[Pdbg] [PATCH 1/2] libpdbg: Add default device-tree selection to libpdbg
Alistair Popple
alistair at popple.id.au
Mon Jul 1 17:52:08 AEST 2019
For portability reasons libpdbg intentionally did not deal with the
selection and retrieval of the device tree for a given system. This
means that by design each application was responsible for selecting
and loading the correct device tree for the system it was on.
This is convenient for embedded systems as it removes the dependency
on some libc functions such as open. However there are currently no
embedded users of libpdbg and forcing end user applications to select
the correct device tree is likely to be error prone and inconsistent.
Instead this patch adds the ability for applications to call
pdbg_targets_init(NULL) and have libpdbg attempt to detect and load
the correct device tree for the current system. This doesn't change
any existing behaviour as applications may still pass an explicit
device-tree to pdbg_targets_init() which will always be used.
An environment variable is provided so users may override the
auto-detected device-tree when the application does not provide one.
This patch will bloat the overall size of the library as it will now
include all the device-trees. It also likely makes things harder for
embedded users. However if either of these is an issue we should be
able to easily add a build time option to exclude this and/or only
build in specific device-trees.
Signed-off-by: Alistair Popple <alistair at popple.id.au>
---
Makefile.am | 20 +++--
libpdbg/device.c | 10 +++
libpdbg/dtb.c | 216 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
libpdbg/libpdbg.h | 1 +
4 files changed, 241 insertions(+), 6 deletions(-)
create mode 100644 libpdbg/dtb.c
diff --git a/Makefile.am b/Makefile.am
index 10c56b2..b421706 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -55,20 +55,22 @@ EXTRA_DIST = \
tests/test_driver.sh \
$(PDBG_TESTS)
-if TARGET_ARM
DT_ARM = p8-fsi.dts p8-i2c.dts p8-kernel.dts \
p9w-fsi.dts p9r-fsi.dts p9z-fsi.dts p9-kernel.dts
+
+if TARGET_ARM
ARCH_FLAGS="-DTARGET_ARM=1"
endif
-if TARGET_PPC
DT_PPC = p8-host.dts p9-host.dts
+
+if TARGET_PPC
ARCH_FLAGS="-DTARGET_PPC=1"
endif
DT = fake.dts $(DT_ARM) $(DT_PPC)
-DT_objects = $(DT:.dts=.dtb.o)
+DT_objects = $(DT:.dts=.dtb.lo)
DT_headers = $(DT:.dts=.dt.h)
optcmd_test_SOURCES = src/optcmd.c src/parsers.c src/tests/optcmd_test.c
@@ -127,6 +129,7 @@ pdbg_CFLAGS += -DDISABLE_GDBSERVER
endif
src/main.c: $(DT_headers)
+libpdbg/dtb.c: $(DT_headers)
src/pdbg-gdb_parser.$(OBJEXT): CFLAGS+=-Wno-unused-const-variable
@@ -149,6 +152,7 @@ libpdbg_la_SOURCES = \
libpdbg/debug.c \
libpdbg/debug.h \
libpdbg/device.c \
+ libpdbg/dtb.c \
libpdbg/fake.c \
libpdbg/host.c \
libpdbg/htm.c \
@@ -166,8 +170,10 @@ libpdbg_la_SOURCES = \
libpdbg/target.h \
libpdbg/xbus.c
+libpdbg_la_LIBADD = $(DT_objects)
+
if BUILD_LIBFDT
-libpdbg_la_LIBADD = libfdt/libfdt.la
+libpdbg_la_LIBADD += libfdt/libfdt.la
endif
include_HEADERS = libpdbg/libpdbg.h
@@ -242,8 +248,10 @@ p9z-fsi.dts: p9z-fsi.dts.m4 p9-fsi.dtsi
%.dt.h: %.dts
$(GEN_V)$(srcdir)/generate_dt_header.sh $< > $@
-%.dtb.o: %.dtb
- $(AM_V_CC)$(CC) -c $(srcdir)/template.S -DSYMBOL_PREFIX=$(shell basename $@ | tr '.-' '_') -DFILENAME=\"$<\" -o $@
+%.dtb.lo: %.dtb
+ $(AM_V_CC)$(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) \
+ --mode=compile $(CC) -c $(srcdir)/template.S \
+ -DSYMBOL_PREFIX=$(shell basename $@ | tr '.-' '_' | sed 's/lo/o/') -DFILENAME=\"$<\" -o $@
%.c: %.rl
$(RAGEL_V)$(RAGEL) -o $@ $<
diff --git a/libpdbg/device.c b/libpdbg/device.c
index b7fd49f..ba9e05e 100644
--- a/libpdbg/device.c
+++ b/libpdbg/device.c
@@ -638,7 +638,17 @@ uint64_t pdbg_target_address(struct pdbg_target *target, uint64_t *out_size)
void pdbg_targets_init(void *fdt)
{
+ /* Root node needs to be valid when this function returns */
pdbg_dt_root = dt_new_node("", NULL, 0);
+
+ if (!fdt)
+ fdt = pdbg_default_dtb();
+
+ if (!fdt) {
+ pdbg_log(PDBG_ERROR, "Could not find a system device tree\n");
+ return;
+ }
+
dt_expand(fdt);
}
diff --git a/libpdbg/dtb.c b/libpdbg/dtb.c
new file mode 100644
index 0000000..145b497
--- /dev/null
+++ b/libpdbg/dtb.c
@@ -0,0 +1,216 @@
+/* Copyright 2019 IBM Corp.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ * implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <assert.h>
+#include <inttypes.h>
+#include <errno.h>
+
+#include "libpdbg.h"
+
+#include "fake.dt.h"
+
+#include "p8-i2c.dt.h"
+#include "p8-fsi.dt.h"
+#include "p8-kernel.dt.h"
+#include "p9w-fsi.dt.h"
+#include "p9r-fsi.dt.h"
+#include "p9z-fsi.dt.h"
+#include "p9-kernel.dt.h"
+#include "p8-host.dt.h"
+#include "p9-host.dt.h"
+
+#define AMI_BMC "/proc/ractrends/Helper/FwInfo"
+#define OPENFSI_BMC "/sys/bus/platform/devices/gpio-fsi/fsi0/"
+#define FSI_CFAM_ID "/sys/devices/platform/gpio-fsi/fsi0/slave at 00:00/cfam_id"
+#define XSCOM_BASE_PATH "/sys/kernel/debug/powerpc/scom"
+
+#define CHIP_ID_P8 0xea
+#define CHIP_ID_P8P 0xd3
+#define CHIP_ID_P9 0xd1
+
+enum backend { FSI, I2C, KERNEL, FAKE, HOST };
+
+/* Determines the most appropriate backend for the host system we are
+ * running on. */
+static enum backend default_backend(void)
+{
+ int rc;
+
+ rc = access(XSCOM_BASE_PATH, F_OK);
+ if (rc == 0) /* PowerPC Host System */
+ return HOST;
+
+ rc = access(AMI_BMC, F_OK);
+ if (rc == 0) /* AMI BMC */
+ return I2C;
+
+ rc = access(OPENFSI_BMC, F_OK);
+ if (rc == 0) /* Kernel interface. OpenBMC */
+ return KERNEL;
+
+ return FAKE;
+}
+
+/* Try and determine what system type we are on by reading
+ * /proc/cpuinfo */
+static void *ppc_target(void)
+{
+ const char *pos = NULL;
+ char line[256];
+ FILE *cpuinfo;
+
+ cpuinfo = fopen("/proc/cpuinfo", "r");
+ if (!cpuinfo)
+ return NULL;
+
+ while ((pos = fgets(line, sizeof(line), cpuinfo)))
+ if (strncmp(line, "cpu", 3) == 0)
+ break;
+ fclose(cpuinfo);
+
+ if (!pos) {
+ /* Got to EOF without a break */
+ pdbg_log(PDBG_ERROR, "Unable to parse /proc/cpuinfo\n");
+ return NULL;
+ }
+
+ pos = strchr(line, ':');
+ if (!pos || (*(pos + 1) == '\0')) {
+ pdbg_log(PDBG_ERROR, "Unable to parse /proc/cpuinfo\n");
+ return NULL;
+ }
+
+ pos += 2;
+
+ if (strncmp(pos, "POWER8", 6) == 0) {
+ pdbg_log(PDBG_INFO, "Found a POWER8 PPC host system\n");
+ return &_binary_p8_host_dtb_o_start;
+ }
+
+ if (strncmp(pos, "POWER9", 6) == 0) {
+ pdbg_log(PDBG_INFO, "Found a POWER9 PPC host system\n");
+ return &_binary_p9_host_dtb_o_start;
+ }
+
+ pdbg_log(PDBG_ERROR, "Unsupported CPU type '%s'\n", pos);
+ return NULL;
+}
+
+static void *bmc_target(void)
+{
+ FILE *cfam_id_file;
+ uint32_t cfam_id = 0;
+ int rc;
+
+ /* Try and determine the correct device type */
+ cfam_id_file = fopen(FSI_CFAM_ID, "r");
+ if (!cfam_id_file) {
+ pdbg_log(PDBG_ERROR, "Unabled to open CFAM ID file\n");
+ return NULL;
+ }
+
+ rc = fscanf(cfam_id_file, "0x%" PRIx32, &cfam_id);
+ if (rc != 1) {
+ pdbg_log(PDBG_ERROR, "Unable to read CFAM ID: %s", strerror(errno));
+ }
+ fclose(cfam_id_file);
+
+ switch((cfam_id >> 4) & 0xff) {
+ case CHIP_ID_P9:
+ pdbg_log(PDBG_INFO, "Found a POWER9 OpenBMC based system\n");
+ return &_binary_p9_kernel_dtb_o_start;
+ break;
+
+ case CHIP_ID_P8:
+ case CHIP_ID_P8P:
+ pdbg_log(PDBG_INFO, "Found a POWER8/8+ OpenBMC based system\n");
+ return &_binary_p8_kernel_dtb_o_start;
+ break;
+ }
+
+ pdbg_log(PDBG_ERROR, "Unrecognised CFAM ID register 0x%08" PRIx32 "\n", cfam_id);
+ return NULL;
+}
+
+/* Opens a dtb at the given path */
+static void *mmap_dtb(char *file)
+{
+ int fd;
+ void *dtb;
+ struct stat statbuf;
+
+ fd = open(file, O_RDONLY);
+ if (fd < 0) {
+ pdbg_log(PDBG_ERROR, "Unable to open dtb file '%s'\n", file);
+ return NULL;
+ }
+
+ if (fstat(fd, &statbuf) == -1) {
+ pdbg_log(PDBG_ERROR, "Failed to stat file '%s'\n", file);
+ goto fail;
+ }
+
+ dtb = mmap(NULL, statbuf.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+ if (dtb == MAP_FAILED) {
+ pdbg_log(PDBG_ERROR, "Failed top mmap file '%s'\n", file);
+ goto fail;
+ }
+
+ return dtb;
+
+fail:
+ close(fd);
+ return NULL;
+}
+
+/* Determines what platform we are running on and returns a pointer to
+ * the fdt that is most likely to work on the system. */
+void *pdbg_default_dtb(void)
+{
+ char *dtb = getenv("LPDBG_DTB");
+
+ if (dtb)
+ return mmap_dtb(dtb);
+
+ switch(default_backend()) {
+ case HOST:
+ return ppc_target();
+ break;
+
+ case I2C:
+ /* I2C is only supported on POWER8 */
+ pdbg_log(PDBG_INFO, "Found a POWER8 AMI BMC based system\n");
+ return &_binary_p8_i2c_dtb_o_start;
+ break;
+
+ case KERNEL:
+ return bmc_target();
+ break;
+
+ default:
+ pdbg_log(PDBG_WARNING, "Unable to determine a valid default backend, using a fake one for testing purposes\n");
+ return &_binary_fake_dtb_o_start;
+ break;
+ }
+}
diff --git a/libpdbg/libpdbg.h b/libpdbg/libpdbg.h
index 14a41ab..7030139 100644
--- a/libpdbg/libpdbg.h
+++ b/libpdbg/libpdbg.h
@@ -103,6 +103,7 @@ enum pdbg_target_status pdbg_target_probe(struct pdbg_target *target);
void pdbg_target_release(struct pdbg_target *target);
enum pdbg_target_status pdbg_target_status(struct pdbg_target *target);
void pdbg_target_status_set(struct pdbg_target *target, enum pdbg_target_status status);
+void *pdbg_default_dtb(void);
uint32_t pdbg_target_index(struct pdbg_target *target);
char *pdbg_target_path(const struct pdbg_target *target);
struct pdbg_target *pdbg_target_from_path(struct pdbg_target *target, const char *path);
--
2.11.0
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