[U-Boot] [RFC][PATCH] Generate CRC of structure of Global Data for standalone apps
Graeme Russ
graeme.russ at gmail.com
Sat Sep 3 13:21:43 CEST 2011
There has been some discussion of late on the mailing list as to whether
or not a change to the Global Data structure should trigger an increment
to XF_VERSION. The issue is complicated by the fact that some arches have
#ifdef's in the definition of the structure.
This patch auto-generates a CRC32 checksum of the structure (as opposed to
the contents) of the Global Data structure. Standalone applications can
read U-Boot's CRC via the new exported get_gd_crc(). If the CRCs do not
match, using Global Data in the standalone application would be very
unwise.
This method allows the global data structure to be modified without having
to worry about whether existing standalone applications will suddenly fail
with unexpected results when accessing global data - Of course, this will
only work for standalone applications which actually use get_gd_crc() - By
incrementing XF_VERSION, all existing standalone application (should) fail
gracefully on a version mismatch anyway
The CRC is generated by:
- Pre-processing common.h (which includes global_data.h after all the
board, arch and SoC defines are set)
- Searches for a chunk of text delimited by 'typedef struct global_data {'
and '} gd_t;'
- Strips all blank lines and whitespaces (pre-processor already took care
of comments)
- Pipes the result through 'tools/gencrc32header/gencrc32header'
NOTE: There is something a bit funny about the make dependencies for
gencrc32header - Changes to gencrc32header.c do not trigger a rebuild
---
Makefile | 14 +++++-
common/exports.c | 6 +++
examples/standalone/hello_world.c | 6 +++
include/_exports.h | 1 +
include/exports.h | 3 +-
tools/gencrc32header/Makefile | 62 +++++++++++++++++++++++++
tools/gencrc32header/gencrc32header.c | 80 +++++++++++++++++++++++++++++++++
7 files changed, 170 insertions(+), 2 deletions(-)
create mode 100644 tools/gencrc32header/Makefile
create mode 100644 tools/gencrc32header/gencrc32header.c
diff --git a/Makefile b/Makefile
index 049b169..df61b02 100644
--- a/Makefile
+++ b/Makefile
@@ -465,7 +465,8 @@ updater:
depend dep: $(TIMESTAMP_FILE) $(VERSION_FILE) \
$(obj)include/autoconf.mk \
$(obj)include/generated/generic-asm-offsets.h \
- $(obj)include/asm/arch/asm-offsets.h
+ $(obj)include/asm/arch/asm-offsets.h \
+ $(obj)include/global_data_crc.h
for dir in $(SUBDIRS) $(CPUDIR) $(dir $(LDSCRIPT)) ; do \
$(MAKE) -C $$dir _depend ; done
@@ -545,6 +546,17 @@ $(TOPDIR)$(CPUDIR)/$(SOC)/asm-offsets.s: $(TOPDIR)/include/autoconf.mk.dep \
-o $@ $(TOPDIR)/$(CPUDIR)/$(SOC)/asm-offsets.c -c -S \
, at echo $(TOPDIR)/$(CPUDIR)/$(SOC)/asm-offsets.c does not exist - skipping)
+$(obj)include/global_data_crc.h: $(obj)tools/gencrc32header/gencrc32header \
+ $(src)include/asm/global_data.h
+ $(CPP) $(CPPFLAGS) -E $(TOPDIR)/include/common.h | \
+ sed -ne '/^typedef\s*struct\s*global_data\s*{/,/^}\s*gd_t;/p' | \
+ sed '/^$$/d' | \
+ sed 's/[ ]//g' | \
+ $(obj)tools/gencrc32header/gencrc32header > $@
+
+$(obj)tools/gencrc32header/gencrc32header:
+ $(MAKE) -C tools/gencrc32header/ all
+
#########################################################################
else # !config.mk
all $(obj)u-boot.hex $(obj)u-boot.srec $(obj)u-boot.bin \
diff --git a/common/exports.c b/common/exports.c
index 717e4af..8e767cc 100644
--- a/common/exports.c
+++ b/common/exports.c
@@ -1,5 +1,6 @@
#include <common.h>
#include <exports.h>
+#include <global_data_crc.h>
DECLARE_GLOBAL_DATA_PTR;
@@ -12,6 +13,11 @@ unsigned long get_version(void)
return XF_VERSION;
}
+unsigned long get_gd_crc(void)
+{
+ return XF_GLOBAL_DATA_CRC;
+}
+
/* Reuse _exports.h with a little trickery to avoid bitrot */
#define EXPORT_FUNC(sym) gd->jt[XF_##sym] = (void *)sym;
diff --git a/examples/standalone/hello_world.c b/examples/standalone/hello_world.c
index 067c390..18e3a51 100644
--- a/examples/standalone/hello_world.c
+++ b/examples/standalone/hello_world.c
@@ -23,6 +23,7 @@
#include <common.h>
#include <exports.h>
+#include <global_data_crc.h>
int hello_world (int argc, char * const argv[])
{
@@ -33,6 +34,11 @@ int hello_world (int argc, char * const argv[])
printf ("Example expects ABI version %d\n", XF_VERSION);
printf ("Actual U-Boot ABI version %d\n", (int)get_version());
+ printf ("Example expects Global Data Structure CRC 0x%8.8lx\n",
+ XF_GLOBAL_DATA_CRC);
+ printf ("Actual U-Boot Global Data Structure CRC 0x%8.8lx\n\n",
+ get_gd_crc());
+
printf ("Hello World\n");
printf ("argc = %d\n", argc);
diff --git a/include/_exports.h b/include/_exports.h
index 349a3c5..6ffa7b5 100644
--- a/include/_exports.h
+++ b/include/_exports.h
@@ -3,6 +3,7 @@
* in the final configuration (such as i2c).
*/
EXPORT_FUNC(get_version)
+EXPORT_FUNC(get_gd_crc)
EXPORT_FUNC(getc)
EXPORT_FUNC(tstc)
EXPORT_FUNC(putc)
diff --git a/include/exports.h b/include/exports.h
index 9492566..fc11a18 100644
--- a/include/exports.h
+++ b/include/exports.h
@@ -7,6 +7,7 @@
/* These are declarations of exported functions available in C code */
unsigned long get_version(void);
+unsigned long get_gd_crc(void);
int getc(void);
int tstc(void);
void putc(const char);
@@ -44,7 +45,7 @@ enum {
XF_MAX
};
-#define XF_VERSION 6
+#define XF_VERSION 7
#if defined(CONFIG_X86)
extern gd_t *global_data;
diff --git a/tools/gencrc32header/Makefile b/tools/gencrc32header/Makefile
new file mode 100644
index 0000000..612d872
--- /dev/null
+++ b/tools/gencrc32header/Makefile
@@ -0,0 +1,62 @@
+# (C) Copyright 20011
+# Graeme Russ, <graeme.russ at gmail.com>
+#
+# See file CREDITS for list of people who contributed to this
+# project.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation; either version 2 of
+# the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+# MA 02111-1307 USA
+
+include $(TOPDIR)/config.mk
+
+# Generated executable files
+BIN_FILES-y += gencrc32header
+
+# Source files which exist outside the tools/gencrc32header directory
+EXT_OBJ_FILES-y += lib/crc32.o
+
+# Source files located in the tools/gencrc32header directory
+OBJ_FILES-y += gencrc32header.o
+
+# now $(obj) is defined
+SRCS += $(addprefix $(SRCTREE)/,$(EXT_OBJ_FILES-y:.o=.c))
+SRCS += $(addprefix $(SRCTREE)/tools/,$(OBJ_FILES-y:.o=.c))
+BINS := $(addprefix $(obj),$(sort $(BIN_FILES-y)))
+
+all: $(BINS)
+
+$(obj)gencrc32header: $(obj)gencrc32header.o $(obj)crc32.o
+ $(CC) $(HOSTCFLAGS) $(HOSTLDFLAGS) -o $@ $^
+ $(STRIP) $@
+
+## Some of the tool objects need to be accessed from outside the tools/gencrc32header directory
+$(obj)%.o: %.c
+ $(CC) -g $(HOSTCFLAGS) -c -o $@ $<
+
+$(obj)%.o: $(SRCTREE)/lib/%.c
+ $(CC) -g -DUSE_HOSTCC -I $(SRCTREE)/include $(HOSTCFLAGS) -c -o $@ $<
+
+
+clean:
+ rm -rf *.o gencrc32header
+
+#########################################################################
+
+# defines $(obj).depend target
+include $(SRCTREE)/rules.mk
+
+sinclude $(obj).depend
+
+#########################################################################
diff --git a/tools/gencrc32header/gencrc32header.c b/tools/gencrc32header/gencrc32header.c
new file mode 100644
index 0000000..ce82684
--- /dev/null
+++ b/tools/gencrc32header/gencrc32header.c
@@ -0,0 +1,80 @@
+/*
+ * (C) Copyright 20011
+ * Graeme Russ, <graeme.russ at gmail.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#define BUFFER_GRANULE_SIZE 256
+extern unsigned long crc32(unsigned long crc, const char *buf, unsigned int len);
+
+int main (int argc, char **argv)
+{
+ char *buf = NULL;
+ long byte_count = 0;
+ long buf_len = 0;
+ unsigned long crc;
+
+ int in_char;
+
+ buf_len = BUFFER_GRANULE_SIZE;
+ buf = malloc(buf_len);
+
+ while (buf && ((in_char = fgetc(stdin)) != EOF)) {
+ if (byte_count >= buf_len) {
+ buf_len += BUFFER_GRANULE_SIZE;
+ buf = realloc(buf, buf_len);
+ }
+ if (buf)
+ buf[byte_count++] = (char)in_char;
+ }
+
+ if (buf) {
+ crc = crc32(0, buf, byte_count);
+
+ printf("#ifndef __GLOBAL_DATA_CRC_H__\n");
+ printf("#define __GLOBAL_DATA_CRC_H__\n");
+ printf("/*\n");
+ printf(" * DO NOT MODIFY.\n");
+ printf(" *\n");
+ printf(" * This file was auto-generated\n");
+ printf(" *\n");
+ printf(" */\n");
+ printf("\n");
+ printf("#define XF_GLOBAL_DATA_CRC\t0x%8.8lxUL\n", crc);
+ printf("\n");
+ printf("#endif\n");
+
+ return 0;
+ }
+
+ return -1;
+}
+
+
--
1.7.5.2.317.g391b14
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