the header at the buffer start with the correct length */
• fhdr.length = (u16)used;
• bytes_w = cscfg_file_write_fhdr(buffer, buflen, &fhdr);
• /* no CHECK_WRET as used must not be updated */
• if (bytes_w < 0)

• return bytes_w;
  

• return used;

+} diff --git a/samples/coresight/coresight-cfg-bufw.h b/samples/coresight/coresight-cfg-bufw.h new file mode 100644 index 000000000000..00b16c583cad --- /dev/null +++ b/samples/coresight/coresight-cfg-bufw.h @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/*

• • Copyright (c) 2020 Linaro Limited, All rights reserved.
• • Author: Mike Leach mike.leach@linaro.org
• */

+#ifndef _CORESIGHT_CFG_BUFW_H +#define _CORESIGHT_CFG_BUFW_H

+#include "coresight-config-file.h"

+/*

• • Function to take coresight configurations and features and
• • write them into a supplied memory buffer for serialisation
• • into a file.
• • Resulting file can then be loaded into the coresight
• • infrastructure via configfs.
• */

+int cscfg_file_write_buffer(u8 *buffer, const int buflen,

• 	    struct cscfg_config_desc *config_desc,
  

• 	    struct cscfg_feature_desc **feat_descs);
  

+#endif /* _CORESIGHT_CFG_BUFW_H */ diff --git a/samples/coresight/coresight-cfg-filegen.c b/samples/coresight/coresight-cfg-filegen.c new file mode 100644 index 000000000000..c8be18ee97b6 --- /dev/null +++ b/samples/coresight/coresight-cfg-filegen.c @@ -0,0 +1,89 @@ +// SPDX-License-Identifier: GPL-2.0 +/*

• • Copyright (c) 2020 Linaro Limited, All rights reserved.
• • Author: Mike Leach mike.leach@linaro.org
• */

+#include <linux/types.h> +#include <linux/unistd.h> +#include <stdio.h> +#include <unistd.h>

+#include "coresight-cfg-bufw.h"

+/*

• • generate example binary coresight configuration files for loading
• • into the coresight subsystem via configfs
• */

+/* create a similar configuration example as the coresight-cfg-sample.c file. */

+/* we will provide 4 sets of preset parameter values */ +#define AFDO2_NR_PRESETS 4 +/* the total number of parameters in used features - strobing has 2 */ +#define AFDO2_NR_PARAM_SUM 2

+static const char *afdo2_ref_names[] = {

• "strobing",

+};

+/*

• • set of presets leaves strobing window constant while varying period to allow
• • experimentation with mark / space ratios for various workloads
• */

+static u64 afdo2_presets[AFDO2_NR_PRESETS][AFDO2_NR_PARAM_SUM] = {

• { 2000, 100 },
• { 2000, 1000 },
• { 2000, 5000 },
• { 2000, 10000 },

+};

+struct cscfg_config_desc afdo3 = {

• .name = "autofdo3",
• .description = "Setup ETMs with strobing for autofdo\n"
• "Supplied presets allow experimentation with mark-space ratio for various loads\n",
• .nr_feat_refs = ARRAY_SIZE(afdo2_ref_names),
• .feat_ref_names = afdo2_ref_names,
• .nr_presets = AFDO2_NR_PRESETS,
• .nr_total_params = AFDO2_NR_PARAM_SUM,
• .presets = &afdo2_presets[0][0],

+};

+static struct cscfg_feature_desc *sample_feats[] = {

• NULL

+};

For completeness there would be value in providing an example that requires features.

+static struct cscfg_config_desc *sample_cfgs[] = {

• &afdo3,
• NULL

+};

Any reason to declare sample_cfgs[] when there can only be one configuration?

Lastly I get the following [1] when compiling this set - I have not investigated further.

Thanks, Mathieu

[1]. https://pastebin.com/Nw2DTqTC

+#define CSCFG_BIN_FILENAME "example1.cscfg"

+int main(int argc, char **argv) +{

• u8 buffer[CSCFG_FILE_MAXSIZE];
• int used;
• FILE *fp;
• printf("Coresight Configuration file Generator\n\n");
• used = cscfg_file_write_buffer(buffer, CSCFG_FILE_MAXSIZE,

• 		       sample_cfgs[0], sample_feats);
  

• if (used < 0) {

• printf("Error %d writing configuration %s into buffer\n",
  

•        used, sample_cfgs[0]->name);
  

• return used;
  

• }
• fp = fopen(CSCFG_BIN_FILENAME, "wb");
• if (fp == NULL) {

• printf("Error opening file %s\n", CSCFG_BIN_FILENAME);
  

• return -1;
  

• }
• fwrite(buffer, used, sizeof(u8), fp);
• fclose(fp);
• return 0;

+}

2.17.1